Installation and Maintenance Manual
GEI-M1031-B
10
III. INSTALLATION (cont’d)
D. Power Supply and Connections (cont’d)
2. Allowable Voltage and Frequency
The power supply must agree with the nameplate voltage and frequency. The motors
will operate (but with characteristics somewhat different from nameplate values) on line
voltages within 10% of nameplate value and frequency within 5%, and a combined
variation not to exceed 10%.
Motors identified as “usable at 200V” will not operate full loads on line voltages below
190V. Motors will not meet NEMA MG-1 performance standards (including efficiency)
when operated at 200V.
3. Position of the Conduit Box
When mounting conditions permit, the conduit box may be rotated so that entrance can
be made upward, downward, or from either side.
IV. OPERATION
A. Prior to Starting
B. Insulation Resistance
In accordance with established standards, the recommended minimum insulation
resistance for the stator winding when measured with a 500 volt DC direct indicating
ohmmeter with self-contained power supply (megger), is as follows:
R
s
= 5 MΩ
R
s
is the recommended minimum insulation resistance in megohms at 40C of the entire
stator winding obtained by applying direct potential to the entire winding for one minute.
See IEEE Recommended Practice for Testing Insulation Resistance of Rotating Machines,
Publication No. 43, for more complete information. If the insulation resistance is lower than
this value, it is advisable to eliminate the moisture in one of the following ways:
Warning
If the motor has been stored in a damp location, dry it out thoroughly before
operating. Before energizing the motor for the first time or after an extended shut
down, it is advisable to check Insulation Resistance, power supply and mechanical
freedom of the motor.
Warning
Before measuring insulation resistance, the machine must be at standstill and all
windings to be tested must be electrically connected to the frame and to ground for
a time sufficient to remove all residual electrostatic charge. Failure to observe these
precautions may result in injury to personnel, damage to the equipment or both.