JPH0442914B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a control circuit for an electromagnetic clutch motor using a capacitor motor as a drive source, and particularly to a control circuit for an electromagnetic clutch motor using a capacitor motor as a drive source.
This invention relates to a control circuit that prevents the control circuit from malfunctioning due to capacitor discharge when OFF.

[Background of the invention]

Conventionally, a two-contact type power switch has been employed in a control circuit for an electromagnetic clutch motor using a capacitor motor as a drive source. Therefore, the power switch
No consideration was given to circuit operation due to capacitor discharge after turning off. For this reason, the power
Since the circuit power is still alive even though it is turned off, there is a risk that the motor output shaft will malfunction if an incorrect operation command is input to the controller.

This will be specifically explained using drawings. Fig. 3 is an overall control block diagram of a clutch motor to which the present invention is applied, Figs. 4 and 5 are conventional circuit diagrams using a two-contact switch, and Figs. 6 and 7 are a circuit diagram using a three-contact switch. This is also a conventional circuit diagram.

In FIG. 3, an electric motor 1, an electromagnetic clutch, and a brake section 2 are mechanically coupled. The clutch and brake are controlled by a controller 3, and the output shaft of the electromagnetic clutch and brake unit 2 is connected to the electric motor 1.
Take out the power or stop the output shaft,
Drive the load. The controller 3 operates to drive the load based on commands from the operation command circuit 4. The controller 3 also receives a feedback signal from a detector 5 that detects the driving state. Further, the controller 3 drives a load 6 (including not only a motor but also various solenoids of an industrial sewing machine). Figure 4,
FIG. 5 shows a conventional power switching circuit using a two-contact power switch. FIG. 4 shows a single-phase low voltage circuit, and FIG. 5 shows a single-phase high voltage circuit. Figure 4 shows
When the main power supply 20 enters the two-contact power switch 7 and turns on the power switch 7, the main coil 9, auxiliary coil 8, capacitor 11 and rotor (not shown)
A capacitor motor consisting of the following rotates and power is supplied to the controller power supply 10 at the same time. 5 differs in that the capacitor motor section is composed of a main coil 12 in addition to the main coil 9, auxiliary coil 8, and capacitor 11. FIG. In this dual power supply circuit, even if the power switch 7 is turned off, the capacitor 11 maintains its charged state because there is no discharge circuit. In addition, in this state, auxiliary coil 8 and capacitor 1
1. Since the controller power source 10 forms a closed circuit, the controller power source 10 continues to operate until the discharge of the capacitor 11 is completed. Further, when a microcomputer or the like is used as the controller 3, the power consumption is small and the controller 3 can operate for a considerable period of time. Under this condition, if the operation command 4 is accidentally input to the controller 3, the controller 3 will not operate the electromagnetic clutch, the brake section 2 or the load 6 because the controller power source 1 is live.
Because the drive is controlled, there is a risk of unexpected accidents.

FIGS. 6 and 7 show conventional circuits to solve these problems, in which the power switch 7 is a three-contact power switch. That is, the effect of preventing discharge to the controller power supply 10 due to discharge of the capacitor 11 after the power is turned off is the same as in the embodiment described later. however,
In the devices shown in these drawings, if the lower contact opens earlier than the other two contacts, a surge voltage is applied to the capacitor, which may puncture the capacitor. In particular, in the one in Figure 7, the capacitor 11
Since the voltage across both terminals of the capacitor 11 is more than doubled (several times higher in the case of surge voltage generation), the capacitor 11 cannot be put to practical use unless its withstand voltage limit is increased to more than twice the normal voltage.

[Purpose of the invention]

The purpose of the present invention is to solve the above-mentioned conventional problems, and to prevent the risk of the output shaft rotating in response to an erroneous operation command due to the control circuit remaining alive after the power is turned off, and to An object of the present invention is to provide a control circuit for an electromagnetic clutch motor that prevents damage to the motor.

[Summary of the Invention] The present invention uses a three-contact switch as a power switch, and uses two of the three contacts to open and close the power of a single-phase capacitor motor, and one of the two contacts and the remaining one. The contact point is used to open and close the power supply of the controller, so that the control system is not affected by capacitor discharge and the capacitor is prevented from being destroyed.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1 shows high voltage connections, and FIG. 2 shows low voltage connections. The main points of the improved invention are that a crossover wire 13 is provided on the main power supply 20 side, the power switch 7 is a three-contact switch, the top and middle two contacts drive the capacitor motor, and the top and bottom contacts drive the controller. The circuit configuration is such that the power supply 1 is opened and closed. Note that parts indicated by the same reference numerals as in FIGS. 4 to 7 are the same parts as in the prior art.

〔Effect of the invention〕

As described above, according to the present invention, even if the controller receives an erroneous operation command after the power switch is turned off, the electromagnetic clutch, brake section, and load are not driven and controlled, so safety is greatly improved. Also,
It is also possible to prevent destruction of the capacitor.

[Brief explanation of the drawing]

1 and 2 are control circuit diagrams showing one embodiment of the present invention, FIG. 3 is an overall block diagram,
4 to 7 respectively show conventional examples, FIGS. 4 and 5 are circuit diagrams using a two-contact power switch, and FIGS. 6 and 7 respectively.
The figure is a circuit diagram also using a three-contact power switch. 1...Electric motor, 2...Electromagnetic clutch, brake, 3
...Controller, 4...Operation command, 5...Detector, 6...Load, 7...Power switch, 8...Auxiliary coil, 9...Main coil, 10...Controller power supply, 11...Capacitor,
12... Main coil, 13... Crossover wire, 20... Main power supply.

Claims (1)

[Claims] 1. A capacitor motor that is started and operated by a capacitor, a clutch that transmits the power of the motor to an output shaft, a brake machine that stops the output shaft, a controller that electrically controls this clutch or brake, and the In a device consisting of a power supply unit for a motor and a controller, the power switch has three contacts, two of which open and close the power supply to the capacitor motor, and one of the two contacts to which the capacitor is not connected, and one of the three contacts to which the capacitor is not connected. With one contact remaining,
A control circuit for an electromagnetic clutch motor, characterized in that it is configured to open and close a controller power supply.