JPS6052676B2 - Control device for pole number switching motor - Google Patents

Description

[Detailed description of the invention] The present invention starts by switching the capacitance of the operating capacitor of the pole number switching motor by connecting and disconnecting the auxiliary capacitor during startup and steady operation, regardless of whether the pole number switching motor is a multi-pole motor or a small pole motor. The purpose is to increase torque and perform steady, efficient operation.

Conventionally, pole number switching motors have often been used in devices with low load torque at startup, and even pole number switching motors with low starting torque can be used.

However, when used in equipment such as a refrigeration compressor that has a high load torque at startup, it is possible that the motor will not start due to insufficient starting torque of the pole switching motor. In this case, it is possible to increase the capacity of the operating capacitor during startup to increase the starting torque, but if the number of poles is switched, the switching method for switching the capacitor capacity during startup and steady operation becomes a problem. It is. In other words, in a single pole switching motor, the operating capacitor capacity was switched by a starting relay activated by the auxiliary coil voltage, but in a pole switching motor, the voltage of the auxiliary coil changes as the number of poles is switched, so the starting relay is The problem was the control circuit. The present invention solves the above problem and provides a control device that constantly switches the operating capacitance of a pole switching motor during startup and steady operation, regardless of whether the pole switching motor is a multi-pole motor or a small pole motor. This is what we provide.
An embodiment of the present invention will be described below with reference to the accompanying drawings.

Reference numeral 1 denotes a pole number switching motor, and an electromagnetic switch 2 is provided for switching the number of poles of the motor 1 between two and four poles.

3 is a power plug, one end of which is connected to the operation switch 4.

The operation switch 4 is provided with a motor switch 5 and a coil switch 6 in parallel. 7, 8, 9 and 10
are the first main coil, second main coil, first auxiliary coil, and second auxiliary coil of the pole number switching motor 1, respectively.

One end of the motor switch 5 is connected to the power plug 3, and the other end is connected to a connection point between the first main coil 7 and the first auxiliary coil 9. The coil switch 6 has one end connected to one end of the power plug 3 and the other end connected to the other end of the power plug 3 via a coil 11 that drives the electromagnetic switch 2 . When the coil 11 is energized, the contacts 12, 13, 1 of the electromagnetic switch 2
4 and 15 are closed and the first main coil 7 of the pole number switching motor 1
and the second main coil 8 are connected in parallel, and the first auxiliary coil 9 and the second auxiliary coil 10 are connected in parallel.

16 is an operating capacitor, one end of which is connected to the connection point of the first main coil 7 and second main coil 8 through a contact 12 during two-pole operation, and the other end is connected to the first auxiliary coil through a contact 14. It is connected to the connection point between the coil 9 and the second auxiliary coil 10.

In addition, the operation capacitor 16 has one end connected to the contact 17 during 4-pole operation.
is connected to one end of the second main coil 8 through the other end is the contact 1
It is connected to one end of the second auxiliary coil 10 via 8. Note that if the coil 11 is not energized, the contact 17
, 18 are closed. And the first main coil 7 and the second
The main coils 8 are connected in series. The first auxiliary coil 9 and the second auxiliary coil 10 are connected in series, and the pole number switching motor 1 is connected for four-pole operation. Reference numeral 19 denotes an auxiliary capacitor provided with a discharge resistor 20 in parallel, and is connected in parallel to the operating capacitor 16 via a contact 21 .

Note that the contact point 21 is the above-mentioned pole. A starting relay 2 connected in parallel to the first auxiliary coil 9 of the multiple switching motor 1 via a resistor 22
3, and is opened by excitation of the electromagnetic coil 24. A contact 25 is connected in parallel to the resistor 22 during four-pole operation, and the electromagnetic coil 24 is connected in parallel to the l-th auxiliary coil 9 via this contact 25.

Next, the operation during four-pole operation will be explained along the circuits shown in FIGS. 1 and 2. 1. First, the timing of opening the auxiliary coadensor 19 after the motor 1 is started will be described.
When the induction motor 1 is 60Hz, 3 when operating with 2 poles.
600r. p. m, 1800 r' during 4-pole operation. P.
m is synchronous rotation, and the synchronous rotation speed differs depending on the number of poles, and of course the rotation speed at which transition to synchronous rotation is guaranteed even if the auxiliary capacitor 19 is subsequently opened also differs, but in any case, synchronous rotation When the rotational speed increases to a predetermined percentage of the rotational speed, the transition to synchronous rotation is guaranteed even if the auxiliary capacitor 19 is subsequently opened, and the predetermined percentage at this time is approximately the same value for both 2-pole and 4-pole cases. becomes. In the case of an induction motor 1, the rotation speed at a predetermined % of the above synchronous rotation speed is expressed by the slip value.
Even during polar operation, if the slip value is less than a predetermined value, the auxiliary capacitor 19 is opened, and the expression "slip value" will be used in the following description.

In the case of four-pole operation, the coil switch 6 of the operation switch 4 is open and only the motor switch 5 is closed. In this case, the contacts 17 and 18 of the electromagnetic switch 2 are closed, and the contact 25 is also closed. Therefore, the first main coil 7 and the second main coil 8 of the pole number conversion motor 1 are connected in series via the contact 17, and the first auxiliary coil 9 and the second auxiliary coil 10 are connected via the contact 18. It is connected in series to one end of the operating capacitor 16. Further, the resistor 22 is short-circuited by a contact 25, and the electromagnetic coil 24 of the starting relay 23 is connected in parallel to the first auxiliary coil 9 via the contact 25. By closing the motor switch 5, the pole number switching motor 1 is energized and started.
At startup, the auxiliary capacitor 19 is connected in parallel to the operating capacitor 16 via the contact 21, so the system starts with a large capacitance. The starting torque at this time is extremely large. When the rotation of the pole number switching motor 1 increases, that is, the slip value becomes smaller than a predetermined value, and the voltage applied to the first auxiliary coil 9 increases and exceeds the operating voltage of the electromagnetic coil 24 of the starting relay 23, the electromagnetic coil Contact 21 is opened by energizing 24. Therefore, the pole number switching motor 1 can be rotated steadily using only the operating capacitor 16, and if the capacity of the operating capacitor 16 is selected to an appropriate value, efficient four-pole operation is possible.

Next, the operation of the two-pole operation will be explained in detail with reference to FIGS. 1 and 3.

When the coil switch 6 of the operation switch 4 is closed and the coil 11 is energized, the contacts 12, 13, 14 and 1 of the electromagnetic switch are closed.
5 is a closed pole number switching motor 1, which is a two-pole motor.

That is, the second main coil 8 is connected in parallel to the first main coil 7 via the contact 13, and the first auxiliary coil 9 and the second auxiliary coil 10 are connected via the contact 15. Further, the first main coil 7 and the second main coil 8 connected in parallel are connected to the power plug 3 via a contact 12. Furthermore, the first auxiliary coil 9 and the second auxiliary coil 1 are connected in parallel.
0 is connected to the power plug 3 via the contact 14. Further, the electromagnetic coil 24 of the starting relay 23 is connected in parallel to the second auxiliary coil 10 via the low resistor 22.

When the motor switch 5 is closed in this state, the pole number switching motor 1
With the auxiliary capacitor 19 connected in parallel to the operating capacitor 16, the motor is started with a high starting torque. Then, the rotation of the pole number switching motor 1 increases, that is, the slip value becomes smaller than a predetermined value, and the voltage applied to the first auxiliary coil 9 increases, and the electromagnetic coil 24 of the starting relay 23 is energized and the contact 21 opens. The pole number switching motor 1 is operated only by the operation capacitor 16. In this state, the pole number switching motor 1 can operate steadily and efficiently.
Here, the starting relay 23 during 2-pole operation and 4-pole operation
The voltage applied to the electromagnetic coil 24 will be described. In this embodiment, the electromagnetic coil 24 is connected in parallel to the first auxiliary coil 9, so if the slip value for ensuring subsequent rotation is the same during both 4-pole and 2-pole operation, the electromagnetic coil 24 is connected in parallel to the first auxiliary coil 9. The voltage applied to the coil 24 has approximately the same value.

In other words, if the slip value for ensuring rotation after startup is the same in both 4-pole and 2-pole cases, when the first and second auxiliary coils 9 and 10 are connected in series in the 4-pole case, the first and second auxiliary coils 9 and 10 are connected in series. Second
The value of the voltage generated across the series connection body of the auxiliary coils 9 and 10 is the same as when the first and second auxiliary coils 9 and 10 are connected in parallel when the first and second auxiliary coils 9 and 10 are connected in parallel. This is approximately twice the value of the voltage generated at both ends of the body (actually, it is slightly lower than twice). In other words, the voltage generated in the first auxiliary coil 9, that is, the voltage applied to the electromagnetic coil 24, is approximately the same regardless of whether it is 4-pole or 2-pole.

However, in reality, when connecting 4 poles, the first and second auxiliary coils 9,
Since the voltage generated across the 10 series-connected bodies is not twice the voltage across them when they are connected in parallel as described above, the voltage applied to the electromagnetic coil 24 when the two poles are in this state is becomes high.

Therefore, the resistor 22 and the contact 25 are provided so that the voltage applied to the electromagnetic coil 24 is the same in both the 4-pole and 2-pole states by making this fine adjustment.

In other words, during two-pole operation, the contact 25 opens, and as a result, the resistor 22 is connected in series with the electromagnetic coil 24 as shown in FIG. The voltage becomes equal to that when 4 poles are connected. Therefore, irrespective of the two-pole connection or the four-pole connection, the capacitance of the operating capacitor at startup and during steady rotation can be reliably switched, and the efficiency during steady rotation can be maintained optimally. Generally speaking, the number of contacts required when the pole number switching motor 1 is connected to two poles or small poles is greater than the number of contacts required when connected to four poles or multipole. The contact 25 used for adjustment is a contact that closes during multi-pole connection, thereby reducing the number of contacts that are closed at one time in the electromagnetic switch. This is the first or second
This is made possible by connecting a series circuit of an electromagnetic coil 24 and a resistor 22 in parallel to one of the auxiliary capacitors 9 and 10. Although the electromagnetic coil 24 is connected in parallel to the first auxiliary coil 10, there is no change in the effect even if the electromagnetic coil 24 is connected in parallel to the second auxiliary coil 10 instead of the first auxiliary coil 10.

The control device for a pole number switching motor of the present invention includes at least a first
A pole number switching motor consisting of a main coil, a second main coil, a first auxiliary coil, a second auxiliary coil, a driving capacitor, and an auxiliary capacitor, the first main coil and the second main coil, and the first auxiliary coil. and an electromagnetic switch that connects the second auxiliary coil in series to switch to a multi-pole motor and connects in parallel to switch to a small-pole motor, and connects the auxiliary capacitor to the operating capacitor when starting the pole number switching motor. A starting 1J relay with contacts that can be connected or disconnected in parallel depending on steady operation is provided, and the electromagnetic coil of this starting relay is connected in parallel to either the first auxiliary coil or the second auxiliary coil, resulting in a multi-pole connection. Even when a small number of circuits are connected, an auxiliary capacitor is connected in parallel to the operating capacitor at startup, resulting in smooth startup with high torque.

In addition, regardless of whether a multi-pole connection or a small number of poles are connected, after startup, the voltage applied to the electromagnetic coil of the starting relay for opening the auxiliary capacitor becomes substantially equal, so the opening timing of the auxiliary capacitor is appropriate. As a result, problems such as startup failure caused by the auxiliary capacitor being opened too early, and continued operation in a low efficiency state caused by the auxiliary capacitor being opened too late, do not occur.

Furthermore, in the present invention, since a voltage regulator such as a resistor is connected to the electromagnetic coil only when a small number of circuits are connected, the power consumption is lower than when voltage adjustment is performed by connecting a resistor separately when a small number of circuits and a multi-pole connection are connected. be able to.

[Brief explanation of the drawing]

Fig. 1 is an electric circuit diagram of a control device for a pole switching motor according to an embodiment of the present invention, Fig. 2 is a schematic circuit diagram of the control device during 4-pole operation, and Fig. 3 is a 2-pole circuit diagram of the control device. It is a schematic circuit diagram at the time of operation. 1...Pole number switching motor, 2...Electromagnetic switch, 3...Power plug, 4...Operation switch, 5...Motor opening/closing device, 6... Coil switch, 7... First main coil, . 8...
...Second main coil, 9...First auxiliary coil,
10... Second auxiliary coil, 11... Coil, 12, 13, 14, 15, 17, 18, 21, 25
...Contact, 16...Driving capacitor,
19... Auxiliary capacitor, 20... Discharge resistance, 22... Resistor, 23... Start relay, 24... Electromagnetic coil.

Claims (1)

[Claims] 1 A pole number switching motor consisting of at least a first main coil, a second main coil, a first auxiliary coil, a second auxiliary coil, a driving capacitor, and an auxiliary capacitor; the first main coil and the second main coil; Directly connecting the first auxiliary coil and the second auxiliary coil to a multipolar motor,
An electromagnetic switch that connects in parallel to switch to a motor with fewer poles, and a starting relay that has contacts that connect or disconnect the auxiliary capacitor to the operating capacitor in parallel depending on the startup and steady operation of the pole number switching motor. The electromagnetic coil of this starting relay is connected to the first auxiliary coil or the second auxiliary coil.
A contact that is connected in parallel to one side of the auxiliary coil and selectively shorts a resistor or the like inserted in series with the electromagnetic coil in order to adjust the voltage applied to the electromagnetic coil in response to the switching of the number of poles of the pole number switching motor. A control device for a pole number switching motor, wherein the electromagnetic switch is provided with: