GB469930A - Improvements in, or relating to, starting switches for use in connection with electric motors - Google Patents

Abstract

469,930. Controllers. CRABTREE & CO., Ltd., J. A., and McLOUGHLIN, H. F. Jan. 3, 1936, No. 3136/37. Divided out of 469,935. [Class 38 (iii)] In a star-delta starter in which two electromagnetically operated contactors are operated in succession under the control of a dash-pot regulated auxiliary switch which starts its closing movement when the first contactor is closed, the holding coils, magnets and armatures of the contactors are mounted on an insulating base c, and the armatures are connected to their respective moving contacts which are arranged with the complementary fixed contacts underneath the base. In the de-energized position of the first contactor which completes the connection to the supply, a contact bridge f rests on a stud e<1> which is biassed upwardly by springs e<3>, and holds the stud against the springs. When, at starting, the contactor is energized the bridge f moves upwardly and the stud e<1> operated by the springs against a dash-pot h closes an auxiliary switch which energizes the second contactor to change the connections from star to delta. Upon operation of a stop switch, or overload release the first contactor opens and returns the auxiliary switch to the off position The switch contacts are contained in an oil tank d<1> below a magnet casing d, and the fixed contact g of the auxiliary switch is mounted on a screw g<1> which passes through the base c into the casing d and is easily adjusted, to determine the time interval between the successive operation of the contactors, by removing the cover of the casing without detachment of the oil-tank.