Measuring Winding DC Resistance

Описание: Why should you wait until current reaches steady state to measure winding DC resistance?

Winding DC resistance is an important measurement. This resistance can be used as a quality check as well as used for calculating I^2R losses. This resistance is also used for calculating average winding rise during temperature rise test. It takes a few minutes for current to reach steady state due to the L/R time constant. One way to reduce the time constant is to reduce L by increasing the applied current. However, the applied current should not be more than 10-15% of the full load current of the winding under test to avoid heating, etc.