Why does an electric motor overheat?

I am going to assume this is a motor that has been working. If so, there are usually only a couple of things that change. First would be a loose or burnt connection. Do a visual check with power off to see if the wire ends are burnt. Second is bearing wear and/or failure. You can check the shaft and spin it by hand. IF there is side to side play or it feels rough, the bearings are out. The third possibility is whatever its turning has bound up. This would be the compressor on an air compressor or maybe a binding path on a garage door opener. If its a new motor, then factors like incorrect size and application come into play. In that case, you have to go back to the manufacturer of the product for original specs.  more