Teco Installation and Maintenance Manual
TEFC Squirrel Cage Induction Motors
Teco Electric and Machinery Company
Manual Number: IOM ~ TEFC Rev.01
21
b.
Voltage variation should be confined to /-10% of nameplate
voltage, and the three phase voltages should be balanced.
c.
Check if the phase currents of the motor, without load, are /-5% of
the average values.
4.2.5.
Frequency.
Frequency variation should be confined to /-5% of the nameplate
frequency. The aggregate variation of voltage and frequency should be
confined to /-10% of the absolute value of the rating.
4.2.6.
Run Up Time.
4.3.
CAUTIONARY POINTS TO NOTE:
4.3.1. Bearings:
a.
The motor is fitted with grease lubricated bearings. Following initial start up
the bearing temperatures should be closely monitored. A rapid rate of rise
in bearing temperature is more indicative of impending trouble, however,
when greasing an expected higher temperature is normal and should
equalize after a period of time.
b.
When the rate of bearing temperature rise is less than 1°C per half hour,
the bearing temperature is considered to be stabilised.
c.
If the total bearing temperature exceeds 100°C, the motor should be shut
down immediately and subsequent checks be undertaken.
The Run Up time is longer for motors connected to a load with a large inertia.
However, if the run up time exceeds what is deemed normal or there is
abnormal noise, the motor and load should be examined to establish the
cause before attempting a restart.
