In a circuit breaker, a trip coil and a close coil serve distinct functions related to the operation of the breaker. The trip coil is an electromagnet that, when energized, causes the circuit breaker contacts to open quickly. It is designed to trip the breaker in response to abnormal conditions such as overcurrents, short circuits, or faults in the electrical system. When the trip coil receives a signal from protective relays or manual controls indicating a fault, it generates a magnetic field that pulls the trip latch mechanism, releasing the breaker contacts to open and interrupt the electrical current flow.
On the other hand, the close coil in a circuit breaker is responsible for closing or making the breaker contacts. When the close coil is energized, it generates a magnetic field that attracts the closing mechanism of the breaker. This action brings the contacts together, allowing the circuit to be closed and electrical current to flow through the breaker when normal operating conditions are restored or after maintenance.
The closing coil of an Air Circuit Breaker (ACB) serves the function of closing the contacts of the breaker to complete the electrical circuit. When the ACB is operated to restore power after a trip or for maintenance purposes, the closing coil is energized. This energization creates a magnetic field that pulls the closing mechanism, bringing the contacts together to allow current flow through the breaker. The closing coil is essential for the controlled operation of ACBs, ensuring safe and reliable switching of electrical circuits.
“Trip on breaker” refers to the action of tripping or opening a circuit breaker in response to abnormal electrical conditions. Circuit breakers are designed to automatically trip when they detect faults such as overcurrents, short circuits, or ground faults that exceed safe operating limits. This tripping action is initiated by the trip coil within the breaker, which is activated by protective relays or manual controls. Tripping prevents damage to electrical equipment, minimizes the risk of electrical fires, and protects personnel from electric shock hazards by quickly interrupting the flow of electrical current in the event of a fault.
Some circuit breakers are equipped with two trip coils for specific operational requirements and redundancy. Having two trip coils allows for dual trip paths or multiple protective functions to be implemented in the breaker. For example, one trip coil may respond to overload conditions, while the other could respond to short circuits or ground faults. This dual-trip coil configuration enhances the reliability and flexibility of the circuit breaker’s protective functions, ensuring that it can respond effectively to various fault scenarios and meet stringent operational requirements in industrial, commercial, and utility applications.
A Vacuum Circuit Breaker (VCB) typically contains several coils for different operational functions, including trip and close coils. The exact number of coils in a VCB can vary depending on the specific design and manufacturer specifications. Generally, VCBs are equipped with at least one trip coil and one close coil. The trip coil is used to initiate the opening of the breaker contacts in response to fault conditions, while the close coil is used to close the contacts to restore normal circuit operation. These coils are essential components that enable the controlled switching and protection of electrical circuits in VCBs, ensuring safe and reliable operation in various applications.