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#17904 - 12/04/02 02:37 PM 75hp current draw  
VOLTS  Offline
Member
Joined: Jun 2001
Posts: 21
What would a 75hp 480 vac 3 phase motor draw if it were not connected to anything? Just wired up sitting on a table runnng? Is there a table or a formula anyware all the tables I find are for full load amps.


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#17905 - 12/04/02 03:11 PM Re: 75hp current draw  
JBD  Offline
Member
Joined: Jul 2001
Posts: 599
WI, USA
There are no formulas, too many variables. One rule of thumb I have seen is 75% FLA, but my experience says this is on the high side.


#17906 - 12/04/02 06:36 PM Re: 75hp current draw  
electric-ed  Offline
Member
Joined: Jul 2002
Posts: 175
Canada
70 to 75% of rated current is about right. The reason - The magnetizing component of the current is the same whether the motor is at full load or no load.

Ed


#17907 - 12/04/02 07:23 PM Re: 75hp current draw  
golf junkie  Offline
Member
Joined: Apr 2001
Posts: 507
York, NE
My experience tells me it's closer to 50% than 75%. 50 may be on the low side though.

FWIW
GJ

[This message has been edited by golf junkie (edited 12-04-2002).]


#17908 - 12/04/02 07:42 PM Re: 75hp current draw  
Wirenuttt  Offline
Member
Joined: Nov 2002
Posts: 267
Massachusetts
Just wondering, what's wrong with an amp meter?


#17909 - 12/04/02 07:52 PM Re: 75hp current draw  
go-go  Offline
Member
Joined: Aug 2002
Posts: 42
Fla.
Volts,
Baldor lists a 75hp model JPM2551T as FLA @ 208v-176a FLA @ 460v-88a and the no- load current at 30.2a http://www.baldor.com/products/perf...s&family=Pump%7Cvw%5FACMotors%5FPump

[This message has been edited by go-go (edited 12-04-2002).]


#17910 - 12/04/02 08:49 PM Re: 75hp current draw  
Bjarney  Offline
Moderator
Joined: Apr 2002
Posts: 2,527
West-Southern Inner-Northeast ...
Good, informative link, go-go.

FLC/NLC = 87.7/30.2 amperes = 35% [surprisingly low]

Power Factor (25% load) = 53% [rotten!]

PF at zero load is not listed, but likely less than 50%. [Way rotten!]




[This message has been edited by Bjarney (edited 12-04-2002).]


#17911 - 12/05/02 09:23 AM Re: 75hp current draw  
VOLTS  Offline
Member
Joined: Jun 2001
Posts: 21
The information was helpful thank you!



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