The main contact of the plastic case circuit breaker is closed by manual operation. After the main contact is closed, the free release mechanism locks the main contact at the closing position. The thermal element of the thermal release contacts with the free release mechanism. When the circuit is overloaded, the thermal element of the thermal release bends the bimetal sheet, pushes the action of the free release mechanism, and the main contact disconnects the main circuit.

If there is no new one around, we will use the old one to dismantle it. Left side as parameter

Remove the screw, open the lid, and have a clear look inside!

The state of plastic case circuit breaker after removal of hand power

Molded Case Circuit Breaker Arc Extinguishing Cover

Remove the arc extinguisher and the main contact will see more clearly.

Plastic case circuit breaker closing state, main contact closed.

Plastic case circuit breaker is in open state and main contact is disconnected.

The red ring is a free release mechanism, and the main body is an insulating sheet. Pressing or bending the metal sheet behind will push the release mechanism.

Let's have a manual press demonstration. Now it's off.

Normally, the free release mechanism is like this in the red circle.

When the current exceeds the jump-off setting, the free release mechanism becomes the same as that in the No. 1 loop.

The specific process is to drive the mechanism action in the second circle after the current exceeds the red circle action after the jump setting. The main contacts are separated and the main circuit is disconnected. Current overshoot is caused by the following conditions:

When the circuit is overloaded, the thermal element of the thermal release bends the bimetal sheet, pushes the free release mechanism to move, and the main contact disconnects the main circuit.

When the release button is pressed, the armature of the release device is sucked, so that the free release mechanism can move and the main contact can disconnect the main circuit.

At close range, a piece of metal similar to the nipple on the top is held up by a small piece of iron below, and if the top on the bottom is not attached to the top, it will be released.

Speaking of a simple fault solution, if the circuit breaker trips, excluding other reasons, or can not close the switch, it is necessary to open the circuit breaker, see here, is not the top of the iron sheet below. Adjust it with a screwdriver and try again to close the switch.

On another occasion, the main insulator was broken, resulting in tripping. The temporary rescue yard adopts the method of binding the insulating sheet to the wooden strip to restore the straight line state, and then adjusting the release sheet with a screwdriver. There have been only two such encounters over the years, one of which was a temporary rescue facility. This method is not recommended, have the opportunity to replace immediately, or there will be hidden dangers!

Source: Reprinted and arranged by Hangkaiele Electrical Appliances (Shanghai) Co., Ltd. (http://www.hangkaiele.com/) in the Electrical Home

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