Patent GB-580974-A (GB)
Title: Improvements in or relating to electric circuit breaking apparatus
IPC: H01H9/26
Filed: 1940-03-11
Abstract: 580,974. Automatic circuit-breakers; switch cases. DAVIDSON, G. W., COATES, W. A., and METROPOLITAN-VICKERS ELECTRICAL CO., Ltd. March 11, 1940, No. 4549. [Class 38 (v)] A circuit-breaker arrangement suitable for use on board ship where space is limited, comprises one, and preferably two, circuit-breakers on a vertical base hinged on a horizontal axis parallel to the back of the casing, the base being also parallel to the back of the casing. Two identical circuit-breakers, one for each pole, are mounted at the sides of the base with a common closing solenoid in the centre between them, each breaker being provided with a trip coil serving also as the blow-out coil. The arrangement is a modification of that of Specification 580,972 and controls the connection of feeders to a ring main 1, 2, the connections including muffs 15 and links 16, which have to be removed to allow hinging of the base for inspection of the parts, and there being also provided a control switch 9 for energizing the closing solenoid 8, for de-energizing the solenoid (by short-circuiting) for opening the breakers, and for connecting the solenoid for remote control, Fig. 7 (not shown). The breakers are held closed by the solenoid 8 energized through an economy resistance 14 inserted in the circuit when the breakers close. The L-shaped base 17 which supports all the parts, abuts on the floor and back of the casing 6 when in place, and is-provided with arms 17a pivoted at 17b in the sides of the casing, the lid 6a of which is hinged at 6b. The connection from each link 16 to the associated fixed contact 18 comprises a conductor 21, cranked at 21a and wound to form the trip coil 7, its end being connected at 22 to a bracket 18a on a support 18b on the base 17. The movable contact 19 is hinged at 19a to an arm 19b on a shaft 19d common to both breakers, the shaft being rotatable under control of spring 19c in a bracket 19e on the support 18b, the bracket being connected to a muff 23 on the outgoing conductor 3 above the gland 24. An arc chute 20 and arc horns 27, 26 are also provided, that 26 being connected at 25 to bracket 19g. The combined overload and blow-out coil 7 has a core extension 29 co-operating with an armature 30 on an arm 31 which is pivoted at 32 and has geared engagement with an arm 34 which is pivoted at 36 and controlled by a spring 35 and setting lever 37 and screw 38 moving over a scale segment 39. A pivoted member 34a on the arm 34 carries a segment 34b carrying a screw 34c whereby it can be adjustably clamped to the short end-piece of arm 34, thus varying the setting of a mechanical timelag device 35b which is journaled in a bracket 35c and pivotally connected at 35 with member 34a. Arm 34 also carries an abutment 41 co-operating with an adjustable pin 42 on a pivoted lever 45 which normally forms an abutment for a roller 46 on toggle 47, 48. The end 50 is pivoted to the knee of a further toggle carrying a pin 54 sliding in a fixed slot 57, this further toggle being linked to a toggle 55, 56 the centre pivot 58 of which is linked to the plunger of the closing solenoid. The remote end of the latter toggle is pivoted to the knee of a fourth toggle 64, 65 having a fixed pivot 66 and linked at 67 to an arm 68 on the spindle 19d. Provided the lever 45 is in engagement with roller 64, energization of 8 lifts pivot 58 and nearly straightens toggle 64, 65, so closing the switch, as shown in Fig. 3. The reverse happens when 8 is de-energized. The pivot 66 carries a shaped extension 69 for engagement by a spanner 70 externally of the casing, whereby the switch can be manually opened and closed, the latter by moving the toggle 64, 65 slightly overcentre. When an overload moves the lever 45 the first, second and fourth toggles collapse, the solenoid 8 is then de-energized, and the pivot 58 drops, resetting the lever 45 and roller 46. A spring 71 is connected to a tail of lever 55 to assist the opening movement. The contacts of the control switch 9 are located in the blow-out field of solenoid 8 and the switch is arranged to be locked by the solenoid plunger in the open position so as to ensure opening of the breaker before the switch can be moved on to the remote-control position. A lamp 73 is lighted when the breakers are closed and reveals the segment 39 and screw 34c through a hole 74 in the casing-cover.