ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
ShoutChat
Recent Posts
12 Lead Motor Connection Weird
by emolatur - 01/19/22 02:40 PM
Any women electricians here?
by gfretwell - 01/17/22 01:44 PM
Well There's your problem.
by gfretwell - 01/08/22 12:17 AM
Happy New Year!!
by HotLine1 - 01/04/22 09:50 AM
Sangamo s309.2
by Robski - 12/31/21 04:54 PM
New in the Gallery:
240/208 to a house
240/208 to a house
by wa2ise, October 9
Now you know.
Now you know.
by Tom_Horne, September 7
Who's Online Now
0 members (), 48 guests, and 16 robots.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
#75529 03/01/07 03:49 PM
Joined: Jun 2005
Posts: 821
S
Member
If I had a 3-phase RTU exhaust fan controlled by a 120V contactor coil, what are my options as far as speed control of the motor?

What if the control circuit operated at 24 volts?

And finally, does a motor need to be rated for variable speed for a low, medium, and high speed controlling device?

Thanks in advance.

Joined: Jul 2004
Posts: 783
L
Member
3 phase? Variable Frequency Drive.
Use the 24 VDC control signal(s) to select various pre-programmed speeds.

I do not know if the VFD can be remote mounted close to the fan or if it has to be mounted inside, close to the load center.

Larry C

Joined: Jun 2005
Posts: 821
S
Member
Nevermind my original post. I'm not even sure what I was thinking when I asked if a control circuit could determine the speed of a motor. I was asked today about installing a speed control in a pizza place to control an exhaust fan. Just nevermind. It's all good.


Link Copied to Clipboard
Featured:

Tools for Electricians
Tools for Electricians
 

* * * * * * *

2020 Master Electrician Exam Preparation Combos
2020 NEC Electrician
Exam Prep Combos:
Master / Journeyman

 

Member Spotlight
RH1
RH1
California
Posts: 22
Joined: August 2009
Top Posters(30 Days)
NORCAL 3
grich 1
Popular Topics(Views)
288,000 Are you busy
220,121 Re: Forum
206,117 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.7.5