Patent ID: 6297573
Filing Date: 2001-10-02
Classification: H02H,H02K,H02P

Abstract:
A three-phase motor for operation with a three-phase mains supply,with three single- or multiple-strand windings to form a star-connected set of windings, such that neutral-end terminals at neutral-ends of the windings are accessible outside the set of windings,an electronic switch so constructed and so connected by way of switch terminals to the neutral-end terminals that said neutral-end terminals can be electrically connected to one another during a process of turning the motor on and disconnected from one another during a process of turning off, andwith a control circuit for controlling the electronic switch, so connected to the latter and so constructed that in response to an external signal the electronic switch can be turned on,wherein the electronic switch is mounted in a terminal box attached to the three-phase motor,with at least one temperature sensor constructed so as to monitor the temperature of the electronic switch and connected to the control circuit, the control circuit being so constructed that the electronic switch is turned on only if the temperature sensor signals a temperature that is not dangerous to the electronic switch, andwherein the control circuit is connected to a measurement device that is connected to the neutral-end terminals and monitors neutral-end voltages, the control circuit being so constructed that processes of turning the switch on and off are controlled in dependence on the neutral-end voltages.