How do single phase AC induction motors start in everyday home appliances?

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SUMMARY

Single phase AC induction motors, commonly found in household appliances like hair dryers and kitchen mixers, require additional components to initiate operation due to their inability to start independently. These motors often utilize run windings or capacitors to create a phase shift necessary for generating a rotational magnetic field. In many home applications, shaded pole motors are employed, which do not require centrifugal switches for operation. Capacitors may be present for purposes such as electromagnetic compatibility (EMC) filtering rather than starting the motor.

PREREQUISITES
  • Understanding of single phase AC induction motor operation
  • Knowledge of run windings and capacitors in motor design
  • Familiarity with shaded pole motor technology
  • Basic principles of electromagnetic compatibility (EMC)
NEXT STEPS
  • Research the operational principles of shaded pole motors
  • Study the role of capacitors in AC motor applications
  • Explore electromagnetic compatibility (EMC) standards and practices
  • Investigate alternative starting methods for single phase AC motors
USEFUL FOR

Electrical engineering students, appliance designers, and technicians working with household AC induction motors will benefit from this discussion.

Adenitz
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Hello to all,

I'm a student of electrical engineering. We have learned the basics about AC induction motors and we learned that single phase motor cannot start by itself. There must be some additional part that will produce phase lead or lag in order to create rotational magnetic field. That is clear to me. Furthermore we have learned that these AC motors have either run winding or run capacitor that is disconnected later via centrifugal switch. However, I wonder how this is done in everyday home induction motors like hair dryers kitchen mixers and similar? I don't believe they have centrifugal switch built in somewhere.
Can you give me example how single phase AC motors start in home applications?

My best guess is that these motors have run windings permanent built in and there is no anything like centrifugal switch. I thought that capacitor is used for this purpose since I have found one when disassembling a hair dryer, but my friend told me that this capacitor is not for start but for preventing EMC interference with other devices like TV. He told me that this capacitor faild and that he short circuited it and motor worked without any problems.

Can you clarify these things for me?

Thank you
 
Physics news on Phys.org
These type of motors are called http://en.wikipedia.org/wiki/Shaded-pole_motor" .
 
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