Using two-phase synchronous motor as stepping motor - by phase displacement network which does not give rise to any heat development

摘要

For a two-phase synchronous motor to be built like a step motor, the following conditions have to be fulfilled:- the voltage must be sine-shaped, there must be virtually 90 deg. phase (P1,P2) displacement, and the voltage in both phases must by the same. The motor requires to be coupled to the electrical mains by semi-conductors for a specific number of periods. During the time that it is not coupled to the mains it is connected to a brake and hold direct current feed, also by a semi-conductor. To prevent a capacitive coupling current shock, an inductance or resistance is coupled in series with the capacitors. Changeover from mains to hold DC occurs most suitably when both phases are 45 and 135 deg. beyond zero point, with the same current direction as the hold DC.