How to identify an unknown electrical contact?

Perhaps you’re new to your position in a plant or the motor controller has simply been operating for a long while - but eventually contacts wear out. And when they do it’s critical to get the motor starter functioning as quickly as possible - lost production is lost money. But what happens if the manufacturer or type of contact is unknown? Or perhaps the OEM has closed; changed names or the series has been discontinued. It happens.

Here are some simple steps to identify your contact

First, look for the OEM number of the contact or contact kit. If it’s not available try to determine the current-carrying capacity by NEMA size. Most European and Asian motor control manufacturers will identify the capacity by amperage or horsepower (IEC). See the chart below for reference.

If you still can’t identify your contact, call us!

If the NEMA table isn’t working, try to determine the number of the contactor or motor control device. If that also fails try to identify the contact via the coil number - it can usually be helpful. In the worst-case scenario - and all of the above hasn’t helped - and no nameplate data exists, Repco can help to identify your contact the old fashion way. Trace the contact on regular paper (to size) and copy or photograph it from various views and email or fax these to us. We can match it against our library of reference parts and draw upon the experience of our team. Or you can always send us a duplicate contact for direct examination and identification. You can also send the worn out contact but that’s a bit tougher to match - though we do enjoy a challenge.