JPS5947850B2 - breaker check circuit - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a check circuit for the trip function of a circuit breaker whose opening and closing are controlled by an electronic circuit, and in particular to a check circuit that improves reliability by providing time coordination to each contact during checking. .

Conventionally, this type of breaker was checked by sending a check signal to the electronic circuit to see if the breaker tripped.

Therefore, the circuit breaker would be tripped if a check was made while the current was on, so it could not be used in devices where it would be a problem to interrupt the circuit even temporarily.

In order to eliminate this drawback, a display element is connected in series with the tripping coil of the circuit breaker, and the tripping coil is short-circuited at the same time as the check starts, allowing inspection of electronic circuits without tripping the circuit breaker. However, in such a check circuit, it is difficult to short-circuit the tripping coil before applying the inspection signal, or open the output of the detection current transformer after the tripping coil returns. If the opening and closing times of each contact were not well coordinated, there was a risk that the check circuit would not operate reliably.

In order to eliminate these drawbacks, the present invention checks the tripping function of the breaker without tripping the breaker, and also improves operational reliability by coordinating the opening and closing of each contact necessary for the check. It's meant to enhance it.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a circuit diagram showing an embodiment of the present invention, and FIG. 2 is a relay control circuit diagram for providing time coordination when checking the contacts shown in FIG. 1.

In FIG. 1, 1 is a line (schematically shown as one line) connecting a power source and a load.

), 2 is a current transformer that detects the current flowing in the load line, 3 is a rectifier bridge that rectifies the current detected by current transformer 2, and 4 inputs the rectified output via diode 5. A trip control circuit, 6 is a trip coil of the breaker 1, 7 is connected in series with the trip coil 6, and when an input of a predetermined value or more is applied to the trip control circuit 4, a signal is applied to the gate. conducting thyristor, 8
is a test circuit connected in parallel with the diode 5 and applying a check signal.

A check signal is applied by closing the normally open contact 9 of the check switch.

The above configuration is a general check circuit, and the present invention adds the following configuration.

That is, in FIG. 1, Xl is a contact of relay X that is closed when a check signal is applied, and X2 is a normally open contact of relay X, which is connected in parallel with the trip coil 6 and short-circuits the trip coil 6 when a check signal is applied. .

(X3) 3 is the normally closed contact of relay X and trip coil 6
When the inspection signal is applied, the series circuit of the tripping coil 6 and the rhinoceros 9 stuff is opened.

9 is a light emitting element such as a light emitting diode connected in parallel with the normally closed contact X3.

Yl is a normally open contact of a relay Y controlled by a 9-ray X and is connected in parallel with the current transformer 1.

zl is a normally open contact of 9 relays Z connected in series with relay contact X□, and the test circuit 8 of the constant current circuit has contacts
It is connected to the anode and cathode of the diode 5 via.

In FIG. 2, X, Y, and Z are relays that open and close the contacts shown in FIG. 1, respectively.

Relay X is energized by power supply 10 by closing inspection pushbutton switches P and B, and relay Y is energized by closing normally open contacts X, , X, of relay X.

Relay Y has a normally open contact Y2 connected in parallel with normally open contact X4 of nine relays X.

Relay Z is energized by the closing of normally open contact X6 of relay X, but with a time delay determined by the resistor R and the specified number of capacitors C.

The relay Z also has a normally open contact z2 connected in parallel with the normally open contact X6 of the relay X.

Next, the inspection operation in the above configuration will be explained.

When inspection push button switch P-B is closed, relay X operates, and its contacts X4. Due to the cycle of X, 9
Ray Y also works.

Contacts Xl, X2 and Yl are therefore closed and contact X3
opens.

Also, contact X6 closes due to the operation of relay X, creating a resistance R.

The time constant circuit of capacitor C operates, and relay 2 operates after a predetermined time.

Contact z1 is thereby closed.

After the tripping coil 6 and current transformer 2 are short-circuited by the above operation, an inspection input is applied from the test circuit 8 to the tripping control circuit 4 after a predetermined delay.

Then, the trip control circuit 4 performs a predetermined operation and sends an ignition signal to the thyristor γ to make it conductive.

At this time, the tripping coil 6 is short-circuited at the contact X2, so the breaker 1 does not trip.

On the other hand, the display element 9 of the light emitting diode emits light, and it can be seen that the electronic circuit of the trip stopper is operating normally.

If the display element 9 does not emit light when the inspection signal is applied, it is determined that the electronic circuit is malfunctioning.

Also, when the inspection switch P-B is used as a meter, relay X is deenergized, and the inspection input from constant current test circuit 8 is connected to contact
0 is disconnected, and the trip coil 6 is also released from the short circuit.

Thereafter, after a time delay until the charge in the capacitor C is discharged and falls below the holding voltage of the relay Z, the relay 2 is deenergized, and then the relay Y is deenergized and the current transformer 1 is also turned off by opening the contact Y1. Freed from short circuit.

All functions are thus restored to the state before the first inspection.

Although a current transformer is used as a load current detection means in the above, a detection resistor connected in series with the line may also be used, or a normal lamp may be used as a display element in place of a light emitting diode. .

As described above, the present invention makes it possible to inspect electronic circuits without tripping the circuit breaker, and moreover, applies an inspection signal after short-circuiting the tripping coil and current detection means. Since the current detection means is opened after the current detection means is restored, the operation can be performed reliably.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, and FIG. 2 is a control circuit for the contacts shown in FIG. In the figure, 1 is a breaker, 2 is a current transformer, 4 is a trip control circuit, 6 is a trip coil, 1 is a thyristor,
8 is a test circuit, 9 is a display element, x, y, z are relays,
X1-X6. Yl, Y2, Zl. Z2 is each contact of the relay.

Claims (1)

[Claims] 1 In a circuit breaker which detects the current flowing in a load line by a current detection means and opens and closes it by an electronic circuit based on the detected current, a first normally open circuit breaker connected in parallel with the trip coil of the circuit breaker a normally closed contact connected in series with the first normally open contact and the tripping coil and connected in parallel with a display element; a second normally open contact connected in parallel with the current detection means; , a third normally open contact connected between the electronic circuit of the breaker and a test circuit that applies a test signal to the electronic circuit, prior to closing of the third normally open contact during inspection of the breaker; The first and second normally open contacts are closed and the normally closed contact is opened, and after the inspection is completed, the first normally open contact is opened and the normally closed contact is opened before the second normally open contact is opened. A circuit breaker check circuit equipped with a control circuit that closes the closed contacts.