Patent GB-457127-A (GB)
Title: Improvements in or relating to closing apparatus for electric circuit-breakers
IPC: H01H3/30
Filed: 1935-05-22
Abstract: 457,127. Automatic circuit-breakers. REYROLLE & CO., Ltd., A., Hebburn-on- Tyne, and ALLAN, A., Cragside, Ashleigh Grove, Tynemouth. May 22, 1935, No. 14943. [Class 38 (v)] Spring-motor actuation ; fluid actuation.- Closing apparatus for a circuit-breaker comprises a spring, one end of which is fixed while its other end can be operatively connected to the moving contact-member of the breaker, and a hydraulic jack whose plunger abuts against the free end of the spring for storing energy therein, the jack having means for releasing the stored energy for effecting closure of the breaker. As applied to a closing apparatus which is a separate structural unit which can be applied to any one of a number of breakers, the parts are carried by a wheeled truck A which can be moved to bring the closing member D<1> beneath the appropriate part of the breaker to be closed. The spring is in the form of two oppositely-wound helices B, B of which the upper end of B is fixed to the frame and the lower end of B<1> is fixed to a rod C connected by linkage D to D'. The linkage is so arranged as to compensate for the diminishing force of the spring in expanding, so as to apply the maximum force at the end of the closing stroke, and in closing is arranged to pull member D<1> downwards. To ensure correct closure, the height of the apparatus is such that it cannot be moved into place to close an opened breaker unless D<1> is in its lowest position and the spring fully stressed. The breaker itself is so arranged that it cannot be reset ready for reclosure unless the part of it which is engaged by D<1> is in its lowest position, so that if, subsequently to being reclosed by the apparatus the breaker trips while the apparatus is still in operative position, a further reclosure cannot be effected without first fully stressing the spring B, B<1>. The hydraulic jack comprises a plunger H provided with a part H<1> engaging the block C<1> at the bottom of the spring, and a cylinder F. The cylinder F communicates by way of a passage K<2> and ball non-return valve K<1> with a pump cylinder J, the piston J<1> of which is operated by an arm J<2> into which can be inserted, when the door of the apparatus casing is open, a handle normally carried by clips on the casing. The cylinder J also communicates through a non-return valve with the oil reservoir G so that when the operating handle is worked up and down, oil is pumped from the reservoir G into the cylinder F to raise the plunger H. In order to release the spring-energy for closing the breaker, a toggle O, O<1> is broken by pulling a chain O<2> connected to a lever O<3> acting on the toggle. This frees a lever N<1>, which normally stresses a spring N acting on a ball valve M<2> in the passage M between the cylinder F and reservoir G, thereby opening the passage and allowing rapid escape of oil from the cylinder. The spring N is designed to yield at excess pressures, due, for example, to excessive pumping. A pin O<4> prevents undesired operation of the toggle O, O<1>. The plunger H is cushioned at the end of the stroke by cutting off the outlet to passage M. An adjustable needle valve P allows slow escape of oil from F to G, so as to allow slow closure of the breaker for adjustment of contacts. A mechanical latch may replace the dimensional limitation for locking the releasing device unless the spring is fully stressed.