The core principle of an air circuit breaker is “conduct normally, detect faults, disconnect rapidly.”
During normal operation, the mechanism closes the contacts to ensure stable power flow. When overload or short-circuit faults occur, the tripping system activates, rapidly opening the contacts while the arc-extinguishing device safely quenches the arc, cutting off the faulty circuit.

ACB: Core Principle from

Conduction to Disconnection

Core Components of an Air Circuit Breaker

Air Circuit Breakers (ACBs) are key protection devices in low-voltage power distribution, built around on/off control and fault protection. Their core components include:

Contact System: Provides the main current path. Silver-alloy main contacts ensure stable conductivity, while copper-tungsten arc contacts resist damage during breaking. Contacts close to conduct current and open to isolate the circuit.
Arc-Extinguishing Device: A grid-type chamber of 15–30 U-shaped steel plates that splits, cools, and quickly extinguishes the arc produced during contact separation.
Operating Mechanism: Typically a four-bar spring mechanism with a 4–6 m/s closing speed, operated manually or via motor/electromagnet to control contact opening and closing.
Trip System: Includes thermal units for overload protection and electromagnetic units for rapid short-circuit tripping. Drawer-type ACBs may also include drawers, intelligent units, terminals, remote operation, indicators, and other accessories.

Products We Foucs On ACB Parts

Haipart specializes in manufacturing internal parts for ACB.

We Offer ACB Component

ISO 9001Certification

All our staffs and machines within an Integrated Management System which passedIS0 9001 Quality System to ensure the delivery of services that are at an exception
level of quality, reliability, and value.

Automated Assembly Line

More efficient and more stable quality products for
you.

Semi-automatic Assembly Line

Available OEM and ODM customization needs, from
small orders to quantity orders.

Automatic Product Testing Machine

100% full inspection, reject all unqualifed products