Motor Energy calculation...
Motor Energy calculation...
(OP)
If I have a 7.5 hp 575VAC motor runing all day and I know what the cost of electricity is (12 cents US per KWH) can I roughly estimate my cost by simply multipying the motor power rating (7.5 HP) x (746 W/HP) x (24 h/day) x ($0.12 /KWH) = $16.12/ day operating cost???
U have to know the motor load though, right? cause it may not draw its rated current under normal operations.. is there a % used to guestimate???
U have to know the motor load though, right? cause it may not draw its rated current under normal operations.. is there a % used to guestimate???





RE: Motor Energy calculation...
The load factor can vary widely - from 20% to 110%. I don't think we can be of much help in that area unless we know more about the load.
Hope that helps.
RE: Motor Energy calculation...
If you want to determine load, you can attempt to measure speed OR current OR [flow rate AND dp...assuming this is driving a pump].
If you obtain a current measurement, it would also help to know the nameplate full load amps and the nameplate rpm.
The ideal situation is obviously to measure electrical power with a coordinated current, voltage, phase-angle measuring device...I'm guessing that's not practical.
RE: Motor Energy calculation...
RE: Motor Energy calculation...
RE: Motor Energy calculation...
It's a wild guess... as dpc mentioned the wide range 20-110% surely might be encountered in the real world.
RE: Motor Energy calculation...
Assume 1kw input per HP, Demand charge (7.5 KW)($10.00/KW)=
$ 75.00 to start the motor for the monthl. Total electric bill would be the sum of KWH plus the KW Demand Charge.
RE: Motor Energy calculation...
RE: Motor Energy calculation...
RE: Motor Energy calculation...
http://www.tifac.org.in/offer/tlbo/rep/st152.htm