Matt Mckenzie
Member
- Location
- United States
A 4,000watt heater connected 240 volt consumes how many watts connected 208 3 phase? I get 4,800watts. Is this correct?
Heater from 240 volt to 208 volt
- Thread starter Matt Mckenzie
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- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
No. If the resistance is unchanged the power will be lower at the lower voltage. P=V2/R.
- Occupation
- Licensed Electrician
Divide 208 by 240 times 4000 and you get 3466 Watts.
The old saw about lower voltage means more amps does not work for resistive loads.
The old saw about lower voltage means more amps does not work for resistive loads.
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
Divide 208*208 by 240*240 and multiply that by 4000 and you will get the right answer: 3004 watts.
208/240 alone just gives you the decrease in the current.
- Occupation
- Licensed Electrician
Makes me wish I had paid more attention during those three years of sixth grade. I got pretty close using my best construction worker math. ;-)
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
Not sure what is happening here. Is this a 3 phase heater or a single phase heater?
If you use single phase and go from 240v to 208v then you will have about 75% less wattage at the 208V. 75% of 4000~= 3000 watts...
- Location
- Massachusetts
Many unit heaters are convertible from 208 three phase to 240 single phase.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
Why wouldn't all these calculations be for 3? as stated in the OP?
kwired
Electron manager
- Location
- NE Nebraska
Where I learned math, take 75% away from 4000 and it leaves you with 1000 take 25% away from 4000 and it leaves you with 3000.
But sometimes they change things without telling me
- Occupation
- Licensed Electrician
It?s a way of life for me. I live with a houseful of girls....every rule that was ever written is up for change at any given moment...Where I learned math, take 75% away from 4000 and it leaves you with 1000 take 25% away from 4000 and it leaves you with 3000.
But sometimes they change things without telling me
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
Where I learned math, take 75% away from 4000 and it leaves you with 1000 take 25% away from 4000 and it leaves you with 3000.
But sometimes they change things without telling me
You are correct -- it is 75% of the 240V wattage not what I stated but I did do the math correctly - at least
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