kilowatt to amp
- Thread starter global
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- Location
- Massachusetts
Pierre C Belarge
Senior Member
- Location
- Westchester County, New York
This is an example of the reason learning simple Ohms Law is important to everyday electricians. Without the knowledge, they are mostly "shooting in the dark".
The excuse that no one has taught them is no longer acceptable, as this information is readily available at your fingertips.
The excuse that no one has taught them is no longer acceptable, as this information is readily available at your fingertips.
cadpoint
Senior Member
- Location
- Durham, NC
I don't disagree with your statement of learning Ohm's Law!
I will take issue that a lot of People aren't happy with computers - even in this day and age! Be it thier embarrassed that there kids are way better than them, or don't have or understand frankly what's out there!
I've told people about the wealth of information that is available via the web and specifically this web site, I can tell ten people and only one will go and read here, if that. It's come back to me (second person) that I'm a Geek for reading here, so be it!
Frankly it's a mixed bag, thats mostly empty, some don't care to (MO) advance themselves, it's either I'm embarrassing them or they get put off that they don't know and don't care to know about such information that is obtainable!
It's not a school assignment when I tell people about this place!
Unrelated, I have asked a few Journeyman to look it up themselves if they don't believe me and even sketch a wire diagram or look it up on the I-net, they never come back to show me anything, again its not a school assignment.
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Regularkevin
Member
- Location
- Auburn, WA
Here is a simple application I found using a Google search. Bookmark this one so you can do this super easy now.
Ohm's Law Calculator
Ohm's Law Calculator
David C. Adkins
Member
- Location
- Lafayette, Colorado
Maybe I'm wrong, but the answer is 45 and 40
5.400 watts divided by 120 volts = 45 amps breaker
4.800 watts divided by 120 volts = 40 amps breaker
5.400 watts divided by 120 volts = 45 amps breaker
4.800 watts divided by 120 volts = 40 amps breaker
- Location
- Lockport, IL
- Occupation
- Semi-Retired Electrical Engineer
I can't come up with any calculation method that arrives at those numbers. Care to share how you did it? If you are willing, then perhaps we may be able to help you see where you have gotten it wrong.
- Location
- Lockport, IL
- Occupation
- Semi-Retired Electrical Engineer
- Location
- Massachusetts
Maybe I'm wrong, but the answer is 45 and 40
5.400 watts divided by 120 volts = 45 amps breaker
4.800 watts divided by 120 volts = 40 amps breaker
Charlie covered the calculation error but beyond that from the information provided there is no way to determine the breaker size.
We also are stuck assuming a power factor of 1 without more info.
David C. Adkins
Member
- Location
- Lafayette, Colorado
45 amp and 40 amp = 56.25 amps and 50 amps at 125 percent, so a 60 and 50 amp breaker should be right.
x by 120 volts because at the breaker pole 120 volts exist, not 220
60 amp two pole breaker and a 50 amp two pole breaker
x by 120 volts because at the breaker pole 120 volts exist, not 220
60 amp two pole breaker and a 50 amp two pole breaker
- Location
- Lockport, IL
- Occupation
- Semi-Retired Electrical Engineer
Not true. The load was described as 120/240 volt. That must necessarily mean that the breaker is a two-pole, and that 240 volts is available to the load. Therefore, you divide the VA by 240, not by 120.
- Location
- Illinois
- Occupation
- retired electrician
No...240 exists line to line ... a 60 amp breaker will supply 14.4 kva at 100% or 11.5 kva at 80%.45 amp and 40 amp = 56.25 amps and 50 amps at 125 percent, so a 60 and 50 amp breaker should be right.
x by 120 volts because at the breaker pole 120 volts exist, not 220
60 amp two pole breaker and a 50 amp two pole breaker
- Location
- Massachusetts
There is no reason to assume this load requires 125% on top of the basic calculation, there is no reason to assume this load is not a motor load which may need a breaker 200% to 300% over the basic calculation.
As I said, without more info we are just guessing what size breaker or fuse needs to be used.
- Location
- Massachusetts
By the way David, welcome to the forum.:smile:
David C. Adkins
Member
- Location
- Lafayette, Colorado
Yes if you put the two poles together, you have 240
If we were in Germany, it would be 240 single pole breaker 50hz:smile:
They don't operate with the low voltage of 120 60 hz
If we were in Germany, it would be 240 single pole breaker 50hz:smile:
They don't operate with the low voltage of 120 60 hz
- Location
- New Jersey
- Occupation
- Journeyman Electrician
cadpoint
Senior Member
- Location
- Durham, NC
I'll go along with the thought, because the information was presented!
But, where is the cut-off for a 120v circuit, a single pole 30 Amp, or a single pole 40 Amp. (assuming the 240 wasn't presented),
I'm sure they make them in higher amperages but I've never seen one higher than a 40 amp breaker!
Do use the 240! Maybe a big hint with Electrical math formula's sometimes a whole lot of information is presented thats not usuable to answer the question.
Very sharp... I'll let my other thoughts GO! :grin:
It's being well moderated!!! :grin:
These are some of the big guns here, "pay attention", David : ) ...
Their here for your protection, not to be in their sight, (so to State) (( thinking Nautical, again)) !!!
Yes, that thought struck me too when I read the OP.
And, at 5.4kW, is it beyond the bounds of possibility that it could be a three-phase load?
- Location
- Massachusetts
I thought, and I could be wrong, that 120/240 ruled that out. But again I am a Wye guy.
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