Teco Installation and Maintenance Manual
TEFC Squirrel Cage Induction Motors
Teco Electric and Machinery Company
Manual Number: IOM ~ TEFC Rev.01
32
c.
Steam temperature should be maintained between 50
0
C – 80
0
C.
d.
After cleaning, dry immediately.
6.2.3. Drying Method.
a.
Application:
i. Drying after cleaning.
ii. Motor has absorbed moisture.
b.
Hot air method (using heater and blower).
i.
Parts to be dried are surrounded inside a steel plate leaving an inlet and an
outlet for hot air. Hot air will enter the inlet to dry parts (stator, rotor, etc.),
and will leave via the outlet carrying away moisture.
ii.
The temperature within the area surrounded by the steel plate should be
maintained at 90
0
C – 100
0
C.
c.
Drying with infrared ray lamp:
i.
Install the infrared ray lamp in a baking area surrounded with steel plate
with openings at the bottom.
ii.
This method can cause partial overheating. So attention must be paid to the
parts heated and the temperature must be kept below 100
0
C.
d.
Drying method with electric current:
i.
The winding must have a minimum insulation resistance above 0.5MΩ
measured with 500VDC megger before using this method so as to avoid a
short circuit.
ii.
Lock the rotor (short the secondary winding of the wound rotor motor),
apply rated voltage of approximately 5% - 10% to the winding.
iii.
Temperature control settings:
Squirrel cage rotor induction motor: 70
0
C – 80
0
C for the stator.
e.
Measurement of insulation resistance.
i.
Measure the insulation resistance periodically during drying.
ii.
At the initial stage of drying, insulation resistance may decline slightly.
When it returns to normal, the drying process is complete.
iii.
When the current method is applied, be sure to turn off the power to
measure insulation resistance.
