has cage rotor and the moving
field produced enclosing one side each stator pole solid copper
or brass ring, called shading ring, which displaces the magnetic field and
creates artificial phase shift.
An alternating voltage applied the primary winding produces alter-
nating current, which sets alternating magnetic flux throughout
the core.
Figure 10.
There are more motors operating from single-phase supplies than all other
types motor added together.
Transformers
A transformer electrical machine which used change the value
of alternating voltage.c. trans-
former will only work when alternating voltage connected.21, consists two coils, called the pri-
mary and secondary coils, windings, which are insulated from each
other and wound the same steel iron core. They vary size from miniature units used in
electronics huge power transformers used power stations. This magnetic flux induces emf the secondary winding, as
.20 shows shaded pole motor.
A transformer, shown Fig.
Shaded pole motors are constant speed machines with very low starting
torque and are used very light loads such oven fans, record turntable
motors and electric fan heaters.20
Shaded pole motor.
Shaded pole motors
The shaded pole motor simple, robust single-phase motor, which
is suitable for very small machines with rating less than about 50W. Reversal rotation theoretically possible
by moving the shading rings the opposite side the stator pole face. will not
normally work from d. supply
Stator
winding
Laminated stator Fixing holes
Cage rotor
Copper
shading rings
FIGURE 10.c.
However, practice this often not simple process, but the motors are
symmetrical and sometimes easier reverse the rotor removing the
fixing bolts and reversing the whole motor. Most them operate very small motors
in domestic and business machines where single-phase supplies are most
common.
Definition
A transformer electrical machine
which used change the value of
an alternating voltage. 10.Baisc Electrical Installation Work
212
a. supply such battery
