2 Engineering
2.5 Motor and Application
DC1 Frequency Inverter 10/12 MN04020003Z-EN www.eaton.com 45
2.5.8 Single-phase AC motors
The frequency inverters in the DC1-S2… series are specifically designed for
the speed control of single-phase AC motors (230 V).
These single-phase AC motors, which are listed further below, have the fol-
lowing characteristics:
• Asynchronous operational behavior with elliptical rotating field
• A small starting torque
• Applications run with a reduced starting torque (approximately 50 to
100 % of the motor's rated torque).
Application examples: pumps and fans.
DC1-S2… series frequency inverters can be used to control the following
motor types:
• Shaded-pole motor:
Shaded-pole motors have a laminated core stator with pronounced poles
that are separated from the main pole (shaded poles). These auxiliary
poles have shading coils in which a flux that is lagging behind the main
field is generated by self-induction.
The resulting elliptical rotating field moves the rotor with it. The mechan-
ical arrangement of the shaded poles makes it impossible for the rotat-
ing field to change direction in this type of motor.
Figure 20:Schematic diagram of a shaded-pole motor
• Permanent-split capacitor motor, PSC motor:
In permanent-split capacitor motors, a winding (secondary winding) is
connected in series with a capacitor in order to generate the rotating
field (90° phase shift, elliptical rotating field). The direction of the rotating
field can be changed by changing the secondary winding connection.
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