JP3763704B2 - controller - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a controller, and more particularly to a controller utilizing a frequency converter (inverter) that can save energy by adjusting the number of rotations of a motor that drives devices such as fluid machines.
[0002]
[Prior art]
There is known a technique for saving energy by inserting a frequency converter into a power line connecting an existing motor that drives devices such as a fluid machine and an existing control panel, and adjusting the rotational speed of the motor. This technique is an extremely effective energy saving means not only for applications involving severe load fluctuations such as a water supply apparatus but also for various fluid machines such as a circulation pump and a blower.
[0003]
This type of frequency converter takes into account that the winding temperature rise value of the motor becomes higher than that at the time of driving the commercial power supply due to voltage drop due to inverter driving, etc. The setting is low. Therefore, when it is desired to drive the motor at a commercial power supply frequency for some reason, it is necessary to disconnect the frequency converter from the power line and literally drive the motor directly from the commercial power supply.
Also, if a failure occurs in the frequency converter, it is necessary to change the power line and switch to the commercial power source in the same manner.
[0004]
In order to make it easy to switch the power line from the frequency converter to the commercial power supply, for example, a relay panel (relay box) for switching the commercial power supply (for backup) is provided between the power panel and the frequency converter. Can be applied.
[0005]
[Problems to be solved by the invention]
However, in existing equipment, it is not only difficult to secure the installation space for installing the relay panel, but in order to operate the automatic backup circuit based on this failure signal when the frequency converter breaks down, It is necessary to provide a control circuit in the relay panel and to connect the relay panel and the frequency converter with a signal line.
[0006]
In view of the above problems, the present invention provides a controller with a built-in backup circuit that can easily switch between inverter operation and commercial power supply operation and can easily function commercial power backup when the frequency converter fails. The issue is to provide.
[0007]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention is a controller that is used by being electrically connected between a power panel and a motor that drives equipment such as a fluid machine. A frequency converter that automatically starts output, a case with a substantially sealed structure that houses the frequency converter, input means for supplying power to the frequency converter from the outside of the case, and the frequency converter to the outside of the case Output means for supplying power , heat radiation means fixed to the case, with the open surface closely attached to the pipe to dissipate heat generated by the frequency converter to the fluid in the pipe, and when the frequency converter generates a failure signal Is provided with a commercial power backup circuit that electrically disconnects the input means and the output means from the frequency converter, and directly electrically connects the input means and the output means within the case.
That is, the present invention has a function for automatically switching from inverter drive to commercial power supply in response to a failure signal of a frequency converter (inverter) by incorporating a circuit for commercial power backup operation inside the controller case. is there.
[0008]
Further, the controller as a whole has a substantially sealed structure, and has a water-cooling structure in which the controller is attached to the pump pipe for cooling. In general, inverters are not water-cooled, but are often equipped with an air-cooling fan.However, water-cooling eliminates the need for an air-cooling fan, so it is possible to provide a backup circuit in this space. Effective use is possible.
[0009]
Further, the controller includes a frequency adjustment knob that switches the output frequency in stages, and one of the frequency setting values of the frequency adjustment knob is the same as the commercial power supply frequency. The backup circuit is activated. As a result, switching from inverter driving to commercial power source driving and commercial power source backup operation when the frequency converter fails are possible. Therefore, it is possible to achieve energy saving simply and with high reliability simply by interrupting the power line connecting the existing motor and the existing control panel (power panel).
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of a controller according to the present invention will be described with reference to the drawings.
FIG. 1 is a side view showing an example of installation when using a controller according to the present invention. In FIG. 1, reference numeral 10 denotes a pump unit, and the pump unit 10 has a configuration in which a pump 12 and a motor 13 are provided on a common base 11. The fluid guided from the suction pipe 14 passes through the suction side gate valve 15 and the short pipe 16, and is sucked into the pump 12 from the pump suction port 12a and pressurized, and then discharged from the pump discharge port 12b. The discharged fluid further passes through the check valve 17 and the discharge side gate valve 18 and is guided to the discharge pipe 19.
[0011]
The embodiment shown in FIG. 1 shows an example in which energy is saved by adjusting the number of rotations of the motor 13 of the pump unit 10, and the controller 20 is a heat radiating means made of an aluminum alloy having good thermal conductivity. It is attached to the short pipe 16 through 21.
[0012]
A power cable 28 from the control panel (power panel) 22 is connected to an input side cable 24 which is an input means of the controller 20 by a cable connection box 23. An output side cable 25 that is an output means of the controller 20 is connected to a motor 13 that drives the pump 12. A frequency converter is accommodated in the controller 20, and the frequency of the electric power supplied from the power panel is converted. The frequency converter generates heat during the frequency conversion, but the generated heat is effectively radiated to the pump handling liquid flowing in the short pipe 16 through the heat radiating means 21 and the short pipe 16.
[0013]
2 is a diagram showing details of the apparatus shown in FIG. 1, and FIG. 3 is a sectional view taken along line III-III in FIG. The controller 20 includes a frequency converter body (power module) 30, a backup circuit 31, and a control circuit 32 housed in a case 35 including an upper case 33 and a lower case 34. The upper case 33 and the lower case 34 are made of an aluminum alloy that is excellent in heat dissipation and shields radiation noise, and both are fixed by a bolt (not shown) with a seal member 36 such as a gasket between them, Airtight.
[0014]
To the lower case 34 of the controller 20, a bracket constituting the heat radiating means 21 is closely attached and fixed via a bolt 37. The controller 20 is detachably attached to the short tube 16 by the attachment band 38 with the open surface 21a of the heat radiating means 21 being in close contact with the short tube 16. As a result, since the heat generated by the frequency converter is suitably radiated to the pump handling liquid, an air cooling fan or the like used for a general general-purpose inverter is not necessary. Moreover, there is no worry of poor cooling due to fan failure. In this embodiment, the controller 20 is provided with an external input option cable 39.
[0015]
On the upper part of the upper case 33, a cap 41 is provided to cover the operation substrate 40 and secure the inside and outside airtightness. FIG. 4 is a plan view of the operation board 40. The operation board 40 is provided with a frequency adjustment knob 42 for switching the output frequency in stages. In this embodiment, the frequency adjustment knob 42 is an eight-stage type. When set to 8, the motor 13 is driven by a commercial power source. Below 7, the motor is driven via a frequency converter. Knob No. Is switched to 7, 6, 5, 4, 3, 2, and 1, the output frequency decreases step by step.
[0016]
FIG. 5 shows an internal circuit diagram of the case 35. This circuit includes an input terminal 50 as input means connected to the input side cable 24, an output terminal 51 as output means connected to the output side cable 25, a frequency converter body 30, and a backup circuit 31. And a control circuit 32.
[0017]
The backup circuit 31 opens and closes a first switch 56 that opens and closes an input line 55 that connects the input terminal 50 and the frequency converter body 30, and an output line 57 that connects the frequency converter body 30 and the output terminal 51. The second switch 58 is provided. The backup circuit 31 has a bypass 59 that bypasses the frequency converter body 30 and connects the input line 55 and the output line 57, and a third switch 60 that opens and closes the bypass 59. These switches 56, 58, and 60 may be mechanical contactors or those using semiconductor devices.
[0018]
On the other hand, the control circuit 32 inputs an operation signal from the frequency adjustment knob 42 and a failure signal from the frequency converter body 30, and outputs an operation command to the frequency converter body 30 based on these signals. An opening / closing command is output to each of the switches 56, 58, 60.
[0019]
Next, the operation of the controller configured as described above will be described.
First, in the initial state or after resetting, the first and second switches 56 and 58 are in a closed state, and the third switch 60 is in an open state. In this state, based on the operation signal from the frequency adjustment knob 42, an operation command is output from the control circuit 32 to the frequency converter main body 30, and the power is supplied to the frequency converter main body 30 to convert the frequency. Is supplied to the motor 13. In this case, the frequency converter main body 30 is a device in which an inrush current prevention circuit is devised so that output can be automatically started when power is supplied. Therefore, at the same time as power is supplied to the input means of the controller 20, power of a predetermined frequency is output from the output means.
[0020]
Here, the frequency converter body 30 breaks down for some reason, and a failure signal is output from the frequency converter body 30, this signal is input to the control circuit 32, and switching to the backup circuit 31 is performed. In this case, the control circuit 32 first outputs an open command to the first switch 56, the first switch 56 is opened, and the supply of power to the frequency converter main body 30 is cut off. Subsequently, the control circuit 32 outputs an opening command to the second switch 58, and the second switch 58 is opened to electrically disconnect the motor and the frequency converter. The control circuit 32 finally outputs a close command to the third switch 60. When the third switch 60 is closed, the motor is driven by a commercial power source.
When the input power is turned off once the backup circuit 31 is operating, the switches 56, 58 and 60 return to the initial state.
[0021]
On the other hand, the frequency adjustment knob 42 is an eight-stage type. When set to 8, it is driven by a commercial power source. 7 or less, the motor 13 is driven via the frequency converter. And the knob No. Is switched to 7, 6, 5, 4, 3, 2, 1, the output frequency decreases each time.
[0022]
FIG. 6 is a diagram showing a controller circuit diagram according to another embodiment of the present invention. In the present embodiment, a reduced voltage start circuit 70 such as a soft starter using a reactor start circuit or a silicon rectifier is provided in the backup circuit 31, and is applied to a high output motor.
[0023]
That is, a high output motor often requires a starter such as a star delta start or a reactor start. This is because when a general direct-injection start is performed, a start current of 500 to 700% of the rated value flows, so that when the power supply capacity is small, the voltage drop becomes remarkably large and the motor cannot be started. On the other hand, when the motor is driven via the frequency converter, a function called soft start (slowly increasing the frequency over time) is generally provided, so that a large starting current does not flow.
[0024]
Therefore, in the case of commercial power supply driving, it is necessary to connect the starting device and to disconnect the starting device when driving through the frequency converter. Therefore, this requirement can be met by providing the reduced voltage starting circuit 70 in the backup circuit 31.
[0025]
By configuring the controller of the present invention as shown in FIGS. 1 to 6, energy saving can be achieved simply and with high reliability.
[0026]
【The invention's effect】
As described above, according to the present invention, switching from inverter driving to commercial power source driving and commercial power source backup operation when the frequency converter fails are possible. Therefore, it is possible to achieve energy saving simply and with high reliability simply by interrupting the power line connecting the existing motor and the existing control panel (power panel).
[Brief description of the drawings]
FIG. 1 is a side view showing an example of installation when using a controller according to the present invention.
FIG. 2 is an enlarged view showing details of the controller shown in FIG. 1;
3 is a cross-sectional view taken along line III-III in FIG.
FIG. 4 is a plan view showing an operation board.
FIG. 5 is a circuit diagram of the controller shown in FIG. 1;
FIG. 6 is a diagram showing a circuit diagram of a controller according to another embodiment of the present invention.
[Explanation of symbols]
10 pump unit 11 base 12 pump 13 motor 14 suction pipe 15 suction side gate valve 16 short pipe 17 check valve 18 discharge side gate valve 19 discharge pipe 20 controller 21 heat radiation means 22 control panel (power panel)
23 Cable connection box 24 Input side cable 25 Output side cable 30 Frequency converter body 31 Backup circuit 32 Control circuit 33 Upper case 34 Lower case 35 Case 36 Seal member 37 Bolt 38 Mounting band 40 Operation board 41 Cap 42 Frequency adjustment knob 50 Input Terminal 51 Output terminal 55 Input line 56, 58, 60 Switch 57 Output line 59 Detour line 70 Reduced voltage starting circuit

Claims (2)

In a controller used by being electrically connected between a power panel and a motor that drives equipment such as a fluid machine,
A frequency converter that automatically starts output in conjunction with the supply of power from the power panel;
A substantially hermetically sealed case that houses the frequency converter;
Input means for supplying power to the frequency converter from outside the case;
Output means for supplying power from the frequency converter to the outside of the case;
A heat dissipating means fixed to the case, and having an open surface in close contact with the pipe to dissipate heat generated by the frequency converter to the fluid in the pipe;
Provided with a commercial power backup circuit that electrically disconnects the input means and output means from the frequency converter when the frequency converter generates a failure signal, and directly and electrically connects the input means and output means within the case. A controller characterized by that.   A stepwise frequency adjustment knob for switching the frequency of the electric power supplied to the motor is provided outside the case, and one of the frequency setting values is the same as the commercial power frequency, and when the commercial power frequency is selected, 2. The controller according to claim 1, wherein the frequency converter is electrically disconnected, and the input means and the output means are directly electrically connected within the case.

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