Tech Tip: Motors

What Can Be Done to Help Increase the Life of a Motor?

In order to help increase the life of a motor, inspect them at regular intervals.  Keep units clean and ventilation openings clear of dust, dirt or debris.  If re-lubrication is necessary, do not over grease as excessive lubrication may damage the motor.  Follow the re-greasing instructions in accordance with the supplier recommendations.

Why is Maximum Ambient Temperature Important?

It’s important that the ambient operating temperature of a motor does not exceed its maximum design ambient rated temperature, so that it does not overheat. The maximum ambient temperature in degrees Celsius determines the limit at which the motor can operate continuously at the rated horsepower and service factor without overheating. The NEMA standard is 40˚C (approximately 110˚F), but check the motor name plate for any exceptions.

What to Consider When Fitting a NEMA Premium® Electric Motor to Your Application

When fitting your NEMA Premium motor to your application, there are a number of items to consider.  For example, it should be noted that any increases in efficiency reduce the slip, which will increase the speed of the motor shaft.  If you want to maintain the same output with a more efficient motor, you may have to adjust your driven equipment.  The KVA code letter should be reviewed to determine motor starter size compatibility.  To obtain the best efficiencies, you should run the motor between 75 to 100 percent load.

NEMA & NEMA Premium marks are owned by National Electrical Manufacturers Association.

How Can Excessive Corrosion Be Avoided?

Some corrosion of metal components is unavoidable in applications where humidity can reach 100 percent. Normal levels of corrosion may look ugly, but it won’t prevent a motor from operating.  However, excessive corrosion of the bearing/shaft journal or between the rotor and stator can lead to premature motor failure. To avoid excessive corrosion:

• Reapply a rust preventive to motor surfaces during routine maintenance.
• Turn the motor shaft monthly when the motor is not in operation.
• Use space heaters or trickle voltage to eliminate condensation.

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