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Summary:
How
to Go About "Commissioning" a New Motor? With
trilingual summary
By
Richard L. Nailen, EA Engineering Editor
When a motor
fails prematurely, or exhibits unexpected operating problems, the
question often asked is: "Was it properly installed?" Following a
thorough, step-by-step procedure during the commissioning of new
equipment, and recording all the results, is the best way to be able
to answer that question affirmatively.
The steps to be
taken in readying a new motor for service include evaluation of:
1. The motor
itself -- its condition as received or taken from storage; its
nameplate data; the suitability of its enclosure to the environment;
lubrication status.
2. The electrical
supply system -- correct voltage; the phase sequence; connection
tightness; fuses; grounding.
3. Controls --
protective device settings; control circuit; motor accessories and
their intended functions; sensor connections; space heater integrity.
4. Mounting --
foundation stiffness; alignment and shimming; bolt tightness.
5. Coupling --
suitable for the application; insulation and lubrication as
appropriate; end play requirements.
6. Coordination
with the driven machine -- appropriate motor design type; proper
rotation and speed.
7. Surroundings
-- possible sources of damaging contamination; personnel safety.
Next, the motor
should be run uncoupled for measurement and recording of vibration.
Consult the machinery operator to see if the expected frequency of
starting is within motor capability. Restore the coupling, and have
the operator start the motor normally, observing and recording thtat
procedure and the acceleration time. Record the vibration spectrum;
listen for unusual noise; Also record the ambient temperature, and
the motor bearing housing temperatures if the driven machine is
operating above ambient (such as a hot gas fan).
Finally, account
for all installation hardware. Screws or nuts misplaced during the
process have sometimes found their way into motor windings to cause
early failure.
Such a detailed commissioning procedure offers two
benefits. First, it provides baseline data supporting subsequent
maintenance trends. Second, it allows the installer to confidently
face that question: "Was it properly installed?"
Copyright 2003, Barks Publications, Inc., Chicago.
Reproduction by any means prohibited.
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