Matronics Email Lists :: View topic - Off topic -- Slowing an electric motor

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

Off topic -- Slowing an electric motor

Matronics Email Lists Forum Index -> AeroElectric-List

View previous topic :: View next topic

Author Message

limadelta(at)gmail.com
Guest

Posted: Wed Jan 19, 2011 8:40 pm Post subject: Off topic -- Slowing an electric motor

I built a wind tunnel for my son’s physics project.  Works great!  The issue is that I would like to slow the fan down to generate airspeed below the Reynolds number of a dimpled golf ball.  Current airspeed is about 58 mph.  I need to slow the fan to generate airspeed below 30 mph.  The motor is a permanent split capacitor type: http://www.grainger.com/Grainger/DAYTON-Direct-Drive-Blower-Motor-7E658.  Any thoughts on how to slow it down?  I've read that slowing it with a dimmer might damage the motor.   

   

Thanks,  Dan O’Brien  [quote][b]

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

nuckolls.bob(at)aeroelect
Guest

Posted: Wed Jan 19, 2011 8:50 pm Post subject: Off topic -- Slowing an electric motor

At 11:35 PM 1/19/2011, you wrote:



  	  Quote: 	
		  I built a wind tunnel for my son’s physics project..  Works great!  The issue is that I would like to slow the fan down to generate airspeed below the Reynolds number of a dimpled golf ball.  Current airspeed is about 58 mph.  I need to slow the fan to generate airspeed below 30 mph.  The motor is a permanent split capacitor type:  http://www.grainger.com/Grainger/DAYTON-Direct-Drive-Blower-Motor-7E658 .  Any thoughts on how to slow it down?  I've read that slowing it with a dimmer might damage the motor. 	


   It is difficult to slow these critters. May I suggest

   another motor?  Ebay has a bunch of DC motors and

   controllers intended for treadmill service . . .

   but easily adaptable to other tasks. These controllers

   usually have some form of tach feedback for very

   stable speed control.



   Alternatively, how about putting a damper across

   the inlet to throttle air flow?



 

 

   Bob . . .    [quote][b]

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

raymondj(at)frontiernet.n
Guest

Posted: Wed Jan 19, 2011 11:18 pm Post subject: Off topic -- Slowing an electric motor

do not archive



You can't talk about a wind tunnel and not include at least a photo!! 

Better yet a parts list and a blueprint 



Raymond Julian

Kettle River, MN



On 01/19/2011 09:46 PM, Robert L. Nuckolls, III wrote:

 	  Quote: 	
		   At 11:35 PM 1/19/2011, you wrote:



> I built a wind tunnel for my son’s physics project.. Works great! The

> issue is that I would like to slow the fan down to generate airspeed

> below the Reynolds number of a dimpled golf ball. Current airspeed is

> about 58 mph. I need to slow the fan to generate airspeed below 30

> mph. The motor is a permanent split capacitor type:

> http://www.grainger.com/Grainger/DAYTON-Direct-Drive-Blower-Motor-7E658 .

> Any thoughts on how to slow it down? I've read that slowing it with a

> dimmer might damage the motor.



 It is difficult to slow these critters. May I suggest

 another motor? Ebay has a bunch of DC motors and

 controllers intended for treadmill service . . .

 but easily adaptable to other tasks. These controllers

 usually have some form of tach feedback for very

 stable speed control.



 Alternatively, how about putting a damper across

 the inlet to throttle air flow?

 Bob . . .



 *

 *

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

limadelta(at)gmail.com
Guest

Posted: Mon Jan 24, 2011 7:41 pm Post subject: Off topic -- Slowing an electric motor

Just following up on my question last week about slowing a permanent split capacitor motor for a wind tunnel I built for my son's science project.  A poster indicated that one can slow such motors with a dimmer switch, which is what I did.  Worked great.   We were able to measure the drag coefficients of golf balls with different dimple patterns at different Reynolds numbers.  Cool project.  I've attached a compressed picture of the wind tunnel as one poster requested. 



Thanks for the help guys!

Dan O'Brien

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

wind_tunnel.JPG

Description:

Filesize:

40.86 KB

Viewed:

1740 Time(s)

Display posts from previous:

	Matronics Email Lists Forum Index -> AeroElectric-List	All times are GMT - 8 Hours
Page 1 of 1

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum