JPS6323579A - Speed regulator for motor - Google Patents

Abstract

PURPOSE:To prevent starting failure at time of weak notch, by connecting a thermal switch set in close contact with the winding of a motor, to a speed- regulating condenser used on rotation at the lowest speed, in parallel with each other, CONSTITUTION:By operating the speed change-over switch 8 of a speed regulator 2, a motor section 1 and a power source 3 are directly connected to each other, and a condenser 9 or a condenser 10 is connected, and the change-over is selected from strong, medium, or weak notch. To the winding aplied to a stator 20 at the motor section 1, a thermal switch 13 is butted. When the operation in weak notch is started, then the speed-regulating condenser 10 of the weak notch is short-circuited by the thermal switch 13 and the motor is started by strong notch. When heat is generated on the winding of a motor by operating the motor continuously, then the thermal switch 13 is worked, and the speed- regulating condenser 10 is released from the short-circuited state and is put into the normal operation state of the weak notch.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a speed regulating device for a motor used in industrial equipment or home appliances.

2. Description of the Related Art Conventionally, a speed regulating device for an electric motor of this type has a configuration as shown in FIG. That is, the electric motor 100 includes a series circuit 103 consisting of an auxiliary winding 101 and a capacitor 102,
The speed regulator 200 is composed of a main winding 104 connected in parallel to these, while the speed regulator 200 is composed of a plurality of capacitors 201, 202 and a speed selector switch 203. 200 is power supply 3
They are connected by two lines via o○.

To explain the operation of the electric motor speed adjusting device configured as above, the speed adjustment is performed by switching the electric motor section 100 and the power source 300 using the speed changeover switch 203.
Direct connection, by selecting and connecting one of the capacitors 201 and 202, the motor can be set to high, medium, or
It was meant to switch the weak.

Problems to be Solved by the Invention With such a configuration, if you try to operate the electric motor at a low notch, it is difficult to set the rotation speed low because starting failure may occur due to the weak torque of the electric motor. There was a problem that.

Additionally, in order to prevent startup failures, there is a method of starting the device in the strong or medium notch by operating a switch and then switching to the weak notch, but this method has the problem that malfunctions are likely to occur due to operator carelessness.

The present invention solves the above-mentioned conventional problems, and improves the starting torque only when starting a weak notch, prevents starting failure, and automatically enters a steady state of weak notch operation after starting. An object of the present invention is to provide a speed regulating device for an electric motor that can control the speed of an electric motor.

Means for Solving the Problem In order to solve this problem, the present invention includes an electric motor and a speed adjustment device provided in the energization circuit of the motor, and the speed adjustment device includes a plurality of speed adjustment capacitors. A speed adjustment switch that selects the speed adjustment capacitor and connects it to the motor, and a thermal switch that is provided close to or in contact with the windings of the motor. The configuration is such that they are connected in parallel.

With this configuration, when the motor starts operating at a weak notch, the contacts of the thermal switch are closed, so the speed adjustment capacitor for the motor's weak notch and the thermal switch are connected in parallel, and the speed adjustment capacitor is short-circuited. In addition, the motor starts with a strong notch, and when the motor windings heat up during operation, the contacts of the thermal switch are opened, and the speed adjustment capacitor is released from the short circuit and inserted into the circuit. , it is possible to limit the current flowing to the motor and enter steady operation at a weak notch.

EXAMPLE An example of the present invention will be described below with reference to FIGS. 1 and 2. As shown in the figure, the motor section 1 is composed of a series circuit 6 consisting of an auxiliary winding 4 and a phase advancing capacitor 5, and a main winding 7 connected in parallel to these. A structure that includes a switch 8 and a plurality of capacitors 9 and 10, and by operating the speed selector switch 8, the motor section 1 and the power source 3 are directly connected, and the capacitor 9 or capacitor 1o is connected to select high, medium, and low. It becomes. Stator 2 in the electric motor section 1
A thermal switch 13 is brought into contact with the winding wire placed at zero. This thermal switch 13 is composed of a thermally responsive element 14 that senses the heat generated by the winding and connects and disconnects the movable contact 11 to the fixed contact 12.
is fixed on the winding. This thermal switch 13
The two terminals 18 and 19 are connected in parallel with the two electrodes 16 and 17 of the speed adjustment capacitor 10 for weak notches, and the structure is such that the speed adjustment capacitor 10 is short-circuited or connected and disconnected. .

The operation of the electric motor of this embodiment configured as described above will be explained.

When the electric motor is not operating, the movable contact 11 of the thermal switch 13 is connected to the fixed contact 12. If you start the weak notch operation in this state, the thermal switch 1
Capacitor 1 for speed adjustment during weak notch connected in parallel with 3
0 will be short-circuited by the thermal switch 13, and the current flowing to the motor section 1 will not be restricted and will start at a strong notch. Further, as the motor continues to operate, the windings of the motor generate heat, and when the operating temperature of the thermal switch 13 provided in contact with the windings is reached, the thermally responsive element 14
operates, and the movable contact 11 is disconnected from the fixed contact 12, so the speed adjustment capacitor 10 is released from the short-circuited state and a circuit is formed, which limits the current flowing to the motor and brings it into a steady operating state with a weak notch. enter.

As described above, according to this embodiment, the thermal switch 13 provided close to or in contact with the windings of the motor senses the heat generation of the windings, and automatically shorts or connects the circuit of the speed adjustment capacitor 10. As a result, since the weak notch is started by the strong notch, it is possible to prevent starting failures, and after starting, the weak notch can automatically enter steady operation.

Effects of the Invention As is clear from the above description of the embodiments, according to the present invention, a thermal switch provided close to or in contact with a motor winding senses heat generation in the motor winding, and adjusts the speed of the motor. By automatically short-circuiting or connecting and disconnecting the capacitor, it is possible to change the weak-notch startup operation to strong-notch operation, which prevents startup failures and prevents the thermal switch from turning off after starting. This makes it possible to realize an excellent motor speed control device that automatically achieves steady operation with a weak notch.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram of a speed regulating device for an electric motor according to an embodiment of the present invention, Fig. 2 is a sectional view of a motor equipped with the same thermal switch section, and Fig. 3 is a circuit diagram of a conventional speed regulating device for an electric motor. It is. 1...Electric motor, 2...Speed adjustment device, 4
...Auxiliary winding, 7...Main winding, 9...
... Speed adjustment capacitor, 10 ... Speed adjustment capacitor, 13 ... Thermal switch. Name of agent: Patent attorney Toshio Nakao and one other person? ,
fO ---, Fushiden pump Figure 2 Figure 3

Claims (1)

[Claims] The speed regulating device includes a motor and a speed regulating device provided in the current supply circuit of the motor, and the speed regulating device includes a plurality of speed regulating capacitors and a speed regulating switch that selects and connects the plurality of speed regulating capacitors to the motor. A speed regulating device for a motor, comprising: a thermal switch provided close to or in contact with a winding of the motor; connected in parallel to a capacitor used during the lowest speed rotation among the plurality of speed regulating capacitors.