JPS6244428Y2 - - Google Patents

Description

[Detailed description of the invention] As shown in Fig. 1, the conventional control circuit includes an auxiliary electromagnetic contactor coil 3 for ON operation, an auxiliary electromagnetic coil 4 for OFF operation, and a self-holding contact 3a for ON or OFF. 4a, main circuit operation contacts 3b, 3
A control unit consisting of auxiliary electromagnetic contactors 3 and 4 equipped with motor stop brake circuit contacts 3e and 4e, a resistor 5, and a terminal block 8 is used as a control unit. The electric motor 6 of the electrically operated circuit/breaker is operated by installing it separately or incorporating it into the electrically operated circuit/disconnector. The operation is shown in Figure 1.
When ON operation button switch 1 is closed,
The ON auxiliary electromagnetic contactor coil 3 is excited, and at the same time, the self-holding contact 3a and the main circuit contact 3
b, 3c, and 3d close and the motor stop brake circuit contact 3e opens, causing the motor 6 to rotate. When the circuit or disconnector is operated, the limit switch 7 is switched and the ON auxiliary electromagnetic Contactor coil 3 is released and 3a, 3b, 3c, 3
Since d is open and Be is closed, the motor 6 is short-circuited and comes to a sudden stop due to dynamic braking. A similar operation is performed for the OFF operation.

In circuits that use conventional contacts such as auxiliary electromagnetic contacts, the number of contacts increases, such as configuring multiple contacts in a series to increase the contact capacity in order to share the contact voltage for DC load and disconnection. Since the excitation coil is also larger than that for AC, there is a limit to the miniaturization of the control unit. Alternatively, the surge of the excitation coil may have an adverse effect on other electronic equipment, and a surge absorber must be provided. In addition, there are other problems such as the need to provide a space for installing the control unit on the switchboard or the like.

In addition, when the limit switch 7 switches from one contact to the other, it takes a long time because there is a relay between the end of the limit switch switching and the stopping of the motor, and the operating lever of the breaker comes to the stop position. The limit switch must be operated sooner. However, in general, the operating force of the lever of the sheath disconnector is large at positions other than the lever's stop position, and suddenly decreases near the stop position. If the motor is stopped at a location where the operating force is large, it will stop immediately at that location, so it cannot be stopped.

Therefore, the limit switch must be operated only when the breaker lever is near the stop position, which delays the stopping of the motor and inevitably causes the lever to return a little beyond the stop position. If this return range is large, there is a risk that the breaker may be operated in the opposite direction (meaning it turns OFF when it was intended to turn ON).

In view of the above points, the present invention allows miniaturization by making the contacts of the control circuit stationary.
The purpose is to reduce the negative impact on other electronic devices.

The present invention is characterized in that a control circuit is constructed by using semiconductor switch elements for the conventional main circuit operation contacts, motor brake contacts, and operation self-holding contacts.

An embodiment of the control circuit according to the present invention is shown in FIG. This circuit includes push buttons 10 and 11 for operation, a limit switch 17 for detecting the position of the circuit breaker,
18, Thyristor 13 for main circuit operation, Thyristor 15 for motor stop, Thyristor 13 for main circuit operation
Thyristor 4 for opening and closing of thyristor 15 for stopping the motor, and resistors 19, 20, 2
1, 22, 23, 24, 25, 26, consists of capacitors, and operates by operating push button switch 1
0 is closed, a signal is sent to the gate of the main circuit operating thyristor 13 through the limit switch 17, turning it on, the motor 16 rotates, and the circuit and disconnector are operated. At the same time, relay 12
is excited, the contact 12a is closed, and the capacitor 29 is charged. Here, when the operation of the circuit and disconnector is completed, the limit switch 18 switches from one side to the other, but in the middle of this, the potential of the capacitor 28 rises and the thyristor 1
A signal enters gate 4 and turns it on. At this time, since the level at the terminal of the capacitor 29 suddenly drops, the anode of the thyristor 13 is pulled to a low level and a reverse voltage is applied, causing the thyristor 13 to turn off and the main circuit to open. At the same time, a signal is applied from the capacitor 30 to the gate of the thyristor 15, causing the motor stop thyristor 15 to close, and the motor to stop suddenly due to dynamic braking.

After the thyristor 13 is opened, the relay 12 is de-energized and the contact 12a is opened, so the thyristor 14
Power supply to is stopped.

FIG. 4 is a diagram showing another embodiment of the present invention.
In this embodiment, capacitor 32 is
is charged, and at the same time when the relay 12 is de-energized by operating the limit switch, a signal is sent from the capacitor 32 to the gate of the thyristor via the b contact 12b of the relay 12. In addition, 19, 20, 21, 22, 23, 24, 2 in Fig. 4
6 and 27 are resistors.

In the present invention, the thyristor 14 is immediately closed at the initial stage of operation of the limit switch, that is, as soon as the center contact of the limit switch 17 approaches one of the contacts, and the thyristors 13 and 15 are driven to the open and closed states, respectively. This eliminates the need for a limit switch to switch from one contact point to the other, and since the circuit is composed of semiconductor elements, the operating speed is faster than that of a relay. High braking effect. Note that the relay 12 only opens the thyristor 14, so it may be small.

As is clear from the above explanation, according to the present invention, a thyristor can be provided instead of a large relay as in the conventional method, so the size of the control unit can be reduced and the relay can also be small. The input surge of the excitation coil is also reduced, and the adverse effect on other electronic devices can be reduced.
Furthermore, since the time from the operation of the limit switch to the stop of the electric motor is short, the lever of the shield breaker can be stopped at a predetermined stop position, and mistakes in operating the shield breaker can be prevented.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of the conventional example, Fig. 2a is a plan view of the control unit, Fig. 2b is a front view, Fig. 3 is a circuit diagram of the embodiment of the present invention, and Fig. 4 is another one. FIG. 2 is a circuit configuration diagram of an embodiment of the present invention. 10, 11: Closing switch, 13: Stationary main switch, 14: Stationary control switch, 15: Stationary braking switch, 16: Electric motor for operating circuit breakers, 17, 18: Limit switch.

Claims (1)

[Scope of utility model registration request] A closing switch for operating a motor for circuit and disconnection operation, a static main switch connected in series with the motor and conducting upon receiving a gate signal when the closing switch is closed, and a static main switch connected in parallel with the motor and conducting. A static brake switch short-circuits both ends of the motor, a limit switch that is switched when the operating lever of the cutter reaches a predetermined position as the motor operates, and a limit switch that is opened during the switching operation. a static control switch that receives a gate signal and becomes conductive when the condition is established, and applies a change signal caused by the conduction to both of the static switches to open the main switch and close the brake switch. and disconnection control circuits.