Measurements of Iron Losses in Single-/Phase Squirrel Cage Motors

To determine the iron losses of a shaded pole motor, the authors have removed the shading ring, thus obtaining a single phase motor of particular characteristics. Using Veinott's method, they first obtained 60 Watts under normal conditions, that is to say, 30 Watts per kilogram of lamination. To check this value, they tried to set up two other methods, which are the object of the present paper. In both methods, the motor is represented by the equivalent circuit of a single phase-motor without iron losses, in parallel with a constant resistance which absorbs a power equal to the iron losses (which are thus assumed constant). The first method is based on some geometrical properties of the impedance diagram of a single phase motor. The second method is analytical. A modification of Veinott's method is then presented to explain the results.