How to power up this AC axial fan? Do I need to add a start capacitor?

Discussion in 'General Electronics Chat' started by Rahulk70, Apr 3, 2017.

  1. Rahulk70

    Thread Starter Member

    Dec 16, 2016
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    I recently found this old axial AC fan in my collection of old vintage electronic stuffs. Its a Rotron Whisper WR2H1 115V 7W 50/60Hz fan, probably from some sort of server computer cooling fan or something I guess since it isn't a very large fan. My question is does this fan need any sort of capacitor for starting or it can be directly connected to my 110V outlet? I've not played much with AC motors except one from an old exhaust fan and it had a small capacitor connected to it in parallel, without it I guess the motor would heat up and get damaged. I've attached a few pics of the fan below.
     
    Last edited: Apr 3, 2017
  2. AlbertHall

    AAC Fanatic!

    Jun 4, 2014
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    It is exceedingly unlikely that it needs a capacitor. It is probably a squirrel cage motor.
    BTW DC motors might have a capacitor across the terminals but that is there to suppress interference from the brushes affecting other equipment. It is not needed for the motor to function correctly.
     
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  3. Tonyr1084

    Well-Known Member

    Sep 24, 2015
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    Once worked for a company that did trade system computers. They had a lot of returns from the field and a lot of those fans came back and often went in the scrap bin. I took many of them home. They run on 115 VAC. Just plug them in and let them do the rest. No need for starter caps or anything else. Simple AC fan motor.
     
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  4. AlbertHall

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    And from my experience, most of the problems are caused by the bearings (or rather the bushes).
     
  5. Tonyr1084

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    Sep 24, 2015
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    Yeah, I agree Al. But these systems that often came back were not very used and the fans were in pretty good shape. It amazed me how much stuff they threw in the bin. 13 inch monitors - monochrome (green phosphor), 115 and 230 VAC fans, some 10 inch fans too. Took a lot of that junk home and made window fans for the kids and hooked their games up to the green monitors. They didn't like the green but they got to play their games without having to hook into the family color TV.

    Lots of BNC connectors and cables, lots of BNC to F type connector adaptors, gaud, I can't remember all the stuff they threw out. Whole computer rack frames (six feet tall by (I guess) about 18 inches wide and probably 20 inches deep), power strips.

    OH OH OH, they also threw out a lot of Sealed Lead Acid batteries - 12 volt 40 aH. Took a bunch of those too. Yard sales netted a lot of cash for those AND I put a couple in their ride on toys. Replaced the two six volt 9 amp batteries they came with. The kids could ride those things all day and all night on a single charge. But the batteries DID stick out of the hoods of their cars. But they didn't care.

    Just plug that fan into 115 VAC and it should work. If, like Al said, the bearings are bad - oh well.
     
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  6. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Those Rotron fans are shading ring fans for split phase operation, so as mentioned do not need a cap.
    They can be Triac controlled if needed.
    Max.
     
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  7. Rahulk70

    Thread Starter Member

    Dec 16, 2016
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    I'm gonna try connecting it to 110V supply mains and see how it goes.
     
  8. Rahulk70

    Thread Starter Member

    Dec 16, 2016
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    Yep. I found these from an old store house which had dozens of computers mainly Xeons , C2Quad and C2Duos, few servers, emergency lamps those old ones with indcandscent lamps and circular state of charge ones and plenty of batteries. To say it was a gold mine. Okay, so I connected the fan to the power outlet and it runs smooth. The bearing everything seems to be fine. It isn't very noisy and air output is kinda really good.
     
  9. MaxHeadRoom

    Expert

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    I used them for cooling on Equipment enclosures, usually positive pressure, air directed in through a filter.
    Max.
     
  10. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    Should be 72 CFM output and 37.5 decibels (per datasheet)
     
  11. Rahulk70

    Thread Starter Member

    Dec 16, 2016
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    Yes it isn't very quite or anything but it ain't very loud either. The loudest and most powerful Brushless fan in my collection is a Nidec 12V 2.3A fan from a Dell server. Its a beast.
     
  12. VENKEY NARAYAN

    New Member

    Apr 3, 2017
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    Hi there,I am Venkat Narayan. The motor u showed in the images is a shaded pole motor and u dont require any capacitor.You should directly give the rated supply voltage and frequency to start this motor.
    Thank you
     
  13. MaxHeadRoom

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    Better late than never!o_O
    Max.
     
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  14. Rahulk70

    Thread Starter Member

    Dec 16, 2016
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    I think this one is from an from an old server rack. It was a while back I got them and its pretty old I guess since the datasheets I saw on this fan shows most of them made in Mexico now.
     
  15. Rahulk70

    Thread Starter Member

    Dec 16, 2016
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    Yep mate. I already plugged it to my 110V outlet and it is working fine. I was worried if it needed a cap.
     
  16. Rahulk70

    Thread Starter Member

    Dec 16, 2016
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    Currently I'm using it in a heavy duty charger to cool the circuit and transformer. It does the job really well but the only thing that worries me is, can this Rotron fan run continuously for like 8-10 hours? Or will it burn the fan coil due to overheating?
     
  17. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    We use that kind of fans 24/7 for years without a problem.
    For continuity of the system we exchange them every 3 years.

    Bertus
     
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  18. AlbertHall

    AAC Fanatic!

    Jun 4, 2014
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    Continuous will be OK. It will cool itself!
     
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  19. Rahulk70

    Thread Starter Member

    Dec 16, 2016
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    Thanks. So, I can leave the charger running at night without any worries. :)
     
  20. Rahulk70

    Thread Starter Member

    Dec 16, 2016
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    Thanks.There is a small metal cap in the center at the back side of the fan, it was slightly warm after running for about two hours. I was worried that by morning the fan might get really hot. I usually charge at night. But when u said I realized the fan does blow air in the direction of its coil, so it will cool itself.
     
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