Single Phase Induction Motor
Single Phase Induction Motor
The single-phase induction machine is the most
frequently used motor for refrigerators, washing
machines, clocks, drills, compressors, pumps, and so
forth.
The single-phase motor stator has a laminated iron
core with two windings arranged perpendicularly.
One is the main and
The other is the auxiliary winding or starting
winding
Single Phase Induction Motor
Single Phase Induction Motor
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•
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This “single-phase”
motors are truly twophase machines.
The motor uses a
squirrel cage rotor,
which has a laminated
iron core with slots.
Aluminum bars are
molded on the slots and
short-circuited at both
ends with a ring.
Stator with laminated
iron core
Main winding
Slots with winding
Rotor with
laminated
iron core
+
+
Bars
_
_
Starting winding
Figure 42 Single-phase
induction motor.
Ring to short
circuit the bars
Single Phase Induction Motor
Figure 10 Squirrel cage rotor
Operating principle
Single Phase Induction Motor
•
The single-phase induction motor operation
can be described by two methods:
–
Double revolving field theory; and
–
Cross-field theory.
•
Double revolving theory is perhaps the
easier of the two explanations to understand
•
Learn the double revolving theory only
Single Phase Induction Motor
Double revolving field theory
• A single-phase ac current supplies the main
winding that produces a pulsating magnetic
field.
• Mathematically, the pulsating field could be
divided into two fields, which are rotating in
opposite directions.
• The interaction between the fields and the
current induced in the rotor bars generates
opposing torque
Single Phase Induction Motor
Main winding flux
•
•
•
The interaction between
the fields and the current
induced in the rotor bars
generates opposing
torque.
Under these conditions,
with only the main...