Electric Motor Repair or Replace .pdf
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Electric Motor: Repair or Replace
Key words: rewind motor, electric motor repairs,repair electric motor,motor
repair,motor replacements,replacement motors,electric motor replacement,replacement
electric motors,electric motor rewinding
When a motor fails in facilities, engineering and maintenance managers will
have to face a critical decision: whether to repair or replace it. To solve this
problem, several aspects should be considered.
1. Consider the size of the motor.
Efficiency varies by motor size, with larger motors tends to have higher
efficiency. Motors are often oversized for their function, meaning that they are
not used at the full-load efficiency stated on their nameplate. Thus larger motor
can be replaced by a smaller horsepower motor. An alternative is to install an
adjustable speed drive (ASD) for the motor, which can yield 10% energy
savings for refrigeration applications, 15% for air compressors, and 20% for
pumps and fans. Undersized motor shall be replaced otherwise it will run
hotter than normal, shorting its service life.
2. Consider the Rewinding Time
Careful rewinding can maintain and in some cases improve the motor
efficiency. But in most cases, rewinding results in increased losses, which in
turn result in reduction of efficiency, converting to greater energy consumption
and increased operating cost. The number of rewinds is often thought to be a
maximum of two or three. If a motor has been rewound many times, you might
consider to replace the motor.
3. Consider the Downtime
Failed motors can lead to increased downtime and higher maintenance costs.
Most motors are stock items and are soon available. But special, non-standard
motors may take weeks or even months to be available for a replacement.
Considering the huge production loss, it’s better to repair the motor instead of
4. Consider the Life-cost
Usually the initial purchase price of a motor represents no more than 5% of its
life-cycle cost, and the operating cost accounts for over 90 percent. Thus it’s
economical to replace an older, inefficient motor with a more efficient model,
which will pay for themselves quickly in saved operating costs.
In this aspect, decision can be made by using software tools, spreadsheets
and many other resources. Normally the result is a simple payback, which, if
less than a specified time, replacement would be economical. With motor
horsepower, load, efficiency, energy and demand costs in mind, you can do the
When you make a replacement, how would you deal with the old motor?
Maybe you have considered to recover the copper winding but don’t have an
efficient method. The truth is that there are equipment special for recycling the
motor copper. Use our motor stator recycling machines, you can recycling