Constant Current System for Speed Control of DC Motor: For certain services, where there is a possibility of the motors being stalled such as with excavators, ship's windlasses etc. the constant current system is advantageous…
Booster Speed Control of DC Motor: A booster in series with the armature of the main motor may be employed for varying the voltage across the driving motor. The booster speed control is a sepaÂrately…
Armature Resistance Control Method of DC Motor: In this armature resistance control method of speed control, reduced speeds are obtained by inserting resistance in the armature circuit. It may be employed with series, shunt and…
Paralleling Field Coils for DC Series Motor: In this Paralleling Field Coils method, used in fan motors, several speeds can be obtained by regrouping of field coils, as illustrated in Fig. 1.72 (c). In case…
Tapped Field Control for DC Series Motors: Tapped field control for dc series motors is another method of increasing the speed by reducing the flux and it is accomplished by reducing the number of turns…
Field Diverter Method of Speed Control of DC Series Motors: The field flux can be reduced by shunting a portion of motor current around the series field, thus reducing the excitation mmf and weakening of…
Starting of Synchronous Motor and Precautions: As already stated the synchronous motor has got no self starting torque and the motor must first be brought up to synchronous speed by some external means before it…
Star Delta Starter Working Principle and Circuit Diagram: This star delta starter method of starting of cage induction motors is based upon the principle that with 3 windings connected in star, the voltage across each winding…
Auto Transformer Starter - Working Principle, Advantages and Disadvantages: In auto transformer starter method the reduced voltage is obtained by taking tappings at suitable points from a three phase auto-transformer, as shown in Fig. 1.70(a).…
Primary Resistance Starter - Operation, Wiring Diagram, Advantages and Disadvantages: This method of primary resistance starter of a polyphase cage motor is very simple and provides smooth acceleration of the motor. In this method of…
