230v 250 Watt Heaters operating at 70 Watt with 120v

[xboxhaxorz]

I have the heater mentioned above, and when i plug it in to the wall socket at 120v i only get 60 to 70 watts, i tested this using a kill o watt.

I figured if it wasnt operating at 230v then it would simply take longer to heat or even operate at half the voltage, but at a max of 70 watts im not sure why this is occurring any information is helpful.

[mariushm]

Re: 230v 250 Watt Heaters operating at 70 Watt with 120v

The heating element has the same resistance no matter the input voltage:

Watts = V x V / R

250w = 230v x 230v / R -> R = 230x230/250 = 211 ohm

120v :

Watts = V x V / R = 120vx120v / 211 ohm = 68.2 watts

Same reason but the other way around is why 120v lightbulbs blow up when you use them in 230v sockets.

[xboxhaxorz]

Re: 230v 250 Watt Heaters operating at 70 Watt with 120v

Thanks, makes sense

I am fully aware of components blowing when providing too much voltage, i figured with half voltage they just worked half power

[mariushm]

Re: 230v 250 Watt Heaters operating at 70 Watt with 120v

Yeah, think about it...

ohm's law : v = i x r

Power = v x i ... but from above v = i x r or i = v/r so if you replace, then power = i x i x r or power = v x v / r

It's just basic formulas.

[tom66]

Re: 230v 250 Watt Heaters operating at 70 Watt with 120v

Half voltage, quarter the power.

There are fake 240V to 120V conversion devices on the 'net which have a single diode in them to chop 240V AC into pulsed DC 0-240V peak.

Like this: http://www.amazon.com/Jensen-1600-Po.../dp/B000BB7B82 way to small to be an actual 1600W converter.

From an immediate perspective one would think this would half the power provided by 240V and so equalling the power provided by 120V, and that this would work for heaters, lightbulbs, cookers, etc not dependent on peak voltage.

However, what it actually does is double the power compared to pure 120V, because power is squared... so it fries them.

[xboxhaxorz]

Re: 230v 250 Watt Heaters operating at 70 Watt with 120v

Is there something i could use in say a bud box with the heater that can tolerate 250 watts

Either buy or make is of no issue, i would prefer not to get those huge transformers

From my searching it doesnt appear to be to simple and i may need to just get this http://www.amazon.com/Goldsource%C2%...nsformers+220v

[mariushm]

Re: 230v 250 Watt Heaters operating at 70 Watt with 120v

buy one of these if you want heat and light:

http://www.amazon.com/Cooper-Lightin...gen+floodlight

[budm]

Re: 230v 250 Watt Heaters operating at 70 Watt with 120v

Is this thread related to the thread here?
https://www.badcaps.net/forum/showth...831#post420831

[xboxhaxorz]

Re: 230v 250 Watt Heaters operating at 70 Watt with 120v

yes that is correct

i have various heaters which are all 230v but with different wattages

250, 500, and 600

they actually say 230v on the heaters themselves