Keeping the air vents and cooling fins clean off debris, so the motor can dissipate it's heat.
Check that the machine it is driving, has no binding rotating matters which could slow the motor down, or make starting more difficult. Do a load check when the machine is running and check that the current measured, is within the nameplate rating. Check mains voltage too. Undervoltage to motors will reduce starting torque and may cause a motor to stall and burn out prematurely. Check thermal overload settings set correctly. Check fusing. Correct size, motorrated.
When fully isolated from the supply.
Check end play on bearings. Do an insulation test on the windings.
Hope this will help
Kind regards, Raymond
The product of rotation, excitation and flux produces electricty.
There's not a lot to worry about ... as far as the motor itself is concerned. The right motor, installed correctly, will not only run darn near forever ... it will give lots of warning when it's getting tired.
There are three phase of maintenance: 1) Verify the selection; 2) Check the install; and, 3) Keep testing records
You verify the selection by comparing actual voltage and amp draw to the nameplate info. Check the running temps. As Rod said, keep it clean.
The motor has to be properly mounted, with the shaft/sheaves properly lined up. Belt/chain tension ought to be correct.
If you have a megger, there are a series of tests you can perform. These tests, for the most part, begin when the motor is new, and are periodically repeated. Comparing the results over time will give you ample warning that the motor is about to fail.
How long can a motor last? This is the original 400v 'Drouard' 5hp 3-phase 6 pole 900 rpm motor running my ancient bandsaw. Renovated a couple of years ago, this machine is in constant daily use. Built in Paris about 1931. I think you are supposed to re-grease the bearings on these old motors every 20,000 hours.