I N S TA L L AT I O N , O P ER AT I O N S A N D M A I N T EN A N C E M A N UA L
37
Initial operation of the motor control center
Because of problems that may occur during the
initial energizing of the motor control equipment,
only qualified personnel should carry out this
startup procedure.
Use the following procedure for initial startup of
the motor control equipment. Be sure that the
steps in the previous section, Preparing for Initial
Operation, have been completed.
1. Ensure that all doors are closed and latched and
all external covers on the motor control center
are secured. Visually check that all latches on arc-
resistant enclosures are engaged.
2. Verify that all main and branch disconnects
within the motor control center are OFF.
3. Verify (with an insulation-resistance tester) that
all main incoming feeders to the motor control
center are adequately insulated.
4. Close the upstream feeder to energize the motor
control center.
5. Close the main disconnects, if any, at the
motor control center.
6. Close each branch-circuit disconnect or feeder at
the motor control center. For AFM Units, ensure
that all visual indicators are showing “RED” to
indicate “ENGAGED” stab position and “OPEN”
shutter position.
7. Operate each motor starter individually to verify
satisfactory operation, including the following
parameters:
- Motor rotation
- Pilot light indication
- Electrical interlocking
- Acceleration and sequence timing
8. Adjust instantaneous settings on
magnetic-only circuit breakers and/or fuse sizes
and overload heater selections to achieve proper
motor and branch circuit protection.
(See NEC Article 430.52.) Since the adjustable
trip setting on magnetic-only circuit breakers is
factory set at the minimum trip position,
nuisance tripping may occur on initial
motor starting.
Increase the trip setting in increments until
tripping no longer occurs during motor starting.
Do not exceed the maximum trip settings given in
overload relay tables in this publication. All
adjustable overloads are also factory set at
minimum. Check motor name-plate data and set
overloads accordingly.
WARNING
Because of problems that may occur during the
initial energizing of the motor control equipment,
only qualified personnel should carry out this
startup procedure.
WARNING
15. Conduct electrical insulation resistance tests
from phase to phase, phase to ground, phase
to neutral, and neutral to ground. If any section
tested under the above conditions shows
resistance values less than 1 megohm, inspect
it for possible tracking on insulation or
insulation breakdown. Typical value can be 50
megaohm or greater, but may vary based on
humidity.
16. Similarly, test individual feeder and motor
circuit wiring (field wiring) as each set of
conductors is pulled into the motor control
center, before terminating the conductors at
either end.
17. With all disconnects OFF, close and latch the
doors. For AFM units, ensure that all visual
indicators are showing "RED" to indicate
"ENGAGED" stab position and "OPEN"
shutter position.