the contact with the mechanical circuit of the main circuit of the circuit breaker is mainly used for the display of the circuit breaker's split and closed state. It is connected to the control circuit of the circuit breaker through the circuit breaker. The relevant electrical appliances are controlled or interlocked. For example, a signal is output to a signal lamp, a relay, or the like. Molded case circuit breaker frame rated current 100A for single breakpoint conversion contacts, 225A and above for bridge contact structure, the agreed heating current is 3A; frame rated current 400A and above can be installed with two normally open, two often Closed, the agreed heating current is 6A. The number of operational performance is the same as the total number of operational performance of the circuit breaker.
alarm contact for circuit breaker accident, and this contact only acts when the circuit breaker trips and breaks. It is mainly used for free tripping when the load of the circuit breaker is overloaded or under voltage. The contact is switched from the original normally open position to the closed position, and the indicator light or bell, buzzer, etc. in the auxiliary line is turned on, and the fault trip state of the circuit breaker is displayed or reminded. Since the probability of free tripping of the circuit breaker due to load failure is not too much, the life of the alarm contact is 1/10 of the life of the circuit breaker. The operating current of the alarm contact will generally not exceed 1A.
Shunt trip unit
Shunt trip unit is a trip unit that is excited by a voltage source. Its voltage is independent of the main circuit voltage. The shunt release is an accessory for remotely operated trips. 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 disconnected. The shunt release is a short-time work system. The coil energization time can't exceed 1S, otherwise the line will be burned. In order to prevent the coil from being burnt, the molded case circuit breaker is connected with a micro switch in the shunt trip coil. When the shunt release is engaged by the armature, the micro switch is switched from the normally closed state to the normally open state, because the shunt release power supply The control line is cut off, and even if the button is pressed artificially, the shunt coil will never be energized again, which avoids the occurrence of coil burnout. When the circuit breaker is reclosed, the micro switch is in the normally closed position again.
An undervoltage release is a type of trip that allows the circuit breaker to be delayed or without delay when its terminal voltage drops to a specified range. When the supply voltage drops (even Slowly descending) to the range of 70% to 35% of the rated operating voltage, the undervoltage release shall operate, and the undervoltage release shall be when the supply voltage is equal to 35% of the rated operating voltage of the trip unit. It can prevent the circuit breaker from closing; when the power supply voltage is equal to or greater than the rated working voltage of the 85% undervoltage release, the circuit breaker should be reliably closed under hot conditions. Therefore, when a certain voltage drop occurs in the power supply voltage of the protected circuit, the circuit breaker can be automatically disconnected to cut off the power supply, so that the load electrical equipment or electrical equipment below the circuit breaker is protected from undervoltage. When in use, the undervoltage release coil is connected to the power supply side of the circuit breaker, and the circuit breaker can be closed after the undervoltage release is energized.
Electric operating mechanism
This is an accessory for long-distance automatic opening and closing circuit breakers. The electric operating mechanism has two kinds of motor operating mechanism and electromagnet operating mechanism. The motor operating mechanism is a molded case circuit breaker case. Circuit breaker rated current 400A and above, electromagnet operating mechanism is suitable for circuit breaker circuit breaker frame rated current 225A and below circuit breakers, whether it is electromagnet or electric motor, their suction and rotation directions are the same, only The position of the cam inside the electric operating mechanism is used to achieve the combination. When the circuit breaker is operated by the motor-driven mechanism, the circuit breaker should be reliably closed at any voltage between 85% and 110% of the rated control voltage.
Rotating the operating handle
suitable for the molded case circuit breaker, the mechanism for rotating the operating handle is mounted on the cover of the circuit breaker, the rotating shaft of the handle is mounted in the matching hole of the mechanism, and the other end of the rotating shaft passes through the door opening of the drawer, and the handle of the rotating The handle is mounted on the shaft head exposed on the door of the complete device, and the round or square seat of the handle is screwed on the door. This installation enables the operator to rotate clockwise or counterclockwise through the handle of the handle outside the door. Make sure the circuit breaker is closed or opened. At the same time, turning the handle can ensure that the door cannot be opened when the circuit breaker is closed; only the door of the switch board can be opened only when the rotating handle is opened or refastened. In an emergency, when the circuit breaker is "closed" and needs to open the door panel, press the red release button on the side of the handle handle.
It is an external extension handle that is directly mounted on the handle of the circuit breaker. It is generally used on large-capacity circuit breakers of 600A and above for manual opening and closing operations.
Handle locking device
the card is mounted on the handle frame, the handle is punched and then locked with a padlock. Mainly used for the circuit breaker to be closed.
In the working state, the other person is not allowed to open the door to cause a power outage, or the load side circuit of the circuit breaker needs to be repaired or not allowed to be energized to prevent the circuit breaker from being closed by mistake.