How do those contactors work? My friend Marco said he had wired up a ballpark with like 500 1500W MH flood lights and they all ran of a simple little 15A toggle switch on the wall and he said he used contactors and the 15A wall switch controlled the contactor and the contactor controlled the lights. But how does this work and how does a 15A switch control hundreds of amps of power without literally melting down?
A contactor is basically a relay that handles a high amount of current. In the ballpark, the 15A toggle switch switches the contactor which then switches the light. In this setup the toggle switch only handles the current used by the contactor coil. The current from the lights is handled by the contactor.
The group relay boxes work in a same way. The PC switches on the relay, which then switches on the lights.
Hmm but where does that extra current come from? Like if the lights draw a total of 200 amps and the contactor can handle that, but how do the fixtures draw 200A if there's only 15A to begin with?
Normally the coil would be wired by a simple 15 amp circuit. A Coil is a magnet and closes when voltage is applied. The toggle switch simply breaks that and causes the coil to open which then opens the contactor. The toggle switch may never see a half an amp. You can also wire photocells instead of a toggle switch and get the same action.
Login
The group relay boxes work in a same way. The PC switches on the relay, which then switches on the lights.