JPH1014082A - Operation circuit for circuit breaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To monitor breakage in a trip coil with accuracy by providing a light emitting diode that is serially connected with a current-limiting resistor and a control power supply and emits light when it is not under inspection, and is serially connected with the current-limiting resistor and the trip coil and emits light when it is under inspection. SOLUTION: A first auxiliary relay 14 is not excited when inspection is not under way; its normally closed contact 14b is closed and a light emitting diode 15 emits light. When a phototransistor 13 is provided with an inspection signal of light, the first auxiliary relay 14 is excited, and closes its normally open contact 14a and opens the normally closed contact 14b. For the reason, with power applied, current is passed through the light emitting diode 15, a current limiting resistor 16, normally open contacts 14a, 7 and a trip coil 5, and the light emitting diode 15 emits light as in the above-mentioned case. Therefore, it is possible to confirm that the trip coil 5 is not broken by checking the light emission.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an operation circuit of a circuit breaker, and more particularly to a disconnection monitoring of a trip coil.

[0002]

2. Description of the Related Art FIG. 3 is a circuit diagram of an operation circuit of a conventional circuit breaker, wherein 1 is a positive power bus of a control power supply, 2 is a negative power bus of a control power supply, 3 is a closing coil provided in a circuit breaker 4, 5 is a trip coil, 6 and 7 are a normally closed contact and a normally open contact of a second auxiliary relay also provided in the circuit breaker 4, and the normally closed contact 6 is operated by an operating mechanism when the circuit breaker is turned on. Turns off and turns on during trip operation. The normally open contact 7 is reversed. A manually operated closing switch 8, a normally closed contact 6, and a closing coil 3 are connected in series between the positive and negative buses 1, 2, and a manual trip switch 9, a normally open contact between the positive and negative buses 1, 2. 7 and a trip coil 5 are connected in series, and a monitoring relay 10 is connected in parallel with the trip switch 9. 10a is the normally open contact.

In the above configuration, the normally-closed contact 6 is on in the cut-off state shown in the figure, so when the making switch 8 is turned on, the making coil 3 is excited and the breaker is turned on. At this time, the normally open contact 7 turns on, and the normally closed contact 6 turns off.
In this closed state, current flows through the monitoring relay 10, the normally open contact 7 and the trip coil 5, but since the monitoring relay 10 has a high impedance, only a current of about several tens mA flows and the trip coil 5 And the tripping coil 5 does not operate. Monitoring relay 1
Since 0 has reached the operating current, the normally open contact 10a is turned on, and it is confirmed that the tripping coil 5 is normal without disconnection. When the trip coil 5 is disconnected, the monitoring relay 10 does not operate even in the closed state, and the normally open contact 10a does not turn on, so that the disconnection can be detected.

[0004]

However, in the conventional circuit breaker operation circuit described above, the operating current and the return current of the tripping coil 5 and the monitoring relay 10 or the current value that can be continuously energized are taken into consideration. Since it is necessary to select the impedance of the monitoring relay 10 and the specifications of the trip coil 5 differ depending on the type of the circuit breaker, it is difficult to select the monitoring relay 10. Further, in the closed state, since current always flows through the tripping coil 5 and the monitoring relay 10, the life thereof is shortened due to heat generation. When the monitoring relay 10 is burned, the tripping coil 5 is connected to the tripping coil 5 and the monitoring relay 10. A large current may flow, and the tripping coil 5 may malfunction. Further, when the monitoring relay 10 is disconnected, it may be erroneously recognized that the trip coil 5 is disconnected.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is possible to accurately monitor a disconnection of a tripping coil, to have a simple circuit configuration, and to generate heat of the tripping coil. It is an object of the present invention to obtain an operation circuit of a circuit breaker that can prevent damage and malfunction due to the power supply.

[0006]

According to a first aspect of the present invention, there is provided an operation circuit for a circuit breaker, comprising: a closing coil for closing the circuit breaker; a trip coil for tripping the circuit breaker; The light emitting diode is connected to the power supply in series with the current limiting resistor to emit light, and the control power supply for inspection is provided with a light emitting diode connected to the current limiting resistor and the stripped coil to emit light in series.

A circuit for operating a circuit breaker according to a second aspect of the present invention is operated while being connected to a closing coil for closing the circuit breaker, a trip coil for tripping the circuit breaker, and a non-inspection control power supply. The inspection control power supply is provided with a monitoring relay which operates in series with the trip coil.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a circuit diagram of an operation circuit of a circuit breaker according to a first embodiment. Reference numeral 11 denotes a trip switch provided in a protective relay 12 and connected in parallel with a trip switch 9. Automatically turns on when the condition occurs, the trip coil 5 is excited, and the circuit breaker is shut off. 13 is a phototransistor, 14 is a first auxiliary relay, 14
Reference numerals a and 14b denote normally open contacts and normally closed contacts of the auxiliary relay 14;
5 is a light emitting diode, 16 is a current limiting resistor, and these are also provided in the protection relay 12. Light emitting diode 1
5, the series connection of the current limiting resistor 16 and the normally open contact 14a is connected in parallel with the trip switch 9, and the light emitting diode 15, the current limiting resistor 16 and the normally closed contact 14b are connected in series between the positive and negative buses 1 and 2. The phototransistor 13 and the first auxiliary relay 14 are also connected in series between the positive and negative buses 1 and 2.

In the above configuration, the first auxiliary relay 14
Is not energized when not inspected, its normally closed contact 14b is closed, and the light emitting diode 15 emits light. By detecting this light emission directly or by using a photocoupler or the like, it can be confirmed that the light emitting diode 15 and the current limiting resistor 16 are not short-circuited or disconnected. here,
When an inspection signal by light is given to the phototransistor 13, the phototransistor 13 is turned on and the first auxiliary relay 1 is turned on.
4 is energized, the normally open contact 14a is closed, and the normally closed contact 1 is closed.
4b opens. For this reason, in the closed state, current flows through the light emitting diode 15, the current limiting resistor 16, the normally open contacts 14a and 7, and the trip coil 5, and the light emitting diode 15 still emits light. Therefore, by confirming this light emission, it can be confirmed that the tripping coil 5 is not disconnected. The above current is a very small current, and the trip coil 5 does not operate.

In the first embodiment, it is possible to detect that the tripping coil 5 is not disconnected by the light emission of the light emitting diode 15 when the inspection signal is given.
In addition, since the current flows through the light emitting diode 15 and the current limiting resistor 16 even when the inspection signal is not applied, it is possible to check for a short circuit or disconnection thereof, and a large current flows through the tripping coil 5 when a short circuit occurs. Malfunction is prevented, and the disconnection of the trip coil 5 at the time of disconnection is prevented from being mistaken. In addition, since the operating current of the light emitting diode 15 is very small, the current flowing through the trip coil 5 may be small, and the current flows only when an inspection signal is given, so that damage due to heat generation of the trip coil is prevented.
Further, since the operating current of the light emitting diode 15 is small, there is no need to select it, and the circuit configuration is simplified.

Embodiment 2 FIG. 2 is a circuit diagram of an operation circuit of a circuit breaker according to Embodiment 2, and reference numeral 17 denotes a manual inspection switch. Auxiliary relay 14
Are connected in series, a series connection of the monitoring relay 10 and the normally open contact 14a of the first auxiliary relay 14 is connected in parallel with the trip switch 9, and the monitoring relay 10
And the normally closed contact 14b of the first auxiliary relay 14 are connected in series between the positive and negative buses 1 and 2. The normally open contact 10a of the monitoring relay 10 and the lamp 18 are connected in series between the positive and negative buses 1 and 2.

In the above configuration, the first auxiliary relay is not energized when not inspected, the normally closed contact 14b is closed,
The monitoring relay 10 is excited, its normally open contact 10a is closed, and the lamp 18 is turned on. Thereby, it is confirmed that the monitoring relay 10 does not short-circuit or break. Here, when the inspection switch 17 is turned on, the first auxiliary relay 14 is excited, and the normally open contact 14a is closed. In the closed state, the normally open contact 7 is closed, so that the current flows through the monitoring relay 10, the normally open contacts 14 a and 7, and the trip coil 5.
And the monitoring relay 10 is excited, and the normally open contact 10a
Is closed and the lamp 18 is turned on to confirm that the tripping coil 5 is not disconnected.

In the second embodiment, the inspection switch 1
By turning on the lamp 18 when the switch 7 is turned on, it is confirmed that the tripping coil 5 is not broken, and when the check switch 17 is turned off, current flows through the monitoring relay 10 and the lamp 18 is turned on. Monitoring relay 1
It is confirmed that 0 is not short-circuited or disconnected, so that a large current flows through the tripping coil 5 in the event of a short-circuit and malfunctions are prevented, and the disconnection of the tripping coil 5 is mistaken for a disconnection. Is prevented. Also, current flows through the trip coil 5 only during inspection, so that damage due to heat generation is prevented.

[0014]

As described above, according to the first aspect of the present invention, the light emitting diode which is connected in series with the inspection time-limiting resistor and the tripping coil and emits light is provided, and whether or not the light emitting diode emits light is provided. Thereby, it can be detected whether or not the trip coil is disconnected. In addition, the light emitting diode emits light even when it is not inspected, so it is possible to detect a short circuit or disconnection of the light emitting diode or the current limiting resistor,
It is possible to prevent a large current from flowing through the trip switch when a short circuit occurs and malfunction, and to prevent a mistaken recognition of a trip coil as a break when the wire is broken. Further, since only a small current flows through the trip coil only during inspection, damage due to heat generation is prevented. Further, since the light emitting diode emits light by a very small current, its selection is easy.

According to a second aspect of the present invention, a monitoring relay is provided which operates in series with the trip coil at the time of inspection, and the trip coil is disconnected depending on whether the monitoring relay operates. Can be detected.
In addition, the monitoring relay is operated even during non-inspection, and short-circuit and disconnection of the monitoring relay can be detected, and malfunction of the tripping coil at short-circuit and disconnection of the tripping coil at disconnection can be detected. False recognition can be prevented. or,
Since the current flows through the trip coil only during inspection, damage due to heat generation can be prevented.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of an operation circuit of a circuit breaker according to Embodiment 1 of the present invention.

FIG. 2 is a circuit diagram of an operation circuit of a circuit breaker according to a second embodiment.

FIG. 3 is a circuit diagram of a conventional operation circuit of a circuit breaker.

[Explanation of symbols]

 1, 2, positive and negative buses 3, closing coil 5, trip switch 8, closing switch 9, trip switch 10, monitoring relay 13, phototransistor 14, first auxiliary relay 14a, normally open contact 14b, normally closed Contact 15: Light emitting diode 16: Current limiting resistor 17: Inspection switch 18: Lamp

Claims (2)

[Claims] 1. A closing coil which is connected to a control power supply when the closing switch is turned on to operate and turns on the circuit breaker, and which is connected to the control power supply when the tripping switch is turned on and operates to trip the circuit breaker. And a light emitting diode connected in series with the current limiting resistor to the non-inspection control power supply and emitting light, and having a light emitting diode connected in series with the current limiting resistor and the tripping coil to emit light in the inspection control power supply. An operation circuit for a circuit breaker, comprising: 2. A closing coil which is connected to the control power supply when the closing switch is turned on to operate and turns on the circuit breaker, and which is connected to the control power supply when the tripping switch is turned on and operates to trip the circuit breaker. The trip coil and the non-inspection control power supply are connected and operate.
An operation circuit for a circuit breaker, comprising: a monitoring relay that operates in series with a trip coil and a control power supply during inspection.