Note: Descriptions are shown in the official language in which they were submitted.
CA 02605891 2007-10-05
Attorney Docket No. 010121-8050
CONTROLLER FOR A MOTOR AND A METHOD OF CONTROLLING
THE MOTOR
BACKGROUND
[0001] The invention relates to a controller for a motor, and particularly, a
controller for
a motor operating a pump.
[0002] 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.
[0003] 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.
[0004] Several solutions have been proposed for suction and mechanical
entrapment. For
example, new pool constraction 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. Modem pool drain covers are also designed such that
items cannot
become entwined with the cover.
[0005] 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.
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CA 02605891 2007-10-05
Attorney Docket No. 010121-8050
SUMMARY
100061 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 connectable to the power source and 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 is
configured to
generate a derivative value based on the signal, and to control the motor
based on the derivative
value.
[0007] 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 including 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 coupled to the motor and configured to generate
a signal having a
relation to a power 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 relay circuit. The microcontroller is configured
to generate a
derivative value of a parameter based on the signal, and to control the motor
based on the
derivative value.
[0008] In another embodiment, the invention provides a method of controlling a
motor
operating a pumping apparatus of a fluid-pumping application. The pumping
apparatus includes
a pump having an inlet to receive a fluid and an outlet to exhaust the fluid,
and the motor is
coupled to the pump to operate the pump. The method includes sensing a motor
current, sensing
a motor voltage, and obtaining a derivative value of the motor power based on
the sensed voltage
and the sensed current. The method also includes deterrnining whether the
derivative value
2
.._............ _.._. . ,.... . . I. .... _ ....... .... . . . .
CA 02605891 2007-10-05
Attorney Docket No. 010121-8050
indicates a condition of the pump, and controlling the motor to operate the
pump based on the
condition of the pump.
100091 In another embodiment, the invention provides a pumping apparatus for a
jetted-
fluid system comprising 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 connectable to the power source and
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 derivative device coupled to the sensor and the switch. The
derivative device is
configured to generate a derivative value based on the signal to control the
motor based on the
derivative value.
[0010] 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 comprising 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 a
characteristic of the motor. The pumping apparatus also includes a
microcontroller coupled to
the sensor and the switch. The microcontroller is configured to generate a
value based on the
signal, where the value has a relation to the motor torque, and to control the
motor based on the
value.
[0011] 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 retum. 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.
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CA 02605891 2007-10-05
Attorney Docket No. 010121-8050
The method includes controlling the motor to operate the pump, sensing a
current of the motor,
and calculating a torque of the motor based on the sensed current. The method
also includes
determining whether the torque indicates a condition of the pump, and
controlling the motor to
operate the pump based on the condition of the pump.
[0012] Other features and aspects of the invention will become apparent by
consideration
of the detailed description and accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Fig. 1 is a schematic representation of a jetted-spa incorporating the
invention.
[0014] Fig. 2 is a block diagram of a first controller capable of being used
in the jetted-
spa shown in Fig. 1.
[0015] Figs. 3A and 3B are electrical schematics of the first controller shown
in Fig. 2.
100161 Fig. 4 is a block diagram of a second controller capable of being used
in the
jetted-spa shown in Fig. 1.
[0017] Figs. 5A and 5B are electrical schematics of the second controller
shown in Fig.
4.
100181 Fig. 6 is a block diagram of a third controller capable of being used
in the jetted-
spa shown in Fig. 1.
[0019] Fig. 7 is a graph showing an input power signal and a derivative power
signal as a
function of time.
[0020] Fig. 8 is a flow diagram illustrating a model observer.
[0021] Fig. 9 is a graph showing an input power signal and a processed power
signal as a
function of time.
[0022] Fig. 10 is a graph showing an average input power signal and a
threshold value
reading as a function of time.
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CA 02605891 2007-10-05
Attorney Docket No. 010121-8050
100231 Fig. 11 is a graph showing characterization data and fluid pressure
data as a
function of flow rate.
[0024] Fig. 12 is a chart showing a numeric relationship between input power
and torque.
DETAILED DESCRIPTION
[0025] 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.
100261 Fig. 1 schematically represents a jetted-spa 100 incorporating the
invention.
However, the invention is not limited to the jetted-spa 100 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).
[0027] As shown in Fig. 1, the spa 100 includes a vessel 105. As used herein,
the vessel
105 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 system 110 coupled to the vessel 105. The
fluid-movement
system 110 includes a drain 115, a pumping apparatus 120 having an inlet 125
coupled to the
drain and an outlet 130, and a return 135 coupled to the outlet 130 of the
pumping apparatus 120.
The pumping apparatus 120 includes a pump 140, a motor 145 coupled to the pump
140, and a
controller 150 for controlling the motor 145. For the constructions described
herein, the pump
. . ...,.._,.._..-..---_.,-.,.._~._. _T_._ ._ _. ---- - . _ _..__..._ __ _ _ .
. .. . .. _ i . ._ _ _ _ _....... .._ ._ . . _.. _ . . .
CA 02605891 2007-10-05
Attorney Docket No. 010121-8050
140 is a centrifugal pump and the motor 145 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
retums, or even
multiple fluid movement systems.
[0028] Referring back to Fig. 1, the vessel 105 holds a fluid. When the fluid
movement
system 110 is active, the pump 140 causes the fluid to move from the drain
115, through the
pump 140, and jet into the vessel 105. This pumping operation occurs when the
controller 150
controllably provides a power to the motor 145, resulting in a mechanical
movement by the
motor 145. The coupling of the motor 145 (e.g., a direct coupling or an
indirect coupling via a
linkage system) to the pump 140 results in the motor 145 mechanically
operating the pump 140
to move the fluid. The operation of the controller 150 can be via an operator
interface, which
may be as simple as an ON switch.
[0029] Fig. 2 is a block diagram of a first construction of the controller
150, and Figs. 3A
and 3B are electrical schematics of the controller 150. As shown in Fig. 2,
the controller 150 is
electrically connected to a power source 155 and the motor 145.
[0030] With reference to Fig. 2 and Fig. 3B, the controller 150 includes a
power supply
160. The power supply 160 includes resistors R46 and R56; capacitors C13, C14,
C16, C18,
C19, and C20; diodes D10 and Dl 1; zener diodes D12 and D13; power supply
controller U7;
regulator U6; and optical switch U8. The power supply 160 receives power from
the power
source 155 and provides the proper DC voltage (e.g., 5 VDC and tl2 VDC) for
operating the
controller 150.
100311 For the controller 150 shown in Figs. 2 and 3A, the controller 150
monitors motor
input power and pump inlet side pressure to determine if a drain obstruction
has taken place. If
the drain 115 or plumbing is plugged on the suction side of the pump 140, the
pressure on that
side of the pump 140 increases. At the same time, because the pump 140 is no
longer pumping
water, input power to the motor 145 drops. If either of these conditions
occur, the controller 150
declares a fault, the motor 145 powers down, and a fault indicator lights.
6
, . .. .. . ...~ . . . ..... ... ..._..__ . ._ . . . . . . .. . ,... . .. _
......... ... , __ .._,....... , __J ....... ..... . . . .... ..
CA 02605891 2007-10-05
Attorney Docket No, 010121-8050
100321 A voltage sense and average circuit 165, a current sense and average
circuit 170, a
line voltage sense circuit 175, a triac voltage sense circuit 180, and the
microcontroller 185
perform the monitoring of the input power. One example voltage sense and
average circuit 165
is shown in Fig. 3A. The voltage sense and average circuit 165 includes
resistors R34, R41, and
R42; diode D9; capacitor C 10; and operational amplifier U4A. The voltage
sense and average
circuit 165 rectifies the voltage from the power source 155 and then performs
a DC average of
the rectified voltage. The DC average is then fed to the microcontroller 185.
[0033] One example current sense and average circuit 170 is shown in Fig. 3A.
The
current sense and average circuit 170 includes transformer TI 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 and
average circuit 170
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 the microcontroller 185.
[0034] One example line voltage sense circuit 175 is shown in Fig. 3A. The
line voltage
sense circuit 175 includes resistors R23, R24, and R32; diode D5; zener diode
D6; transistor Q6;
and NAND gate U2B. The line voltage sense circuit 175 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.
[00351 One example triac voltage sense circuit 180 is shown in Fig. 3A. The
triac
voltage sense circuit 180 includes resistors RI, 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.
[0036] One example microcontroller 185 that can be used with the invention is
a
Motorola brand microcontroller, model no. MC68HC908QY4CP. The microcontroller
185
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
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CA 02605891 2007-10-05
Attorney Docket No. 010121-8050
includes data storage memory. The microcontroller 185 can include other
circuitry (e.g., an
analog-to-digital converter) necessary for operating the microcontroller 185.
In general, the
microcontroller 185 receives inputs (signals or data), executes software
instructions to analyze
the inputs, and generates outputs (signals or data) based on the analyses.
Although the
microcontroller 185 is shown and described, the functions of the
microcontroller 185 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 the
microcontroller 185 or
similar circuitry can be distributed among multiple microcontrollers 185 or
similar circuitry. It is
also envisioned that the microcontroller 185 or similar circuitry can perform
the function of some
of the other circuitry described (e.g., circuitry 165-180) above for the
controller 150. For
example, the microcontroller 185, 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.
[00371 The microcontroller 185 receives the signals representing the average
voltage
applied to the motor 145, the average current through the motor 145, the zero
crossings of the
motor voltage, and the zero crossings of the motor current. Based on the zero
crossings, the
microcontroller 185 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.
The microcontroller 185 can then calculate a power with the averaged voltage,
the averaged
current, and the power factor as is known. As will be discussed later, the
microcontroller 185
compares the calculated power with a power calibration value to determine
whether a fault
condition (e.g., due to an obstruction) is present.
[0038) Referring again to Figs. 2 and 3A, a pressure (or vacuum) sensor
circuit 190 and
the microcontroller 185 monitor the pump inlet side pressure. One example
pressure sensor
circuit 190 is shown in Fig. 3A. The pressure sensor circuit 190 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 the pump 140. The pressure sensor circuit 190 and microcontroller 185
translate and
amplify the signal generated by the piezoresistive sensor U9 into a value
representing inlet
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CA 02605891 2007-10-05
Attorney Docket No. 010121-8050
pressure. As will be discussed later, the microcontroller 185 compares the
resulting pressure
value with a pressure calibration value to determine whether a fault condition
(e.g., due to an
obstruction) is present.
[0039] The calibrating of the controller 150 occurs when the user activates a
calibrate
switch 195. One example calibrate switch 195 is shown in Fig. 3A. The
calibrate switch 195
includes resistor R18 and Hall effect switch U10. When a magnet passes Hall
effect switch U10,
the switch 195 generates a signal provided to the microcontroller 185. Upon
receiving the
signal, the microcontroller 185 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.
[0040] As stated earlier, the controller 150 controllably provides power to
the motor 145.
With references to Fig. 2 and 3A, the controller 150 includes a retriggerable
pulse generator
circuit 200. The retriggerable pulse generator circuit 200 includes resistor
R7, capacitor Cl, and
pulse generator UlA, and outputs a value to NAND gate U2D if the retriggerable
pulse generator
circuit 200 receives a signal having a pulse frequency greater than a set
frequency determined by
resistor R7 and capacitor Cl. The NAND gate U2D also receives a signal from
power-up delay
circuit 205, which prevents nuisance triggering of the relay on startup. The
output of the NAND
gate U2D is provided to relay driver circuit 210. The relay driver circuit 210
shown in Fig. 3A
includes resistors R19, R20, R21, and R22; capacitor C7; diode D3; and
switches Q5 and Q4.
The relay driver circuit 210 controls relay K1.
[0041] The microcontroller 185 also provides an output to triac driver circuit
215, which
controls triac Q2. As shown in Fig. 3A, the triac driver circuit 215 includes
resistors R12, R13,
and R14; capacitor C11; and switch Q3. In order for current to flow to the
motor, relay Kl needs
to close and triac Q2 needs to be triggered on.
[0042] The controller 150 also includes a thermoswitch S I for monitoring the
triac heat
sink, a power supply monitor 220 for monitoring the voltages produced by the
power supply 160,
and a plurality of LEDs DSl, DS2, and DS3 for providing information to the
user. In the
construction shown, a green LED DS 1 indicates power is applied to the
controller 150, a red
LED DS2 indicates a fault has occurred, and a third LED DS3 is a heartbeat LED
to indicate the
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CA 02605891 2007-10-05
Attorney Docket No. 010121-8050
microcontroller 185 is functioning. Of course, other interfaces can be used
for providing
information to the operator.
[0043] The following describes the normal sequence of events for one method of
operation of the controller 150. When the fluid movement system 110 is
initially activated, the
system 110 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. The microcontroller
185 includes a
startup-lockout feature that keeps the monitor from detecting the abnormal
conditions during the
priming period.
[0044] After the system 110 is running smoothly, the spa operator can
calibrate the
controller 150 to the current spa running conditions. The calibration values
are stored in the
microcontroller 185 memory, and will be used as the basis for monitoring the
spa 100. If for
some reason the operating conditions of the spa change, the controller 150 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.
[0045] As discussed earlier, the controller 150 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.
100461 The voltage sense and average circuit 165 generates a value
representing the
average power line voltage and the current sense and average circuit 170
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
line voltage sense
CA 02605891 2007-10-05
Attorney Docket No. 010121-8050
circuit 175 provides a signal representing the power line zero crossings. The
triac zero crossings
occur at the zero crossings of the motor current. The triac voltage sense
circuit 180 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 the
microcontroller 185. This data
is then used to calculate the motor input power using equation el.
[el ] V.,g * I,,õg * PF = Motor _ Input _ Power
[0047] 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.
[0048] Fig. 4 is a block diagram of a second construction of the controller
150a, and Figs.
5A and 5B are an electrical schematic of the controller 150a. As shown in Fig.
4, the controller
150a is electrically connected to a power source 155 and the motor 145.
[0049] With reference to Fig. 4 and Fig. 5B, the controller 150a includes a
power supply
160a. The power supply 160a includes 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 Ll and L2, surge suppressors MOV1 and
MOV2, and
optical switch U10. The power supply 160a receives power from the power source
155 and
provides the proper DC voltage (e.g., +5 VDC and +12 VDC) for operating the
controller 150a.
[0050] For the controller 150a shown in Fig. 4, Fig 5A, and Fig. 5B, the
controller 150a
monitors motor input power to detennine if a drain obstruction has taken
place. Similar to the
earlier disclosed construction, if the drain 115 or plumbing is plugged on the
suction side of the
pump 140, the pump 140 will no longer be pumping water, and input power to the
motor 145
drops. If this condition occurs, the controller 150a declares a fault, the
motor 145 powers down,
and a fault indicator lights.
[0051] A voltage sense and average circuit 165a, a current sense and average
circuit
170a, and the microcontroller 185a perform the monitoring of the input power.
One example
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voltage sense and average circuit 165a is shown in Fig. 5A. The voltage sense
and average
circuit 165a includes 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 and
average circuit
165a rectifies the voltage from the power source 155 and then performs a DC
average of the
rectified voltage. The DC average is -then fed to the microcontroller 185a.
The voltage sense
and average circuit 165a further 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 the microcontroller 185a.
[0052] One example current sense and average circuit 170a is shown in Fig. 5B.
The
current sense and average circuit 170a includes transformer T1 and resistor
R53, which act as a
current sensor that senses the current applied to the motor 145. The current
sense and average
circuit 170a also 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 and
average circuit 170a can 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 the
microcontroller 185a. The
current sense and average circuit 170a further 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) to microcontroller 185a.
[0053] One example microcontroller 185a that can be used with the invention is
a
Motorola brand microcontroller, model no. MC68HC908QY4CP. Similar to what was
discussed
for the earlier construction, the microcontroller 185a 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.
The
microcontroller 185a can include other circuitry (e.g., an analog-to-digital
converter) necessary
for operating the microcontroller 185a and/or can perform the function of some
of the other
circuitry described above for the controller 150a. In general, the
microcontroller 185a receives
inputs (signals or data), executes software instructions to analyze the
inputs, and generates
outputs (signals or data) based on the analyses.
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[0054] The microcontroller 185a receives the signals representing the average
voltage
applied to the motor 145, the average current through the motor 145, the zero
crossings of the
motor voltage, and the zero crossings of the motor current. Based on the zero
crossings, the
microcontroller 185a can determine a power factor and a power as was described
earlier. The
microcontroller 185a can then compare the calculated power with a power
calibration value to
determine whether a fault condition (e.g., due to an obstruction) is present.
[0055] The calibrating of the controller 150a occurs when the user activates a
calibrate
switch 195a. One example calibrate switch 195a is shown in Fig. 5A, which is
similar to the
calibrate switch 195 shown in Fig. 3A. Of course, other calibrate switches are
possible. In one
method of operation for the calibrate switch 195a, a calibration fob needs to
be held near the
switch 195a when the controller 150a receives an initial power. After removing
the magnet and
cycling power, the controller 150a goes through priming and enters an
automatic calibration
mode (discussed below).
[0056] The controller 150a controllably provides power to the motor 145. With
references to Fig. 4 and 5A, the controller 150a includes a retriggerable
pulse generator circuit
200a. The retriggerable pulse generator circuit 200a includes resistors R15
and R16, capacitors
C2 and C6, and pulse generators U3A and U3B, and outputs a value to the relay
driver circuit
210a if the retriggerable pulse generator circuit 200a receives a signal
having a pulse frequency
greater than a set frequency deterniined 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
circuit 205a, which prevents nuisance triggering of the relays on startup. The
relay driver
circuits 210a shown in Fig. 5A include resistors R1, R3, R47, and R52; diodes
D1 and D5; and
switches Q1 and Q2. The relay driver circuits 210a control relays K1 and K2.
In order for
current to flow to the motor, both relays K1 and K2 need to "close".
[00571 The controller 150a further includes two voltage detectors 212a and
214a. The
first voltage detector 212a includes resistors R71, R72, and R73; capacitor
C26; diode D 14; and
switch Q4. The first voltage detector 212a detects when voltage is present
across relay Kl, and
verifies that the relays are functioning properly before allowing the motor to
be energized. The
second voltage detector 214a includes resistors R66, R69, and R70; capacitor
C9; diode D13;
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and switch Q3. The second voltage detector 214a senses 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 the controller 150a
can be used with a
single speed motor without the second voltage detector 214a (e.g., controller
150b is shown in
Fig. 6).
[0058] The controller 150a also includes an ambient thermal sensor circuit
216a for
monitoring the operating temperature of the controller 150a, a power supply
monitor 220a for
monitoring the voltages produced by the power supply 160a, and a plurality of
LEDs DS I and
DS3 for providing information to the user. In the construction shown, a green
LED DS2
indicates power is applied to the controller 150a, and a red LED DS3 indicates
a fault has
occurred. Of course, other interfaces can be used for providing information to
the operator.
(0059] The controller 150a further includes a clean mode switch 218a, 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 vessel 105).
Moreover, the red
LED DS3 can be used to indicate that controller 150a is in a clean mode. After
the time period,
the controller 150a returns to normal operation. In some constructions, the
maintenance person
can actuate the clean mode switch 218a for the controller 150a to exit the
clean mode before the
time period is completed.
[0060] In some cases, it may be desirable to deactivate the power monitoring
function for
reasons other than performing cleaning operations on the vessel 105. 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.
[0061] The following describes the normal sequence of events for one method of
operation of the controller 150a, some of which may be similar to the method
of operation of the
controller 150. When the fluid movement system 110 is initially activated, the
system 110 may
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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.
100621 Upon a system power-up, the system 110 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, the
system 110 enters the
normal running period. The controller 150a can 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 the microcontroller 185, and will
be used as the basis
for monitoring the vessel 105.
[00631 If for some reason the operating conditions of the vessel 105 change,
the
controller 150a can be re-calibrated by the operator. In some constructions,
the operator actuates
the calibrate switch 195a to erase the existing one or more calibration values
stored in the
memory of the microcontroller 185. The operator then powers down the system
110, particularly
the motor 145, and performs a system power-up. The system 110 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), the motor 145
will be powered
down and the fault LED DS3 is lit.
[0064] In one construction, the automatic calibration instructions include not
monitoring
the power of the motor 145 during a start-up period, generally preset for a
time duration (e.g., 2
seconds), upon the system power-up. In the case when the system I 10 is
operated for the first
time, the system 110 enters the prime period, upon completion of the start-up
period, and the
power of the motor 145 is monitored to determine the power calibration value.
As indicated
above, the power calibration value is stored in the memory of the
microcontroller 185. After
completion of the 3 minutes of the priming period, the system 110 enters the
normal running
period. In subsequent system power-ups, the monitored power is compared
against the power
CA 02605891 2007-10-05
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calibration value stored in the memory of the microcontroller 185 memory
during the priming
period. More specifically, the system 110 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, the motor 145 is powered down and a fault
indicator is lit.
[0065] 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, the controller 150a can include instructions to perform signal
conditioning
operations to the monitored power. For example, the controller 150a can
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.
[0066] Similar to controller 150, the controller 150a measures motor input
power, and
not just motor power factor or input current. However, it is envisioned that
the controllers 150 or
150a can 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 for
controller 150a for determining whether the water is impeded. Also, it is
envisioned that the
controller 150a can be modified to monitor other parameters (e.g., suction
side pressure) of the
system 110.
[0067] For some constructions of the controller 150a, the microcontroller 185a
monitors
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 that controller
150a was
incorrectly calibrated, and/or also helps detect when the pump is over loaded
(e.g., the pump is
moving too much fluid).
[0068] The voltage sense and average circuit 165a generates a value
representing the
averaged power line voltage and the current sense and average circuit 170a
generates 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
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difference is used to look up the motor power factor from a table stored in
the microcontroller
185a. 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 el 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.
[0069] Redundancy is also used for the power switches of the controller 150a.
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 the motor 145. As an additional safety feature,
the proper operation of
both relays is checked by the microcontroller 185a every time the motor 145 is
powered-on via the
relay voltage detector circuit 212a.
[0070] Another aspect of the controller 150a is that the microcontroller 185a
provides
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 Kl and K2 open and the motor
powers down.
[0071] As previously indicated, the microcontroller 185, 185a can calculate an
input
power based on parameters such as averaged voltage, averaged current, and
power factor. The
microcontroller 185, 185a then 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 the microcontroller 185, 185a and the
controller 150,
150a operable to receive other parameters and determine whether a fault
condition is present.
10072] One aspect of the controller 150, 150a is that the microcontroller 185,
185a can
monitor the change of input power over a predetermine period of time. More
specifically, the
microcontroller 185, 185a determines 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, the controller 150, 150a controls the motor 145
to shut down the
pump 140. This aspect of the controller 150, 150a may be operable in
replacement of, or in
conjunction with, other similar aspects of the controller 150, 150a, such as
shutting down the
motor 145 when the power level of the motor 145 traverses a predetermined
value.
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100731 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 (line 300)
and a power
derivate value (line 305), over a 30-second time period, of a motor 145
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 system 110 (shown in Fig. 1) occurs at
the 20-second
mark. It can be observed from Fig. 7 that the power reading 300 indicates a
power level drop
below the threshold value of 5000 at the 27-second mark, causing the
controller 150, 150a to
shut down the pump 140 approximately at the 28-second mark. It can also be
observed that the
power derivative value 305 drops below the -100 threshold value at the 22-
second mark, causing
the controller 150, 150a to shut down the pump 140 approximately at the 23-
second mark. Other
parameters of the motor 145 (e.g., torque) can be monitored by the
microcontroller 185, 185a, for
determining a potential entrapment event.
[0074] In another aspect of the controller 150, 150a, the microcontroller 185,
185a can
include instructions that correspond to a model observer, such as the
exemplary model observer
310 shown in Fig. 8. The model observer 310 includes a first filter 315, a
regulator 325 having a
variable gain 326 and a transfer function 327, a fluid system mode1330 having
a gain parameter
(shown in Fig. 8 with the value of 1), and a second filter 335. In particular,
the fluid system
model 330 is configured to simulate the fluid-movement system 110.
Additionally, the first filter
315 and the second filter 335 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.
[0075] It is to be understood that the model observer 310 is not limited to
the elements
described above. In other words, the model observer 310 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 the fluid system
model 330, a fluid
system model may be defined utilizing various procedures. In some cases, a
model may be
generated for this particular aspect of the controller 150, 150a from 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.
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[0076] In reference to the model observer 310 of Fig. 8, the first filter 315
receives a
signal (P) corresponding to a parameter of the motor 145 determined and
monitored by the
microcontroller 185, 185a (e.g., input power, torque, current, power factor,
etc.). Generally, the
first filter 315 is configured to substantially eliminate the noise in the
received signal (P), thus
generating a filtered signal (PA). However, the first filter 315 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 loop 340 of the model observer 310 and is
processed by the
regulator 325. The regulator 325 outputs a regulated signal (ro) related to
the fluid flow and/or
pressure through the fluid-movement system 110 based on the monitored
parameter. The
regulated signal can be interpreted as a modeled flow rate or modeled
pressure. The fluid system
model 330 processes the regulated signal (ro) to generate a model signal
(Fil), which is compared
to the filtered signal (PA) through the feed-back loop 340. The regulated
signal (ro) is also fed
to the second filter 335 generating a control signal (roP), which is
subsequently used by the
microcontroller 185, 185a to at least control the operation of the motor 145.
[0077] As shown in Fig. 8, the regulated signal (ro), indicative of fluid flow
and/or
pressure, is related to the monitored parameter as shown in equation [e2].
[e2] ro = (PA - Fil) 1- regulator
The relationship shown in equation [e2] allows a user to control the motor 145
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.
[0078] Fig. 9 is a graph showing an input power (line 345) and a processed
power or
flow unit (line 350) as functions of time. More specifically, the graph of
Fig. 9 illustrates the
operation of the fluid-movement system 110 with the motor 145 having a
threshold value of
5000. For this particular example, Fig. 9 shows that the pump inlet 125
blocked at the 5-second
mark. The input power drops below the threshold mark of 5000, and therefore
the controller
150, 150a shuts down the pump 140 approximately at the 12.5-second mark.
Alternatively, the
processed power signal drops below the threshold mark corresponding to 5000 at
the 6-second
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mark, and therefore the controller 150, 150a shuts down the pump 140
approximately at the 7-
second mark.
[0079] In this particular example, the gain parameter of the fluid system
model 330 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 the motor 145, such as shut down time.
[0080] In another aspect of the controller 150, 150a, the microcontroller 185,
185a can be
configured for determining a floating the threshold value or trip value
indicating the parameter
reading, such as input power or torque, at which the controller 150, 150a
shuts down the pump
140. It is to be understood that the term "floating" refers to varying or
adjusting a signal or
value. In one example, the microcontroller 185, 185a continuously adjusts the
trip value based
on average input power readings, as shown in Fig. 10. More specifically, Fig.
10 shows a graph
indicating an average input power signal (line 355) determined and monitored
by the
microcontroller 185, 185a, a trip signal (line 360) indicating a variable trip
value, and a threshold
value of about 4500 (shown in Fig. 10 with arrow 362) as a function of time.
In this particular
case, the threshold value 362 is a parameter indicating the minimum value that
the trip value can
be adjusted to.
[0081] The microcontroller 185, 185a may calculate the average input power 355
utilizing various methods. In one construction, the microcontroller 185, 185a
may determine a
running average based at least on signals generated by the current sense and
average circuit 170,
170a and signals generated by the voltage sense and average circuit 165, 165a.
In another
construction, the microcontroller 185, 185a may determine an input power
average over
relatively short periods of time. As shown in Fig. 10, the average power
determined by the
microcontroller 185, 185a goes 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 the signal
360 indicating the trip value is adjusted down to about 10% from the value at
the 0-time unit
mark to the 80-time unit mark and is substantially parallel to the average
power 355. More
specifically, the microcontroller 185, 185a adjusts the trip value based on
monitoring the average
input power 355.
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100821 In some cases, the average power signal 355 may define a behavior, such
as the
one shown in Fig. 10, due to sustained clogging of the fluid-movement system
110 over a period
of time, for example from the 0-time unit mark to the 80-time unit mark. In
other words,
sustained clogging of the fluid-movement system 110 can be determined and
monitored by the
microcontroller 185, 185a in the form of the average power signal 355. In
these cases, the
microcontroller 185, 185a can also determine a percentage or value indicative
of a minimum
average input power allowed to be supplied to the motor 145, or a minimum
allowed threshold
value such as threshold value 362. When the fluid-movement system 110 is back-
flushed with
the purpose of unclogging the fluid-movement system 110, the average power
signal 355 returns
to normal unrestricted fluid flow (shown in Fig. 10 between about the 84-time
unit mark and
about the 92-time unit mark, for example). As shown in Fig. 10, unclogging the
fluid-movement
system 110 can result in relative desired fluid flow through the fluid-
movement system 110. As
a consequence, the microcontroller 185, 185a senses an average power change as
indicated near
the 80-time unit mark in Fig. 10 showing as the average power returns to the
calibration value.
[0083] In other cases, the microcontroller 185, 185a can determine and monitor
the
average input power over a relatively short amount of time. For example, the
microcontroller
185, 185a can monitor the average power over a first time period (e.g., 5
seconds). The
controller 185, 185a can 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 the
microcontroller 185,
185a determines the average power. The controller 150, 150a can shut down the
pump 140 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).
[0084] In another aspect of the controller 150, 150a, the microcontroller 185,
185a can be
configured to determine a relationship between a parameter of the motor 145
(such as power or
torque) and pressure/flow through the fluid-movement system 110 for a specific
motor/pump
combination. More specifically, the controller 150, 150a controls the motor
145 to calibrate the
fluid-movement system 110 based on the environment in which the fluid-movement
system 110
operates. The environment in which the fluid-movement system 110 operates can
be defined by
the capacity of the vessel 105, tubing configuration between the drain 115 and
inlet 125, tubing
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configuration between outlet 130 and return 135 (shown in Fig. 1), number of
drains and returns,
and other factors not explicitly discussed herein.
[00851 Calibration of the fluid-movement system 110 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 system 110 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 (line 365), measured in kilowatts and obtained through a calibration
process, and a pump
curve (line 370) indicating head pressure. The characterization data 365 and
the pump curve 370
are graphed as a function of flow measured in gallons per minute (GPM). In the
particular
example shown in Fig. 11, it is possible for a user (or the microcontroller
185, 185a in 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.
[0086] Referring particularly to the characterization data 365 shown in Fig.
11, if an
operating point for the fluid-movement system 110 is determined at point I on
the
characterization data 365, a 30% reduction in flow from 100 GPM to 70 GPM
(point 2 on the
characterization data 365) through the fluid-movement system 110 is monitored
by the
microcontroller 185, 185a and indicates a 7% reduction in input power. For a
different
environment of the fluid-movement system 110, the operating set point can be
established at
point 2, for example. Particularly, a 30% reduction in flow from 70 GPM to 50
GPM (point 3 on
the characterization data 365) through the fluid-movement system 110 is
monitored by the
microcontroller 185, 185a and 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 (or
microcontroller 185, 185a) can establish a trip value or percentage based on
the percent
reduction (e.g., a reduction of 30% in flow) separate from the detennined and
monitored power.
[0087] In another aspect of the controller 150, 150a, the microcontroller 185,
185a can
include a timer function to operate the fluid-movement system 110. In one
example, the timer
function of the microcontroller 185, 185a implements a RUN mode of the
controller 150, 150a.
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More specifically regarding the RUN mode, the controller 150, 150a is
configured to operate the
motor 145 automatically over predetermined periods of time. In other words,
the controller 150,
150a is configured to control the motor 145 based on predetermined time
periods programmed in
the microcontroller 185, 185a during manufacturing or programmed by a user. In
another
example, the timer function of the microcontroller 185, 185a implements an OFF
mode of the
controller 150, 150a. More specifically regarding the OFF mode, the controller
150, 150a is
configured to operate the motor 145 only as a result of direct interaction of
the user. In other
words, the controller 150, 150a is configured to maintain the motor 145 off
until a user directly
operates the controller 150, 150a through the interface of the controller 150,
150a. In yet another
example, the timer function of the microcontroller 185, 185a implements a
PROGRAM mode of
the controller 150, 150a. More specifically regarding the PROGRAM mode, the
controller 150,
150a is configured to maintain the motor 145 off until the user actuates one
of the switches (e.g.,
calibrate switch 195, 195a, clean mode switch 218a) of the controller 150,
150a indicating a
desired one-time window of operation of the motor 145. For example, the user
can actuate one
switch three times indicating the controller 150, 150a to operate the motor
145 for a period of
three hours. In some constructions, the controller 150, 150a includes a run-
off-program switch
to operate the controller 150, 150a between the RUN, OFF, and PROGRAM modes.
It is to be
understood that the same or other modes of operation of the controller 150,
150a can be defined
differently. Additionally, not all modes described above are necessary and the
controller 150,
150a can include a different number and combinations of modes of operation.
[00881 In another aspect of the controller 150, 150a, the microcontroller 185,
185a can be
configured to determine and monitor a value corresponding to the torque of the
motor 145. More
specifically, the microcontroller 185, 185a receives signals from at least one
of the voltage sense
and average circuit 165, 165a and the current sense and average circuit 170,
170a to help
determine the torque of the motor 145. As explained above, the microcontroller
185, 185a can
also be configured to determine and monitor the speed of the motor 145,
allowing the
microcontroller 185, 185a to determine a value indicative of the torque of the
motor 145 and a
relationship between the torque and the input power. In some constructions,
the speed of the
motor 145 remains substantially constant during operation of the motor 145. In
these particular
cases, the microcontroller 185, 185a can include instructions related to
formulas or look-up
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tables that indicate a direct relationship between the input power and the
torque of the motor 145.
Determining and monitoring the torque of the motor 145 allows the
microcontroller 185, 185a to
establish a trip value or a percentage based on torque to shut off the motor
145 in case of an
undesired condition of the motor 145. For example, Fig. 12 shows a chart
indicating a
relationship between input power and torque for a motor 145 under the
observation that the
speed of the motor 145 changes less than 2%. Thus, the microcontroller 185,
185a can
determine and monitor torque based on input power and under the assumption of
constant speed.
[00891 In some constructions, the fluid-movement system I 10 can operate two
or more
vessels 105. For example, the fluid-movement system 110 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 the controller 150, 150a for the
controller 150, 150a to
operate the motor 145 to control fluid flow to the pool, the spa, or both. The
fluid-movement
system 110 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
system 110
includes one solenoid valve, a user can operate the valve to direct flow to
one of the pool and the
spa. Additionally, the controller 150, 150a can include a sensor or receiver
coupled to the valve
to determine the position of the valve. Under the above mentioned conditions,
the controller
150, 150a can 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 of vessels 105, where fluid flow to the number of vessels 105 can be
controller by one or
more fluid-movement systems 110.
(0090] While numerous aspects of the controller 150, 150a were 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 the controller 150, 150a shown in the
figures.
[0091] 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.
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