What is a circuit breaker?

A circuit breaker is a mechanical switch device that can connect, carry, and interrupt the current under normal circuit conditions. It can also connect, carry for a certain period, and interrupt the current under specified abnormal circuit conditions. It functions as a protector against short-circuits and overloads.

Typically, a circuit breaker can be replaced by an isolating switch in series with a suitable fuse. The only difference is that when the fuse blows, the fuse core needs to be replaced. When the circuit breaker trips due to overload, it only needs to be reset by pushing the switch back up.

Circuit breakers with a rated current of 125A or below are commonly referred to as miniature circuit breakers.

DC mcb

How does a circuit breaker safeguard circuit safety?

  1. In the event of a general overload in the circuit, the overload current generates a certain amount of heat in the thermal element, prompting the bimetal strip to bend upwards due to heat. This pushes the lever to disconnect the hook from the latch, breaking the main contacts and cutting off the power supply.
  2. When a short circuit or severe overload current occurs in the circuit, if the short circuit current exceeds the preset current value of the instantaneous trip device, the electromagnetic trip device produces a strong enough attraction force. This pulls the armature in and strikes the lever, causing the hook to rotate upwards around the shaft seat and disengage from the latch. The latch, under the action of the return spring, breaks the main contacts, thus cutting off the power supply.
  3. Auxiliary contacts are contacts mechanically linked to the main circuit’s open/close mechanism in the circuit breaker. They are primarily used to display the open/close status of the circuit breaker and are connected to the circuit breaker’s control circuit. They control or interlock related electrical equipment through the opening and closing of the circuit breaker.
  4. A shunt trip device is a trip device excited by a voltage source. Its voltage can be unrelated to the main circuit voltage, and it’s an accessory for remote operation of tripping. When the power supply voltage is between 70%-110% of the rated control power supply voltage, the circuit breaker can be reliably tripped.

Circuit breakers act to connect, disconnect, and carry the rated working current and fault currents such as short-circuits and overloads in the circuit. When overload, short circuit, and under-voltage situations occur in the line and load, they rapidly break the circuit, offering reliable protection.

Internal structure of battery breaker

Why choose ONCCY circuit breakers?

ONCCY boasts a professional circuit breaker development team with years of experience. From the introduction of energy storage mini breakers to date, they have continuously been recognized by customers. ONCCY is currently providing high-quality products to numerous top global energy storage battery and system manufacturers, having become a supplier for many mainstream energy storage battery and system manufacturers, and this share is continually increasing.

In particular, their non-polar miniature circuit breaker has received high praise from the industry. This non-polar DC miniature circuit breaker relies on a new miniature circuit breaker arc extinguishing system, which solves the issues of casing rupture due to high-temperature gases produced by arc extinguishing, poor arc extinguishing effects, and complex structures in traditional miniature circuit breakers.

EDB1-125 1P DC MCB
EDB1-125 1P DC MCB

Recommend a circuit breaker suitable for energy storage batteries.

The ONCCY battery DC miniature circuit breaker is recommended. Its interrupting capacity reaches 10kA, the maximum rated voltage is 200VDC, and the rated current can reach 125A. With its non-polar design, the protection effect is enhanced. The electrical life can reach 1500 times, and the mechanical life is up to 20,000 times.