Patent GB-191020565-A (GB)
Title: Improvements in Motor Starting Rheostats.
Inventor: PERRY WILLIAM FELLOWS
IPC: H02P1/18
Filed: 1910-09-03
Granted: 1911-09-04
Abstract: 20,565. Perry, W. F. Sept. 3. Controllers, actuating-mechanism for; controllers with overload and underload release.- Relates to rheostats of the type in which the circuit-breaker arm is held on by an electromagnet provided with a second winding which, nn an overload, de-energizes the magnet and opens the circuit-breaker. The circuit-breaker arm and the control lever may be mechanically connected at will. As shown in Fig. 1, current passes from the positive main 1 through the circuit-breaker arm 3 and switch arm 4, which are pivoted together at 14 or may be joined by a flexible wire, resistance 6, series magnet coil 11, armature to lead 8, and second circuitbreaker 9 to the negative main 7. Current also passes from the pivot 14 through a hold-on coil 10 and shunt field to line 8. The arm 3 is held on by the shunt coil 10, which is surrounded by the series coil 11, so that, on an overload, the coil 11 de-energizes the magnet to release the circuit-breaker, which is then pulled off its contact by a spring 12, Fig. 2. Either of the coils 10 or 11 may be provided with an adjustable resistance shunt 17 for regulating. The circuit-breaker and switch arm 4 are so interlocked that, when the arm 4 is moved, the circuit-breaker is closed, but is free to open afterwards and the arm 4 is free to move backwards over the contacts to cut out resistance. The arm 9 carries a projection 18 adapted to engage projections 19, 20 on the arm 3, so that the switch 9 is operated by the arm 3 to open or close at the same time as the switch 3. As shown in Figs. 3 and 4, the handle has a plunger 16 engaging one end of a pivoted lever 40 controlled by a spring 41, so that, on depression, the other end of the lever 40 engages a projection 42 on the arm 3, locking the arms together. If the plunger is released before the " no " resistance " position is reached, a depending piece 44 on the lever 40 contacts with a segment strip 25 connected to one end of the hold-on coil 10, which is short-circuited, releasing the circuit-breaker. The plunger, which is provided with a disk 43, may be omitted, and the handle connected direct to the lever 40. In order to prevent the motor from being started too rapidly, means are provided to short-circuit the hold-on coil when resistance is cut out too quickly. The starter is fixed to a wall and the arm 4 carries a pivoted lever 27, Fig. 5, having a cam piece 28 and carrying a weight 26. Normally, the cam 28 does not touch the strip 25, but if the arm 4 is moved too quickly, the weight will lag behind and cause the cam to engage the strip and short - circuit the hold - on coil. A steadying-spring 29 is provided. In a modification, the upper end of the lever 27 has a pawl adapted to engage ratchet teeth on the underside of the strip 25; or, according to the Provisional Specification, the teeth may be on the top side of the strip. The device is enclosed in a casing having a round opening. A circular disk 33 of insulating-material, having a gastight joint between its periphery and casing, is arranged to move with the control lever.