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Coninsan
30 November 2010, 0623
Hello, I think i'll have to call upon the collective knowledge of Elmoto for this dilemma, since you know a thing or two about electricity, figures.

My problem is, that I, on my trip to Japan a month ago, bought a Electric Kettle, that runs on 100v, but here in Denmark we run on 230v. Dumb as i was i didn't give a rats ass "A transformer will be easy to get hold off"
Turns out it isn't. Doh!

The only ones cheaply available are 230-110v step down, and 110v would kill my poor Kettle.. And a 230-100v costs about 3 times that of a 110v step down, that's 200$.

So I'm hoping that someone either knows a place where I can find a 230-100v step down transformer, or a 230-110v + a 110-100v for less than 150$.. If that would even be a smart idea. :)

OR! My second option: Building a 230-100v step down transformer myself, would that be too bad of an idea? :p

lugnut
30 November 2010, 0633
OR! My second option: Building a 230-100v step down transformer myself, would that be too bad of an idea? :p

Take 9% of the turns off the secondary winding of the 230-110V transformer.

BaldBruce
30 November 2010, 0653
What VA do you need?

Coninsan
30 November 2010, 0726
well, the kettle is a 950VA, so between 1500 and 2000VA

Coninsan
30 November 2010, 0744
Take 9% of the turns off the secondary winding of the 230-110V transformer.
Well if Wikipedia knows its physics, that wouldn't decrease the output voltage, it would likely increase it up to 120 volt.

lugnut
30 November 2010, 0806
Well if Wikipedia knows its physics, that wouldn't decrease the output voltage, it would likely increase it up to 120 volt.

I think I'm right. Vs / Vp = Ns / Np. Or Vs = Vp * Ns / Np. Therefore if you reduce the secondary turns (Ns) by 9%, you reduce the secondary voltage (Vs) by 9%.

teddillard
30 November 2010, 0832
first flashlights, now electric kettles? what's elmoto coming to? :D

http://www.kaibo.com/kettle.htm

Coninsan
30 November 2010, 0844
Okay, I'm convinced. You obviously know your stuff :)

But i may have found a solution in form of building my own transformer to spec.
I've just found a source of Toroidal Transformer units, locally, that could supply me two 800VA 230-2x50V units, the secondary windings would then be serial connected to produce 100V and the two units used in paralel to up the VA to 1600, with a 100V 8A Bridge Recifier mounted close to each unit before the paralel connection to stop any interferance.
Questions is though. Should a Bridge Recifier be used by the units input if I wanted to paralel that too?

Coninsan
30 November 2010, 0850
first flashlights, now electric kettles? what's elmoto coming to? :D

http://www.kaibo.com/kettle.htm

Actually, this is the said kettle: http://www.zojirushi.com/ourproducts/zuttos/zuttos.html :D

lugnut
30 November 2010, 0858
Actually, this is the said kettle: http://www.zojirushi.com/ourproducts/zuttos/zuttos.html :D

Spec on those pots say 120 V. And if the appliance is intended for AC, do not rectify the source voltage. Nasty things may happen.

edit: You know, often times appliances operate over a range of input voltage and are called a nominal voltage for convenience. Like when we say 110 volt AC, most household outlets are like 115 or 117 V. So what you thought was 100 volt might just be a nominal voltage to differentiate it from the 220 V model. I don't know about your kettle for sure, but the manual should specify a range of acceptable input voltage (and frequency).

magicsmoke
30 November 2010, 0926
Pah! never mind transformers.
For something this simple, just stick a suitably rated diode in series with the Live. This will knock the volts in half.
I'm at work at the moment so can't spec. a proper one, but a quick glance in the books looks like a 600V / 50A is gonna be less than $5.

Rob

Coninsan
30 November 2010, 0935
Spec on those pots say 120 V. And if the appliance is intended for AC, do not rectify the source voltage. Nasty things may happen.

edit: You know, often times appliances operate over a range of input voltage and are called a nominal voltage for convenience. Like when we say 110 volt AC, most household outlets are like 115 or 117 V. So what you thought was 100 volt might just be a nominal voltage to differentiate it from the 220 V model. I don't know about your kettle for sure, but the manual should specify a range of acceptable input voltage (and frequency).

Note, that that is the American version of Zojirushi's webpage, the actual site with my kettle on it is in pure Japanese and wouldn't make much sence to you guys. I didn't think about anyone actually checking the ratings of that site. :)
I've already downloaded the manual of the Japanese site and it says the kettle takes 100V nominal (90-110V 10%+-) at 50/60Hz. (Japan has both 50 and 60Hz)

And thanks for the tip on recitifiers, I won't use any then. :)

EVcycle
30 November 2010, 1432
Do I smell Smoke?

:):)

Coninsan
05 January 2011, 0903
Well, here's a minor update, in case you were wondering.

I looked around and the only transformers for 100V were very expensive 250-300$ units, poorly built, stacked type transformers. And that was just wrong..
I looked a little further, onto the Japanese sites (very hard even though i know some Japanese) and they cost even more! Up to 600$..

Soooo I built my own:
Cost 100$ per 1000VA Toroidal Transformer unit, got me two of those, a few bits and pieces and voila, a 250$ 2000W 230-100V Transformer :D

And I have to say, the Tee tastes sweet :p