Control of electric winding and hoisting engines

The paper first discusses in brief the general features of the different systems of winding engines, viz., direct-current winding motors with controlling generator (Ward-Leonard, Ilgner), direct-current winding motors with rheostatic control, and alternating-current winding motors with rheostatic control. The control apparatus is then described and illustrated. The dependence of the motor speed in each of the systems on the load and on the controller resistance is discussed. A considerable part of the paper is devoted to investigations on the use of the motors as electrical brakes, and the conditions of regenerative control, braking with counter-current, and braking by supplying current to independent resistance are considered. The effect of speed variation and excitation upon the torque is investigated with direct-current motors, and with alternating-current motors excited by direct current, and test results are given. Lastly, the application of the eddy-current brake is mentioned, test results of different sizes of eddy-current brake are analysed, and the difference between such apparatus with copper and iron armatures is explained.