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#59696 12/12/05 11:03 PM
Joined: May 2003
Posts: 74
J
jkraft Offline OP
Member
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.

#59697 12/12/05 11:37 PM
Joined: Sep 2004
Posts: 174
B
Member
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
Joined: Feb 2002
Posts: 375
G
Member
maybe only #10.

#59699 12/13/05 12:31 AM
Joined: Feb 2002
Posts: 182
B
Bob Offline
Member
JK
Have you tried to do the VD caculations yourself?

#59700 12/13/05 01:50 AM
Joined: Jul 2004
Posts: 9,923
Likes: 32
G
Member
10 drops 6.6v, 12 drops 10.6v @ 11a


Greg Fretwell
#59701 12/13/05 06:53 AM
Joined: May 2003
Posts: 74
J
jkraft Offline OP
Member
Bob,

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

Joe

#59702 12/13/05 08:02 AM
Joined: Nov 2000
Posts: 2,148
R
Member
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
Joined: Jan 2005
Posts: 5,445
Likes: 2
Cat Servant
Member
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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