US20080095638A1 - Controller for a motor and a method of controlling the motor - Google Patents

Abstract

A pumping apparatus for a jetted-fluid system includes a pump having an inlet connectable to the drain, and an outlet connectable to the return. The pump is adapted to receive the fluid from the drain and jet fluid through the return. The apparatus includes a motor coupled to the pump to operate the pump, a sensor configured to generate a signal having a relation to a parameter of the motor, and a switch coupled to the motor and configured to control at least a characteristic of the motor. The apparatus also includes a microcontroller coupled to the sensor and the switch. The microcontroller includes a model observer configured to receive a first value based on the signal and to generate a second value representative of at least one of a modeled flow or a modeled pressure based on the first value. The microcontroller is configured to control the motor based on the second value.

Description

BACKGROUND
• The invention relates to a controller for a motor, and particularly, a controller for a motor operating a pump.
• Occasionally on a swimming pool, spa, or similar jetted-fluid application, the main drain can become obstructed with an object, such as a towel or pool toy. When this happens, the suction force of the pump is applied to the obstruction and the object sticks to the drain. This is called suction entrapment. If the object substantially covers the drain (such as a towel covering the drain), water is pumped out of the drain side of the pump. Eventually the pump runs dry, the seals burn out, and the pump can be damaged.
• Another type of entrapment is referred to as mechanical entrapment. Mechanical entrapment occurs when an object, such as a towel or pool toy, gets tangled in the drain cover. Mechanical entrapment may also effect the operation of the pump.
• Several solutions have been proposed for suction and mechanical entrapment. For example, new pool construction is required to have two drains, so that if one drain becomes plugged, the other can still flow freely and no vacuum entrapment can take place. This does not help existing pools, however, as adding a second drain to an in-ground, one-drain pool is very difficult and expensive. Modern pool drain covers are also designed such that items cannot become entwined with the cover.
• As another example, several manufacturers offer systems known as Safety Vacuum Release Systems (SVRS). SVRS often contain several layers of protection to help prevent both mechanical and suction entrapment. Most SVRS use hydraulic release valves that are plumbed into the suction side of the pump. The valve is designed to release (open to the atmosphere) if the vacuum (or pressure) inside the drain pipe exceeds a set threshold, thus releasing the obstruction. These valves can be very effective at releasing the suction developed under these circumstances. Unfortunately, they have several technical problems that have limited their use.
SUMMARY
• In one embodiment, the invention provides a pumping apparatus for a jetted-fluid system having a vessel for holding a fluid, a drain, and a return. The pumping apparatus is connected to a power source and includes a pump having an inlet connectable to the drain, and an outlet connectable to the return. The pump is adapted to receive the fluid from the drain and jet fluid through the return. The pumping apparatus also includes a motor coupled to the pump to operate the pump, a sensor configured to generate a signal having a relation to a parameter of the motor, and a switch coupled to the motor and configured to control at least a characteristic of the motor. The pumping apparatus also includes a microcontroller coupled to the sensor and the switch. The microcontroller includes a model observer configured to receive a first value based on the signal and to generate a second value representative of at least one of a modeled flow or a modeled pressure based on the first value. The microcontroller is configured to control the motor based on the second value.
• In another embodiment, the invention provides a pumping apparatus for a jetted-fluid system having a vessel for holding a fluid, a drain, and a return. The pumping apparatus is connected to a power source and includes a pump having an inlet connectable to the drain, and an outlet connectable to the return. The pump is adapted to receive the fluid from the drain and jet fluid through the return. The pumping apparatus also includes a motor coupled to the pump to operate the pump, a sensor configured to generate a signal having a relation to a parameter of the motor, and a switch coupled to the motor and configured to control at least a characteristic of the motor. The pumping apparatus also includes a microcontroller coupled to the sensor and the switch. The microcontroller includes a model observer configured to receive a first value based on the signal and to generate a second value representative of a modeled pressure based on the first value. The microcontroller is configured to control the motor based on the second value.
• In another embodiment, the invention provides a method of controlling a motor operating a pumping apparatus of a jetted fluid system having a vessel for holding a fluid, a drain, and a return. The pumping apparatus includes a pump having an inlet connectable to the drain, and an outlet connectable to the return. The pump is adapted to receive the fluid from the drain and jet fluid through the return, and the motor coupled to the pump to operate the pump. The method includes determining a power of the pump motor, applying the power to a model observer, and obtaining a value representative of a flow based on the power and the model observer. The method also includes determining whether the value indicates a condition of the pump, and controlling the motor to operate the pump based on the condition of the pump.
• In another embodiment, the invention provides a method of controlling a motor operating a pumping apparatus of a jetted fluid system having a vessel for holding a fluid, a drain, and a return. The pumping apparatus includes a pump with an inlet connectable to the drain, and an outlet connectable to the return. The pump adapted to receive the fluid from the drain and jet fluid through the return, and the motor coupled to the pump to operate the pump. The method includes determining a power of the pump motor, applying the power to a model observer, and obtaining a value representative of a pressure based on the power and the model observer. The method also includes determining whether the value indicates a condition of the pump, and controlling the motor to operate the pump based on the condition of the pump.
• In another embodiment, the invention provides a method of controlling a fluid-movement system having a motor and a pump. The motor is coupled to the pump to operate the pump. The method includes calibrating the system to obtain a calibration value for a motor parameter, obtaining a relationship between the motor parameter and a fluid parameter, and determining a trip value based on the calibration value and the relationship. The method also includes controlling the motor to operate the pump, and monitoring the operation of the pump. The monitoring act includes determining a value for the motor parameter, comparing the value to the trip value, and determining whether the comparison indicates a condition of the pump. The method of controlling the fluid-movement system also includes controlling the motor to operate the pump based on the condition of the pump.
• In another embodiment, the invention provides a method of controlling a fluid-movement system having a motor and a pump. The motor is coupled to the pump to operate the pump. The method includes determining a relationship between an input power to the motor and a flow rate through the pump, determining a calibration value for the input power, and determining a percentage drop for the relationship. The method also includes determining a trip value based on the relationship, the calibration value, and the percentage drop, and monitoring the operation of the pump. The monitoring act includes determining a first value for the input power, comparing the first value to the trip value, and determining whether the first value indicates a condition of the pump. The method of controlling the fluid-movement system also includes controlling the motor to operate the pump based on the condition of the pump.
• Other features and aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a schematic representation of a jetted-spa incorporating the invention.
• FIG. 2 is a block diagram of a first controller capable of being used in the jetted-spa shown inFIG. 1.
• FIGS. 3A and 3B are electrical schematics of the first controller shown inFIG. 2.
• FIG. 4 is a block diagram of a second controller capable of being used in the jetted-spa shown inFIG. 1.
• FIGS. 5A and 5B are electrical schematics of the second controller shown inFIG. 4.
• FIG. 6 is a block diagram of a third controller capable of being used in the jetted-spa shown inFIG. 1.
• FIG. 7 is a graph showing an input power signal and a derivative power signal as a function of time.
• FIG. 8 is a flow diagram illustrating a model observer.
• FIG. 9 is a graph showing an input power signal and a processed power signal as a function of time.
• FIG. 10 is a graph showing an average input power signal and a threshold value reading as a function of time.
• FIG. 11 is a graph showing characterization data and fluid pressure data as a function of flow rate.
• FIG. 12 is a chart showing a numeric relationship between input power and torque.
DETAILED DESCRIPTION
• Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings.
• FIG. 1 schematically represents a jetted-spa100 incorporating the invention. However, the invention is not limited to the jetted-spa100 and can be used in other jetted-fluid systems (e.g., pools, whirlpools, jetted-tubs, etc.). It is also envisioned that the invention can be used in other applications (e.g., fluid-pumping applications).
• As shown inFIG. 1, thespa100 includes avessel105. As used herein, thevessel105 is a hollow container such as a tub, pool, tank, or vat that holds a load. The load includes a fluid, such as chlorinated water, and may include one or more occupants or items. The spa further includes a fluid-movement system110 coupled to thevessel105. The fluid-movement system110 includes adrain115, apumping apparatus120 having aninlet125 coupled to the drain and anoutlet130, and areturn135 coupled to theoutlet130 of thepumping apparatus120. Thepumping apparatus120 includes apump140, amotor145 coupled to thepump140, and acontroller150 for controlling themotor145. For the constructions described herein, thepump140 is a centrifugal pump and themotor145 is an induction motor (e.g., capacitor-start, capacitor-run induction motor; split-phase induction motor; three-phase induction motor; etc.). However, the invention is not limited to this type of pump or motor. For example, a brushless, direct current (DC) motor may be used in a different pumping application. For other constructions, a jetted-fluid system can include multiple drains, multiple returns, or even multiple fluid movement systems.
• Referring back toFIG. 1, thevessel105 holds a fluid. When thefluid movement system110 is active, thepump140 causes the fluid to move from thedrain115, through thepump140, and jet into thevessel105. This pumping operation occurs when thecontroller150 controllably provides a power to themotor145, resulting in a mechanical movement by themotor145. The coupling of the motor145 (e.g., a direct coupling or an indirect coupling via a linkage system) to thepump140 results in themotor145 mechanically operating thepump140 to move the fluid. The operation of thecontroller150 can be via an operator interface, which may be as simple as an ON switch.
• FIG. 2 is a block diagram of a first construction of thecontroller150, andFIGS. 3A and 3B are electrical schematics of thecontroller150. As shown inFIG. 2, thecontroller150 is electrically connected to apower source155 and themotor145.
• With reference toFIG. 2 andFIG. 3B, thecontroller150 includes apower supply160. Thepower supply160 includes resistors R46 and R56; capacitors C13, C14, C16, C18, C19, and C20; diodes D10 and D11; zener diodes D12 and D13; power supply controller U7; regulator U6; and optical switch U8. Thepower supply160 receives power from thepower source155 and provides the proper DC voltage (e.g., ±5 VDC and ±12 VDC) for operating thecontroller150.
• For thecontroller150 shown inFIGS. 2 and 3A, thecontroller150 monitors motor input power and pump inlet side pressure to determine if a drain obstruction has taken place. If thedrain115 or plumbing is plugged on the suction side of thepump140, the pressure on that side of thepump140 increases. At the same time, because thepump140 is no longer pumping water, input power to themotor145 drops. If either of these conditions occur, thecontroller150 declares a fault, themotor145 powers down, and a fault indicator lights.
• A voltage sense andaverage circuit165, a current sense andaverage circuit170, a linevoltage sense circuit175, a triacvoltage sense circuit180, and themicrocontroller185 perform the monitoring of the input power. One example voltage sense andaverage circuit165 is shown inFIG. 3A. The voltage sense andaverage circuit165 includes resistors R34, R41, and R42; diode D9; capacitor C10; and operational amplifier U4A. The voltage sense andaverage circuit165 rectifies the voltage from thepower source155 and then performs a DC average of the rectified voltage. The DC average is then fed to themicrocontroller185.
• One example current sense andaverage circuit170 is shown inFIG. 3A. The current sense andaverage circuit170 includes transformer T1 and resistor R45, which act as a current sensor that senses the current applied to the motor. The current sense and average circuit also includes resistors R25, R26, R27, R28, and R33; diodes D7 and D8; capacitor C9; and operational amplifiers U4C and U4D, which rectify and average the value representing the sensed current. For example, the resultant scaling of the current sense andaverage circuit170 can be a negative five to zero volt value corresponding to a zero to twenty-five amp RMS value. The resulting DC average is then fed to themicrocontroller185.
• One example linevoltage sense circuit175 is shown inFIG. 3A. The linevoltage sense circuit175 includes resistors R23, R24, and R32; diode D5; zener diode D6; transistor Q6; and NAND gate U2B. The linevoltage sense circuit175 includes a zero-crossing detector that generates a pulse signal. The pulse signal includes pulses that are generated each time the line voltage crosses zero volts.
• One example triacvoltage sense circuit180 is shown inFIG. 3A. The triacvoltage sense circuit180 includes resistors R1, R5, and R6; diode D2; zener diode D1; transistor Q1; and NAND gate U2A. The triac voltage sense circuit includes a zero-crossing detector that generates a pulse signal. The pulse signal includes pulses that are generated each time the motor current crosses zero.
• Oneexample microcontroller185 that can be used with the invention is a Motorola brand microcontroller, model no. MC68HC908QY4CP. Themicrocontroller185 includes a processor and a memory. The memory includes software instructions that are read, interpreted, and executed by the processor to manipulate data or signals. The memory also includes data storage memory. Themicrocontroller185 can include other circuitry (e.g., an analog-to-digital converter) necessary for operating themicrocontroller185. In general, themicrocontroller185 receives inputs (signals or data), executes software instructions to analyze the inputs, and generates outputs (signals or data) based on the analyses. Although themicrocontroller185 is shown and described, the functions of themicrocontroller185 can be implemented with other devices, including a variety of integrated circuits (e.g., an application-specific-integrated circuit), programmable devices, and/or discrete devices, as would be apparent to one of ordinary skill in the art. Additionally, it is envisioned that themicrocontroller185 or similar circuitry can be distributed amongmultiple microcontrollers185 or similar circuitry. It is also envisioned that themicrocontroller185 or similar circuitry can perform the function of some of the other circuitry described (e.g., circuitry165-180) above for thecontroller150. For example, themicrocontroller185, in some constructions, can receive a sensed voltage and/or sensed current and determine an averaged voltage, an averaged current, the zero-crossings of the sensed voltage, and/or the zero crossings of the sensed current.
• Themicrocontroller185 receives the signals representing the average voltage applied to themotor145, the average current through themotor145, the zero crossings of the motor voltage, and the zero crossings of the motor current. Based on the zero crossings, themicrocontroller185 can determine a power factor. The power factor can be calculated using known mathematical equations or by using a lookup table based on the mathematical equations. Themicrocontroller185 can then calculate a power with the averaged voltage, the averaged current, and the power factor as is known. As will be discussed later, themicrocontroller185 compares the calculated power with a power calibration value to determine whether a fault condition (e.g., due to an obstruction) is present.
• Referring again toFIGS. 2 and 3A, a pressure (or vacuum)sensor circuit190 and themicrocontroller185 monitor the pump inlet side pressure. One examplepressure sensor circuit190 is shown inFIG. 3A. Thepressure sensor circuit190 includes resistors R16, R43, R44, R47, and R48; capacitors C8, C12, C15, and C17; zener diode D4, piezoresistive sensor U9, and operational amplifier U4-B. The piezoresistive sensor U9 is plumbed into the suction side of thepump140. Thepressure sensor circuit190 andmicrocontroller185 translate and amplify the signal generated by the piezoresistive sensor U9 into a value representing inlet pressure. As will be discussed later, themicrocontroller185 compares the resulting pressure value with a pressure calibration value to determine whether a fault condition (e.g., due to an obstruction) is present.
• The calibrating of thecontroller150 occurs when the user activates a calibrateswitch195. One example calibrateswitch195 is shown inFIG. 3A. The calibrateswitch195 includes resistor R18 and Hall effect switch U10. When a magnet passes Hall effect switch U10, theswitch195 generates a signal provided to themicrocontroller185. Upon receiving the signal, themicrocontroller185 stores a pressure calibration value for the pressure sensor by acquiring the current pressure and stores a power calibration value for the motor by calculating the present power.
• As stated earlier, thecontroller150 controllably provides power to themotor145. With references toFIGS. 2 and 3A, thecontroller150 includes a retriggerablepulse generator circuit200. The retriggerablepulse generator circuit200 includes resistor R7, capacitor C1, and pulse generator U1A, and outputs a value to NAND gate U2D if the retriggerablepulse generator circuit200 receives a signal having a pulse frequency greater than a set frequency determined by resistor R7 and capacitor C1. The NAND gate U2D also receives a signal from power-up delay circuit205, which prevents nuisance triggering of the relay on startup. The output of the NAND gate U2D is provided to relaydriver circuit210. Therelay driver circuit210 shown inFIG. 3A includes resistors R19, R20, R21, and R22; capacitor C7; diode D3; and switches Q5 and Q4. Therelay driver circuit210 controls relay K1.
• Themicrocontroller185 also provides an output to triacdriver circuit215, which controls triac Q2. As shown inFIG. 3A, thetriac driver circuit215 includes resistors R12, R13, and R14; capacitor C11; and switch Q3. In order for current to flow to the motor, relay K1 needs to close and triac Q2 needs to be triggered on.
• Thecontroller150 also includes a thermoswitch S1 for monitoring the triac heat sink, apower supply monitor220 for monitoring the voltages produced by thepower supply160, and a plurality of LEDs DS1, DS2, and DS3 for providing information to the user. In the construction shown, a green LED DS1 indicates power is applied to thecontroller150, a red LED DS2 indicates a fault has occurred, and a third LED DS3 is a heartbeat LED to indicate themicrocontroller185 is functioning. Of course, other interfaces can be used for providing information to the operator.
• The following describes the normal sequence of events for one method of operation of thecontroller150. When thefluid movement system110 is initially activated, thesystem110 may have to draw air out of the suction side plumbing and get the fluid flowing smoothly. This “priming” period usually lasts only a few seconds, but could last a minute or more if there is a lot of air in the system. After priming, the water flow, suction side pressure, and motor input power remain relatively constant. It is during this normal running period that the circuit is effective at detecting an abnormal event. Themicrocontroller185 includes a startup-lockout feature that keeps the monitor from detecting the abnormal conditions during the priming period.
• After thesystem110 is running smoothly, the spa operator can calibrate thecontroller150 to the current spa running conditions. The calibration values are stored in themicrocontroller185 memory, and will be used as the basis for monitoring thespa100. If for some reason the operating conditions of the spa change, thecontroller150 can be re-calibrated by the operator. If at any time during normal operations, however, the suction side pressure increases substantially (e.g., 12%) over the pressure calibration value, or the motor input power drops (e.g., 12%) under the power calibration value, the pump will be powered down and a fault indicator is lit.
• As discussed earlier, thecontroller150 measures motor input power, and not just motor power factor or input current. Some motors have electrical characteristics such that power factor remains constant while the motor is unloaded. Other motors have an electrical characteristic such that current remains relatively constant when the pump is unloaded. However, the input power drops on pump systems when the drain is plugged, and water flow is impeded.
• The voltage sense andaverage circuit165 generates a value representing the average power line voltage and the current sense andaverage circuit170 generates a value representing the average motor current. Motor power factor is derived from the difference between power line zero crossing events and triac zero crossing events. The linevoltage sense circuit175 provides a signal representing the power line zero crossings. The triac zero crossings occur at the zero crossings of the motor current. The triacvoltage sense circuit180 provides a signal representing the triac zero crossings. The time difference from the zero crossing events is used to look up the motor power factor from a table stored in themicrocontroller185. This data is then used to calculate the motor input power using equation e1.
• 
  V_avg*I_avg*PF=Motor_Input_Power  [e1]
• The calculated motor_input_power is then compared to the calibrated value to determine whether a fault has occurred. If a fault has occurred, the motor is powered down and the fault LED DS2 is lit.
• FIG. 4 is a block diagram of a second construction of thecontroller150a, andFIGS. 5A and 5B are an electrical schematic of thecontroller150a. As shown inFIG. 4, thecontroller150ais electrically connected to apower source155 and themotor145.
• With reference toFIG. 4 andFIG. 5B, thecontroller150aincludes apower supply160a. Thepower supply160aincludes resistors R54, R56 and R76; capacitors C16, C18, C20, C21, C22, C23 and C25; diodes D8, D10 and D11; zener diodes D6, D7 and D9; power supply controller U11; regulator U9; inductors L1 and L2, surge suppressors MOV1 and MOV2, and optical switch U10. Thepower supply160areceives power from thepower source155 and provides the proper DC voltage (e.g., +5 VDC and +12 VDC) for operating thecontroller150a.
• For thecontroller150ashown inFIG. 4,FIG. 5A, andFIG. 5B, thecontroller150amonitors motor input power to determine if a drain obstruction has taken place. Similar to the earlier disclosed construction, if thedrain115 or plumbing is plugged on the suction side of thepump140, thepump140 will no longer be pumping water, and input power to themotor145 drops. If this condition occurs, thecontroller150adeclares a fault, themotor145 powers down, and a fault indicator lights.
• A voltage sense andaverage circuit165a, a current sense andaverage circuit170a, and themicrocontroller185aperform the monitoring of the input power. One example voltage sense andaverage circuit165ais shown inFIG. 5A. The voltage sense andaverage circuit165aincludes resistors R2, R31, R34, R35, R39, R59, R62, and R63; diodes D2 and D12; capacitor C14; and operational amplifiers U5C and U5D. The voltage sense andaverage circuit165arectifies the voltage from thepower source155 and then performs a DC average of the rectified voltage. The DC average is then fed to themicrocontroller185a. The voltage sense andaverage circuit165afurther includes resistors R22, R23, R27, R28, R30, and R36; capacitor C27; and comparator U7A; which provide the sign of the voltage waveform (i.e., acts as a zero-crossing detector) to themicrocontroller185a.
• One example current sense andaverage circuit170ais shown inFIG. 5B. The current sense andaverage circuit170aincludes transformer T1 and resistor R53, which act as a current sensor that senses the current applied to themotor145. The current sense andaverage circuit170aalso includes resistors R18, R20, R21, R40, R43, and R57; diodes D3 and D4; capacitor C8; and operational amplifiers U5A and U5B, which rectify and average the value representing the sensed current. For example, the resultant scaling of the current sense andaverage circuit170acan be a positive five to zero volt value corresponding to a zero to twenty-five amp RMS value. The resulting DC average is then fed to themicrocontroller185a. The current sense andaverage circuit170afurther includes resistors R24, R25, R26, R29, R41, and R44; capacitor C11; and comparator U7B; which provide the sign of the current waveform (i.e., acts as a zero-crossing detector) tomicrocontroller185a.
• Oneexample microcontroller185athat can be used with the invention is a Motorola brand microcontroller, model no. MC68HC908QY4CP. Similar to what was discussed for the earlier construction, themicrocontroller185aincludes a processor and a memory. The memory includes software instructions that are read, interpreted, and executed by the processor to manipulate data or signals. The memory also includes data storage memory. Themicrocontroller185acan include other circuitry (e.g., an analog-to-digital converter) necessary for operating themicrocontroller185aand/or can perform the function of some of the other circuitry described above for thecontroller150a. In general, themicrocontroller185areceives inputs (signals or data), executes software instructions to analyze the inputs, and generates outputs (signals or data) based on the analyses.
• Themicrocontroller185areceives the signals representing the average voltage applied to themotor145, the average current through themotor145, the zero crossings of the motor voltage, and the zero crossings of the motor current. Based on the zero crossings, themicrocontroller185acan determine a power factor and a power as was described earlier. Themicrocontroller185acan then compare the calculated power with a power calibration value to determine whether a fault condition (e.g., due to an obstruction) is present.
• The calibrating of thecontroller150aoccurs when the user activates a calibrateswitch195a. One example calibrateswitch195ais shown inFIG. 5A, which is similar to the calibrateswitch195 shown inFIG. 3A. Of course, other calibrate switches are possible. In one method of operation for the calibrateswitch195a, a calibration fob needs to be held near theswitch195awhen thecontroller150areceives an initial power. After removing the magnet and cycling power, thecontroller150agoes through priming and enters an automatic calibration mode (discussed below).
• Thecontroller150acontrollably provides power to themotor145. With references toFIGS. 4 and 5A, thecontroller150aincludes a retriggerablepulse generator circuit200a. The retriggerablepulse generator circuit200aincludes resistors R15 and R16, capacitors C2 and C6, and pulse generators U3A and U3B, and outputs a value to therelay driver circuit210aif the retriggerablepulse generator circuit200areceives a signal having a pulse frequency greater than a set frequency determined by resistors R15 and R16, and capacitors C2 and C6. The retriggerable pulse generators U3A and U3B also receive a signal from power-up delay circuit205a, which prevents nuisance triggering of the relays on startup. Therelay driver circuits210ashown inFIG. 5A include resistors R1, R3, R47, and R52; diodes D1 and D5; and switches Q1 and Q2. Therelay driver circuits210acontrol relays K1 and K2. In order for current to flow to the motor, both relays K1 and K2 need to “close”.
• Thecontroller150afurther includes twovoltage detectors212aand214a. Thefirst voltage detector212aincludes resistors R71, R72, and R73; capacitor C26; diode D14; and switch Q4. Thefirst voltage detector212adetects when voltage is present across relay K1, and verifies that the relays are functioning properly before allowing the motor to be energized. Thesecond voltage detector214aincludes resistors R66, R69, and R70; capacitor C9; diode D13; and switch Q3. Thesecond voltage detector214asenses if a two speed motor is being operated in high or low speed mode. The motor input power trip values are set according to what speed the motor is being operated. It is also envisioned that thecontroller150acan be used with a single speed motor without thesecond voltage detector214a(e.g.,controller150bis shown inFIG. 6).
• Thecontroller150aalso includes an ambientthermal sensor circuit216afor monitoring the operating temperature of thecontroller150a, a power supply monitor220afor monitoring the voltages produced by thepower supply160a, and a plurality of LEDs DS1 and DS3 for providing information to the user. In the construction shown, a green LED DS2 indicates power is applied to thecontroller150a, and a red LED DS3 indicates a fault has occurred. Of course, other interfaces can be used for providing information to the operator.
• Thecontroller150afurther includes aclean mode switch218a, which includes switch U4 and resistor R10. The clean mode switch can be actuated by an operator (e.g., a maintenance person) to deactivate the power monitoring function described herein for a time period (e.g., 30 minutes so that maintenance person can clean the vessel105). Moreover, the red LED DS3 can be used to indicate thatcontroller150ais in a clean mode. After the time period, thecontroller150areturns to normal operation. In some constructions, the maintenance person can actuate theclean mode switch218afor thecontroller150ato exit the clean mode before the time period is completed.
• In some cases, it may be desirable to deactivate the power monitoring function for reasons other than performing cleaning operations on thevessel105. Such cases may be referred as “deactivate mode”, “disabled mode”, “unprotected mode”, or the like. Regardless of the name, this later mode of operation can be at least partially characterized by the instructions defined under the clean mode operation above. Moreover, when referring to the clean mode and its operation herein, the discussion also applies to these later modes for deactivating the power monitoring function and vice versa.
• The following describes the normal sequence of events for one method of operation of thecontroller150a, some of which may be similar to the method of operation of thecontroller150. When thefluid movement system110 is initially activated, thesystem110 may have to prime (discussed above) the suction side plumbing and get the fluid flowing smoothly (referred to as “the normal running period”). It is during the normal running period that the circuit is most effective at detecting an abnormal event.
• Upon a system power-up, thesystem110 can enter a priming period. The priming period can be preset for a time duration (e.g., a time duration of 3 minutes), or for a time duration determined by a sensed condition. After the priming period, thesystem110 enters the normal running period. Thecontroller150acan include instructions to perform an automatic calibration to determine one or more calibration values after a first system power-up. One example calibration value is a power calibration value. In some cases, the power calibration value is an average of monitored power values over a predetermined period of time. The power calibration value is stored in the memory of themicrocontroller185, and will be used as the basis for monitoring thevessel105.
• If for some reason the operating conditions of thevessel105 change, thecontroller150acan be re-calibrated by the operator. In some constructions, the operator actuates the calibrateswitch195ato erase the existing one or more calibration values stored in the memory of themicrocontroller185. The operator then powers down thesystem110, particularly themotor145, and performs a system power-up. Thesystem110 starts the automatic calibration process as discussed above to determine new one or more calibration values. If at any time during normal operation, the monitored power varies from the power calibration value (e.g., varies from a 12.5% window around the power calibration value), themotor145 will be powered down and the fault LED DS3 is lit.
• In one construction, the automatic calibration instructions include not monitoring the power of themotor145 during a start-up period, generally preset for a time duration (e.g., 2 seconds), upon the system power-up. In the case when thesystem110 is operated for the first time, thesystem110 enters the prime period, upon completion of the start-up period, and the power of themotor145 is monitored to determine the power calibration value. As indicated above, the power calibration value is stored in the memory of themicrocontroller185. After completion of the 3 minutes of the priming period, thesystem110 enters the normal running period. In subsequent system power-ups, the monitored power is compared against the power calibration value stored in the memory of themicrocontroller185 memory during the priming period. More specifically, thesystem110 enters the normal running period when the monitored power rises above the power calibration value during the priming period. In some cases, the monitored power does not rise above the power calibration value within the 3 minutes of the priming period. As a consequence, themotor145 is powered down and a fault indicator is lit.
• In other constructions, the priming period of the automatic calibration can include a longer preset time duration (for example, 4 minutes) or an adjustable time duration capability. Additionally, thecontroller150acan include instructions to perform signal conditioning operations to the monitored power. For example, thecontroller150acan include instructions to perform an IIR filter to condition the monitored power. In some cases, the IIR filter can be applied to the monitored power during the priming period and the normal operation period. In other cases, the IIR filter can be applied to the monitored power upon determining the power calibration value after the priming period.
• Similar tocontroller150, thecontroller150ameasures motor input power, and not just motor power factor or input current. However, it is envisioned that thecontrollers150 or150acan be modified to monitor other motor parameters (e.g., only motor current, only motor power factor, or motor speed). But motor input power is the preferred motor parameter forcontroller150afor determining whether the water is impeded. Also, it is envisioned that thecontroller150acan be modified to monitor other parameters (e.g., suction side pressure) of thesystem110.
• For some constructions of thecontroller150a, themicrocontroller185amonitors the motor input power for an over power condition in addition to an under power condition. The monitoring of an over power condition helps reduce the chance thatcontroller150awas incorrectly calibrated, and/or also helps detect when the pump is over loaded (e.g., the pump is moving too much fluid).
• The voltage sense andaverage circuit165agenerates a value representing the averaged power line voltage and the current sense andaverage circuit170agenerates a value representing the averaged motor current. Motor power factor is derived from the timing difference between the sign of the voltage signal and the sign of the current signal. This time difference is used to look up the motor power factor from a table stored in themicrocontroller185a. The averaged power line voltage, the averaged motor current, and the motor power factor are then used to calculate the motor input power using equation e1 as was discussed earlier. The calculated motor input power is then compared to the calibrated value to determine whether a fault has occurred. If a fault has occurred, the motor is powered down and the fault indicator is lit.
• Redundancy is also used for the power switches of thecontroller150a. Two relays K1 and K2 are used in series to do this function. This way, a failure of either component will still leave one switch to turn off themotor145. As an additional safety feature, the proper operation of both relays is checked by themicrocontroller185aevery time themotor145 is powered-on via the relayvoltage detector circuit212a.
• Another aspect of thecontroller150ais that themicrocontroller185aprovides pulses at a frequency greater than a set frequency (determined by the retriggerable pulse generator circuits) to close the relays K1 and K2. If the pulse generators U3A and U3B are not triggered at the proper frequency, the relays K1 and K2 open and the motor powers down.
• As previously indicated, themicrocontroller185,185acan calculate an input power based on parameters such as averaged voltage, averaged current, and power factor. Themicrocontroller185,185athen compares the calculated input power with the power calibration value to determine whether a fault condition (e.g., due to an obstruction) is present. Other constructions can include variations of themicrocontroller185,185aand thecontroller150,150aoperable to receive other parameters and determine whether a fault condition is present.
• One aspect of thecontroller150,150ais that themicrocontroller185,185acan monitor the change of input power over a predetermine period of time. More specifically, themicrocontroller185,185adetermines and monitors a power derivative value equating about a change in input power divided by a change in time. In cases where the power derivative traverses a threshold value, thecontroller150,150acontrols themotor145 to shut down thepump140. This aspect of thecontroller150,150amay be operable in replacement of, or in conjunction with, other similar aspects of thecontroller150,150a, such as shutting down themotor145 when the power level of themotor145 traverses a predetermined value.
• For example,FIG. 7 shows a graph indicating input power and power derivative as functions of time. More specifically,FIG. 7 shows a power reading (line300) and a power derivate value (line305), over a 30-second time period, of amotor145 calibrated at a power threshold value of 5000 and a power derivative threshold of −100. In this particular example, a water blockage in the fluid-movement system110 (shown inFIG. 1) occurs at the 20-second mark. It can be observed fromFIG. 7 that thepower reading300 indicates a power level drop below the threshold value of 5000 at the 27-second mark, causing thecontroller150,150ato shut down thepump140 approximately at the 28-second mark. It can also be observed that thepower derivative value305 drops below the −100 threshold value at the 22-second mark, causing thecontroller150,150ato shut down thepump140 approximately at the 23-second mark. Other parameters of the motor145 (e.g., torque) can be monitored by themicrocontroller185,185a, for determining a potential entrapment event.
• In another aspect of thecontroller150,150a, themicrocontroller185,185acan include instructions that correspond to a model observer, such as theexemplary model observer310 shown inFIG. 8. Themodel observer310 includes afirst filter315, aregulator325 having avariable gain326 and atransfer function327, afluid system model330 having a gain parameter (shown inFIG. 8 with the value of 1), and asecond filter335. In particular, thefluid system model330 is configured to simulate the fluid-movement system110. Additionally, thefirst filter315 and thesecond filter335 can include various types of analog and digital filters such as, but not limited to, low pass, high pass, band pass, anti-aliasing, IIR, and/or FIR filters.
• It is to be understood that themodel observer310 is not limited to the elements described above. In other words, themodel observer310 may not necessarily include all the elements described above and/or may include other elements or combination of elements not explicitly described herein. In reference particularly to thefluid system model330, a fluid system model may be defined utilizing various procedures. In some cases, a model may be generated for this particular aspect of thecontroller150,150afrom another model corresponding to a simulation of another system, which may not necessarily be a fluid system. In other cases, a model may be generated solely based on controls knowledge of closed loop or feed back systems and formulas for fluid flow and power. In yet other cases, a model may be generated by experimentation with a prototype of the fluid system to be modeled.
• In reference to themodel observer310 ofFIG. 8, thefirst filter315 receives a signal (P) corresponding to a parameter of themotor145 determined and monitored by themicrocontroller185,185a(e.g., input power, torque, current, power factor, etc.). Generally, thefirst filter315 is configured to substantially eliminate the noise in the received signal (P), thus generating a filtered signal (PA). However, thefirst filter315 may perform other functions such as anti-aliasing or filtering the received signal to a predetermined frequency range. The filtered signal (PA) enters a feed-back loop340 of themodel observer310 and is processed by theregulator325. Theregulator325 outputs a regulated signal (ro) related to the fluid flow and/or pressure through the fluid-movement system110 based on the monitored parameter. The regulated signal can be interpreted as a modeled flow rate or modeled pressure. Thefluid system model330 processes the regulated signal (ro) to generate a model signal (Fil), which is compared to the filtered signal (PA) through the feed-back loop340. The regulated signal (ro) is also fed to thesecond filter335 generating a control signal (roP), which is subsequently used by themicrocontroller185,185ato at least control the operation of themotor145.
• As shown inFIG. 8, the regulated signal (ro), indicative of fluid flow and/or pressure, is related to the monitored parameter as shown in equation [e2].
• 
  ro=(PA−Fil)*regulator  [e2]
• The relationship shown in equation [e2] allows a user to control themotor145 based on a direct relationship between the input power or torque and a parameter of the fluid flow, such as flow rate and pressure, without having to directly measure the fluid flow parameter.
• FIG. 9 is a graph showing an input power (line345) and a processed power or flow unit (line350) as functions of time. More specifically, the graph ofFIG. 9 illustrates the operation of the fluid-movement system110 with themotor145 having a threshold value of 5000. For this particular example,FIG. 9 shows that thepump inlet125 blocked at the 5-second mark. The input power drops below the threshold mark of 5000, and therefore thecontroller150,150ashuts down thepump140 approximately at the 12.5-second mark. Alternatively, the processed power signal drops below the threshold mark corresponding to 5000 at the 6-second mark, and therefore thecontroller150,150ashuts down thepump140 approximately at the 7-second mark.
• In this particular example, the gain parameter of thefluid system model330 is set to a value of 1, thereby measuring a unit of pressure with the same scale as the unit of power. In other examples, the user can set the gain parameter at a different value to at least control aspects of the operation of themotor145, such as shut down time.
• In another aspect of thecontroller150,150a, themicrocontroller185,185acan be configured for determining a floating the threshold value or trip value indicating the parameter reading, such as input power or torque, at which thecontroller150,150ashuts down thepump140. It is to be understood that the term “floating” refers to varying or adjusting a signal or value. In one example, themicrocontroller185,185acontinuously adjusts the trip value based on average input power readings, as shown inFIG. 10. More specifically,FIG. 10 shows a graph indicating an average input power signal (line355) determined and monitored by themicrocontroller185,185a, a trip signal (line360) indicating a variable trip value, and a threshold value of about 4500 (shown inFIG. 10 with arrow362) as a function of time. In this particular case, thethreshold value362 is a parameter indicating the minimum value that the trip value can be adjusted to.
• Themicrocontroller185,185amay calculate theaverage input power355 utilizing various methods. In one construction, themicrocontroller185,185amay determine a running average based at least on signals generated by the current sense andaverage circuit170,170aand signals generated by the voltage sense andaverage circuit165,165a. In another construction, themicrocontroller185,185amay determine an input power average over relatively short periods of time. As shown inFIG. 10, the average power determined by themicrocontroller185,185agoes down from about 6000 to about 5000 in a substantially progressive manner over a time period of 80 units of time. It can also be observed that thesignal360 indicating the trip value is adjusted down to about 10% from the value at the O-time unit mark to the 80-time unit mark and is substantially parallel to theaverage power355. More specifically, themicrocontroller185,185aadjusts the trip value based on monitoring theaverage input power355.
• In some cases, theaverage power signal355 may define a behavior, such as the one shown inFIG. 10, due to sustained clogging of the fluid-movement system110 over a period of time, for example from the O-time unit mark to the 80-time unit mark. In other words, sustained clogging of the fluid-movement system110 can be determined and monitored by themicrocontroller185,185ain the form of theaverage power signal355. In these cases, themicrocontroller185,185acan also determine a percentage or value indicative of a minimum average input power allowed to be supplied to themotor145, or a minimum allowed threshold value such asthreshold value362. When the fluid-movement system110 is back-flushed with the purpose of unclogging the fluid-movement system110, theaverage power signal355 returns to normal unrestricted fluid flow (shown inFIG. 10 between about the 84-time unit mark and about the 92-time unit mark, for example). As shown inFIG. 10, unclogging the fluid-movement system110 can result in relative desired fluid flow through the fluid-movement system110. As a consequence, themicrocontroller185,185asenses an average power change as indicated near the 80-time unit mark inFIG. 10 showing as the average power returns to the calibration value.
• In other cases, themicrocontroller185,185acan determine and monitor the average input power over a relatively short amount of time. For example, themicrocontroller185,185acan monitor the average power over a first time period (e.g., 5 seconds). Thecontroller185,185acan also determine a variable trip value based on a predetermine percentage (e.g., 6.25%) drop of the average power calculated over the first time period. In other words, the variable trip value is adjusted based on the predetermined percentage as themicrocontroller185,185adetermines the average power. Thecontroller150,150acan shut down thepump140 when the average power drops to a value substantially equal or lower than the variable trip value and sustains this condition over a second period of time (e.g., 1 second).
• In another aspect of thecontroller150,150a, themicrocontroller185,185acan be configured to determine a relationship between a parameter of the motor145 (such as power or torque) and pressure/flow through the fluid-movement system110 for a specific motor/pump combination. More specifically, thecontroller150,150acontrols themotor145 to calibrate the fluid-movement system110 based on the environment in which the fluid-movement system110 operates. The environment in which the fluid-movement system110 operates can be defined by the capacity of thevessel105, tubing configuration between thedrain115 andinlet125, tubing configuration betweenoutlet130 and return135 (shown inFIG. 1), number of drains and returns, and other factors not explicitly discussed herein.
• Calibration of the fluid-movement system110 is generally performed the first time the system is operated after installation. It is to be understood that the processes described herein are also applicable to recalibration procedures. In one example, calibration of the fluid-movement system110 includes determining a threshold value based on characterizing a specific motor/pump combination and establishing a relationship between, for example, input power and pressure via a stored look-up table or an equation.FIG. 11 shows a chart having characterization data (line365), measured in kilowatts and obtained through a calibration process, and a pump curve (line370) indicating head pressure. Thecharacterization data365 and thepump curve370 are graphed as a function of flow measured in gallons per minute (GPM). In the particular example shown inFIG. 11, it is possible for a user (or themicrocontroller185,185ain an automated process) to establish a trip value based on a percent reduction in flow or pressure instead of a percent reduction in input power.
• Referring particularly to thecharacterization data365 shown inFIG. 11, if an operating point for the fluid-movement system110 is determined atpoint1 on thecharacterization data365, a 30% reduction in flow from 100 GPM to 70 GPM (point2 on the characterization data365) through the fluid-movement system110 is monitored by themicrocontroller185,185aand indicates a 7% reduction in input power. For a different environment of the fluid-movement system110, the operating set point can be established atpoint2, for example. Particularly, a 30% reduction in flow from 70 GPM to 50 GPM (point3 on the characterization data365) through the fluid-movement system110 is monitored by themicrocontroller185,185aand indicates an 11% reduction in power. For the two cases described above, it is possible that a 30% reduction in flow is a desired operating condition, thus a user (ormicrocontroller185,185a) can establish a trip value or percentage based on the percent reduction (e.g., a reduction of 30% in flow) separate from the determined and monitored power.
• In another aspect of thecontroller150,150a, themicrocontroller185,185acan include a timer function to operate the fluid-movement system110. In one example, the timer function of themicrocontroller185,185aimplements a RUN mode of thecontroller150,150a. More specifically regarding the RUN mode, thecontroller150,150ais configured to operate themotor145 automatically over predetermined periods of time. In other words, thecontroller150,150ais configured to control themotor145 based on predetermined time periods programmed in themicrocontroller185,185aduring manufacturing or programmed by a user. In another example, the timer function of themicrocontroller185,185aimplements an OFF mode of thecontroller150,150a. More specifically regarding the OFF mode, thecontroller150,150ais configured to operate themotor145 only as a result of direct interaction of the user. In other words, thecontroller150,150ais configured to maintain themotor145 off until a user directly operates thecontroller150,150athrough the interface of thecontroller150,150a. In yet another example, the timer function of themicrocontroller185,185aimplements a PROGRAM mode of thecontroller150,150a. More specifically regarding the PROGRAM mode, thecontroller150,150ais configured to maintain themotor145 off until the user actuates one of the switches (e.g., calibrateswitch195,195a,clean mode switch218a) of thecontroller150,150aindicating a desired one-time window of operation of themotor145. For example, the user can actuate one switch three times indicating thecontroller150,150ato operate themotor145 for a period of three hours. In some constructions, thecontroller150,150aincludes a run-off-program switch to operate thecontroller150,150abetween the RUN, OFF, and PROGRAM modes. It is to be understood that the same or other modes of operation of thecontroller150,150acan be defined differently. Additionally, not all modes described above are necessary and thecontroller150,150acan include a different number and combinations of modes of operation.
• In another aspect of thecontroller150,150a, themicrocontroller185,185acan be configured to determine and monitor a value corresponding to the torque of themotor145. More specifically, themicrocontroller185,185areceives signals from at least one of the voltage sense andaverage circuit165,165aand the current sense andaverage circuit170,170ato help determine the torque of themotor145. As explained above, themicrocontroller185,185acan also be configured to determine and monitor the speed of themotor145, allowing themicrocontroller185,185ato determine a value indicative of the torque of themotor145 and a relationship between the torque and the input power. In some constructions, the speed of themotor145 remains substantially constant during operation of themotor145. In these particular cases, themicrocontroller185,185acan include instructions related to formulas or look-up tables that indicate a direct relationship between the input power and the torque of themotor145. Determining and monitoring the torque of themotor145 allows themicrocontroller185,185ato establish a trip value or a percentage based on torque to shut off themotor145 in case of an undesired condition of themotor145. For example,FIG. 12 shows a chart indicating a relationship between input power and torque for amotor145 under the observation that the speed of themotor145 changes less than 2%. Thus, themicrocontroller185,185acan determine and monitor torque based on input power and under the assumption of constant speed.
• In some constructions, the fluid-movement system110 can operate two ormore vessels105. For example, the fluid-movement system110 can include a piping system to control fluid flow to a pool, and a second piping system to control fluid flow to a spa. For this particular example, the flow requirements for the pool and the spa are generally different and may define or require separate settings of thecontroller150,150afor thecontroller150,150ato operate themotor145 to control fluid flow to the pool, the spa, or both. The fluid-movement system110 can include one or more valves that may be manually or automatically operated to direct fluid flow as desired. In an exemplary case where the fluid-movement system110 includes one solenoid valve, a user can operate the valve to direct flow to one of the pool and the spa. Additionally, thecontroller150,150acan include a sensor or receiver coupled to the valve to determine the position of the valve. Under the above mentioned conditions, thecontroller150,150acan run a calibration sequence and determine individual settings and trip values for the fluid system including the pool, the spa, or both. Other constructions can include a different number ofvessels105, where fluid flow to the number ofvessels105 can be controller by one or more fluid-movement systems110.
• While numerous aspects of thecontroller150,150awere discussed above, not all of the aspects and features discussed above are required for the invention. Additionally, other aspects and features can be added to thecontroller150,150ashown in the figures.
• The constructions described above and illustrated in the figures are presented by way of example only and are not intended as a limitation upon the concepts and principles of the invention. Various features and advantages of the invention are set forth in the following claims.

Claims (38)

1. A pumping apparatus for a jetted-fluid system comprising a vessel for holding a fluid, a drain, and a return, the pumping apparatus being connectable to a power source and comprising:

a pump including an inlet connectable to the drain, and an outlet connectable to the return, the pump adapted to receive the fluid from the drain and jet fluid through the return;

a motor coupled to the pump to operate the pump;

a sensor configured to generate a signal having a relation to a parameter of the motor;

a switch coupled to the motor and configured to control at least a characteristic of the motor; and

a microcontroller coupled to the sensor and the switch, the microcontroller including a model observer configured to receive a first value based on the signal and to generate a second value representative of at least one of a modeled flow or a modeled pressure based on the first value, the microcontroller configured to control the motor based on the second value.

2. The pumping apparatus ofclaim 1, wherein the sensor includes a voltage sensor configured to generate a first signal having a relation to a voltage applied to the motor, and a current sensor configured to generate a second signal having a relation to a current applied to the motor, and wherein the microcontroller is configured to generate the first value based on the first signal and the second signal.

3. The pumping apparatus ofclaim 1, wherein the sensor includes a voltage sensor and a current sensor, and wherein the first value includes a motor power value.

4. The pumping apparatus ofclaim 1, wherein first value includes a motor torque value.

5. The pumping apparatus ofclaim 1, wherein the model observer includes a model that simulates the pumping apparatus.

6. The pumping apparatus ofclaim 1, wherein the model observer includes a model that simulates at least part of the jetted-fluid system.

7. The pumping apparatus ofclaim 1, wherein the microcontroller is further configured to

monitor the second value,

determine whether the monitored second value indicates an undesired flow of fluid through the pump, and

control the motor to cease operation of the pump when the determination indicates an undesired flow of fluid through the pump and zero or more other conditions exist.

8. A pumping apparatus for a jetted-fluid system comprising a vessel for holding a fluid, a drain, and a return, the pumping apparatus being connectable to a power source and comprising:

a pump including an inlet connectable to the drain, and an outlet connectable to the return, the pump adapted to receive the fluid from the drain and jet fluid through the return;

a motor coupled to the pump to operate the pump;

a sensor configured to generate a signal having a relation to a parameter of the motor;

a switch coupled to the motor and configured to control at least a characteristic of the motor; and

a microcontroller coupled to the sensor and the switch, the microcontroller including a model observer configured to receive a first value based on the signal and to generate a second value representative of a modeled pressure based on the first value, the microcontroller configured to control the motor based on the second value.

9. The pumping apparatus ofclaim 8, wherein the sensor includes a voltage sensor configured to generate a first signal having a relation to a voltage applied to the motor, and a current sensor configured to generate a second signal having a relation to a current applied to the motor, and wherein the microcontroller is configured to generate the first value based on the first signal and the second signal.

11. The pumping apparatus ofclaim 8, wherein the sensor includes a voltage sensor and a current sensor, and wherein the first value includes a motor power value.

12. The pumping apparatus ofclaim 8, wherein first value includes a motor torque value.

13. The pumping apparatus ofclaim 8, wherein the model observer includes a model that simulates the pumping apparatus.

14. The pumping apparatus ofclaim 8, wherein the model observer includes a model that simulates at least part of the jetted-fluid system.

15. The pumping apparatus ofclaim 8, wherein the microcontroller is further configured to

monitor the second value,

determine whether the monitored second value indicates an undesired flow of fluid through the pump, and

control the motor to cease operation of the pump when the determination indicates an undesired flow of fluid through the pump and zero or more other conditions exist.

16. A method of controlling a motor operating a pumping apparatus of a jetted fluid system comprising a vessel for holding a fluid, a drain, and a return, the pumping apparatus comprising a pump having an inlet connectable to the drain, and an outlet connectable to the return, the pump adapted to receive the fluid from the drain and jet fluid through the return, and the motor coupled to the pump to operate the pump, the method comprising:

determining a power of the pump motor;

applying the power to a model observer;

obtaining a value representative of a flow based on the power and the model observer;

determining whether the value indicates a condition of the pump; and

controlling the motor to operate the pump based on the condition of the pump.

17. The method ofclaim 16, wherein monitoring the operation of the pump further comprises

determining a torque of the motor; and

applying the torque to the model observer.

18. The method ofclaim 16, wherein monitoring the operation of the pump further comprises providing the model observer with a fluid system model simulating at least a portion of the jetted-fluid system.

19. The method ofclaim 16, wherein determining whether the value indicates a condition of the pump further comprises

determining a trip value; and

comparing the value with the trip value.

20. A method of controlling a motor operating a pumping apparatus of a jetted fluid system comprising a vessel for holding a fluid, a drain, and a return, the pumping apparatus comprising a pump having an inlet connectable to the drain, and an outlet connectable to the return, the pump adapted to receive the fluid from the drain and jet fluid through the return, and the motor coupled to the pump to operate the pump, the method comprising:

determining a power of the pump motor;

applying the power to a model observer;

obtaining a value representative of a pressure based on the power and the model observer;

determining whether the value indicates a condition of the pump; and

controlling the motor to operate the pump based on the condition of the pump.

21. The method ofclaim 20, wherein monitoring the operation of the pump further comprises

determining a torque of the motor; and

applying the torque to the model observer.

22. The method ofclaim 20, wherein monitoring the operation of the pump further comprises providing the model observer with a fluid system model simulating at least a portion of the jetted-fluid system.

23. The method ofclaim 20, wherein determining whether the value indicates a condition of the pump further comprises

determining a trip value; and

comparing the value with the trip value.

24. A method of controlling a fluid-movement system including a motor and a pump, the motor being coupled to the pump to operate the pump, the method comprising:

calibrating the system to obtain a calibration value for a motor parameter;

obtaining a relationship between the motor parameter and a fluid parameter;

determining a trip value based on the calibration value and the relationship;

controlling the motor to operate the pump;

monitoring the operation of the pump, the monitoring act including

determining a value for the motor parameter,

comparing the value to the trip value, and

determining whether the comparison indicates a condition of the pump; and

further controlling the motor to operate the pump based on the condition of the pump.

25. The method ofclaim 24, wherein the fluid parameter includes a flow rate.

26. The method ofclaim 24, wherein the fluid parameter includes a pressure of the pump

27. The method ofclaim 24, wherein the motor parameter includes motor input power.

28. The method ofclaim 24, wherein the motor parameter includes motor torque.

29. The method ofclaim 24, wherein the determining a trip value includes determining at least one characterization value based on the motor and the pump, and determining the trip value based on the at least one characterization value and the calibration value.

30. The method ofclaim 24, wherein the calibrating the system includes calculating a calibration value related to torque.

31. The method ofclaim 24, wherein the determining a trip value includes obtaining a second value based on the calibration value and the relationship, and wherein the calculating the trip value includes determining a percentage reduction of the second value.

32. The method ofclaim 24, wherein the controlling the motor based on the condition of the pump includes inhibiting current through the motor to stop operation of the pumping apparatus.

33. The method ofclaim 24, wherein the relationship includes an equation relating the fluid parameter and the motor parameter.

34. The method ofclaim 24, wherein the relationship includes a table relating the fluid parameter and the motor parameter.

35. A method of controlling a fluid-movement system including a motor and a pump, the motor being coupled to the pump to operate the pump, the method comprising:

determining a relationship between an input power to the motor and a flow rate through the pump;

determining a calibration value for the input power;

determining a percentage drop for the relationship;

determining a trip value based on the relationship, the calibration value, and the percentage drop;

monitoring the operation of the pump, the monitoring act comprising

determining a first value for the input power,

comparing the first value to the trip value, and

determining whether the first value indicates a condition of the pump; and

controlling the motor to operate the pump based on the condition of the pump.

36. The method ofclaim 35, wherein the controlling the motor based on the condition of the pump includes inhibiting current through the motor to stop operation of the pumping apparatus.

37. The method ofclaim 35 the determining a trip value includes applying the calibration value to the relationship to result in a flow rate value, adjusting the flow rate value by a percentage, applying the flow rate value to the relationship to result in the trip value.

38. The method ofclaim 35, wherein the relationship includes an equation relating the fluid parameter and the motor parameter.

39. The method ofclaim 35, wherein the relationship includes a table relating the fluid parameter and the motor parameter.

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