GB190504504A - Improved Method of and Means of Governing or Controlling Electrically-driven Winding Machinery, Rolling Mills and the like. - Google Patents

Abstract

4504. Pieper, H. March 4. Distributing; regulating. -Relates to a method of controlling electric motors for driving intermittently-working machines such as colliery and like winding engines, rolling-mills, and the like, whereby the output of the generator is maintained uniform, power being accumulated by a By-wheel connected with a supplementary dynamo-electric machine when the motor is running on light load and restored to the motor when the load is increased. In working the system, as shown applied to a winding-engine in Fig. 4, three-phase current is transformed by means of a synchronous motor 2 coupled to the generator 1 or by means of any other rotary transformer into continuous current, by which the generator 1, the fly-wheel dynamo 4, and the motor 3, which are connected in series, are excited. The output of the generator is maintained uniform, despite variations in the current it supplies to the motor 3, by means of a rheostat 10 which is operated by a three-phase motor 11 under the control of an adjustable spring 12. The maximum output of the generator 1, and therefore the maximum speed of the motor 3, is controlled by a rheostat 13 which is operated by hand. In order to start the motor after one of its stoppages, in which the electromotive forces of the generator 1 and fly-wheel machine 4 are equal and opposite, the current in the excitation coils of the fly-wheel machine 4 is gradually decreased to zero and then increased in the opposite direction by means of a switch 6 operated by a hand-lever 9, the fly-wheel machine being thus converted from a motor to a generator. To slacken the speed and stop the motor 3, the reverse operation is performed. The motor 3 may be independently controlled by a switch 8 operated by a hand-lever 5. By means of this switch the armature and the series winding 7 ,of the motor 3 may. be short-circuited, the independent excitation regulated, and the direction of the current in the armature reversed so as to reverse the rotation of the motor. The fly-wheel machine may be short-circuited by the switch 15, and the speed of the motor 3 regulated by varying the excitation of the generator 1 by the rheostat 13.