Motor field control of large D-C reversing mill motors

This paper analyses the performance of the field-current regulator on a large d-c reversing mill drive. A study is made of the transfer functions associated with the shunt-field-controlled d-c motor. The results obtained from an analog computer study of the problem are discussed and a brief description of the analog setup used for the study is given in Appendix I. Particular attention is paid to the performance of the current-limit control. The over-all study revealed certain weaknesses in the type of system used in practice, and the paper concludes with a brief description of a control system which embodies improved features which were an outcome of the study.