How to Test a Contactor: Step-by-Step Guide

Most of the testing of contractors out there tests of machines consist almost entirely of power electronics, machine and other devices in industry.
Contactors
A contactor is an electrical operated switch is used for making and breaking in and on and off switching operations. Circuits whose control is through motor control circuits, and for heating and lighting control also use contactors. Knowing how to test a contactor correctly will save you many a penny of damage to dear equipment and costly down-time. In this simple guide well be describe touching your pulse but will teach you to test the contactor in al step by step way. Using a mutlimeter its actually cut and dry read on to find out . . .
Step 1 :Safety First
Of course safety come first above all whether working with electricity or not. Here’s just part of the long long list of tips you must abide by:
Make absolutely sure that the supply is off to the contractor itself and whatever load connected to it.
Wear protective of course if you are from shock and other three ring dangers.Bearly alarm bells
Test not only the supply but that contractor itself isnt live before attempting to follow guide.
Step 2 :Testing Visually
A visual test is pretty much always the first step on such testingWhat youre doing is looking for anything that isnt obviously in the wrong way looking for the telltale signs of wear and tear.Contact condition.Look for some nice reg conditions.Are any of the contacts burnt or pitted? Any visible cracks or any other obvious damage? If you see burn marks or anything that looks out of place, the contactor must be replaced before you do any more checking.
Step 3: Test Coil Continuity
The coil is what actually puts the energy into the mechanism to open/close the actual contacts. If for some reason the coil appears to be bad, the contactor will not work!
To check the coil:
Put your meter in ohm / resistance mode.
Put the lead on the contacts of the contactor coil
If it is good you should see low resistance (generally between 10 and100 ohms) with the meter looking at it.
If you get open / infinite resistance, then the coil bad and the contactor must be replaced.
Step 4: Check the Points
A contactor has no good unless the contacts that are making / breaking the circuit are good. After a while they may be burned or pitted and the contactor is nothing more than a high resistance! This may cause an excessive heating and burn out the contactorm or open the circuit in them.
To check the points:
Set your multimeter to put it in “continuity” (or “resistance”) mode.If you have normally open (NO) contacts!With meter test probes, one on the inputs of the contact, one on the output side Step 4 – Test energised coil Isolate the circuit. With the contactor not powered, you should see ‘Energise the contactor, voltage through the coil (and wiring stays relatively easy to check). Once you have energised you should find very little resistance (zero) between each set of probes. If you energise as above and find they are high resistance/all open circuit, take one contact -50/50 approach, otherwise they’re most likely burned out/worn Step 5 -Test contact pressure The heat generated will be dependant on contact pressure. The lower the pressure, the last good the contact earths the contacts should be. You should have contact pressure gauge to test this. Replace contactor, if pressure too low. Step 6 -Test mechanical action Not pushing the contacts together properly, when coil is energised, will cause you problems. You need to be able to watch/se/mechanically check the contacts operation, when coil is energised. Apply volts to coil. Listen and for a click, with the closing f the contactors and for cogging/sticking with it (or not opening/closing properly off a guy gantry). The move freely, there is no obstruction. If not there’s a mechanical problem/or coil. Step 7 -Verification of operation Now you should put the contactor back in service and try It under load. Do the contact disengage easily when they should do, officially indicating load taken of (by clearing switch). Try it under load, do you sense it works as normal? Conclusion Contactors should never be tested as described above. Visually inspections is one think and testing and checking functionality another. You can see o need to make sure a machine works, thus saving on break downs idles equipment and heart attack. if your industry is reliant upon silicon carbide for power electronics on power systems applications in cool, EV, or Guido? photovoltaics then you want reliable contact performance. Integrating testing and technology upgrade to your contactors will be key toning out the worries, repair niggles and optimise performance.