Contactor help ????

[Fabric8r]

Could someone please explain to me how these work a diagram would be nice if you could.
This is my idea I'm not sure if im right or not. It has a low votage to suck it in then it connects and lets the higher voltage through. Is there a way I can check to see if the ones I have are working correctly. If I need to use a voltmeter where do I put the leads and on what setting.
Sorry I'm kinda new at this. Any help would be appreciated.
Thank you, scott

[Al_The_Man]

A contactor is just a heavy duty relay, works on the same principal so a search for relay will give you esentially the same answer.
What you have to do is identify the coil connections and the voltage and whether AC or DC.
Essentially the difference is that a contactor has heavier duty contacts and generally is used to switch high current single phase and 3 phase loads. There will possibly be auxiliary contacts that can be used to latch the coil in, or other monitoring tasks.
If you apply the right voltage to the coil, you will see the armature pick up.
With a search you should be able to find a standard control on/emergency off circuit, that will give you an idea.
Yhis is a link that shows how overloads are placed in series with the coil circuit.
http://www.allaboutcircuits.com/vol_4/chpt_5/2.html
Al.