Patent GB-191113469-A (GB)
Title: Improvements in Controlling Apparatus for Electric Motors, chiefly as used with Electric Lifts.
Inventor: TURNER ALBERT
IPC: H02P1/16
Filed: 1911-06-06
Granted: 1911-12-07
Abstract: 13,469. Turner, A., and Wilkinson, R. H. June 6. Electric equipment. - Both poles of a lift or hoist motor are connected to the supply mains by one of two electromagnetically-actuated switches according to the direction of rotation desired. The windings of the switches are controlled by a switch which also controls the energization of the winding of a regulating-switch. The motor is provided with a shunt field winding circuit which contains a normally short-circuited resistance which is cut in when all the armature resistance is cut out ; and a series field winding which is short-circuited when the armature resistance is cut out. To stop the motor, its armature is close-circuited through a resistance, while its shunt field winding is closecircuited through a resistance and the series field winding. In the arrangement shown in Fig. 1, the terminals 3, 2 of the controlling-switch are connected to the terminals of the windings D', D<2> respectively of the electromagnetic switches. The second terminal of the winding D<1> is connected to a terminal 19, and the second terminal of the winding D<2> to a terminal 14. The winding C of the regulating-switch is connected to a terminal 4 of the controlling-switch, and its circuit contains a resistance A<3> which is normally short-circuited by a switch L. The plungers X of the windings D', D', Fig. 2, are connected to spindles Y', Y<2> ; the spindle Y' carrying contacts E', E<2>, E<3>, and the spindle Y<2> contacts E<4>, E<5>, E<6>. The core of the winding C operates the movable contact bar 0 of the regulating-switch B, and also carries an arm which opens the switches L, M, Fig. 1, after the whole of the armature resistance has been cut out. The operation of the arrangement is as follows: To operate the motor in one direction, the controlling switch is operated to complete the circuit of the winding D<1> through the terminal 6, lead a, switch 28, 0, 27, lead b, terminals 15, 18, lead c, winding D', and terminals 3,1. The plunger of the winding D' then operates to cause the contact E' to bridge the terminals 5, 6, 7, the contact E<2> to bridge the contacts 8, 9, and the contact E' to bridge the contacts 10, 11. The motor armature circuit is then completed through contacts 6, E<1>, 7, lead d, resistances A<3>, A<1>, series field H, lead e, contacts 9, E<2>, 8, armature F, and contacts 26, 11, E<3>, 10, 24. The shunt field winding G is connected between the positive terminal of the regulating-switch B and the contact 26. These circuits produce a slow rotation of the armature F, to accelerate which the controlling-switch is caused to connect terminals 1, 4, thereby completing the circuit of the winding C. The resistances A', A<2> are gradually shortcircuited and the full speed of the armature F obtained by short-circuiting the series winding H and cutting the resistance A<4> into the shunt field circuit. To stop the motor, the contacts 1, 4 are first disconnected, thereby inserting the resistances A<4>, A<2>, A<1> in the series field H, after which the circuit of the winding D' is broken, thereby disconnectirg the motor from the mains at the contacts 6, 7 and 10, 11, as shown in Fig. 1. A braking action is thus obtained by close-circuiting the armature F through a resistance I, while the circuit of the shunt field winding G is closed through contacts 26, E', resistance I, contact E', winding G, resistances A<2>, A<1>, series winding H, lead e, contacts 9, 25, and resistance J. To reverse the direction of rotation of the armature F, the circuit of the winding D' is completed by closing the contacts 1, 2 of the controlling-switch, the plunger of the winding D<2> operating to reverse the connexions of the armature F.