Page 1 of 1
Electric Clutch Current Draw
Posted: Tue Mar 17, 2009 7:14 am
by Dirty
I am just wiring up an Endless Air compressor and need to make sure that the compressor clutch doesn't drag too much current for the pressure switch, power switch or a lamp that I wanted to put in series.
Basically, do I need to run a relay or not.
- David.
Posted: Tue Mar 17, 2009 8:17 am
by chimpboy
Most A/C compressors run a relay. However I think the need for this is not so much to do with current draw as to do with voltage drop. If you don't have a good solid power supply with minimal voltage drop at the clutch, it may not engage all the time or may engage poorly which will reduce its lifespan or even kill it really fast.
I think the actual draw is under 10A though. Not 100% sure but it is not terribly high.
I can see why you'd have the switches in series but wouldn't the lamp be in parallel?
Posted: Tue Mar 17, 2009 8:52 am
by Dirty
Chimpboy,
Thanks for that.
I am using one of these Carling switches:
So the LED light bar at the bottom will come on with the switch, and I was going to used the large decal light to come on when the compressor was actually pumping.
But I doubt that the globe would like 10A running though it and the voltage drop at the clutch is not acceptable. So I will add a relay into the system.
- David
Posted: Tue Mar 17, 2009 9:24 am
by stuee
Dont put a any lamps in series with any control circuits. If you blow a lamp you lose your control circuit, rather than just the indication. Always put lamps or indication lights in parallel. This doesn't mean just adding in a relay though.
When I get home I'll put a diagram up if someone doesn't beat me to it.
Posted: Tue Mar 17, 2009 10:54 am
by Dirty
stuee wrote:Dont put a any lamps in series with any control circuits. If you blow a lamp you lose your control circuit, rather than just the indication. Always put lamps or indication lights in parallel. This doesn't mean just adding in a relay though.
When I get home I'll put a diagram up if someone doesn't beat me to it.
Stu,
Good point, I was too busy trying to make this a simple as possible and didn't consider that.
I will just run a relay from the pressure switch and then do the compressor/indicator light in parallel from the relay.
- David