Challenges in the segregation of losses in cage induction machines

The possibility to separate the components of total losses in a cage induction machine by using measurements is investigated. The total losses of the test machines applied are measured utilizing a standard no-load test. For determining the electromagnetic losses, a slip-control measurement is proposed. In the measurement, the mechanical losses of a test machine are compensated by a slip-ring machine mounted on a same shaft. The friction losses of the test machines are measured by three types of experiments, by a variable-voltage, retardation and variable-frequency test. The results obtained do not only clarify the challenges in the loss separation but also indicate the problems in the experimental definition of the friction losses.