Definition
A transformer electrical machine
which used change the value of
an alternating voltage.20
Shaded pole motor.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.
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. supply
Stator
winding
Laminated stator Fixing holes
Cage rotor
Copper
shading rings
FIGURE 10.c. supply such battery. will not
normally work from d. They vary size from miniature units used in
electronics huge power transformers used power stations. Most them operate very small motors
in domestic and business machines where single-phase supplies are most
common. trans-
former will only work when alternating voltage connected.
An alternating voltage applied the primary winding produces alter-
nating current, which sets alternating magnetic flux throughout
the core. This magnetic flux induces emf the secondary winding, as
. Reversal rotation theoretically possible
by moving the shading rings the opposite side the stator pole face.c.
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.
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.
A transformer, shown Fig. 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.
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. 10.
Figure 10.20 shows shaded pole motor.Baisc Electrical Installation Work
212
a
