GB895107A - Electric switch - Google Patents

Abstract

895,107. Control of A.C. motors; electromagnetic switches. ELLENBERGER & POENSGEN G.m.b.H. Aug. 18, 1959 [Sept. 26, 1958], No. 28180/59. Classes 38 (3) and 38 (5). A split-phase motor is started by closing a main switch (not shown) to energize main motor windings 55, 56, and starting winding 59, the circuit to a heating coil 9 being also completed at this time. After the operating speed of the motor is reached, bimetallic strip 6 is bent so that contact 12 engages contact 14 on spring 13, whereby relay-coil 27 is energized to attract armature 30. In this position, the starting circuit is opened at contacts 32, 35, and the heating-coil 9 is de-energized to return the strip 6 to its original position. A holding circuit for the relay-coil 27 is completed through contacts 33, 36. When the main switch is opened, a spring 31 returns the armature 30 to re-close contacts 32, 35, and to open contacts 33, 36, thus restoring the system to its original condition. The spring 13 is bimetallic to compensate for ambient temperature, and cooperates with a grub-screw 20 for setting the distance between the contacts 12, 14. In another arrangement, closure of the main switch energizes the main motor windings (connected to strips 69, 70) as well as the starting winding (connected to strips 5, 69). The heating-coil 9 is also energized and the bimetal 6 is bent until it engages stop-member 72 on spring 62. This disengages contacts 63, 64, so that resistor 65 is connected in series with the coil 9 to reduce the heating current. Further bending of the strip 6, at a slower rate, engages contact 12 with contact 14 on spring 13 to energize relay-coil 27. The armature 30 is attracted to separate contacts 32, 35, and to close holding contacts 33, 36, so that the starting circuit and the heating-coil 9 are deenergized. The strip 6 cools and returns to its original position, thus releasing the spring 62 to re-engage contacts 63, 64. The armature 30 co-operates with a contact 75 for bridging signal contacts 80, 81, and 78, 79, alternately. The spring 62 consists of a bimetal and resistor 65 forms a heating-coil therefor, whereby the contacts 12, 14 are engaged after the same delay regardless of the distance between the contacts and the temperature of the strip 6 when the motor is switched on.