GB533861A - Overload time limit relay - Google Patents

Abstract

533,861. Electrically - tripped switches. MASCHINENFABRIK OERLIKON. Dec. 5, 1939, No. 31541. Convention date, Dec. 13, 1938. [Class 38 (v)] A time-limit overload relay comprises a trip lever 7 and armature 6 both pivoted at 8 and joint 16 of which is held by a lever 17 until the lag expires. The toggle is pivoted to an extension 12 of lever 7 and to a fork 15 which is pivoted at 18, and restrained by an adjustable spring 20. The initial movement of 6, 7, on overload, causes 12 to move clear of a pin 34 and release an induction-motor rotor 3 driving a worm 19, and also causes fork 18 to rotate against a stop 21 and move a disc 24 and worm wheel 11 axially on a spindle 25, whereby the worm 19 meshes with the wheel 11. At the end of the time-delay, a pin 26 on the wheels. 11 deflects the latch 17, the toggle breaks upwards, and the armature 6 and lever 7 are released, a spring 27 and the weight of the armature subsequently restoring the parts to their original positions. The member 17 can be engaged for instantaneous tripping by an armature 31 subject to the stray field, the adjusting pin 5 being movable into the hook 32 to lock this armature, which can also be manually displaced. The time-lag is adjustable by a sector 28, which engages the worm wheel 11 and is movable by a pin 37 on a lever 38. The pin 34 is connected to the motor 3 by a spiral spring, and the rotor-spindle 36 carries a pointer. which indicates the releasecurrent value on a scale, Fig. 3 (not shown). On heavy overloads, armature 6 is at once fully attracted and tensions a spring 40 which subsequently actuates the trip lever 7, the spring being normally unstressed and connected to a lever 42 which is pivoted at 43 to lever 7 and is slotted to engage a pin 41 on the armatures.