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operating cost? #74705
02/02/07 11:34 AM
02/02/07 11:34 AM
Rob  Offline OP
Joined: Dec 2003
Posts: 15
New York
How do you determine operating cost of a 3 phase motor. 460 volt 15 amp.
My utility rate is .08 cents per kwh.
Is there a common formula?

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Re: operating cost? #74706
02/02/07 11:58 AM
02/02/07 11:58 AM
renosteinke  Offline
Cat Servant
Joined: Jan 2005
Posts: 5,316
Blue Collar Country
Measure the actual amps drawn on each leg. Average. Multiply by 1.73. That's your amp load.

From there, it's the usual amps x volts x time x rate = electrical cost.

This will give you figures good enough to work with. Actual results will vary a bit, due to changes in load, power factor, harmonics, etc ... but the number you get will be close enough for budgeting.

Re: operating cost? #74707
02/02/07 06:20 PM
02/02/07 06:20 PM
JBD  Offline
Joined: Jul 2001
Posts: 599
One quick and dirty method is to estimate 1KVA of input power for each HP of output.

For a fully loaded motor you can use 1KW per HP. For lightly loaded motors use 1.1KW per HP instead.


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