The introduction of the disassembling of a MCCB. Let’s take a look at the internal structure of MCCB.

Today we will bring you simple dismantling and emergency troubleshooting of moulded case circuit breakers.

Let us talk about the principle:

The main contact of the MCCB is closed by manual operation. After the main contact is closed, the free tripping mechanism locks the main contact in the closing position. The thermal element of the thermal release is in contact with the free tripping mechanism. When the circuit is overloaded, the thermal element of the thermal release releases heat and the bimetal is bent, pushing the free tripping mechanism and the main contact disconnects the main circuit.

disassembling of a MCCB
disassembling of a MCCB

There is no new MCCB around,use this old one to dismantle it. The left side is the parameter.

disassembling of a MCCB2
disassembling of a MCCB2

Remove the screw, open the lid, the internal look is crystal clear!

disassembling of a MCCB3
disassembling of a MCCB3

The handle can be removed. The exact name really does not know how to shout, ah ha ha!

Arc mask

disassembling of a MCCB4
disassembling of a MCCB4

Remove the arc mask, the main contact to see more clearly!

disassembling of a MCCB5
disassembling of a MCCB5

In the closing state, the main contact is closed.

disassembling of a MCCB6
disassembling of a MCCB6

In the open state, the main contact opens.

disassembling of a MCCB7
disassembling of a MCCB7

The red circle is a free tripping mechanism and the main body is an insulating sheet. Pressing or bending the metal sheet behind will push the trip mechanism.

disassembling of a MCCB8
disassembling of a MCCB8

Come to a manual press demo and it’s now tripped.

disassembling of a MCCB9
disassembling of a MCCB9

In the normal state, the free tripping mechanism is like this in the red circle.

 

When the current exceeds the trip setting, the free trip mechanism becomes no.1 circle after the action.

disassembling of a MCCB10
disassembling of a MCCB10

The specific process is to drive the mechanism of No. 2 circle after the red circle action of No. 1 after the current exceeds the trip setting. The main contacts are separated and the main circuit is disconnected. Current detachment is caused by the following conditions:

When the circuit is overloaded, the thermal element of the thermal release causes the bimetal to bend, pushing the free tripping mechanism, and the main contact opens the main circuit.

When the shunt trip button is pressed, the shunt release armature pulls in and causes the free trip mechanism to act and the main contact opens the main circuit.

disassembling of a MCCB11
disassembling of a MCCB11

A close-up photograph shows that the above-mentioned baby bottle-like metal piece is supported by a small piece of iron underneath. If the top of the bottle is not covered with the top one, it will trip.

Say a simple fault solution, if the circuit breaker trips, remove other reasons, or close the gate, it is necessary to open the circuit breaker, look here, is not the top of the iron below the top of the iron piece Now. Adjust it with a screwdriver and try again to close the brake.

On another occasion, it was the tripping of the main insulator that caused the trip. Temporary rescue uses a method of tying the insulating strips to the wooden strip and restoring it to a straight state, and then adjusting the tripping iron strip with a screwdriver. Only encountered 2 times in so many years, including 1 temporary rescue. This method is not recommended, there is a chance to immediately change, or there will be hidden dangers!

The above is a brief introduction of the circuit breaker, thanks for watching!

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