Results 1 to 15 of 15

Thread: Shop Fan - SPEED CONTROL - Bad for Motor?

  1. #1
    Join Date
    May 2016
    Location
    California
    Posts
    8
    Post Thanks / Like

    Shop Fan - SPEED CONTROL - Bad for Motor?

    My shop fan says DO NOT use with a speed control.
    I would like to use a speed control, and run the fan at a slower speed.
    Is this bad for the motor?
    Will the motor windings get too hot?
    Is this unsafe?
    I might use this speed control, which says do not use on a brushless type motor. I believe my fan is an AC induction type electric motor. This might not even work with my fan?


    Name:  vidG4AI.jpg
Views: 226
Size:  54.3 KB
    Name:  5QWhUho.png
Views: 223
Size:  15.1 KB
    Name:  llkikqD.png
Views: 223
Size:  11.3 KB
    Name:  TrxwFYA.png
Views: 226
Size:  243.2 KB
    Last edited by jonnymacuser; 09-20-2020 at 12:16 PM.

  2. #2
    Join Date
    Jan 2016
    Location
    northeast USA
    Posts
    9,221
    Post Thanks / Like

    Re: Shop Fan - SPEED CONTROL - Bad for Motor?

    your asking a question you already answered..the fan says dont use one and the controllers say dont use on a brushless motor..how much more info do you want that says its a BAD idea??? most likley if you do it will burn up the motor and get so hot a fire could start in the windings...it looks like your fan has a high and low speed setting..if thats not good buy another fan..

  3. Likes jonnymacuser liked this post
  4. #3
    Join Date
    Sep 2013
    Location
    central Wis.
    Posts
    4,876
    Post Thanks / Like

    Re: Shop Fan - SPEED CONTROL - Bad for Motor?

    Pretty much like using a toaster around water. Even if it was safe, would I really want saturated toast?

  5. Likes CAVEMANN, jonnymacuser liked this post
  6. #4
    Join Date
    Oct 2015
    Location
    NW New Jersey
    Posts
    504
    Post Thanks / Like

    Re: Shop Fan - SPEED CONTROL - Bad for Motor?

    My shop fan says DO NOT use with a speed control. - Don't

    I would like to use a speed control, and run the fan at a slower speed. -Why

    Is this bad for the motor? - Yes

    Will the motor windings get too hot? - Yes

    Is this unsafe? - Yes (only from the standpoint of you failing to heed the directions/warnings)


    The fan will overheat fairly quickly , which will cause the one time overcurrent protection to fail. It is a tiny fuse soldered into the winding requiring disassembly to repair. Why not use a small $20 box fan instead , it would be far simpler if you wanted less air flow.


    Its a hundred dollar fan why ruin it , you might need it for something else later. Why do you want to slow down a High Velocity Fan, it already has 2 speeds ?

    HTH
    Airco 250 ac/dc Heliwelder Square wave
    Miller Synchrowave 180 sd
    Miller Econo Twin HF
    Lincoln 210 MP
    Dayton 225 ac/dc
    Victor torches
    Snap-On YA-212
    Lotos Cut60D

  7. Likes jonnymacuser liked this post
  8. #5
    Join Date
    Feb 2012
    Posts
    4,173
    Post Thanks / Like

    Re: Shop Fan - SPEED CONTROL - Bad for Motor?

    I've used those controllers. Big differance in cheap vs more expensive.

    That maybe a brushless fan and won't work a controller. An alternative would be to make a two foot extension cord with a 20 amp diode inline. Should make the fall run half speed. I don't know how efficient it will be on the motor. It would be worth a try

  9. Likes jonnymacuser liked this post
  10. #6
    Join Date
    Feb 2012
    Posts
    4,173
    Post Thanks / Like

    Re: Shop Fan - SPEED CONTROL - Bad for Motor?

    Quote Originally Posted by Insaneride View Post
    I've used those controllers. Big differance in cheap vs more expensive.

    That maybe a brushless fan and won't work a controller. An alternative would be to make a two foot extension cord with a 20 amp diode inline. Should make the fall run half speed. I don't know how efficient it will be on the motor. It would be worth a try

    Something like this but cut the black or white wire and splice diode in. I showed two diodes because I don't amps of either without looking it up.
    Attached Images Attached Images  

  11. Likes jonnymacuser liked this post
  12. #7
    Join Date
    Jan 2016
    Location
    northeast USA
    Posts
    9,221
    Post Thanks / Like

    Re: Shop Fan - SPEED CONTROL - Bad for Motor?

    Quote Originally Posted by Insaneride View Post
    I've used those controllers. Big differance in cheap vs more expensive.

    That maybe a brushless fan and won't work a controller. An alternative would be to make a two foot extension cord with a 20 amp diode inline. Should make the fall run half speed. I don't know how efficient it will be on the motor. It would be worth a try
    thats the same thing as a speed controller except you just cut the speed in half rather than have variable... you are cutting the amount of power going to the motor..so it will over heat the same and possibly burn up..poof..

  13. Likes ronsii, jonnymacuser liked this post
  14. #8
    Join Date
    Mar 2011
    Location
    Western Washington
    Posts
    8,264
    Post Thanks / Like

    Re: Shop Fan - SPEED CONTROL - Bad for Motor?

    Quote Originally Posted by Hobbytime View Post
    thats the same thing as a speed controller except you just cut the speed in half rather than have variable... you are cutting the amount of power going to the motor..so it will over heat the same and possibly burn up..poof..
    I think a lot of the 'issues' come into play when you compound the 'electronics' (in fan)on top of more 'electronics' (in speed controller) most of those speed controllers use an SCR or TRIAC to 'chop' the power on the downside of the sine wave curve... so while you are 'cutting' power from the fan motor you are not really lowering the peak voltage going to it... but you are lowering the RMS voltage to it... and if the fan already counts on full RMS voltage to make the electronics do thir thing once you affect that then bad things will happen I have not seen the latest/greatest chinese offerings in their fan motors but have worked on the older ones... they had an actual two speed motor so you could run a speed controller on the full speed set of windings... or at least I did without problems

  15. Likes jonnymacuser liked this post
  16. #9
    Join Date
    Jan 2016
    Location
    northeast USA
    Posts
    9,221
    Post Thanks / Like

    Re: Shop Fan - SPEED CONTROL - Bad for Motor?

    Quote Originally Posted by ronsii View Post
    I think a lot of the 'issues' come into play when you compound the 'electronics' (in fan)on top of more 'electronics' (in speed controller) most of those speed controllers use an SCR or TRIAC to 'chop' the power on the downside of the sine wave curve... so while you are 'cutting' power from the fan motor you are not really lowering the peak voltage going to it... but you are lowering the RMS voltage to it... and if the fan already counts on full RMS voltage to make the electronics do thir thing once you affect that then bad things will happen I have not seen the latest/greatest chinese offerings in their fan motors but have worked on the older ones... they had an actual two speed motor so you could run a speed controller on the full speed set of windings... or at least I did without problems
    I have a few of those chicom fans, the small ones, and the motors are sealed..you cant crack them to even try and fix them..the fan is just disposable....well most of the chicom electronics are disposable..

  17. Likes ronsii liked this post
  18. #10
    Join Date
    Oct 2014
    Posts
    2,636
    Post Thanks / Like

    Re: Shop Fan - SPEED CONTROL - Bad for Motor?

    It's a 2 speed high velocity fan. Live with it or get a different fan. This is like buying a tapped voltage Mig machine and wanting to make it a variable voltage. If you want variable, get variable.

  19. #11
    Join Date
    Jun 2012
    Location
    Sebeka and Bemidji MN
    Posts
    14,564
    Post Thanks / Like

    Re: Shop Fan - SPEED CONTROL - Bad for Motor?

    Quote Originally Posted by albrightree View Post
    Why not use a small $20 box fan instead , it would be far simpler if you wanted less air flow.
    That's what I use, full size cheap box fans. I even installed 2 in the ceiling of my shop.
    They were there for 15 years and never burned up - but look horrible from all the smoke they exhausted
    Dave J.

    Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~

    Airco 300 - Syncro 350
    Invertec v250-s
    Thermal Arc 161 and 300
    MM210
    Dialarc
    Tried being normal once, didn't take....I think it was a Tuesday.

  20. Likes ronsii liked this post
  21. #12
    Join Date
    Feb 2012
    Posts
    4,173
    Post Thanks / Like

    Re: Shop Fan - SPEED CONTROL - Bad for Motor?

    Quote Originally Posted by Hobbytime View Post
    thats the same thing as a speed controller except you just cut the speed in half rather than have variable... you are cutting the amount of power going to the motor..so it will over heat the same and possibly burn up..poof..
    I don't know Hobbytime, I think a diode inline would be more like switching the fan off and on 60 times a second.

    ronsi gave a brief explanation of the scr controller. I will add that the scr can be triggered during the positive cycle and the negative. It seems to me that an scr should be able to control that fan.

    I looked up data sheets for the diodes in my pic. One is 40 amp. The other is hi voltage low amps. I think I have a ceiling fan (brushless motor) somewhere. I'll give it a try and let you know how it works. I see no reason why it should not work other than cooling the motor.

  22. #13
    Join Date
    Jan 2016
    Location
    northeast USA
    Posts
    9,221
    Post Thanks / Like

    Re: Shop Fan - SPEED CONTROL - Bad for Motor?

    Quote Originally Posted by Insaneride View Post
    I don't know Hobbytime, I think a diode inline would be more like switching the fan off and on 60 times a second.

    ronsi gave a brief explanation of the scr controller. I will add that the scr can be triggered during the positive cycle and the negative. It seems to me that an scr should be able to control that fan.

    I looked up data sheets for the diodes in my pic. One is 40 amp. The other is hi voltage low amps. I think I have a ceiling fan (brushless motor) somewhere. I'll give it a try and let you know how it works. I see no reason why it should not work other than cooling the motor.
    yeah, im not 100% sure a diode would work or not, but the diode in laymen terms slows down the current flow( they have other uses too)..so it may also depend on the quality of the motor if it has built in safteys for low voltage to avoid damage to the motor or just let it burn up...by reducing voltage or flow the fan may struggle to get started and burn up trying to get to full RPM...give it a try and see what happens...

  23. Likes ronsii liked this post
  24. #14
    Join Date
    Mar 2011
    Location
    Western Washington
    Posts
    8,264
    Post Thanks / Like

    Re: Shop Fan - SPEED CONTROL - Bad for Motor?

    Quote Originally Posted by Hobbytime View Post
    yeah, im not 100% sure a diode would work or not, but the diode in laymen terms slows down the current flow( they have other uses too)..so it may also depend on the quality of the motor if it has built in safteys for low voltage to avoid damage to the motor or just let it burn up...by reducing voltage or flow the fan may struggle to get started and burn up trying to get to full RPM...give it a try and see what happens...
    LOL!!!!! you just used the words 'quality' and safety' in the same sentence when talking about a chinese motor LOL!!!!!!!!!!

  25. #15
    Join Date
    Jan 2016
    Location
    northeast USA
    Posts
    9,221
    Post Thanks / Like

    Re: Shop Fan - SPEED CONTROL - Bad for Motor?

    Quote Originally Posted by ronsii View Post
    LOL!!!!! you just used the words 'quality' and safety' in the same sentence when talking about a chinese motor LOL!!!!!!!!!!
    well I did say " it depends" on it..not that it was there....LOL

  26. Likes ronsii liked this post

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Page generated in 1,604,042,477.99055 seconds with 15 queries