JPH07245985A - Control method for reversible operation machine - Google Patents

Abstract

PURPOSE:To simplify the control circuit of a reversible operation machine and improve the reliability of its control. CONSTITUTION:A reversible operation machine M and its control unit C are connected with each other through a common circuit, a normal rotation circuit and a reverse rotation circuit. A polarity inverting relay is placed in the common circuit as a normal/reverse switching means E. A switching semiconductor device is placed as a means D for driving the relay in the common circuit in the stage preceding to the relay. During the switching operation of the relay the switching semiconductor device is in the off state, and application of voltage to the relay contacts is interrupted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control system for a reversible operating device.

[0002]

2. Description of the Related Art For example, in the case of a reversible motor, conventionally, two mechanical relays or switching semiconductors (SSR) are used as an operating device as shown in FIG. 3, and a required rotation direction is obtained by reversible operation. In the control method of FIG. 3, when the motor is driven in the forward direction, a current is passed through the winding L1, so the relay R1 is turned on. When the motor is driven in the reverse direction, a current is passed through the winding L2 and the relay R2 is turned on. And However, since the motor drive voltage is always applied between the contacts of the relays R1 and R2, there is a problem that sparks are generated when the contacts are turned on and off to deteriorate the contacts. Further, in the case of a mechanical relay, chattering of several msec to several tens of msec occurs after the contact enters the ON operation, but this also causes sparks and deteriorates the contact.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and its object is to simplify the control circuit of a reversible operating device and to improve the reliability and controllability of the control. To improve.

[0004]

In order to solve the above-mentioned problems, the present invention connects a reversible operating device and a control unit for controlling the reversible operating device by a common circuit, a forward rotation circuit and a reverse rotation circuit, and a forward rotation circuit, One polarity reversing relay is connected to the common circuit as a switching means for switching to the reversing circuit, and one switching semiconductor device is connected to the common circuit in the preceding stage of the relay as a means for driving the relay. A measure is taken to stop the voltage application to the relay contact portion by turning off the switching semiconductor device during the switching operation of the relay.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The control system of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment in which the reversible operating device M is an AC reversible motor. L1 and L2 are windings respectively, and when the motor is driven in the forward direction as in the prior art. A current is passed through the winding L1 and a current is passed through the winding L2 when driving in the reverse direction. Each winding L1, L
Reference numeral 2 is connected to a common circuit, a forward rotation circuit and a reverse rotation circuit, and is guided to the control section C.

The controller C has an SSR (solid state relay, zero-crossing type semiconductor switching element) in a common circuit for driving a reversible AC motor.
A polarity reversing relay is connected to it as the polarity switching means E. F indicates an AC power supply.

In the case of the control method by the AC load drive having such a configuration, when the switching operation of the relay which is the switching means E is performed, the switching semiconductor device SSR which is the driving means D is turned off and the relay contact portion is connected. Stop applying voltage. Therefore, it is possible to avoid the occurrence of sparks on the relay contacts. Further, in the conventional example using the mechanical relay, chattering of several msec and several tens msec is inevitable, but in the method according to the present invention, SS
Since R is turned off, chattering apparently does not occur.

FIG. 2 shows an embodiment in which the reversible operating device M is a DC motor. In this case, an FET (field effect switching transistor) is provided in a common circuit as a switching semiconductor device for driving the DC motor. A polarity reversing relay is connected to the subsequent stage as the polarity switching means E. In this case, F ₁ and F ₂ represent DC power supplies.

It can be said that the control system based on the DC load drive is a circuit in which the SSR portion of the AC load drive described above is replaced with an FET. Therefore, since the FET is provided in front of the relay E as the driving means D, the spark phenomenon disappears when the contact is turned on and off as in the conventional case, and the FET is turned off when the relay is switched. Also, chattering will not occur.

In the embodiment, an example in which the control method according to the present invention is applied to a reversible motor has been described, but the invention can be applied to control of a solenoid valve using a pressure fluid. In each figure, LS indicates a limit switch built in the drive unit.

[0012]

The present invention is configured and operates as described above, and since only one switching means is required in the control circuit of a reversible operating machine such as a reversible motor, simplification of the circuit can be achieved. In addition, since sparks disappear and chattering apparently does not occur, the reliability and controllability of the circuit and control can be improved.

Further, by using a relay for polarity reversal, there is an effect of cutting the transmission voltage generated in the non-excitation side winding, and it is possible to prevent adverse effects on the semiconductor.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a first embodiment of a control system for a reversible operating device according to the present invention.

FIG. 2 is a circuit diagram showing a second embodiment of the same.

FIG. 3 is a circuit diagram showing a conventional control method.

Claims (3)

[Claims] 1. A reversible operating device and a control unit for controlling the reversible operating device are connected by a common circuit, a forward rotation circuit and a reverse rotation circuit,
One polarity reversing relay is connected to a common circuit as switching means between the forward rotation circuit and the reverse rotation circuit, and one switching semiconductor device is connected to a common stage in front of the relay as means for driving the relay. A control system for a reversible operating device, comprising connecting to a circuit and turning off a switching semiconductor device during a switching operation of the relay to stop applying a voltage to a relay contact portion. 2. The reversible operating device is an AC reversible motor,
The control system for a reversible operating device according to claim 1, wherein the switching semiconductor device is a zero-crossing type semiconductor switching element. 3. The control system for the reversible operating device according to claim 1, wherein the reversible operating device is a DC motor, and the switching semiconductor device is a field effect switching transistor.