Increase AC frequency to speed up motor

Discussion in 'The Projects Forum' started by go4cdt, May 26, 2010.

  1. go4cdt

    Thread Starter New Member

    May 26, 2010
    1
    0
    Hi all
    I am new to this forum. I have a project to increase a single-phase motor speed (RPM). I would appreciate if anyone could help me with a diagram/circuit to increase the AC frequency (from 60Hz to about 70Hz).
    Thanks a million.
    Chris:confused:
     
  2. BMorse

    Senior Member

    Sep 26, 2009
    2,675
    234
    depending on the type of motor it is besides being single phase AC, it may not work with a VFD (Variable Frequency Drive) most of what I have seen using these types of drives are usually 3 phase motors....

    read this to get more info on VF drives...http://en.wikipedia.org/wiki/Variable-frequency_drive

    B. Morse
     
  3. R!f@@

    AAC Fanatic!

    Apr 2, 2009
    8,754
    760
    This is not a practical application
     
  4. awright

    Well-Known Member

    Jul 5, 2006
    84
    7
    Tell us what your application is and what you are trying to accomplish. To expand slightly on the comment by R!f@@, this does not sound like a practical approach to solving a speed adjustment problem unless you have a highly unusual/restrictive situation and have plenty of time or money to apply the the problem. Perhaps you selected frequency adjustment as a means of achieving your speed adjustment goal without realizing the complexity involved in such a solution. There is a reason that VFDs are fairly complex and costly. Design of an adjustable speed drive is not an undertaking for a relative newcomer to electronics (I'm guessing here).

    As BMorse said, VFDs are almost always applied to 3-phase motors, both because they are inherently less expensive than single phase motors and because they are simpler to start (by simply ramping up voltage and frequency from zero). Starting a single-phase motor involves phase shifting circuits, start windings, start capacitors, centrifugal switches, etc that complicate (but do not make impossible) control by a VFD. VFDs are, in fact, available for single phase motors but they are unusual.

    awright
     
  5. R!f@@

    AAC Fanatic!

    Apr 2, 2009
    8,754
    760
    couldn't have said better myself awright :rolleyes:
     
  6. BMorse

    Senior Member

    Sep 26, 2009
    2,675
    234

    Yes, but most of these applications you refer to usually employ 3 phase motors..... Since 3 phase motors are far more efficient than single phase

    B. Morse
     
  7. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    There is a mechanical means of achieving a range of speeds from a fixed RPM source - http://www.hi-lo.com/

    The company at the link is simply representative of the principle, plus the first hit with Google.
     
Loading...