JP3225205B2 - Water supply system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water supply apparatus having a plurality of inverter-driven electric pumps provided in parallel, and more particularly, to a water supply apparatus directly connected to a water main.
The present invention relates to a water supply device for a water supply in which the pressure drop below a specified value of each of a suction pressure and a discharge pressure is discriminated and displayed as an abnormality so that the abnormality can be promptly dealt with.

[0002]

In turbomachinery such as the Related Art turbo pump or a turbo-type blowers, water supply, air volume is proportional to the operating speed, the supply water pressure, wind pressure is proportional to the square of the operating speed, and, these mechanical output It is proportional to the cube of the operating speed. This indicates that the operation speed can be reduced as the load amount is reduced, and there are merits such as energy saving.

Conventionally, a plurality of inverters have been used to control the speed so that the pressures on the discharge sides of a plurality of turbomachines maintain a certain relationship, and to control the operation order of the plurality of inverters and the turbomachine. The fact is that the number of operating units is controlled.

When a plurality of turbomachines are driven by a plurality of inverters to control the speed and the number of operating units, the amount of water supply, the amount of air, the amount of water supply, the wind pressure, etc. can be controlled relatively easily and efficiently according to the load fluctuation. . For this reason, it is considered that the speed control by the inverter will further spread in the future.

As an example of a conventional turbomachine, an example in which an inverter is used in a water supply device will be described with reference to FIGS. FIG. 4 is a configuration diagram of a water supply device, 1 is a water supply pipe,
2-1 and 2-2 are branch pipes of water distribution pipes, 3-1, 3-2, 3-
3, 3-4 are gate valves, 4-1 and 4-2 are pumps, 5-
1,5-2 is an electric motor, 6-1 and 6-2 are check valves, 7 is a water supply pipe, 8 is a pressure tank having an air reservoir inside,
Reference numerals 9 and 10 denote pressure sensors for detecting the pressures on the pump suction side and the pump discharge side, respectively, and emit electric signals corresponding to the pressures of the detection units.

Further, FS1 and FS2 are flow switches, which are turned off when the amount of water QS is below the quantity QS shown in FIGS. The CNU is a control device, and includes a power circuit section including inverters INV1 and INV2 for driving the electric motors 5-1 and 5-2 at variable speeds, earth leakage breakers ELB1 and ELB2 for earth leakage protection, a relay circuit section R, and a controller CU. It is composed of The relay circuit R includes a transformer TR and a stabilized power supply Z.
And relays 52X1 and 52X2, and an interface I / O with the controller CU.

The controller CU is an arithmetic processing unit CPU
(Hereinafter abbreviated as CPU), an A / D converter for converting signals (analog amounts) from the pressure sensors 9 and 10 into digital signals, and a water supply system for supplying the desired speed command signal N1 to the inverters INV1 and INV2. , N2, a power supply terminal E for supplying power to the controller CU, and an output for transmitting the signal S4 to the interface I / O for driving the above-described relays 52X1, 52X2. A port PIO-1.

Similarly, the controller CU includes an input port PIO-2 for reading a set value set by the setting means C so as to operate according to the operating characteristics of the pump shown in FIGS. 2 and 3, and an earth leakage breaker. Contact points ELBAL1 and ELBAL2 that operate when each of ELB1 and ELB2 trips due to a short circuit or the like, and inverters INV1 and ELB1
An input port PIO-3 for reading the state of the contacts INVAL1 and INVAL2 that operates when the INV2 trips due to an overload or the like. That is, the CPU stops the pump in response to these failure states, switches to the other pump that is inactive, and instructs the pump to operate, and executes its operation control.

FIG. 2 shows the water supply device described above.
FIG. 6 is an operation characteristic diagram when one pump is operated alone or two pumps are alternately operated, in which a vertical axis indicates a pressure H and a horizontal axis indicates a water amount Q. A curve A is a QH performance curve when the pump is driven at the operation speed N3, that is, at the operation speed of 100% by the inverter. Similarly, curves B, C, and D are QH performance curves when the pump is driven at operating speeds of N2, N1, and N0, respectively.

A curve F is a pipeline resistance curve. For example, when the used water amount changes from the water amount Q1 to the water amount Q0, if the water is supplied at a pressure higher than the curve F on the discharge side of the pump, a desired water flow at the terminal faucet is obtained. It shows that pressure can be obtained.
The above-mentioned inverters INV1 and INV2 control set conditions, for example, how long the acceleration / deceleration time is, and what value V / F (output voltage / output frequency characteristic) rotates. These conditions are based on the console CO
Set externally by NS1 and CONS2. That is,
The water supply device operates the pump on the curve F along O3 → O2 → O1 → O0.

In FIG. 4, the earth leakage breakers ELB1, EB
When the LB2 is turned on and the control power circuit breaker CB is turned on, the power of the controller CU is established, and the CPU performs initial setting based on a program stored in the memory M in advance, and reads setting information from the setting means C. , The state of the inverter and the earth leakage breaker (no failure) are read from the input port PIO-3.
The signal of 0 is read via the A / D converter. The feedwater pressure corresponds to a change in the operation speed, and stores, for example, a pipeline resistance curve F as a load operation control characteristic. Thus, the operation preparation is completed.

Under this condition, when the consumer uses water, the water supply pressure drops. When the water pressure drops below the starting pressure HON shown in FIG. 2, the CPU sends the interface I / O through the output port PIO-1. A signal for energizing the relay 52X1 is output, and a signal of the operation speed N1 is output to the inverter INV1 via the D / A converter. Thus, the inverter INV1 is started, and the electric motor 5-1 is driven. After the operation, the water supply pressure is controlled based on the signal of the pressure sensor 10 so as to be on the curve F. When the amount of water used decreases and the pump stop condition is established, the CPU deactivates the relay 52X1 and cancels the currently output speed command signal N1 to the inverter INV1. As a result, the pump 4-1 stops. When water is used again and the starting pressure becomes equal to or less than the starting pressure HON and the starting condition is established, an energizing signal of the relay 52X2 and a signal of the operating speed N2 are issued,
This time, the other inverter INV2 is driven and the motor 5
-2 is driven, and the pump 4-2 starts operating. Thereafter, similarly, the switching control is performed and the alternate operation is performed.

FIG. 3 is a characteristic diagram when two pumps are operated in parallel, and those indicated by the same reference numerals as those in FIG. 2 have the same meaning. That is, as shown in FIG. 2, two pumps are alternately operated one by one, and when the amount of water used further increases, the two pumps 4-1 and 4-2 are simultaneously operated. If the amount of water used becomes Q3 or more while operating with one pump, the operating speed N3 is the maximum speed, so that one pump has insufficient water supply capacity, and the water supply pressure drops to HL.
As a result, the CPU outputs an energizing signal to the relays 52X1 and 52X2, and outputs the speeds N1 and N2 to the respective inverters.
Is issued. In this manner, the two electric motors 5-1 and 5-1-2 are driven by the two inverters INV1 and INV2.
2 are operated at the same time, and the two pumps 4-1 and 4-2 are operated in parallel. After the parallel operation of the pumps, control based on the signal from the pressure sensor 10 is performed so that the feed water pressure is on the curve F.

In FIG. 3, when the amount of water used decreases, the operating speed changes from N4 to N3, and the supply pressure increases to HH, one of the two units stops and operates alone. As a known example of these, Japanese Patent Publication No. 5-231332 is cited.

[0015]

However, the above-mentioned prior art has the following problems. (1) In order to optimally control the two inverters according to the load, for example, to control the feedwater pressure to be on a predetermined load characteristic curve even when the usage amount fluctuates, it is necessary to use an external inverter. It is necessary to provide a control unit CU, a relay circuit unit R, and the like. Therefore, the cost of the control panel is increased, and the size and weight are increased.

(2) To apply the conventional general-purpose inverter to a turbomachine such as a water supply device configured as a multiplex system, and to alternately or parallelly operate the inverters, a microcomputer having a higher rank than each inverter It is necessary to provide a control device including the above and output a command to each inverter. This control device needs to be connected to a sensor group for detecting an operating state, an abnormal state, and a load state of the turbomachine as needed, and there is a problem that the system is complicated. Further, in order to perform the alternating operation or the parallel operation, it is necessary to interlock the inverters with each other, detect these states, and output an operation command.

(3) The inverter has a built-in trip function to protect the device from power fluctuations and overload. Therefore, when this protection function operates, the turbomachine cannot be operated. Therefore, it is necessary to check the load state of the turbomachine and the abnormal state of the inverter and perform a retry operation if necessary. For this reason, a control device that issues a command to each inverter higher than the inverter is required. Required.

(4) An indicator is provided on a control panel or the like, and a state quantity such as an operating state or an abnormal state, and a physical quantity such as a pressure or a frequency are displayed on the indicator. However, the cost of the indicator increases. Therefore, cost reduction of the apparatus is desired.

It is an object of the present invention to provide a motor control system, particularly when each of the suction pressure and the discharge pressure falls below a specified value.
It is possible to provide a water supply device capable of promptly coping with the pressure drop by displaying / outputting whether the pressure drop is on the suction pressure side or the discharge pressure side. .

[0020]

SUMMARY OF THE INVENTION The object of the present invention is to provide a plurality of electric pumps provided in parallel for drawing water from a water main and discharging the water to a demand side, and a first pressure detecting means for detecting a suction side pressure of the electric pump. Means, a second pressure detecting means for detecting a discharge side pressure of the electric pump, a plurality of inverters provided for each electric pump, for controlling the speed of each electric pump, and the detected suction side pressure, or When the discharge-side pressure falls below the respective prescribed values, the display is configured to include an indicator that displays the detected pressure drop as an abnormal state by distinguishing between the suction-side pressure drop and the discharge-side pressure drop. Is achieved in. The above object is also achieved by a plurality of electric pumps provided in parallel for sucking water from a water main and discharging the water to a demand side, first pressure detecting means for detecting a suction side pressure of the electric pump, and a discharge of the electric pump. Second pressure detecting means for detecting the side pressure, a plurality of inverters provided for each electric pump and controlling the speed of each electric pump, and the detected suction side pressure or the detected discharge side pressure being a specified value. This is achieved by providing a means for distinguishing the detected pressure drop into a suction-side pressure drop and a discharge-side pressure drop, and outputting the detected pressure drop to the outside as an abnormal signal.

[0021]

Since the indicator is provided in the water supply device, there is no need to provide the indicator on the control panel, and the cost can be reduced. Further, when the suction pressure and the discharge pressure each fall below the specified value, when the pressure drop is displayed / output as a state in which of the suction pressure and the discharge pressure is generated is determined. Since it is immediately known whether the pressure drop has occurred on the suction side or the discharge side when viewed from the pump, the cause of the pressure drop is immediately investigated and the countermeasure is taken.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an overall configuration diagram showing an example in which a turbomachine control device according to one embodiment of the present invention is applied to a water supply device, and the same reference numerals are used for the same components as those in FIG. And description thereof is omitted. In FIG. 1, a control unit CNU includes earth leakage breakers ELB1 and ELB2, inverters INV1 and INV2, and a noise filter ZCL.
0, ZCL1 and ZCL2. This is because the relay circuit unit R and the control unit (both hardware and software) CU shown in FIG.
This is due to the incorporation into V2.

That is, the inverters INV1, INV2
Is the trip signal A of the earth leakage breakers ELB1 and ELB2.
L to the terminal DI via the signal line S1 or the signal line S2.
3, DI4 and flow switch FS1 or F4
The signal FS1b or FS2b of S2 is input to the terminal FWCOM via the signal line S4 or S5, and the signals from the pressure sensors 9 and 10 are input to the terminals AN0, AN1 and L via the signal lines S6 and S7, respectively. . Since the pressure sensors 9 and 10 are used in common by the inverters INV1 and INV2, they are connected by a signal line S8.
Terminals DI1, DI2 of inverters INV1, INV2
DO1 and DO2 are connected by a signal line S3 to exchange signals such as an operation state, a failure state, and an operation request. Furthermore,
The signal lines S9 and S10 output a failure state and an operation state of the apparatus to a central monitoring panel and the like.

FIG. 5 and FIG. 6 are flowcharts for explaining the control procedure and operation procedure of a dual inverter device constructed by connecting two inverter devices according to one embodiment of the present invention. FIG. 7 shows the earth leakage breakers ELB1 and ELB.
2, trip operation, inverters INV1, INV2
4 is a timing chart for explaining the operation at the time of trip and the alternate operation operation.

FIG. 8 shows the panel surface of the inverter shown in FIG. 1 in detail. Reference numeral 13 denotes a display unit, which is composed of, for example, 7-segment LEDs or liquid crystal. Reference numeral 14 denotes a RUN / STOP, that is, a touch switch for instructing operation and stop. Reference numeral 15 denotes, for example, a touch switch for setting operation conditions, and indicates a command. 1
Reference numerals 6 and 17 denote touch keys for incrementing (+1 updating) or decrementing (-1 updating) the address when calling a command written in the memory. Reference numeral 18 denotes a data key for inputting data, for example, alphanumeric characters, and 19 denotes a key for confirming a command operation. Reference numeral 20 denotes a display unit for explaining a state indicated by the display unit 13, which is usually constituted by a nameplate.

FIG. 10 is a diagram for explaining the touch key function described above. The function of each touch key is as follows. (1) Press down the command key “C” 15. As a result, the character “C” lights up on “A” of the display unit 13. (2) Designate a memory address using the alphanumeric keys 18. As a result, the designated address is displayed on “b” and “c” of the display unit 13. (3) Press the enter key “R” 19. As a result, the set values corresponding to the above (1) and (2) are displayed on the display unit 13 as “A”.
"B" and "C" are displayed as default values. (4) The default value displayed in the above (3) can be corrected by the touch keys 15, 16, 17, 18, and 19 as necessary.

FIG. 11 is a diagram showing a setting example of the inverter state quantity set as described above. Further, how the inverter is operated is set in accordance with the pump load characteristics shown in FIGS. In addition, 2
Which of the inverters INV1 and INV2 is to be operated first is set in advance using this setting unit.

FIG. 9 shows the external output section S of the signal shown in FIG.
9 and S10, for example, the inverter I
If NV1 and INV2 trip due to some trouble,
The internal CPU outputs an “H” signal to its output port 1. As a result, the relay X1 is energized, and an ON signal indicating a failure is output to the signal terminal K0. Similarly, the signal terminal K
For example, a signal indicating a decrease in inflow pressure is output from 1,
From the signal terminal K2, for example, a signal indicating a decrease in the discharge pressure is output.

Next, the driving operation will be described in detail with reference to FIGS. Earth leakage breaker ELB1, E of FIG.
When LB2 is turned on and the power supply of the inverters INV1 and INV2 is established (see steps 501 to 503 in FIG. 5),
For example, “000” is displayed on the display unit 13. In step 504 of FIG. 5, it is determined whether or not the key switch 14 has been pressed. If NO, the process proceeds to step 505, and YES
If so, proceed to step 506. This key switch 14
Is a RUN / STOP (run / stop) command switch, which means a run command at the first time and a stop command when pressed again. In step 506, the key switch 15 is depressed to check whether or not the above-described various conditions such as operating conditions are set. As a result of confirmation, if set, 50
Go to step 8; otherwise go to step 505. In steps 505 to 507, various settings described above are performed.

In this example, with the first machine as the priority machine, the priority operation flag PR10F is set to OFH (in this case, H
Means hexadecimal. ) And set Unit 2 to 00H
Is set to (artificial setting). Thereafter, the process proceeds to step 508, and the interrupt processing routine shown in FIG. 6 is permitted.

In the interrupt processing INT0 shown in FIG. 6A, as shown in steps 601 to 604, the internal state is checked, and the earth leakage breakers LB1 and ELB2 are tripped or the inverters INV1 and INV2 are tripped. If so, the operable flag is reset in step 607. If these are not trip states and are normal, the operable flag is set at step 609, and if they are trip states, the operation is stopped at step 608 and processing corresponding to this is executed. Further, in steps 603 to 605, it is determined whether or not there is a parallel operation request, and if there is a parallel operation request, the priority operation flag PR10F is set to 01F.
Otherwise, 01H is masked.

In the interrupt processing INT1 shown in FIG.
Inverter internal state quantity (refer to step 612: measurement of voltage, power supply, pressure, and frequency and display on the display unit according to the command. Detailed display contents are shown in FIG. 8) and check of input / output ports (Refer to step 613:
It monitors the input / output terminals DI1 to D04 and stores the data in the memory) and checks the signals of the sensors (see step 614: monitor AN0, AN1, L, etc. and stores the data in the memory).

Returning to FIG. 5, in step 509, it is determined which inverter or pump is set as the starting machine. For example, the inverter INV1 is a priority unit (priority operation flag PR10F is set to 0FFH) at the time of initial power-on, and the inverter INV2 is a non-priority unit (priority operation flag PR10F is set to 00H). (0FFH has priority, 01H is parallel operation request, 00H follows). As a result of this determination, the process proceeds to the next step 510, with the inverter INV1 as the starter (because the priority operation flag PR10F in FIG. 5 is 0FFH, which will be described in detail later). Since the flag state of the inverter INV2 is 00H, 0FFH
Wait in 509 steps until

If the pressure signal detected by the pressure sensor 10 in step 510 is equal to or lower than the starting pressure H0N shown in FIGS. 2 and 3, the inverter INV1 proceeds to step 511.
Here, the inverter INV1 and the pump 4-1 are started. Hereinafter, under the load conditions set for the inverter in step 505, the operation according to the load fluctuation is continued (51).
2,513 steps).

When the amount of used water decreases from such a state, the low water amount detection means (such as the load current detection means provided inside the inverter, the flow switch FS1, the flow switch FS2, etc.) operates. Therefore, in the next step 514, it is determined whether or not the low water amount detecting means detects the low water amount, that is, if it is a flow switch,
It is determined whether or not this is in the OFF state. In this determination, when the pump is in the OFF state, in other words, the amount of water is small and the pump stop condition is established (in consideration of the suppression of the start frequency,
It is determined whether the stop condition is established over a period of several minutes. ), Stop processing is executed in the next 515 step. Thereafter, the process returns to step 509, and the subsequent processes are repeated.

By the way, as shown in FIG. 3, when the amount of water used is increased to Q3 or more, it is no longer possible to operate one pump to meet the demand. In this state, a two-unit parallel operation request signal is generated. That is, 60 in FIG.
Priority operation flag PR10F is set to 01 in 3,605 steps
Set to H. Note that the parallel operation request condition is, for example, in FIG. 3 when the inverter operation speed is suitable for the maximum speed N3 and the feedwater pressure has reached HL or less. Means that the inverter operation speed has reached the minimum speed N4 and the feedwater pressure has reached HH or higher. In this case, 01H of the priority operation flag PR10F is masked.

As described above, when the parallel operation request condition is satisfied, the priority operation flag PR10F is 01H as a result of the determination in step 510, and the inverter INV2 and the pump 4
-2 is started and parallel operation is performed. After the parallel operation, both inverters INV1, INV2, pumps 4-1 and 4-
2, and the electric motors 5-1 and 5-2 correspond to the above-described 512 to 5
When the stop condition is established in each of the 13 steps, the operation is stopped.

Next, with reference to a time chart shown in FIG. 7, the alternate operation and the operation at the time of abnormality will be described. FIG.
At time 1, one operation request signal is output and the operation priority is given to the first unit. Therefore, the inverters INV1 and No. 1 pump 4-1 are operated, and D01 of the signal S3 is transmitted to the inverter INV2. To declare that the inverter INV1 is operating. Inverter INV2 receives this signal at terminal DI1, and outputs an answerback signal (inverter INV2, No. 2 pump 4-2 is not in an operable state) from terminal D01 to inverter INV1. The inverter INV1 outputs this signal to the terminal D
Receive at I1.

There is no operation request signal between times 2 and 3, and the inverter and the pump are stopped. At this time, the operation priority flag PR10F of the inverter INV1 is set to 00H, the operation state signal D01 is set to L, and the inverter INV2
Is set to 0FFH, and the operation state signal D01 is set to L.

Next, when an operation request signal is input at time 3, the inverter I whose operation priority flag PR10F is 0FFH is set.
The NV2, No. 2 pump 4-2 is operated, and it is output to the inverter INV1 that D01 is set to H to indicate that it is operating. In this way, signals are exchanged between the inverter INV1 and the inverter INV2, and alternate operation is performed.

Next, between times 5 and 6, the inverter INV
Consider a case where the inverter or the earth leakage breaker trips while the No. 1 and No. 1 pump 4-1 is operating. Upon tripping, the inverter INV1 is immediately stopped, the operation state signal D01 is set to L, and the failure state signal D02 is set to H.
And a signal for setting the operation priority signal PR10F to 00H is issued. At the same time, the failure determination timers RESC1 and t0 seconds for the inverter INV1 are activated, and the failure forced stop timers REST1 and t1 seconds are activated. In response to these signals, the inverter INV2 operates the operation priority signal PR1.
The operation is started with 0F set to 0FFH and the operation state signal set to D01 at H.

At time 6, the operation request signal disappears, the inverter INV2 stops, and the operation state signal D01 is set to L. At time 7, the operation request signal is issued again.
Since T1 and t1 seconds are counting and the failure state signal D02 of the inverter INV1 is in the H state, the inverter INV1
2 is driven.

Between time 7 and time 8, the inverter IN
The failure forced stop timer REST1, t1 seconds of V1 ends counting, and the failure state signal D02 changes from H to L. At time 8, the inverter INV2 is stopped, and the operation priority flag PR
10F is set to 00H, and the inverter INV1 sets this signal to 0FFH. At the time of the operation request at time 9, the inverter INV1 is operated. Thereafter, the inverter INV
If 1 breaks down, it emits the signal described above and stops, and again
The forced stop timer REST1 is started, time measurement for t1 seconds is started, and the operation is switched to the operation of the inverter INV2. Less than,
The above operation is repeated until time 11.

At time 11, an operation request is issued, and inverter I
When the NV1 operates and trips after the operation, the forced stop time t1 ends at time 12, and three cycles of the failure of the inverter INV1 occur during t0 seconds of the failure determination timer RESC1.
NV1 is regarded as a failure and the operation is disabled, the operation state signal D01 is set to L, the failure state signal D02 is set to H, and the operation priority flag PR10F is set to 00H. At the same time, E01 is displayed on the display section of FIG. 8, an H signal is output to the output port 1 of the CPU shown in FIG. 9, the relay X1 is activated, and K0 is output to the outside.
Signal. After this, the operation of only Unit 2 is performed.

It should be noted that if the operation / failure of the inverter is retried three times within t0 seconds of the failure determination timer RESC1, it is regarded as a failure, and as shown by the broken line at time 11 in FIG.
If it returns to normal, that is, if it returns to normal after less than three retries, it is possible to continue the operation without causing a failure.
The failure referred to here is the earth leakage breakers ELB1, ELB2
7 and the trips of the inverters INV1 and INV2. FIG. 7 shows an example of the inverter trip.

The following is a description of the trip of the earth leakage breakers ELB1 and ELB2. That is, 1
When the signal leakage breaker ELB1 trips, its main power is turned off and an alarm signal S1 is input. Inverter INV
1 is supplied to the terminals R1 and R2 via the circuit protector CP1. Alarm signal S
1 based on the operation state signal D01 and the failure state signal D0
2 is set to H, and the operation priority flag PR10F is set to 00H. Further, the operation during the pump parallel operation will be described as follows. In FIG. 7, at time 13, the inverter IN
When V1 is operating and a two-vehicle operation request signal is output at time 14, the operation priority flag PR10 of the inverter INV2 is output.
Let F be 01H. Then, the processing after step 509 in FIG. 5 is executed, the inverter INV2 is operated, and a signal in which the operation state signal D01 is set to H is issued.

Next, referring to FIG. 1 and FIG. 9, another countermeasure at the time of failure will be described. When the pressure of the water distribution pipe 1 becomes lower than a specified value (usually 1 to 3.5 kgf / cm ² , the pipe is ruptured or the construction is cut off, for example, reduced to 0.5 kgf / cm ² or less), the pump suction side Is detected by the pressure sensor 9 installed in the device. At this time, the inverters INV1 and INV2 detect this state by the signals S6 and S8, and the inverters INV1 and INV2 detect the state.
2 is stopped, and when the pressure of the water distribution pipe 1 returns to a specified value or more, both inverters can be operated.

In the same manner, when the pressure on the pump discharge side becomes equal to or less than a specified value (for example, 50% or less of the pressure desired by the water supply system due to the biting of the pump air), the pressure sensor 10 detects this. (The operation is disabled), the signal S
At steps S7 and S8, the inverters INV1 and INV2 are stopped, and when they return to the specified value or more, both inverters can be operated. Then, when this abnormal state, that is, when the suction side pressure is reduced, E02 is displayed on the display unit, an H signal is issued from the output port 2 of FIG. 9, the relay X2 is energized, and the K1 signal is output to the outside. Output. When the discharge side pressure decreases, E03 is displayed on the display unit, an H signal is issued to the output port in FIG. 9, and the relay X3 is energized to output the signal K2 to the outside.

The dual inverter according to the embodiment of the present invention described above is briefly described as follows. In other words, the externally mounted inverter is equipped with a high-level advanced control device and a relay circuit that are conventionally used in the inverter (almost all are replaced with microcomputer software in the inverter), and the same inverter is composed of two units. Then, the inverter has a dual configuration. Each inverter has a CPU and a storage unit inside, and a display unit and a setting unit are provided on a panel surface thereof. Further, the two inverters are connected by a signal line for transmitting an operation state and a failure state, and are configured to exchange signals with each other. Further, in these inverters, how to operate the inverter or the operation pattern of the load is set in advance by a setting unit, and a priority machine is set which is operated first. In this way, alternate and parallel operation, retry at abnormal time, and backup operation can be performed.

The operating state (particularly, pressure, current, frequency, voltage, etc.) and the failure state are displayed on the display of the inverter. The failure content is displayed as an error code. Further, a pressure sensor for detecting a suction side pressure state and a load state can be shared by two inverters.

The earth leakage circuit breaker protects the main circuit from short-circuit and the secondary side from earth leakage, shuts off the main circuit, and connects its signal line to the inverter. The inverter drives the turbomachine and is constituted by a complete duplex system, and directly takes in signal lines of a pressure sensor for detecting a load state, an underload state detection means, and a suction side pressure sensor. Each inverter is provided with microcomputer software describing a control method and a procedure in advance. At the beginning of use, when the earth leakage breaker is turned on, the power of both inverters is established, and the one set in advance as the priority machine starts operation.

When the pressure sensor for detecting the load state detects the preset starting pressure, the inverter on standby is started. A sensor that detects an underload condition detects this, and when a preset stop condition is established, the inverter is stopped, and the stopped inverter is made operable by the stop signal of the preceding machine, and started as described above. , Stop. Further, when the pressure sensor for detecting the load state detects the preset parallel operation pressure state,
The inactive inverters are set in an operable state and are operated in parallel.

Further, when the earth leakage breaker trips and the inverter trips, this state is transmitted to each other by a signal line connecting the two inverters, the abnormal side is stopped and switched to the other side, an internal signal is generated, and a retry is performed. . Furthermore,
This status is indicated by an error code on the display panel of the inverter, and a signal is issued to the outside. In addition, the display unit is used to display values of pressure, current, voltage, and frequency.

Thus, according to the embodiment of the present invention, 2
Since the control circuit, operation procedure, and control contents are stored in one inverter, alternate operation or alternate / parallel operation can be performed without the need for an external relay circuit unit and a high-level advanced control device. There is an effect that the control device is simplified, small and lightweight, and cost reduction can be realized. Furthermore, reliability is improved because the number of parts is reduced.

In addition, the short circuit and leakage of the main circuit are monitored by the leakage breaker, and the other failure states on the load side are monitored by the inverter itself due to the change of the internal state quantity of the inverter. Switching operation is possible. Further, since the priority unit can be set externally by the inverter in advance, the operation order is not disturbed (for example, at the time of power recovery). Furthermore, since the retry operation at the time of failure is added, there is an effect that the failure state can be reliably detected.

Furthermore, since the operating state and the failure state are displayed using the display unit of the inverter, it is possible to realize simple and low cost. Furthermore, since the pressure sensor for detecting the load state and the pressure sensor for detecting the suction side pressure can be shared by the two inverters, it is simple and inexpensive. Furthermore, since a failure backup is taken by a complete multiplex system (duplex system in the embodiment),
There is an effect that the reliability can be further improved.

[0057]

As described above, according to the present invention, in particular, when each of the suction pressure and the discharge pressure drops below a specified value, the pressure drop is reduced to either the suction side or the discharge side. Is displayed / output as a state in which it is determined whether or not the pressure drop has occurred, so that the pressure drop can be promptly dealt with.

[Brief description of the drawings]

FIG. 1 is a configuration diagram in which a turbomachine control device according to one embodiment of the present invention is applied as a water supply device.

FIG. 2 is an operation characteristic diagram when the pump is operated independently or alternately.

FIG. 3 is an operation characteristic diagram when two pumps are operated in parallel.

FIG. 4 is an overall configuration diagram of a conventional water supply system.

FIG. 5 is a flowchart showing an operation procedure of the turbomachine control device shown in FIG. 1;

FIG. 6 is a flowchart showing a control method of the turbomachine control device shown in FIG.

FIG. 7 is a timing chart showing a control operation of the dual inverter.

FIG. 8 is a detailed diagram of a display unit and a setting unit of the inverter.

FIG. 9 is an external output circuit diagram of a fault state of the inverter.

FIG. 10 is an explanatory diagram of functions of an inverter display unit and a setting unit.

FIG. 11 is a diagram showing a setting example of an inverter internal state quantity.

[Explanation of symbols]

4-1, 4-2 each pump being a turbomachine, 5
-1, 5-2: motor, FS1, FS2: underload detection means, ELB1, ELB2: earth leakage breaker, INV1,
INV2: Inverter.

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Takayuki Oshiga 7-1-1, Higashi Narashino, Narashino-shi, Chiba Industrial Machinery Division, Hitachi, Ltd. (72) Inventor Hiroshi Kunii 7-1-1 Higashi-Narashino, Narashino-shi, Chiba No. 1 Hitachi, Ltd.Industrial Equipment Division (72) Inventor Tsunehiro Endo 7-1-1 Higashi Narashino, Narashino City, Chiba Prefecture Hitachi, Ltd.Industrial Equipment Division (72) Inventor Satoshi Honma Narashino, Chiba Prefecture 7-1-1, Narashino, Higashi-shi Hitachi, Ltd. Industrial Equipment Division (56) References JP-A-5-240186 (JP, A) JP-A-4-72470 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) F04D 15/00 H02M 7/48 H02P 7/74

Claims (2)

(57) [Claims] 1. A plurality of electric pumps provided in parallel for drawing water from a water main and discharging the water to a demand side, first pressure detecting means for detecting a suction side pressure of the electric pump, and discharging of the electric pump. a second pressure detecting means for detecting a side pressure, and a plurality of inverters for speed control of the electric pump is provided for each electric pump, said detected suction side pressure or the discharging side pressure force each of the specified value, When the pressure drops below, suction the detected pressure drop
Water for use in liquid feed device, characterized in that it comprises a display device for displaying an abnormal state is respectively divided into a discharge side pressure drop and the side pressure drop. 2. A plurality of electric pumps provided in parallel for drawing water from a water main and discharging the water to a demand side, first pressure detecting means for detecting a suction side pressure of the electric pump, and discharging of the electric pump. a second pressure detecting means for detecting a side pressure, and a plurality of inverters for speed control of the electric pump is provided for each electric pump, said detected suction side pressure or the discharging side pressure force each of the specified value, When the pressure drops below, suction the detected pressure drop
Means for separately outputting a side pressure drop and a discharge side pressure drop as an abnormal signal to the outside.