A resistor is provided in parallel with the capacitor of a phase compensating circuit in order that a rapid transition may be made to a steady velocity state when a motor is started, a target velocity (reference velocity) is changed, or a large fluctuation in load occurs. When the steady velocity state...http://www.google.es/patents/US4902949?utm_source=gb-gplus-sharePatente US4902949 - Motor servo circuit
