Help wiring multi-speed PSC motor

Discussion in 'General Electronics Chat' started by terror_storm, Jun 26, 2016.

  1. terror_storm

    Thread Starter New Member

    Nov 28, 2010
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    Hello,

    I picked up a fan motor and am having a problem wiring it properly. The fan wheel has directional marking on it.

    I measured the resistance of all wires and attempted to determine how to connect it, see attached table.

    The wire colors are non-standard. I have not been able to find a schematic that is even close to what I have to work with. I sketched the circuit as I think it exists, see attached.

    The only function that seems correct is Low. However, the motor does not seem to start very smoothly, and it gets pretty hot. The operating current is correct at 2.0A. Rotation direction is correct.

    Medium and High are definitely not correct. The motor runs in reverse rotation and seems to pull a lot of current, it dims the lights pretty bad.


    Any thoughts on how to operate this thing properly?


    Thanks!
     
  2. Hypatia's Protege

    Distinguished Member

    Mar 1, 2015
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    At 'first blush' your schematic looks ok! Please see post #7 --- Please consider the following points...

    1) Are you certain the 5.4Ω Wdg (as opposed to the 9Ω Wdg) is the auxiliary winding?
    2) Have you verified the condition/optimal value of the capacitor?
    3) Have you checked the windings against ground leakage, etc...?


    In my experience the following schematic represents a typical multi-speed single phase induction motor arrangement.
    (Note; For these purposes, transposition of 'neutral' and 'hot' is without significance)


    EDIT -- Image deleted due to erroneous content:oops:

    A correct wiring diagram appears in post #7:)

    Best regards and good luck!
    HP:)
     
    Last edited: Jun 30, 2016
  3. MaxHeadRoom

    Expert

    Jul 18, 2013
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    As a general rule, the run winding has the lowest resistance over the start/run winding(s).
    Max.
     
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  4. Hypatia's Protege

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    Thanks for that @MaxHeadRoom :cool: --- Inasmuch as (per the OPs schematic) said criterion applies during operation at 'high' speed (said compromise being 'par for the course' with multi-speed motors?) -- I suggest that an (electrically) 'leaky' cap is the probable diagnosis... --- @terror_storm -- please keep us posted!:)

    Best regards
    HP:)
     
  5. terror_storm

    Thread Starter New Member

    Nov 28, 2010
    3
    0
    Thank you for your replies!

    I tried a number of different wiring configurations but none seem to be any better than the "low" speed I had originally. The motor gets hot but hasn't quit on me yet. It claims to have thermal protection built-in.

    A little background: I found the fans at the local H4H Re-store, got a box of 6 fans for $10. They are new and came with matching capacitors. There was a whole pallet of them. I'm starting to wonder if they were built incorrectly at the factory, and now someone is just trying to unload them.

    I am attempting to use one fan for a dust collector, and possibly use another as a vacuum source.
     
  6. Hypatia's Protege

    Distinguished Member

    Mar 1, 2015
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    Your difficulty is far more likely down to a defective or 'mismatched' capacitor -- What is the value of the capacitor? Have you tested it against electrical leakage?

    Best regards
    HP:)
     
  7. MaxHeadRoom

    Expert

    Jul 18, 2013
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    It should be more like this.
    There is a difference.
    Max.



    [​IMG]
     
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  8. Hypatia's Protege

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    Mar 1, 2015
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    --Emphasis added--

    Interesting...
    The difference being that the Cap 'parallels' the auxiliary winding plus only the effective run winding{s} for a given setting -- Such would explain why the OP's arrangement works best at the low setting:cool:

    Best regards
    HP:)
     
    Last edited: Jun 27, 2016
  9. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Actually the cap is in series with the start/auxiliary winding as normal in a PSC motor.
    The run winding is across the supply.;)
    Max.
     
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  10. Hypatia's Protege

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    My perspective took mutual inductance 'between' the auxiliary and 'run' windings into account:confused: --- Uggg!o_O - I'll take your word for it!:) Seems I'm a bit 'weak on magnetics' :eek::rolleyes::oops:

    Chastened and rebuked - Well... Rebuked anyway...
    HP:)
     
    Last edited: Jun 28, 2016
  11. MaxHeadRoom

    Expert

    Jul 18, 2013
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    This you most likely know, the object is to aim for 90° phase shift in the aux WRT the 'main' winding.:cool:
    Max.
     
  12. Hypatia's Protege

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    Yes indeed:cool:... -- Perhaps someday I'll learn to overcome the temptation to analyze the ostensible role of inter-winding mutual inductance (i.e. 'transformer action', if you will) and accept the obvious at face value (where induction motors are concerned) - 'tho I'm not holding my breath:rolleyes::oops:

    Very best regards
    HP:)
     
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  13. Aleph(0)

    Member

    Mar 14, 2015
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    HP that's exactly like wiring for stator in xray tube housings:)! Except w/o taps on run winding cuz speed is controlled with frequency:cool:! So I'm asking how you missed that:p?
     
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  14. Hypatia's Protege

    Distinguished Member

    Mar 1, 2015
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    Spot on!:)

    I dunno?:oops: Perhaps I was 'distracted' by the taps?:confused:

    b150stat.jpg

    Best regards
    HP:)
     
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