0195136047.pdf

13.2 INDUCTION MACHINES 581

S = 1

(zero speed)

S = 0

(synchronous speed)

Torque, per unit

2

1

Speed

or slip

(a) (b)

+

−

Auxiliary winding

Main

winding

Figure 13.2.14Permanent-split-capacitor motor.(a)Schematic diagram.(b)Typical torque–speed
characteristic.

Centrifugal

switch

(a)

+

−

Auxiliary winding

Main

winding

Torque, per unit

Starting capacitor

Running capacitor

(b)

3

2

1

S = 1

(zero speed)

S = 0

(synchronous speed)

Speed

or slip

Switching

speed

Figure 13.2.15Two-value-capacitor motor.(a)Schematic diagram.(b)Typical torque–speed characteristic.

S = 1

(zero speed)

S = 0

(synchronous speed)

Torque, per unit

2

1

Speed

or slip

(a) (b)

Cage rotor

Shading band

or coil

Figure 13.2.16Shaded-pole motor.(a)Schematic diagram.(b)Typical torque–speed characteristic.