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