JPS648844B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a capacitor control circuit that controls turning on and off of a capacitor using an automatic power factor adjustment device.

Conventional capacitor control circuits for turning on and off capacitors using automatic power factor adjusters include not only capacitor control based on signals from the automatic power factor adjuster, but also manual control circuits, status display circuits, protection circuits, etc. It was necessary. In particular, the protection circuit detected overcurrent, internal pressure of the temperature capacitor, undervoltage, overvoltage, etc., turned off the electromagnetic contactor for switching the capacitor, and disconnected the capacitor from the circuit. To fulfill this function, each element required a detection element and a protective relay.

For example, in the event of a power outage, it is necessary to disconnect the capacitor from the circuit to prevent inrush current when the power is restored, so an undervoltage relay is used, and a control circuit that detects the voltage drop and generates a cutoff signal to disconnect the capacitor from the circuit. was necessary.

The present invention has been made in view of this point, and can be used in an automatic power factor adjustment device and an AC relay that outputs an A contact signal that is turned on for a certain period of time as a closing signal, and a B contact signal that is turned off for a certain period of time as a cutoff signal. It is an object of the present invention to provide a capacitor control circuit which has a relatively simple circuit configuration and can reliably disconnect the capacitor from the circuit during a power outage.

An embodiment of the present invention will be described below based on the drawings. In the figure, reference numeral 100 denotes an automatic power factor adjustment device that outputs a contact signal that has independent on/off signals and is turned on and off for a certain period of time. 1a, 1b, 1c
is an output contact on the closing side, and 3 is a common line for these output contacts. 2a, 2b, 2c are output contacts on the cut-off side, and 4 is a common line for these output contacts. 5a, 5
Relay solenoids b and 5c are connected to the output contacts 2a, 2b, and 2c on the cutoff side, respectively. Here, for convenience of explanation, one circuit of the relay solenoid 5a will be explained. It is assumed that AC power is applied between the relay solenoid 5a and the common line 4 of the cut-off side output contact. Since the contact 2a of the relay solenoid 5a is a B contact, it is normally excited, and therefore the contact 6 of this relay is normally in an on state.

The capacitor closing operation will be explained. First, when the output contact 1a on the closing side is turned on, the relay solenoid 7 is connected to the power supply line 8 of the sequence circuit, and current flows therethrough and the relay solenoid 7 is excited. Note that the sequence circuit power supply is a DC power supply. When the relay solenoid 7 is energized, the contact 9 of this relay is turned on, and current flows through the relay solenoid 7 via the contacts 6 and 9, so that it is self-holding and continues to be energized. Further, the contact 10 is turned on, and the solenoid 21 of the electromagnetic contactor 200 is energized. This turns off the auxiliary contact 22, but current flows through the saving resistor 23 to excite the solenoid 21. Excitation of the solenoid 21 turns on the main contact 24 of the electromagnetic contactor 200, connecting the capacitor 26 and the series reactor 25 to the circuit.

In the case of a cutoff operation, the output contact 2a on the cutoff side is turned off, so the relay solenoid 5a is deenergized and the contact 6 is turned off. Therefore, relay solenoid 7 is deenergized and contacts 9 and 10 are turned off. As a result, the self-holding of the relay solenoid 7 is released, and at the same time, the solenoid 21 of the electromagnetic contactor 200 is deenergized, its main contact 24 is turned off, and the capacitor 26,
Disconnect the series reactor 25 from the circuit.

Next, in the event of a power outage, the AC power is cut off, so the solenoid 5a of the relay is de-energized and the contact 6 is turned off, so that the capacitor can be disconnected from the circuit by the same operation as the above-mentioned cut-off operation.

Although omitted in the above explanation, the remaining closing side output contacts 1b, 1c and closing side output contacts 2b, 2
It goes without saying that a similar circuit is constructed for c. In addition, when the capacity of the output contact of the automatic power factor adjustment device 100 is insufficient, the relay solenoid 5
a, 5b, and 5c also have the effect of acting as a relay for increasing the width.

Further, although omitted in the explanation of this circuit, it has the advantage that manual turn-on and manual cut-off circuits can be easily constructed. This can be done by using a changeover switch, and making the portions corresponding to the contacts 1a and 6 push buttons.

As described above, according to the present invention, an automatic power factor adjustment device and an AC relay are used, which output an A contact signal that is turned on for a certain period of time as a closing signal, and a B contact signal that is turned off for a certain period of time as a cutoff signal. The capacitor can be disconnected from the circuit during a power outage without requiring a voltage drop detection circuit using an undervoltage relay or the like as shown in the figure, and the circuit configuration is simple and inexpensive.

[Brief explanation of the drawing]

The figure is a circuit diagram showing one embodiment of the present invention. In the figure, 100 is an automatic power factor adjustment device, 1a, 1b,
1c is the output contact on the input side, 3 is the common point, 2a, 2
b, 2c are the output contacts on the blocking side, 4 is the common line, 5
a, 5b, 5c are relay solenoids; 6 is a contact driven by the relay solenoid 5a; 7 is a relay solenoid; 8 is a control circuit power line; 9, 10
is a contact driven by relay solenoid 7, 2
00 is the electromagnetic contactor, 21 is the solenoid of the electromagnetic contactor, 22 is the auxiliary contact of the electromagnetic contactor, 23 is the saving resistor, 24 is the main contact, 25 is the series reactor, 26
is a capacitor.

Claims (1)

[Claims] 1: an automatic power factor adjustment device that independently outputs an a-contact signal that is turned on for a certain period of time as a closing signal, and a b-contact signal that is turned off for a certain period of time as a cutoff signal, and the automatic power factor adjustment device that is connected to the cutoff signal contact; A normally-excited relay circuit powered by an AC power source in a system whose power factor is improved by A capacitor control comprising: a relay self-holding circuit powered by a DC power source; and a capacitor opening/closing switch powered by the DC power source and driven by closing of a contact of the self-holding circuit. circuit.