Machine Parts

In a series motor the flux depends upon the current in the series field, which is the same current that flows through the armature. At light loads the armature current is small; therefore the flux and torque are small. An increase in the load increases both the armature current and the flux. The basic speed equation                                    S =        Vt   - IaRa   - IaRa           KФ Since the current in the series field is the armature current, the equation may be rewritten substituting Ia for Ф.                                ...