JPS5916109B2 - compressor protector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a compressor protection device which includes a compressor driven by a pole switching motor and prevents the pole number of the pole switching motor from being frequently switched due to erroneous operation. It is.

Conventionally, in a pole number switching electric motor that drives a compressor, various control devices have been considered that use a pole number switching switch to switch the number of poles.

For example, in order to prevent reverse control torque generated in the motor when the motor is switched from small-pole operation to multi-pole operation using the above-mentioned pole number switching switch, the motor is temporarily stopped, and after a certain delay using another switch, When switching the number of poles and restarting the motor, or when switching from multi-pole operation to low-pole operation, the motor is temporarily stopped and restarted using another switch to ensure the change of the number of poles. However, the above-mentioned pole switching switch switches frequently, causing the compressor to repeatedly start and stop, leading to burnout of the pole switching motor that drives the compressor and accelerated wear on the compressor sliding parts. There was a risk of malfunction occurring.

That is, for example, if the above-mentioned pole number switching switch switches while the compressor is in multi-pole operation, and the moment the compressor stops, it is erroneously operated to start multi-pole operation again, without a certain delay. Multipolar operation is resumed again.

However, at this time, the compressor is stopped, the pressure difference between the high pressure side and the low pressure side of the compressor is large, and the starting load torque exceeds the starting torque of the electric motor, causing a starting failure and burning out the electric motor. In addition, since the starting load torque is large, abnormal pressure is applied to the sliding surfaces of the compressor, resulting in boundary lubrication, which may cause the sliding surfaces to become rough and eventually seize.

The present invention eliminates these conventional drawbacks, and prevents frequent switching of the number of poles of the pole switching motor that drives the compressor due to erroneous operation, thereby changing the number of poles from small to multi-pole operation. There is no risk of reverse braking torque being applied to the pole number switching motor when the motor is switched, and the starting load is reduced by stopping the compressor and then switching the number of poles from multi-pole operation to small-pole operation. The purpose of this is to enable restarting with low torque.

'In order to achieve this purpose, the present invention provides a pole number switching motor that drives the compressor, a switch that switches the number of poles of this pole number switching motor, and a pole number switching switch that selects the operation of this switch. and an operation switch that controls energization and de-energization of the pole-switching motor, and in response to the operation switch, when the pole-switching motor stops energizing, the compressor means such as a four-way switching valve that equalizes the discharge refrigerant pressure and suction refrigerant pressure, and means such as a contact that sets the operation of the pole number changeover switch via the pole number changeover switch, and responds to the operation switch. A self-holding circuit is provided to prevent the operation of the pole number switching switch from changing when the pole number switching motor is energized.

Because the number of poles is switched by this configuration, there is no risk of reverse braking torque acting on the pole number switching motor when switching from small-pole operation to multi-pole operation, and the compressor can also be used to switch the number of poles from multi-pole operation to small-pole operation. This will help you stop and do it more easily.

Hereinafter, one embodiment of the present invention will be described in detail with reference to FIGS. 1 and 2 of the drawings.

1 is a compressor that compresses refrigerant, and during cooling operation, the compressed high-pressure refrigerant is sent from a discharge pipe 2 to a heat source side heat exchanger 4 via a four-way switching valve 3, where it is condensed and liquefied. 5 to the first throttle device 6 where it is depressurized and expanded, the room air is cooled by the utilization side heat exchanger 7, passes through the four-way switching valve 3 again, and is passed through the accumulator 8 to the suction pipe 9 of the compressor 1. More compressor 1
is inhaled.

Next, during heating operation, the four-way switching valve 3 is switched, and the high-pressure refrigerant discharged from the compressor 1 enters the user-side heat exchanger 7 via the four-way switching valve 3, heating the indoor air, and the refrigerant itself is liquefied and condensed. It is led to the second throttle device 11 via the check valve 10, where it is depressurized and expanded, passed through the heat source side heat exchanger 4 through an endothermic evaporation port, and then passed through the four-way switching valve 3 again, via the accumulator 8, and then compressed from the suction pipe 9. Inhaled into machine 1.

Reference numeral 12 denotes an air blower, which is driven by a motor 13 and has fans 14 and 15 that ventilate the user side heat exchanger 7 and the heat source side heat exchanger 4, respectively.

The pole number switching motor 16 that drives the compressor is a three-phase induction motor, and the windings of each phase are connected in series to become a four-pole motor, and connected in parallel to become a two-pole motor.

The above-mentioned pole number switching motor 16 is a contact 18 of a 4-pole switch 1T.
The multi-pole terminals 16a and 16b are connected through the multi-pole terminals 16a and 16b.

16c is connected to the power source P for four-pole operation, and is connected to the small-pole terminal 16d via the contact 20 of the two-pole switch 19.

16e and 16f are connected to power supply P to perform two-pole operation.

21 is a control power supply applied between terminals 22 and 23, and terminal 22 is connected to an operation switch 24.

This operation switch 24 has a first contact Sωno for controlling the energization to the pole number switching motor 16.

A second contact Sω229 and a third contact Sω330 are associated with the pole number changeover switch 26 and control the energization to the coil 28 of the pole number changeover switch 27, and control the energization to the coil 31 that operates the four-way switching valve 3. The motor 1 of the blower 12 has a fourth contact Sω432 and an operating capacitor 33.
A fifth contact Sω, 34, and a sixth contact Sω635 for switching the speeds of the three speeds are provided.

The first contact Sω125 is a series circuit consisting of a low temperature contact 37 of the temperature regulator 36 that is closed when the temperature is low, a contact 39 that is closed during heating operation of the cooling/heating changeover switch 38, and the temperature regulator 36.
A high temperature contact 40 that closes when the temperature is high and a cooling/heating selector switch 3
It is connected to a normally open contact 42 and a normally closed contact 43 of the pole number switching switch 27 through a parallel circuit with a series circuit of contacts 41 that are closed during cooling.

The normally open contact 42 is further connected to the coil 44 of the 4-pole switch 17, and the normally closed contact 43 is connected to the 2-pole switch 1.
It is connected to the coil 45 of No. 9.

In addition, the coil 31 of the four-way switching valve 3 is connected to the cooling/heating switch 38.
The first contact Sω125 is connected to the first contact Sω125 via another contact 46 that is closed during the heating operation, and the other contact 4 is closed during the cooling operation.
7 to the fourth contact Sω432.

The coil 28 of the pole number switching switch 27 has its self-holding contact 4
8 to the third contact Sω330, and also connected to the second contact Sω229 via the pole number changeover switch 26.

Next, the operating method will be explained.

The operation switch 24 has the functions of "stop operation", "strong operation", "low operation", and "ventilation 2", and when "stop operation" all contacts 25, 29, 30° 32.34.3
5 is open, and all power supply to the control device is stopped.

(1) In the case of heating operation, the contacts 39 and 46 of the cooling/heating changeover switch 38 are closed, and in the case of operating the compressor 1 at high capacity, the pole number changeover switch 26 is left open.

When the operation switch 24 is changed from "stop" to "air blowing 1", the fifth contact Sω, 34 is closed, so the motor 13 rotates at high speed and the indoor air can be circulated with strong wind.

Next, when switching to "strong operation", the fifth contact 9ω, 34 continues to close and strong wind operation is performed, and the first contact Sω125
The coil 31 is energized via the contact 46 of the cooling/heating switch, operating the four-way switching valve 3 to switch the refrigerant circuit to the heating circuit, and the low temperature contact 37' of the temperature controller 36.
, the coil 45 is energized via the contact 39 of the cooling/heating changeover switch 38 and the normally closed contact 43 of the pole number changeover switch 27.
The pole switch 19 operates, and the pole number switching motor 16 operates in two pole mode.

For example, the indoor air temperature is detected by the temperature regulator 36, and when the temperature exceeds the set temperature, the contact 37 is opened, the current supply to the coil 45 is stopped, and the compressor 1 is stopped.

If you switch from "strong operation" to "weak operation", the fifth contact S
ω, 34 is opened, the sixth contact S ω 635 is closed, and the motor 13 rotates at a low speed, resulting in weak wind operation.

During this "strong operation" and "weak operation", even if the pole number changeover switch 26 is closed to change the number of poles of the pole number changeover motor 16 to four poles, the second Since the contact Sω229 is open, the coil 28 of the pole number switching switch 27 is not energized, so the number of poles is not switched.

Next, when switching to "Blower 2", the first contact Sω125 is opened, the current to the coil 45 is stopped, the compressor 1 is stopped, and the current to the coil 31 is also stopped, so the refrigerant circuit is cooled. The circuit is switched, the discharge pipe 2 of the compressor 1 is connected to the low-pressure refrigerant, the suction pipe 9 is connected to the high-pressure refrigerant, and the refrigerant pressure on the discharge side and the refrigerant pressure on the suction side of the compressor 1 quickly become equal.

Further, at this time, the sixth contact Sω635 continues to be closed, so the motor 13 continues to rotate at a low speed and continues to operate in a weak wind.

If the pole number changeover switch 26 is closed at this time, the coil 28 is energized from the second contact Sω229 and the pole number changeover switch 27 is switched, but since the first contact Sω125 is open, , the coil 44 is not energized.

Next, if the operation switch 24 is further operated to set "stop operation", all electricity to the control device is stopped.

Next, a case where the compressor is operated at a low capacity, that is, operated at four poles, will be explained.

If you close the pole number changeover switch 26 and set it to "Blower 1", the second
The coil 28 is energized through the contact Sω229, the pole number switching switch 27 is activated, the normally open contact 42 is closed, the normally closed contact 43 is opened, and the self-holding contact 48 is closed. to the coil 28 via the third contact Sω330.
is connected to the power supply 21.

Next, when switching to "strong operation", the second contact Sω229 opens, but the third contact Sω330 continues to close, so the pole number switching switch 27 continues to maintain itself, and
In order to close the first contact Sω125, the coil 44 is energized via the normally open contact 42 of the pole number switching switch 2T, the 4-pole switch 17 is operated, and the pole number switching motor 16 is switched to 4 poles. It becomes driving.

Even in the case of "strong operation" and "weak operation", the third contact Sω330 is closed and the self-holding circuit continues, so even if the number of poles changeover switch 26 is opened, the number of poles will be 2 poles instead of 4 poles. It will not switch to

When set to "Blower 2", the blower 12 operates weakly as described above, the compressor 1 stops, and the four-way selector valve 3 switches, and the refrigerant pressure on the discharge side and the refrigerant pressure on the suction side of the compressor 1 are suddenly equalized. The starting load torque when the compressor 1 is restarted after being compressed is very low, and the restart can be performed reliably.

(2) In the case of cooling operation, the contacts 41 and 47 of the cooling/heating changeover switch 38 are closed.The contact 41 is connected to the high temperature contact 40 of the hot air regulator 36, and in contrast to the heating operation, for example, the indoor air temperature is set to the set temperature. When the voltage is higher, the pole number switching motor will be energized.

The number of poles is not switched between "strong operation" and "weak operation" during this cooling operation, which is the same as during heating operation, but the difference is in the operation of the four-way switching valve 3.

That is, since the contact 46 of the cooling/heating changeover switch 38 is open, the coil 31 is not energized during "strong operation" and "weak operation" and the four-way switching valve 3 switches the refrigerant circuit to the cooling circuit.

However, in order to equalize the pressure on the discharge side and the pressure on the suction side of the compressor 1 by switching the four-way switching valve 3 when the compressor 1 stops, the fourth contact S ω is used during “blow 1” and “blow 2”.
432 is closed, the coil 31 is energized through the contact 47 of the cooling/heating changeover switch 38, the four-way switching valve 3 is switched from the cooling circuit to the heating circuit, and the refrigerant pressure on the discharge side and the refrigerant pressure on the suction side of the compressor 1 are changed. It equalizes the pressure.

In the above embodiment, the second contact S in "air blower 2"
ω229, third contact Sω330, fourth contact Sω43
2 was closed by operating ``stop operation'' → ``blow fan 1'' → ``strong operation'', which is the opposite.

"Stop operation" → "Blower 2" → "Weak operation"...
This is to allow operations such as...

In addition, the operation switch can be used to energize the compressor 1 and blower 1.
Although the control of No. 2 and the control of switching the number of poles have been carried out, it is clear that these may be carried out by separate switches or by using an electromagnetic switch.

Further, the positions of the coils 45 and 44 of the two-pole switch 19 and the four-pole switch 17 may be replaced, and the energization of the coils 45 and 44 may be controlled by a pole number switching switch having one self-holding contact. 27 normally open contacts 42. Although this is done using the normally closed contact 43, two switches each having a self-holding point may be used to control the respective coils 45 and 44, and the switches may be connected to each other so that they do not operate at the same time. Obviously, it is also possible to take measures to interlock the

As is clear from the above embodiments, the compressor protection device of the present invention includes a pole switching motor that drives the compressor, a switch that switches the number of poles of the pole switching motor, and a switch that controls the operation of the switch. It has a pole number changeover switch that controls energization to the selected pole number switching switch, and an operation switch that controls energization and de-energization of the pole number switching motor, and the number of poles is switched in response to this operation switch. Means such as a four-way switching valve that equalizes the discharge refrigerant pressure and suction refrigerant pressure of the compressor when the electric motor is stopped, and means such as a contact that sets the operation of the pole number changeover switch via the pole number changeover switch. A self-holding circuit is provided to prevent the operation of the pole switching switch from changing when the pole switching motor is energized in response to the operation switch, and to stop the operation of the compressor. Since the number of poles is then switched, there is no risk of reverse braking torque acting on the pole number switching motor when switching from low-pole operation to multi-pole operation, and the number of poles switching from multi-pole operation to low-pole operation is also compressed. Since this is done after the compressor has been stopped, it is possible to restart the machine with a low starting load torque, and even if the pole number changeover switch is frequently opened and closed, which could not be solved in the past, the problem remains the same while the compressor is running. For example, even if a child accidentally opens and closes the pole number changeover switch repeatedly, the number of poles will not change each time, and the compressor will not start up due to frequent switching of the number of poles. This has an excellent effect of preventing defects and failures of the control device.

[Brief explanation of drawings]

FIG. 1 is a refrigerant circuit diagram showing an embodiment in which a compressor equipped with the protection device of the present invention is applied to an air conditioner, and FIG. 2 is an electric circuit diagram of the protection device. 1...Compressor, 16...Pole number switching motor, 24...Operation switch, 26...
Pole number changeover switch. 27...Pole number switching switch.

Claims (1)

[Claims] 1. A pole number switching motor that drives the compressor, a switch that switches the number of poles of this pole number switching motor, and a pole number changeover switch that controls energization to the pole number switching switch that selects the operation of this switch. , has an operation switch for controlling energization and de-energization of the pole number switching motor, and equalizes the discharge refrigerant pressure and suction refrigerant pressure of the compressor when the pole number switching motor is stopped energized in response to the operation switch. A means such as a four-way switching valve that presses the switch and a means such as a contact that sets the operation of the pole switching switch via the pole switching switch, and in response to the operation switch, when the pole switching motor is energized. A compressor protection device provided with a self-holding circuit that prevents changes in the operation of the pole number switching switch.