Figure 7-37. - Capacitor motor used for a wall fan.
Figure 7-38. - Three-phase motor.
tapped for different speeds and is connected in series with the main winding. The starting winding is connected across the transformer secondary.
Acapacitor motor for a wall fan (fig. 7-37) contains a capacitor of approximately 1 microfarad (µf) in the starting-winding circuit. To increase the effective capacity and consequently the starting torque of this motor, connect the capacitor. across an autotransformer. The taps on the transformer permit a choice of various speeds.
Figure 7-39. - Three-phase stator.
Construction of a three-phase motor consists of three main parts: stator, rotor, and end bells. Its construction is similar to a split-phase motor, but the three-phase motor has no centrifugal switch (fig. 7-38).
The stator, as shown in figure 7-39, consists of a frame and a laminated steel core, like that used in split- phase and repulsion motors, and a winding formed of individual coils, placed in slots.
The rotor may be a die-cast aluminum squirrel-cage type or a wound type. Both types contain a laminated core pressed onto a shaft. The squirrel-cage rotor (fig. 7-40) is like the rotor of a split-phase motor. The wound
Figure 7-40. - Squirrel-cage rotor.Continue Reading