Finding correct Power for AC Fan motor

Discussion in 'Power Electronics' started by elephunk, Nov 27, 2016.

  1. elephunk

    Thread Starter New Member

    Nov 21, 2016
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    Hey guys. I'm building an extraction unit with a fan from an old kitchen extraction hood. I hastily stripped just the fan out then chucked the hood out when I first got it, and didn't think to take pictures of any sticker relating to power. It's got 4 wires black, red, brown, white and I have got pictures if needed. It wasnt a good brand hood so I'm guessing its just a 3 speed motor with no bells and whistles. So can i wire it up with normal light switches to control the speeds?? and do you have to supply power to speed 1 + 2 when you want speed 2, and 1 + 2 + 3 when you want speed 3??

    Cheers Iain
     
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Usually there is a common, and the others are switched in as needed, but only one at a time, in the absence of a capacitor then most likely a shaded pole motor.
    Odds are the black or white is common!
    May have to do a quick test, or see what the independent resistances are and which are at the extreme of the total winding's.
    Max.
     
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  3. tranzz4md

    Member

    Apr 10, 2015
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    3-speed would be very unusual for such units in my experience.

    Again, I doubt it. Are you in the USA?
     
  4. elephunk

    Thread Starter New Member

    Nov 21, 2016
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    No Im in the UK.

    And I'm not saying you're wrong, but all domestic extraction units I've come across have been 3 speed.

    Cheers Iain
     
  5. MaxHeadRoom

    Expert

    Jul 18, 2013
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    I have a range hood with multi-speed fan.;)
    Max.
     
  6. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    All four of our houses had range hoods with two or three speed fans.
     
  7. tranzz4md

    Member

    Apr 10, 2015
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    I've seen 1 and 2-speed, but multi's with electronic controls on microwave hoods. So what's the wiring?
     
  8. MaxHeadRoom

    Expert

    Jul 18, 2013
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    I don't see any mention of electronic controls?;)
    The last place we had had an infinity variable version, THAT could have been electronic.
    Max.
     
  9. tranzz4md

    Member

    Apr 10, 2015
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    So is it tapped winding, or multi winding? For more than 2 speed it'd practically have to be tapped. PSC dominates Europe, but could be shaded pole. That's what tells us the wiring diagram.
     
  10. elephunk

    Thread Starter New Member

    Nov 21, 2016
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    Ok you guys are getting too technical for me and i have no idea what any of those words mean.

    So on to a brighter note, I blew the first one up. I only found out while looking for a replacement that maybe red was used as COM, who'd of thought that. Anyway I have my replacement and it looks to use a bit more of a regular colour scheme. I have Blue, Brown, Yellow, Black, White, Grey.

    Logically to me the Blue Brown Yellow should be neutral live earth, then for speed the white grey black in that order.

    Could you elaborate on what test I can do to work this out for myself.

    Cheers Iain
     
  11. MaxHeadRoom

    Expert

    Jul 18, 2013
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    All winding's will normally be connected so the thing to do is identify the series pattern of the windings.
    This is a couple of typical conections as a guide.

    [​IMG]

    [​IMG]

    Does it have any brand name or other info on the frame?
    Max.
     
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  12. elephunk

    Thread Starter New Member

    Nov 21, 2016
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    Cheers Max, The fan housing does have a sticker on with a wiring diagram but gives no colours for the wires. The model number on it is Logik L90CHDB11. I have searched and found nothing upto now, even in the user manual. If you need info off the motor itself I will take the housing apart now for any on there.

    I understand what you are saying about the windings, and with this one being a more modern unit and health and safety being a bit nuts in the UK I would imagine the others stand true.
     
  13. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Sorry I got confused with another post with a similar question, if you have no cap then it is likely a shaded pole motor which would just need to identify the series string of wingdings and the resistance of each.
    Max.
     
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  14. elephunk

    Thread Starter New Member

    Nov 21, 2016
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    So how do I test the resistance of each winding? One probe to COM and the other to each colored wire??? Then the highest resistance is the lowest speed. Do I need to visually see where on the motor the wires go? I will probably strip the housing off, but I don't have my sockets handy tonight, but if I can test without visually inspecting the motor I will tonight.
     
  15. MaxHeadRoom

    Expert

    Jul 18, 2013
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    By using an Ohm meter, find the pair of most resistance make one a common then measure all from that and you should be able to plot the series string by extrapolation.
    Max.
     
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  16. elephunk

    Thread Starter New Member

    Nov 21, 2016
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    Ok guys, still having a little trouble with this. I broke out the multimeter and tested the black grey and white wires and they had varying resistance with white being the highest resistance and black being the lowest. So I have wired it up like the following
    [​IMG]
    But now every time i plug it in, it trips the breaker on the fuse box for all the sockets in the house whether any of the switches are on or off, and the socket its plugged into can be on or off.

    Any help would be gratefully received.
    Many thanks
     
  17. elephunk

    Thread Starter New Member

    Nov 21, 2016
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    Ok so I tried to get the motor out of the fan housing but have failed miserably. But I have found another wiring diagram which gives a better idea for colour codes. I can't get better pictures of the second wiring diagram as I can't get the motor out of the housing.
    wiring3.jpg
    wiring2.jpg

    So after ordering a 750MFD 250v starting capacitor I am looking at wiring it up like so.
    FanMotorCircuit2.jpg

    Anyone have any advance on how this is looking. Have I got the right capacitor??
    Cheers
     
  18. elephunk

    Thread Starter New Member

    Nov 21, 2016
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    Ok so I tried it on first speed wired as above, and it started but is really slow 60-120rpm eyeballing it. Not wanted to try a different speed as thats when the last one popped.
     
  19. MaxHeadRoom

    Expert

    Jul 18, 2013
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    You have a starting cap value WAY to big.
    I would expect no more than a 12μf RUN capacitor.
    The winding colours are all there not so it should be relatively easy to hook up once you get the right cap.
    The 750μf is only intended for BRIEF starting only.
    Max.
     
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  20. elephunk

    Thread Starter New Member

    Nov 21, 2016
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    Thanks once again max. So how do you tell between a motor that needs a start capacitor and one that requires a run?? I'll look into it, but thanks again.
     
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