Heating Elements on Different Voltage and Hz

If the OP has an actual 150W transformer and not a 150W inverter that he's calling a transformer then no power will get through the transformer. The OP might pop a fuse in car but that is all that will happen. If it is a 150W inverter then you got it exactly right Jack. Plugging in a 550W load will cause the inverter's output protection (fuse) to save the rest of the inverter.

PS: What would happen with a bulb ? like a 220V/50Hz fluorescent bulb in a 110V/60Hz country. Explode ? Not give out as many light ?

Sorry, misread this one. A fluorescent electronic energy saving lamp contains an electronic ballast and will likely not operate at all unless it is designed to work on such a wide voltage range.

http://en.wikipedia.org/wiki/Compact_fluorescent_lamp

What would happen with a bulb ? like a 220V/50Hz fluorescent bulb in a 110V/60Hz country. Explode ? Not give out as many light ? Your light bulb, assuming incandescent, would not be as bright. I have seen what happens to 110v incandescent bulbs when attached to 277v. They tend to glow quite brightly then explode.

<....Have heating element (hair straightener) 220V/50Hz / 35W (I= 220/35= 6.28A)
Go to USA and use it on 110V/60Hz.
How will it perform ?
...will the heating element still reach it's operating temperature....>

The above arithmetic is incorrect. 35W/220V = 0.16A

If the device operates at all, the heat dissipated from it will be around 25% of that on the correct voltage.

It is not possible to say whether or not it will reach the operating temperature, as this depends largely upon external factors.

<...buy a 220V/500W heating element to heat up water.
take it on my car when traveling and plug it to a 12V/220V-150W transformer.
What happens ?...>

As the device is a 500W load, and it is plugged into a 150W transformer, either

1. preferably a circuit protective device will operate, or
2. in the absence of sufficient circuit protection there will be a catastrophic failure of some part of the transformer, its connections or its wiring. Please ensure that all CR4 readers are out of the vehicle lest it should catch fire.
   

GA. You were the first to recognize (assuming linearity in the heating element) that you would get 1/4 the power, i.e half voltage (.5) also gets you half current (.5) by Ohm's Law so P=I*V has the (.5)*(.5) = .25 factor.

That was a common mistake made by students in my EE302 class (Basic Circuit Analysis) at the Hudson School for Boys (and girls now too).

Cheers !!

Had to buy a "universal" voltage hair straightener for my daughter when she made a trip out of the U.S. Straighteners that will operate from 100-220VAC @50-60 Hz are not much more than single-voltage units here in the U.S.

As others have pointed out, in the car/heating element scenario, you say "transformer" but the proper term is "inverter", and it would shut down or die on such a load, and it could possibly damage the cig lighter socket before or after doing so.

On the fluorescent lamps, you can probably find electronic ballasts that would be "universal", but usually they are designed to work on one or the other. Voltage too low, no light, voltage too high, might burst the tube if no protection is in place.

Tom D.

Have heating element (hair straightener) 220V/50Hz / 35W (I= 220/35= 6.28A)
Go to USA and use it on 110V/60Hz.
How will it perform ?
P = V x I
Will the Amps be the same as on 220V ?
II believe the power will be lower, but wil the heating element still reach it's operating temperature or not ? (no matter if it takes double of the time )

With half the voltage, you get half the current and one quarter the wattage

2.
buy a 220V/500W heating element to heat up water.
take it on my car when traveling and plug it to a 12V/220V-150W transformer.
What happens ?
only takes to long to heat ?
blows up the transformer ?
damages the heating element ?
damages my car 12V plug ?

Thank you :)

The transformer will saturate, and get hot and will not transfer 500W to the heater. Some lesser amount, but I cannot predict that.

PS: What would happen with a bulb ? like a 220V/50Hz fluorescent bulb in a 110V/60Hz country. Explode ? Not give out as many light ?

What about the other way around ? explode ? too much light ?

A fluoresecent light will be feek and weeble on half the voltage and a little higher frequency, might be 20-30%, hard to say, since it is a phase limiting reactance ballast.

Running 120 on 240 will give a shorter and brighter life

'n don't forget Z = square root of Xl sq + Xc sq, 'n Xl is 2 X Pi f l, different f, then we have a different Z. Not that we need to worry about that, but it's all in the soup.

Hey, Sal. Don't. Buy a hair dryer when you get there, your piece of "string' will not fit in the States. You need a piece of "American String".

Hey Sal,

hair straightener: it depends on the type of heating element.

If it's real ceramic (PTC thermistors) it will work just a little cooler (say 3 deg C) on 120 V. What is the brand? e. g. Ga-Ma (Italy) has PTC heating.

Some users say 3 degrees will make a difference. Tell them curled hair is in again.

brgds

Snel

I am assuming that it is a resistive type of heater. This type of heater is not affected any way by the frequency of supply but it is only the voltage that matters. If you halve the voltage, the watt rating of the heater will go down to 1/4 th, since power is proportional to the square of the voltage. At such a low wattage, you may not get the desired temperature and the unit could be useless. You may carry a transformer wound for 60 Hz frequency, of ratio 110v / 220 v and of power rating approx 30 % higher than the drier rating.

PRIYADARSHAN

Please take a look at

http://www.epcos.com/inf/55/db/PTC_09/Heating_B59102_R102.pdf

The curves on page 4 show why the temperature is self-regulating and has little dependence on voltage. Resistance is multiplied (>10,000 -fold) within a few degrees.

Power is not constant, it depends on how much heat is taken away.

The thing is specified for 230 V operation, but it's even UL-approved for 120 V.

If Sal's hair straightener (not a dryer) uses this heating element then it will be worthwile buying a pin adapter.

brgds

Snel

Nice catch. Nichrome has a similar, but not as extreme resistance change with temperature. However, because 120VAC to 220VAC adapter plugs are not a common sale (I wonder which of the many 220VAC plugs he has), I would not be surprised if one of these adapters costs as much as a 120VAC hair straightener.

Problem:-1 220v/50hz/35w I1=6.28A 110v/50hz/35w I2=12.56A As you can see, current will be doubled. According to I(sqr)R formula, heat generated will be more. II - Heating element will reach its operating temperature in half of the time compared to earlier one. But as the device is operating at its double rating, it will burn.(& it will serve you no more!! ;) Problem:-2 If a 220V/500W heating element will be operated by 12V/220V - 150W transformer, the transformer will draw 500/150=3.33 times the rated current & if switch for transformer will not operated, it will definitely burn. Possibilities:- If the device is run continuously, transformer winding will be heated up first. By the time when temp will go so high, insulation will burn (you will start to smell burning!!). If still it will continue, insulation will be damaged (you will see smoke coming out!!) & there will be intern-turn short OR short circuit between windings.Transformer will explode. PS: fluorescent tube, if operated at 110V/60HZ... It will start lighting after some delay, as voltage is half compared to earlier one.(Choke will have to work much to build up desired voltage across filament) After that power being the function of voltage, (P=V x I) light will be the half of earlier one.

Sorry Ankitj, but with a PTC, power will be the same, 220x6.28 = 110x12.56. R is not a constant and will settle at about 1/4 of the original value @ 220 V. The hair straightner will not be damaged, this is the way the "universal" ones work.

brgds

Snel