Electronic overload relay power source

摘要

An overload relay, and an overload relay control circuit power source are disclosed herein. The overload relay includes an electronic trip circuit, a contactor such as a three-phase contactor, a current transformer associated with each power conductor coupled to the contactor, and a transformer associated with the contactor. The current transformers are coupled to the control circuit which controls the supply of power to the solenoid of the contactor based upon the level of current flowing in the power conductors connected to the contactor. The solenoid of the contactor is connected to at least one power conductor and maintains the contacts closed when the solenoid is energized. The transformer is magnetically coupled to the windings of the solenoid and produces the power required by the control circuit when the solenoid is energized and the contacts of the contactor are closed.