What the Electromagnetic Contactor (Schneider / Chint / ABB) does
Contactors switch heavy loads by remote control. In generator systems they make the changeover between mains and generator, start large motors and shed non-essential loads.
A contactor's main contacts wear each time they switch under load. Pitted, burnt or welded contacts cause overheating, voltage drop and, in a changeover, the risk of failing to transfer.
Signs it needs replacing
- Burnt, pitted or welded main contacts.
- Contactor overheating or discoloured.
- Failure to close or open; mechanical sticking.
Get the right part first time
Send us these on WhatsApp and our engineers will confirm the exact part before you pay:
- Brand, model and current rating from the existing contactor.
- Coil voltage and number of poles.
- Load current it switches.
Fitting notes
Isolate and prove both sources dead. Size the contactor for the load current and type of load — motor loads need a higher rating. In changeovers, mechanical and electrical interlocking must be retained so mains and generator can never connect together.
Frequently asked questions
What size contactor do I need?+
It depends on the load current and the type of load. Send us the existing contactor details or the load and we will size it.
Are 3-pole or 4-pole contactors used for changeover?+
It depends on the earthing arrangement and whether the neutral must be switched. Our engineers advise based on your installation.
Why is the interlock important?+
It prevents mains and generator being connected together, which can destroy the generator and endanger workers on the grid.