Temperature
The
temperatures rise at various parts of the motor due to the heat loss
dissipated in the motor. An excessive temperature rise will cause the
deterioration of the insulation, and so the temperatures of the coils
and adjacent core are to be kept below the specified temperature rise
limit. There are the following three different methods for temperature
measurement.
Thermometer Method
This
is a method of measuring temperatures by fitting thermometers to the
measuring parts of a motor. Usually, thermometers are fitted to the
frame or to the bearings. This method is widely used for temperature
measurement.
Resistance Method
This
is a method of measuring the mean temperature of the coil by utilizing
the change of the coil resistance with the temperature; the temperature
is calculated in the following way.
where,
continue and see the next part http://hayatei.blogspot.com/2010/12/trouble-shooting-for-hv-motors.html