Circuit Breaker Components

internal accessories
Auxiliary contact: A contact that is mechanically linked to the opening and closing mechanism of the main circuit of the circuit breaker. It is mainly used to display the opening and closing status of the circuit breaker. It is connected to the control circuit of the circuit breaker and is connected to the circuit breaker through the opening and closing of the circuit breaker. Relevant electrical appliances are controlled or interlocked. For example, output signals to signal lights, relays, etc. The rated current of the molded case circuit breaker frame is 100A, which is a single-break point change-over contact, and the rated current of 225A and above is a bridge contact structure, and the agreed heating current is 3A; the frame rated current of 400A and above can be equipped with two normally open and two normally open contacts. Closed, the heating current is agreed to be 6A. The number of operating performance times is the same as the total number of operating performance times of the circuit breaker.
Alarm contact: Alarm contact used for circuit breaker accidents, and this contact only operates when the circuit breaker is tripped and broken. It is mainly used to trip freely and alarm when the load of the circuit breaker has overload, short circuit or under-voltage faults. The contacts are converted from the original normally open position to the closed position, and the indicator light, bell, buzzer, etc. in the auxiliary circuit is turned on to display or remind the fault tripping status of the circuit breaker. Since the probability of the circuit breaker tripping due to load failure is not very high, the life of the alarm contact is 1/10 of the life of the circuit breaker. The operating current of the alarm contact generally does not exceed 1A.
Shunt release: The shunt release is a release that is excited by a voltage source, and its voltage has nothing to do with the main circuit voltage. The shunt tripper is an accessory that controls the opening of the switch remotely. When the power supply voltage is equal to any voltage between 70% and 110% of the rated control power supply voltage, the circuit breaker can be reliably opened. The shunt tripper is a short-time working system, and the coil energization time generally cannot exceed 1S, otherwise the line will be burned. In order to prevent the coil from burning out, a microswitch is connected in series to the shunt trip coil of the molded case circuit breaker. When the shunt tripper is closed through the armature, the microswitch changes from the normally closed state to the normally open state. Due to the power supply of the shunt tripper The control circuit is cut off, even if the button is manually pressed, the shunt coil will never be energized again, which avoids coil burnout. When the circuit breaker is closed again, the micro switch is in the normally closed position again.
Undervoltage release: The undervoltage release is a release that allows the circuit breaker to open with or without delay when its terminal voltage drops to a certain specified range. When the power supply voltage drops (even Slowly decrease) to the range of 70% to 35% of the rated operating voltage, the undervoltage release should operate. When the power supply voltage is equal to 35% of the rated operating voltage of the release, the undervoltage release should It can prevent the circuit breaker from closing; when the power supply voltage is equal to or greater than 85% of the rated operating voltage of the undervoltage release, it should be able to ensure that the circuit breaker is reliably closed under hot conditions. Therefore, when a certain voltage drop occurs in the power supply voltage in the protected circuit, the circuit breaker can be automatically opened to cut off the power supply, so that the load appliances or electrical equipment below the circuit breaker are protected from under-voltage damage. When in use, the undervoltage release coil is connected to the power side of the circuit breaker. The circuit breaker can be closed only after the undervoltage release is powered on.