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#59696 - 12/12/05 11:03 PM suggested wire size  
jkraft  Offline
Member
Joined: May 2003
Posts: 74
I'm installing a 1.5 hp 230V 11 amp single phase fan motor from a 120/208V panel about 250 feet away. Any suggestions for wire size.


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#59697 - 12/12/05 11:37 PM Re: suggested wire size  
bot540  Offline
Member
Joined: Sep 2004
Posts: 174
Vernon Hills, IL
YOU'LL NEED TO PULL NO. 8 WIRE


Jesus may have been a capenter,but God was an electrician.Genesis1:3

#59698 - 12/13/05 12:08 AM Re: suggested wire size  
George  Offline
Member
Joined: Feb 2002
Posts: 375
maybe only #10.


#59699 - 12/13/05 12:31 AM Re: suggested wire size  
Bob  Offline
Member
Joined: Feb 2002
Posts: 182
Mobile, AL, USA
JK
Have you tried to do the VD caculations yourself?


#59700 - 12/13/05 01:50 AM Re: suggested wire size  
gfretwell  Offline


Member
Joined: Jul 2004
Posts: 9,104
Estero,Fl,usa
10 drops 6.6v, 12 drops 10.6v @ 11a


Greg Fretwell

#59701 - 12/13/05 06:53 AM Re: suggested wire size  
jkraft  Offline
Member
Joined: May 2003
Posts: 74
Bob,

I apologize, I have not. I was hoping someone would have previous experience with this.

Joe


#59702 - 12/13/05 08:02 AM Re: suggested wire size  
resqcapt19  Offline
Member
Joined: Nov 2000
Posts: 2,148
IL
Not all 230 volt rated motors are suitable for use on 208 volt systems. The voltage drop will make this problem worse.
Don

[This message has been edited by resqcapt19 (edited 12-13-2005).]


Don(resqcapt19)

#59703 - 12/13/05 10:17 PM Re: suggested wire size  
renosteinke  Offline
Cat Servant
Member
Joined: Jan 2005
Posts: 5,316
Blue Collar Country
Don is quite right; even under the best of conditions, you're really pushing it when you try to run a "230v" motor on 208 volts.

As a general rule of thumb, a motor may be used at plus or minus 10% of the nameplate marked voltage. So if your nameplate avtually reads simply "230v", then it should have a minimum of 207 volts at all times- and make sure that value is measured "under load!"

Now, if the motor is marked 220, or 208/230, etc...well, you get the picture.

I would also be very conservative in allowing for voltage drop. Remember, motors- especially those used in compressors- have a considerably higher curent required for starting; you almost want to base your voltage-drop calculations on the "LRA", or 'locked rotor amps.'

An exhaust fan isn't really fighting a load as it is starting up; so the inrush current needed isn't as great as it might be in other applications. You will probably be able to use #8.

One thing to also consider is a motor satrter with electronic overloads ("heaters"). Even though strictly not necessary, it will provide additional protection for the motor. The electronic elements provide protection against many other power problems than simple 'heaters' do.



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