For many years, dc motors have been the workhorse of variable speed drives in the paper industry. Many mills have inquired about operating motors beyond the original motor rating. With armature voltage limited by the drive, motor speed may be increased by reducing the shunt field current but not without consideration of vibration, machine adjustment, brush performance, and possible commutation issues, because the machine was not designed and tested at those conditions. This article examines and presents test/field data displaying the effects of field weakening on dc machine performance and maintenance.
展开▼
