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