From: Mike Poulton
Subject: Re: Higher loads on triac light dimmer ???
Date: 17 Sep 2002 20:28:29 GMT
Organization: MTP Technologies
On 17 Sep 2002, "elektrode" said:
> "CS" wrote in message
>> Hi, I'm moving a coffee machine from the USA 110V to Australia 220V
>> which has a heating element rated at 1300W.
>> Rather than using a bulky & expensive step down transformer, I would
>> to use a standard thyristor light dimmer to control the heating
>> element since it is just a resistive load, but every light dimmer
>> I've seen is limited to about 600W.
>> Is it possible to modify something to get this to work, like add a
>> to the 600W light dimmer ??
> Even if you found a dimmer with a high enough rating it would only
> reduce the voltage, not increase it. Why don't you see if you can get
> a new element rated at 220 volts for your machine? If not, scrap it
> and start again. --
What? Read it again, John. He has a heater for 110V, and he wants to
use it in 220. Therefore, he needs to divide the applied voltage by
two! A triac circuit will work fine for this, although it doesn't
really decrease the voltage. The best way to go is to use a "universal
control" designed for 220V stove elements. These are cheap, made for
220V (can't use a 120V dimmer on 220!), and will easily handle the
power. Check an appliance repair shop. Keep in mind that you will need
to measure the power somehow, and a regular volt meter won't cut it --
the waveform is totally funky. You could do it with a really good RMS
meter, or with an oscilloscope and some fun math.
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