JPH07298579A - Single-phase induction motor for refrigerator compressor - Google Patents

Abstract

PURPOSE:To provide a highly efficient single-phase induction motor at low cost. CONSTITUTION:In a single-phase induction motor 11 comprising a main coil 12 and an auxiliary coil 13, a circuit 15 for changing capacitance of the capacitor is connected to the auxiliary coil 13 in series. The capacitance of the capacitor of the circuit 15 of the operating capacitor is controlled with a capacitance control part 18. In the circuit 15 for the operating capacitor, at least two or more circuits wherein an operating capacitor 16 and switches 17 and 17' are connected in series are connected in parallel. A signal is transmitted from an external temperature sensor 19 to the capacitance control part 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a single-phase induction motor for a compressor used in a refrigerator or the like.

[0002]

2. Description of the Related Art In recent years, single-phase induction motors for refrigeration compressors have tended to be highly efficient in order to comply with North American energy regulations and the like.

A conventional single-phase induction motor is disclosed in, for example, Japanese Patent Laid-Open No.
There is one disclosed in JP-A 1-269693.

A conventional single-phase induction motor for a compressor will be described below with reference to the drawings. In FIG. 3, 1
Is a power source, and a single-phase induction motor 3 via a voltage control element 2
Applied to. A compression element 4 constitutes an electric compressor 5 together with the single-phase induction motor 3. Reference numeral 7 denotes a trigger generation circuit, which sends a signal for controlling the applied voltage of the single-phase induction motor 3 to the voltage control element 2 according to the output of the pressure detector 6.

The operation of the compressor single-phase induction motor configured as described above will be described.

The change in the gas compressed and discharged by the compression element 4 is detected as the change in the load applied to the single-phase induction motor 3, and is output from the pressure detector 6 to the trigger generation circuit 7. The trigger generation circuit 7 sends a signal to the voltage control element 2 so as to change the voltage applied to the single-phase induction motor 3 depending on the magnitude of the signal from the pressure detector 6. The voltage control element 2 changes the applied voltage according to the received signal.

[0007]

However, in the above configuration, it is necessary to install the pressure detector 6 on the compression element 4 or the piping of the refrigeration cycle, and the electric compressor 5 or the refrigeration cycle is changed. Must be done for its installation. Further, the cost of the voltage control element 2 and the voltage control unit itself is high.

In view of the above problems, the present invention provides a highly efficient single-phase induction motor at low cost.

[0009]

In order to solve the above problems, the present invention relates to a single-phase induction motor comprising a main coil and an auxiliary coil, in which a circuit of an operating capacitor whose capacity can be varied is connected in series to the auxiliary coil. It is configured by a circuit configuration and a capacity control unit that controls the capacitor capacity of the circuit of the operating capacitor.

The operating capacitor circuit is a circuit in which an operating capacitor and a switch are connected in series and at least two circuits are connected in parallel.

The capacity control unit is provided with a structure for transmitting a signal from the outside air temperature sensor.

[0012]

According to the present invention, according to the above configuration, the capacity control section switches the capacitor capacity of the circuit of the operating capacitor according to the load of the refrigerating compressor, and the impedance of the auxiliary circuit in the single-phase induction motor is adjusted according to the load. Since it can be optimally varied, the efficiency of the single-phase induction motor can be optimally varied.

Further, since the circuit configuration of the operating capacitor capable of varying the capacitor capacity is a simple structure of only switching operation of the switch, a highly efficient single-phase induction motor unit can be provided at low cost.

Further, since the load fluctuation of the single-phase induction motor can be detected only by the outside air temperature sensor, a highly efficient single-phase induction motor unit can be provided at a low cost.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a single-phase induction motor in operation according to an embodiment of the present invention. FIG. 2 is an efficiency-load characteristic diagram of the single-phase induction motor used in the same embodiment.

In FIG. 1, 11 is a single-phase induction motor,
It is composed of a main coil 12 and an auxiliary coil 13. The main coil 12 is connected to the power supply 22 in parallel with the auxiliary circuit 14. The auxiliary circuit 14 includes the auxiliary coil 13 and the auxiliary coil 13.
It consists of a circuit 15 of operating capacitors connected in series with the. The circuit 15 of the operating capacitor comprises a 10 μF operating capacitor 16 and a switch 17 connected in series.
And a parallel circuit of another 10 μF operating capacitor 16 and a switch 17 'connected in series. 18
Is a capacity control unit for controlling the capacity of the operating capacitor circuit 15. An outside air temperature sensor 19 detects the outside air temperature and transmits a signal to the capacity control unit 18. 20
Is a compression element and constitutes the refrigeration compressor body 21 together with the single-phase induction motor 11.

The operation of the single-phase induction motor constructed as above will be described. The outside air temperature sensor 19 detects the outside air temperature and sends a signal to the capacity control unit 18 to operate the switch 17 and the switch 17 'of the circuit 15 of the operating condenser. The operating conditions are set such that the switch 17 is normally closed, the switch 17 'is closed when the outside air temperature is 20 ° C. or more, and open when the outside air temperature is less than 20 ° C.

FIG. 2 shows the efficiency of the single-phase induction motor 11 of this embodiment with respect to load fluctuations. The horizontal axis represents the load (W) at each outside temperature (° C). The vertical axis represents efficiency (%).

In general, the load applied to the single-phase induction motor 11 of the refrigerating compressor 21 also changes as the outside air temperature changes. That is, the load increases as the outside air temperature rises.

As described above, in FIG. 2 of this embodiment, the outside temperature is 2
The switch 17 of the circuit 15 of the condenser operating at 0 ° C
And the switch 17 'operates to switch the capacitor capacity of the circuit 15 of the operating capacitor to 10 μF or 20 μF, and the impedance of the auxiliary circuit 14 in the single-phase induction motor 11 can be optimally changed according to the load.

That is, in FIG. 2, a load of 100 W
When the temperature exceeds the outside temperature (20 ° C.), the efficiency curve with respect to the load change switches from the dotted line (capacitor capacity of the operating capacitor circuit 10 μF) to the solid line (capacitor capacity of the operating capacitor circuit 15 20 μF). Therefore, the efficiency of the single-phase induction motor 11 can be optimally changed according to the load of the refrigeration compressor 21.

Further, since the circuit 15 of the operating condenser whose capacity can be varied has a simple structure and the efficiency of the single-phase induction motor 11 can be optimally varied by sensing the outside temperature, a highly efficient single-phase induction motor can be realized. It can be provided at low cost.

For example, in the conventional single-phase induction motor, the impedance of the auxiliary circuit is fixed because the capacitor capacity of the circuit of the operating capacitor is fixed at 10 μF.
In other words, for efficiency fluctuations with respect to the load of the single-phase induction motor,
The efficiency of the single-phase induction motor could not be optimally changed according to the load.

[0025]

As described above, according to the present invention, in a single-phase induction motor including a main coil and an auxiliary coil, a circuit of an operating capacitor whose capacity can be varied is connected in series to the auxiliary coil, and a circuit of the operating capacitor. By configuring with the capacity control unit that controls the capacity of the condenser, the capacity control unit switches the capacity of the circuit of the operating condenser according to the load of the refrigeration compressor, and the impedance of the auxiliary circuit in the single-phase induction motor is changed. Can be optimally varied according to the load, so that the efficiency of the single-phase induction motor can be optimally varied.

As described above, according to the present invention, since the circuit of the operating capacitor has a configuration in which at least two circuits in which the operating capacitor and the switch are connected in series are connected in parallel, the operating capacitor capable of varying the capacitor capacity. The circuit is simple in structure, and a highly efficient single-phase induction motor unit can be provided at low cost.

Further, since a signal is transmitted from the outside air temperature sensor to the capacity control section, it is easy to detect load fluctuations in the single-phase induction motor, so that a highly efficient single-phase induction motor unit can be manufactured at low cost. Can be provided.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a single-phase induction motor according to an embodiment of the present invention.

FIG. 2 is a characteristic diagram of a single-phase induction motor in the same embodiment.

FIG. 3 is a block diagram of a conventional single-phase induction motor.

[Explanation of symbols]

 11 Single-Phase Induction Motor 12 Main Coil 13 Auxiliary Coil 15 Operating Capacitor Circuit 16 Operating Capacitor 17, 17 'Switch 18 Capacity Control Unit 19 Outdoor Temperature Sensor

Claims (3)

[Claims] 1. In a single-phase induction motor comprising a main coil and an auxiliary coil, a circuit configuration in which a circuit of a motion capacitor whose capacity can be varied is connected in series to the auxiliary coil, and a capacity for controlling the capacitor capacity of the circuit of the operating capacitor. A single-phase induction motor for a refrigerating compressor, which is configured by a control unit. 2. The circuit of an operating condenser whose capacity can be varied is characterized in that at least two circuits in which an operating condenser and a switch are connected in series are connected in parallel to each other. Phase induction motor. 3. The single-phase induction motor for a refrigerating compressor according to claim 1, wherein a signal is transmitted from the outside air temperature sensor to the capacity control unit.