Patent GB-191005278-A (GB)
Title: Improvements in or relating to Controllers for Electric Motors.
IPC: H02P1/06
Filed: 1910-03-02
Granted: 1911-03-02
Abstract: 5278. Adams Manufacturing Co., [Cutler Hammer Manufacturing Co.]. March 2. Automatic circuit-breakers; interlocked switches.-Relates to motor controllers of the kind in which an independent circuit-breaker is mechanically interlocked with a starting-device, so that this cannot be operated until the circuit-breaker is closed, mechanical means being provided for retaining the circuitbreaker closed, which means are tripped by an overload device to open the circuit-breaker. According to the invention, the circuitbreaker is closed by a handle which is retained in position to hold the circuit-breaker closed by mechanical means engaging the handle, which means are tripped by an overload device to release the handle and allow the circuit - breaker to open. The starting-device comprises multiple manually operated interlocked switches 1, 2, 3, 4, Fig. 1, of the kin d described in Specification 5261/10. Each switch has an arm 10 pivoted to a bracket 12 and carrying contacts bridging contacts 16 and a contact-strip 17. - An actuating-arm 19, Fig. 2, is pivoted on a lug 20 on the arm 10, and is connected by links 22 to the bracket 12, thereby forming a toggle. A lug 25 on each switch engages a loose latch 23, moving it up to engage a lug 24 on the previous switch to hold it in position. A pin 29, Fig. 1, on the last switch engages a hooked armature on a hold-on magnet 26. If the switches are closed in any other order than 1, 2, 3, 4, the lug 25 jams against the blunt end of the latch 23. The circuit-breakers are of similar construction, and each comprises a switch arm 30, Fig. 4, pivoted on a bracket 32, and an operating-handle 40 provided with an enlarged portion 41 pivoted at 42 on the arm 30 and links 43 forming a toggle. The circuitbreaker tends to move to open position by gravity like the switches, and a spring may be added to increase the tendency. A latch 44 holds it closed by engaging a roller 45 on the part 41, and is provided with a projection 50, which, when raised by the armature 49, Fig. 1, of the overload electro-magnet 47, disengages the roller and opens the circuit-breaker. The armature may be adjusted by a device 52, Fig.4, and downward movement of the latch 44 is limited by a lug 46 thereon engaging the bracket 32. The interlock between the circuitbreaker and the first switch comprises a dog 53, Fig. 3, with extensions 58, 56. Normaily, a spring 55 holds the dog in such a position that, if the first switch is closed when the circuitbreaker is in the open position, a pin 54 thereon engages a notch on the end of the dog 53, preventing further closure. When the circuitbreaker is closed first, a pin 57 thereon covered with insulating-material 57<a>, Fig. 1, engages the extension 58 and moves the dog 53 out of the path of the pin 54 so that the switches can be closed in sequence. If desired, a similar interlock may be provided between the two circuit-breakers. If the hold-on magnet 26 is de-energized, the switches 1, 2, 3, 4, open, but the circuit-breakers remain closed by reason of the mechanical latch 44 which is unaffected.