Patent GB-219430-A (GB)
Title: Improvements in or relating to apparatus for short-circuiting the rotor windings of alternating current dynamo-electric machines, motor-converters and the like
IPC: H02K17/22
Filed: 1923-05-12
Abstract: 219,430. Peebles & Co., Ltd., B., and Henderson, G. May 12, 1923. Switches, electric-motor actuation.-The rotor windings of alternating-current dynamo-electric machines are short-circuited by a motor-driven cam the rotation of which in the same direction opens and closes the short-circuit. In one arrangement, Fig. 2, the motor F drives a. cam J through reduction gearing, the cam being provided with a continuous helical slot J<1> engaged by a roller K on one end of a lever K the other end of which is forked and re-operates with a groove in a slidable short-circuiting sleeve mounted on the rotor shaft and provided with spring contacts. The cam has an arm J<2>, and a further arm J<3> is carried by the cam spindle H<1>, these arms being located 180‹ apart and co-operating respectively with projections M<1>, M<2> on the switch spindle H to disconnect the motor F on the completion of its short-or open-circuiting operations. The switch gear may comprise two two-way switches arranged to leave the circuit to the motor F made through one switch when the other switch is opened. When the motor-driven cam is employed for operating the short-circuiting member on a motor-converter set, the motor F is controlled as shown in Fig. 4. On closing the synchronizing switch R an extra contact T is also closed and current is passed to the motor through the switch contact N<1>, the motor thereupon operating the short-circuiting member, opening the switch contact N' and closing N<2>. When the switch R is opened and the converter is to be shut down a connection to the switch contact N<2> is provided for by the switch U which is closed when the main switch S is opened, the motor F now operating to open the short-circuiting member. In another arrangement, Fig. 6, primarily intended for use in an automatic sub-station, provision is made for operating the cam J by hand. The gear spindle G<1> carries a cage G<3> in which is mounted a pawl G<4> engaging a ratchet wheel G<5> loosely mounted on the spindle G<1> the pinion G<6> being rigidly connected to the ratchet wheel. Similarly a hand wheel H<5> is loosely mounted on the shaft H<1> and operates through a ratchet and wheel H<3>, H<2> the arrangement permitting the hand wheel to be rotated independently of the motor F. The cam J is provided with additional arms J<4>, J<5> co-operating with additional projections M<4>, M<5> on a spindle M<3> operatively connected with the switch spindle M. The spindle M, Fig. 8, carries three arms L<1> - - L<3>, L<1> being closed when the others are open. When the motor converter is started the coil V is built up by the direct-current voltage and the switches V<2>, V<4> are closed the latter being in circuit with the synchronizing switch coil W<1>. When the coil W<1> is energized the switch W<2> is closed, the relay W<3> actuated, and the motor F starts up to perform the short-circuiting operation. On completion of this operation the arms J<2>, J<4> rock the switch spindle M through the projections M<1>, M<4>, opening L, closing L<2>, L<3>, and stopping the motor F. When the motor converter is shut down the opening of the main switch S closes the switch U and completes a circuit to the motor F through the arm L<2> and relay W<3>. The motor F then starts up and opens the short-circuiting member whereupon the arms J<3>, J<5> engage the projections M<2>, 1\1' and rock the switch spindle back to the position shown in the Figure, L<2> breaking the circuit to the relay W<3> and thus stopping the motor. Specifications 28682/11, [Class 35, Dynamoelectric generators &c.], and 215,189. [Class 38 (ii), Electric currents, Converting &-c.], are referred to.