Basic Electrical Installation Work

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All a. Its applications are for constant speed machines such fans and pumps.18 Various speed–torque characteristics for induction motor. The windings may be connected star delta and the end connections brought out slip rings mounted the shaft. Reversal rotation achieved reversing any two the stator winding connections. motors . Alternatively the load may connected after the motor has been run up to full speed. Torque Speed (a) (c) (b) Load torque line FIGURE 10. The wound rotor consists laminated cylinder silicon steel with cop- per coils embedded slots around the circumference. Single-phase a.c. The speed almost constant. The cage induction motor has small starting torque and should used with light loads started with the load disconnected. Connection carbon brushes can then be made external resistance improve starting.c. supply produces pulsating magnetic field, not the rotating magnetic field produced three-phase supply.17 Construction cage rotor. motors A single-phase a.Baisc Electrical Installation Work 210 Arrangement conductor bars cage rotor Skewed rotor conductors Shorting ring FIGURE 10.c