Stepping motor control - prevents resonance effects limiting speed during speed changes using separate current monitors

摘要

The control circuit, for stepping motors, prevents resonance effects limiting the motor speed during rapid speed changes by using several control circuits in parallel. The motor phase winding (10) is bridged by a diode (13) and supplied from a d.c. source (12) via the parallel control circuits (11). Each circuit contains a device (14) for measuring current, a switch and a Schmitt trigger (16) with timing components. Each circuit behaves as follows: when the current in the winding reaches a given max. the current monitor causes the trigger to operate, and the trigger opens the switch. The current in the winding now flows through the diode and drops. After a given time the current monitor and trigger close the switch and current is again supplied to the winding.