Patent GB-190812508-A (GB)
Title: Improvements in Motor Controlled Switches.
Inventor: BARLOW ALFRED JAMES
Filed: 1908-12-07
Granted: 1909-05-27
Abstract: 12,508. Barlow, A. J. Dec. 7. Switches ; motor control systems. - Relates to motor-controlled starters for electric motors used to work lifts, winding-gears, pumps, &c., in which the pilot motor is always operatively geared direct to the switch spindle without the interposition of clutches of any kind, and has its circuit broken automatically when all the resistance in the main motor circuit has been cut out. The invention consists in providing additional contacts, whereby, for intermittent rotation of the main motor in any one direction, the main switch is left in starting position when the main motor is stopped, without further rotation of the pilot motor. In the developed diagram, Fig. 3, the additional contacts 1<1> ... 8<1> are mounted on a sleeve which is freely revoluble on the controller spindle, the latter carrying starting and braking contacts 9<1> ... 24<1>. In the off position of the switch, contacts 1<1>, 2<1>, 5<1>, 6<1> rest on their corresponding stationary contacts, and, when the master switch A is moved to connect, say, the contacts 26 ... 30, current passes from the main X through the contacts 26, 27, pilot motor B, contacts 30, 29, pilot-motor field 37, and contacts 5, 6, to the main Y. The no-volt magnet 34 is independently energized through the contacts 27, 28 and wire 33. The pilot motor then drives the main spindle through one revolution, during the first part of which, and while the starting &c. contacts on one side of the controller are sliding idly over the stationary contacts, an arm 31, Fig. 4, on the spindle pushes the armature 48 against the magnet 34. The armature is mounted on an arm 46, which is pivoted at 47 and is connected by a link 50 with the loose sleeve carrying the additional contacts, so that of the latter Nos. 3<1>, 4<1>, 7<1>, 8<1> are brought over the stationary contacts. The pilot-motor circuit now passes through the contacts 9<1>, 10<1> instead of through 5<1>, 6<1>, and when the contact 24<1> reaches the contact 24, the circuit of the main motor field is as follows : from the main X through the contacts 3<1>, 4<1>, 24<1>, 23', motor field 53, brake magnet 54, contacts 12<1>, 11<1>, 8<1>, 7<1> to the main Y. The armature current passes from the contact 22<1> through the resistance D, contacts 17', 16<1>, the armature C, and contacts 13<1>, 11<1> to the main Y as before. When all the resistance has been cut out, the pilotmotor circuit is broken at the contacts 9<1>, 10<1> and the controller remains at rest, with the main motor running full speed. On failure of voltage or on return of the master.switch A to the zero position, a spring 49 pulls the arm 46 and link 50 to restore the contacts 1<1>, 2<1>, 5<1>, 6<1> to starting position. This disconnects the main motor from the mains, and connects the armature in a closed circuit through the resistance D and contacts 1', 2<1>. Where the main motor has to rotate in one direction only, the number of starting and braking contacts is reduced, and an ordinary switch used instead of the master switch A. In the preferred form of construction the pilot motor is mounted on the top of the controller casing, and a worm on its armature spindle gears with a wheel on the controller spindle.