Patent ID: 6794967
Filing Date: 2004-09-21
Classification: H01H

Abstract:
An electromagnetic switch device for star-delta connections comprising:a body; first through third power terminals arranged at one side portion of the body on an upper surface of the body and respectively connected to three-phase power lines; first through third main starting terminals arranged at an intermediate portion of the body on the upper surface of the body and respectively connected to one-side terminals of a three-phase electric motor; first through third star-delta terminals arranged at the other side portion of the body on the upper surface of the body and connected to the other-side terminals of the three-phase electric motor, respectively; a star connection plate set on the upper surface of the body and adapted to connect the first through third star-delta terminals to a star circuit; first through third contacts set beneath the star connection plate and adapted to connect the first through third star-delta terminals to a delta circuit; a timer assembled to the body at a bottom of the body while being integral with the body, the timer serving to control a start-up time for the three-phase motor; an electromagnet for a main circuit and an electromagnet for star-delta connections each including a fixed core and a coil assembled in the interior of the body, each of the electromagnets being selectively magnetized in accordance with a cooperation of the fixed core and coil thereof; a main circuit switching unit assembled to an upper portion of the body at one side of the body so that it is integral with the body, the main circuit switching unit serving to selectively connect the first through third power terminals with the first through third main terminals, respectively, in accordance with the magnetization of the main circuit-end electromagnet; and a star-delta connection switching unit assembled to the upper portion of the body at the other side of the body so that it is integral with the body, the star-delta connection switching unit serving to connect the star connection plate to the first through third star-delta terminals in accordance with the magnetization of the main circuit-end electromagnet under a condition in which the first through third power terminals are connected with the first through third main terminals, thereby allowing the three-phase motor to be start up in a star connection state, the star-delta connection switching unit also serving to connect the first through third delta connection contacts to the first through third star-delta terminals when the star-delta connection-end electromagnet is magnetized in accordance with an operation of the timer after the start-up of the three-phase motor, thereby causing the three-phase motor to be driven in a delta connection state.