Iron losses in d.c. machines

In Section I the iron loss in six d.c. machines with undistorted flux has been analysed to determine:¿ (a) The effect of high flux-density upon the hysteresis loss. (b) The hysteresis and eddy-current exponents over a wide range of flux density. (c) The ranges of frequency and of flux density over which the total iron loss can be represented by an expression of the from k1fxBy. (d) The values of k1, x and y 0.018 in lohys laminations. (e) The agreement between values of iron loss calculated from k1f1.5B2 with the measured values over wide ranges of frequency and of flux density. In Section 2 the increase of iron loss with load is examined. The iron loss due to the commutating-pole flux is considered, and a method of calculating the iron loss for any degree of distortion of the main flux is suggested. The values calculated by this method are compared with those measured on a dynamo in which different degrees of distortion were obtained by means of a compensating winding.