How Do You Determine Kilowatts From Amps? I Have 288 Amps How Do You Determine How Many Kilowatts That Is?
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Amps To Kilowatts
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Re: Amps To Kilowatts
Originally posted by UnregisteredYou made an error in the reply that makes it confusing
288A * 110V = 31,680 Watt
but 288A on a 110V grid is unlikely; I would expect it is 480V in a three phase grid; that makes it even more difficult :)
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Re: Amps To Kilowatts
Originally posted by UnregisteredHow Do You Determine Kilowatts From Amps? I Have 400 Amps How Do You Determine How Many Kilowatts That Is?
I Have 400 Amps How Do You Determine How Many Kilowatts That Is? at 3phase 208volts
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Re: Kilowatts to amps
Originally posted by mohamedi hav motor for machine 380 v /3 phas /30 kw i whant know how many amps this motor ned
I will assume it is line to neutral
30 kW/380 V = 78.9 A
That is the sum of the three phase currents, each phase is 26.3 A, assuming the load is balanced.
(It may need higher current during starting.)
Edit: It is actually more likely that it is 219 V line to neutral and 380 line to line.
30 kW/219 V = 137 A, 45.7 A in each phase (assuming balanced load)Last edited by JohnS; 04102009, 06:34 AM.
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Re: Kilowatts to amps
Originally posted by JohnSThe question is whether the 380 V is measured line to neutral or line to line. If it is line to line, then it is only 219 V line to neutral.
I will assume it is line to neutral
30 kW/380 V = 78.9 A
That is the sum of the three phase currents, each phase is 26.3 A, assuming the load is balanced.
(It may need higher current during starting.)
Edit: It is actually more likely that it is 219 V line to neutral and 380 line to line.
30 kW/219 V = 137 A, 45.7 A in each phase (assuming balanced load)
Amps. That being said, overcurrent protection will have to be sized to carry momentary starting load of about 250%. This could be even higher in an application with large inertial loading. The calculation is assuming 100% efficiency as well, so you need to know if 30kW is the size of the motor or the consumption under load and divide the current figure by efficiency.
Note that the square root of the phasing is used as actual voltage (an hence current) in a three phase circuit is 120 electrical degrees apart so the actual currents peak 1/150 of a second apart in 50 Hz or 1/180 of a second at 60 Hz.
Motor name plate data should indicate FLA (full load amps) and LRA (locked rotor amps). Local code requirements or good engineering practice will dictate wire size and overcurrent protection.
Sounds like you are looking at wire in the #6 AWG range (~15 sq mm) with an increase in size of (~5 sq mm) for each 30m increase in length.
Of course that's looking at it from half a world away.Last edited by MJWorner; 04132009, 06:59 AM.
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Re: Amps To Kilowatts
Originally posted by Unregistered111400amps @ 3p208
400*(3*208)=249,600w
249,600/1000=249.6
You have to take the square root of the phases because they don't peak simultaneously but sequentially 1/180 of a second apart.
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Re: Amps To Kilowatts
Everyone in here forgot that to determine kW in 3 phase applications you must use the following formula:
V x A x 1.73 = W
So if you have a load of 30kW at 380V/3 Ph you would need to multiply volts times 1.73, then divide 30kW by the result.
380V x 1.73 = 657.4 30,000W/657.4 = 45.6A
If you do not use the three phase factor of 1.73 your calculation will be very incorrect, causing loss of equipment and/or personnel.
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Re: Amps To Kilowatts
I am looking to put a capicitor on my a/c units how much will i sve per month if the follow are assumed.
3 phase 280 volt
when i do a ready on of a test unit i am saving 2 amps
my kilowatt per hour rate is .0983 from my utitlity bill the ac units run aproxiamatley 20 hours per day
here is my calculation did i do it right
amps(2) * 280 volts = volts 560 =kilo watts .56 * kwh cost of $.0983 =.055 * 22 hours a day * 30 days a month = $33.00 per month in savings
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