High-voltage Contactor (Main Relay)
Contactors are heavy-duty relays that connect or disconnect the high-voltage battery.
What is High-voltage Contactor (Main Relay)?
They open when the car is off or in a crash. They click when the car starts. They can weld if overloaded. Most cars have contactors on both the positive and negative side of the battery for redundancy. The quiet clunk heard when an electric car is switched on or off is usually the contactors. In a crash, the airbag control unit signals the battery system to open the contactors and isolate the high voltage.
How it works
A coil pulls contacts together to close the circuit.
Why it matters for your car
Contactor faults prevent driving. Replacement requires HV procedures.
Other terms
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- DAB Digital Radio
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- Total Cost Of Ownership (TCO)
- Vehicle-to-grid (V2G, Bidirectional Charging)