JPS5916110B2 - Control device for pole switching compressor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a compressor driven by a pole number switching motor, in which when the number of poles of the motor is switched, the switching is reliably controlled by stopping the motor and then restarting it. It is an object of the present invention to provide a control device that prevents the number of poles of a motor from continuously switching when a number switching control section fails.

Conventionally, in a control device for a compressor driven by a pole number switching motor, in order to prevent reverse braking torque that occurs when the motor is switched from a few pole operation to a multi pole operation, a control device for a compressor driven by a pole number switching motor is used. To facilitate switching to polar operation,
A delay timer that temporarily stops the motor and then restarts the motor after a certain delay is used for switching from low-pole operation to multi-pole operation, and 1 delay timer for switching from multi-pole operation to low-pole operation.
However, if the delay timer malfunctioned, the motor would not stop and the number of poles would change continuously, and in particular, the number of poles would change continuously from low-pole operation to multi-pole operation. In such a case, as described above (reverse braking torque will be generated in the electric motor and a large force will be applied to the shaft connected to the compressor, causing damage).

Conversely, if multi-pole operation is continuously switched from multi-pole operation to low-pole operation, the starting torque of the motor during low-pole operation is low, and the differential pressure between the discharge side and suction side of the compressor is large, and the load torque exceeds the motor starting torque. This had drawbacks such as causing failure in starting the upper rotation and causing burnout of the motor.

Therefore, the present invention solves the various problems mentioned above by adopting the following configuration.

That is, a compressor driven by a pole switching electric motor;
A multi-pole switch and a small-pole switch that respectively connect the multi-pole terminal and the small-pole terminal of the pole number switching motor to a power source, a pole number switching switch, and a pole number switching switch that respond to the pole number switching switch. ,
an auxiliary switch that operates after a certain delay, a pair of normally open contacts and a normally closed contact of the pole number switching switch, and a pair of contacts of a normally closed contact and a normally open contact of the auxiliary switch; Connect the series circuits in parallel to a power source, and connect the coil 1 of the multi-pole switch and the coil of the small-pole switch to each series circuit, respectively.
A series circuit of a normally closed contact of the pole number switching switch and a normally open contact of the auxiliary switch, and a series circuit of a normally open contact of the pole number switching switch and a normally closed contact of the auxiliary switch are connected to a power source in parallel. It is something.

An embodiment of the present invention that eliminates the above-mentioned conventional drawbacks will be described below with reference to the drawings.

In the figure, 1 is a pole number switching motor that drives a compressor (not shown), and it is a three-phase motor.The windings of each phase are connected in series to form a 4-pole motor, and 2 are connected in parallel to form a 4-pole motor. It becomes a pole electric motor.

The electric motor 1 has multi-pole terminals 1a, 1b, and 1c connected to the power supply P by the contacts 3 of the 4-pole switch 2, and operates with 4 poles.
The contact 5 of the pole switch 4 connects the small pole terminal 1d.

1e and 1f are connected to power supply P to perform two-pole operation.

Reference numeral 6 denotes a control power source, and power supply is controlled by a power switch 7.

On the other hand, the power switch 7 is a normally open contact 9 of the pole number switching switch 8.
．． Normally closed contact 10. normally open contact 12 of delay switch 11;
It is connected to a pole number changeover switch 14 that controls energization of the coil 13 that drives the pole number changeover switch 8 .

The normally open contact 9 of the pole number switching switch 8 is connected to the auxiliary switch 1 via a coil 15 that operates the contact 3 of the 4-pole switch 2.
6, and the normally closed contact 10 is connected to the normally open contact 19 of the auxiliary switch 16 via a coil 18 that operates the contact 5 of the two-pole switch 4. In addition, the normally closed contact 10 is connected to a heater 20 that heats the normally open contact 12 of the delay switch 11 made of bimetal.

Further, the contact 12 is connected in series to a coil 21 that operates the contacts 17 and 19 of the auxiliary switch 16 to control the auxiliary switch 16.

Next, the operation of the above configuration will be described.

1) At 2-pole startup If the power switch 7 is turned on and the pole number changeover switch 14 is opened, the control power supply 6 is connected to the delay switch 11 via the power switch 7 and the normally closed contact 10 of the pole number changeover switch 8. Heater 20
is energized to heat the contact 12, and after a certain delay, the contact 12
is closed, the coil 21 of the auxiliary switch 16 is energized, the normally open contact 19 is closed, the coil 1B of the two-pole switch 4 is energized, the contact 5 is closed, and the motor 1 is operated with two poles.

2) When switching from 2-pole operation to 4-pole operation When the motor 1 is in 2-pole operation, if the pole number changeover switch 14 is turned on, the coil 13 of the pole number changeover switch 8 is energized, and the normally closed contact 10 is opened and normally closed. Open contact 9 is closed.

Since the normally closed contact 10 is opened, the energization to the coil 18 of the two-pole switch 4 is stopped, and the contact 5 is opened, so that the motor 1
Power to the equipment shall be stopped.

On the other hand, the power supply to the heater 20 of the delay switch 11 is stopped, but the contact 12 has been heated by the heater 20 until then, so it remains a contact.

12 remains closed and the coil 21 of the auxiliary switch 16 continues to be energized, the normally closed contact 17 remains open, and the 4-pole switching is performed via the normally open contact 9 of the pole number switching switch 8. The current supply to the coil 15 of the device 2 remains stopped.

After a certain delay after the operation of the pole number switching switch 8, the normally open contact 12 of the delay switch 11 is cooled and opened, the energization to the coil 21 of the auxiliary switch 16 is stopped, and the normally closed contact 17 is closed. The coil 15 of the 4-pole switch 2 is energized and the contact 3
is closed and the motor 1 restarts as a four-pole motor.

After the above-mentioned certain delay has elapsed, the pressures on the discharge side and the suction side of the compressor driven by the electric motor 1 become almost the same, and the starting load torque becomes low and restarting becomes easy.

Further, the reverse braking torque that occurs when switching continuously from two-pole operation to four-pole operation to temporarily stop the compressor is not generated.

As described above, the two-pole operation is switched to the four-pole operation.

3) At the time of switching from 4-pole operation to 2-pole operation, the pole number changeover switch 14 is opened while the motor 1 is in 4-pole operation.

The energization to the coil 13 of the pole number switching switch 8 is stopped, the normally open contact 9 is opened, the energization to the coil 15 of the 4-pole switch 2 is stopped, the contact 3 is opened, and the motor 1 is stopped.

On the other hand, the normally closed contact 10 is closed, but since the normally open contact 19 of the auxiliary switch 16 is open, the two-pole switch 4 does not operate.

The heater 20 of the delay switch 11 is energized from the normally closed contact 10, and after the pole number switching switch 8 is operated, the normally open contact 12 is closed after a certain delay.

As a result, the coil 21 of the auxiliary switch 16 is energized, the normally open contact 19 is closed, the coil 18 of the two-pole switch 4 is energized, the contact 5 is closed, and the motor 1 becomes a two-pole motor and restarts. to start.

At this time of restart, the pressure on the discharge side and the suction side of the compressor are almost equal as described above, so the restart is easy.

4) If the power switch 7 is opened at the time of stop, the energization to the coil 18 of the 2-pole switch 4 or the coil 15 of the 4-pole switch 2 is stopped, so the energization from the power source P to the motor 1 is stopped. death,
Electric motor 1 stops.

5) At 4-pole startup Turn on the power switch 1 and the number of poles changeover switch 14.

The coil 13 of the pole number changeover switch 8 is energized via the power switch 7 and the pole number changeover switch 14, and the normally open contact 9 is closed.

On the other hand, since the coil 21 of the auxiliary switch 16 is not energized, the normally closed contact 17 remains closed, and as a result, the coil 15 of the 4-pole switch 2 is energized and the motor 1 starts as a 4-pole motor.

The above describes startup, switching of the number of poles, and stopping when each control part of the control device operates normally, but the control device of the present invention also allows switching of the number of poles even if a part of each control part breaks down. It does not switch continuously.

That is, if the pole number changeover switch 14 or the pole number changeover switch 8 fails, the normally open contact 9 or the normally closed contact 10 of the pole number changeover switch 8 remains closed; If it remains closed, the normally closed contact 10 is opened and only the 4-pole switch 2 is operated, so that only 4-pole operation is performed.

Conversely, if the normally closed contact 10 remains closed, the normally open contact 9 will be open and only two-pole operation will be performed.

In addition, if the delay switch 11 or the auxiliary switch 16 fails, the normally closed contact 17 or normally open contact 19 of the auxiliary switch 16 remains closed, and as above, only 4-pole operation or 2-pole operation is possible. The number of poles is not continuously switched, just by pole operation or by just stopping without energizing the motor 1.

This means that the normally open contact 9 and the normally closed contact 10 of the pole number switching switch 8 are switching contacts, and the normally closed contact 1 of the auxiliary switch 16 is
This effect is even greater if 7 and the normally open contact 19 are switching contacts.

Further, although the auxiliary switch 16 is operated by the delay switch 11, it goes without saying that the delay switch 11 may be the auxiliary switch 16.

6) When the power is turned on after a power outage ■ During two-pole operation If there is a power outage during two-pole operation, there are two situations.

One of them is that if the power outage time is short and the control power supply 6 is reenergized while the normally open contact 12 of the delay switch 11 remains closed, the coil of the auxiliary switch 16 is connected via the normally open contact 12. 21 is reenergized, the normally open contact 19 is closed again, and the two-pole switch 4 is activated to restart the two-pole switch.

On the other hand, the power outage time is long (normally open contact 1 of delay switch 11
When the control power supply 6 is reenergized after the switch 2 is opened, the delay switch 1 is switched on after a certain delay as in the case of the two-pole start-up described above.
The normally open contact 12 of No. 1 is closed and the motor is restarted as a two-pole motor.

@During 4-pole operation If a power outage occurs during 4-pole operation, the power switch 7 and the number of poles changeover switch 14 remain closed.

When the control power supply 6 is reenergized, the coil 13 of the pole number switching switch 8 is energized and the normally open contact 9 is closed, while the coil 21 of the auxiliary switch 16 is not energized, so the normally closed contact 17 is closed. Therefore, the coil 15 of the 4-pole switch 2 is energized and the motor 1 is operated again with 4 poles.

As described above, the 4-pole switch 2 is connected to the normally open contact 9 of the pole switching switch 8 and the normally closed contact 17 of the auxiliary switch 16 through the series circuit, and the normally closed contact 10 of the pole switching switch 8 and the auxiliary switch are connected to each other. Since the 2-pole switch 4 is controlled by the series circuit of the normally open contacts 19 of the switch 16, the 4-pole switch 4 is always switched on after the pole number changer 8 or the auxiliary switch 16 is activated, even when restarting after a power outage. Since energization to the switch 2 and the two-pole switch 4 is started, no malfunction occurs.

The same thing will happen even if the coil 15 of the 4-pole switch 2 and the coil 18 of the 2-pole switch 4 are replaced.

In the above embodiment, the delay switch 11 is provided to operate the auxiliary switch 16 after a certain delay in response to the pole number switching switch 8, but this is because the compressor A certain delay is performed for the purpose of making it easier to restart the motor by reducing the pressure difference between the discharge side and the suction side to a certain value or less, and the delay switch is connected to the discharge side of the compressor. It is obvious that a differential pressure switch or the like that detects the pressure difference between the auxiliary switch and the suction side may be used instead to open and close the auxiliary switch.

As described above, the present invention provides a multi-pole switch and a small-pole switch for connecting the multi-pole terminal and the small-pole terminal of the pole-changing motor, respectively, to a power supply in a compressor driven by a pole-changing motor. a switch, a pole switching switch, and an auxiliary switch that responds to the pole switching switch and operates after a certain delay, the contact of the pole switching switch and the contact ratio of the auxiliary switch Since this control device is characterized by controlling the multi-pole switch and the small-pole switch using a series circuit of It is possible to restart the compressor when the torque decreases, making the restart easy and reliable.It also prevents reverse braking torque that occurs when continuously switching from small-pole operation to multi-pole operation. In addition to ensuring the protection of the motor, even if the auxiliary switch, which responds to the above-mentioned pole number switching switch and operates after a certain delay, and its related parts, etc., fail, the motor will continue to operate continuously. There is no need to change the number of poles.

Further, by a series circuit of a normally closed contact of the pole number switching switch and a normally open contact of the auxiliary switch, and a series circuit of a normally open contact of the pole number switching switch and a normally closed contact of the auxiliary switch, Since the control device is characterized by controlling the multi-pole switch and the small-pole switch, the control device may malfunction even when the power is reenergized after a power outage, and the multi-pole switch or the small-pole switch may malfunction. It is possible to provide a safe control device that does not cause the small pole switch to malfunction and cause the motor to start with a different number of poles for a moment, and does not cause chattering of the control device. be.

[Brief explanation of the drawing]

The drawing is a circuit diagram showing one embodiment of the control device of the present invention. 1...Pole change motor, 1a, ib, lc...
...Multi-pole terminal, 1d, 1e, 1f...Small pole terminal, 2...4-pole switch, 4...
・2-pole switch, 6... Control power supply, 8...
・・Pole number switching switch, 9・・Normally open contact, 10・
... Normally closed contact, 16 ... Auxiliary switch, 1
7--, - normally closed contact, 19... normally open contact.

Claims (1)

[Claims] 1. A compressor driven by a pole switching motor, a multipole switch and a small pole switch that connect the multipole terminal and small pole terminal of the pole switching motor to a power supply, respectively, and a pole switching motor. a switch, and an auxiliary switch that responds to the pole number switching switch and operates after a certain delay, a pair of contacts of a normally open contact and a normally closed contact of the pole number switching switch, and the auxiliary switch. Connect each series circuit of a pair of normally closed contacts and normally open contacts to a power supply in parallel, and connect the coil of the multi-pole switch and the coil of the small-pole switch to each series circuit, respectively. A series circuit of a normally closed contact of a multi-pole switching switch and a normally open contact of an auxiliary switch, and a series circuit of a normally open contact of the multi-pole switching switch and a normally closed contact of the auxiliary switch are connected in parallel to a power source. Control device for several switching compressors.