is it possible? 1600W step-down transformer so tiny!

On 30 Mar 2006 11:39:13 -0800, "Tim Shoppa" Gave us:

Good answer!

There is certainly no transformer in that device!

It would be a very bad thing for electronic circuits with brains.

Auto-transformers are smaller than transformers because they use the same windings for primary and secondary. Iron sheet volume follows. The reverse effect is that there's no isolation.

"Slurp" a écrit dans le message news:

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The converter has no ground connection. The oven has a large metal case that normally is grounded. Running a oven with a large metal case without ground connection isnt exactly what i think of being perfectly safe, especially not when the line/ground voltage is twice of what it was made for.

Also, the oven states it has a automatical timer, which will not like being run off such a converter and will likely fail.

It doesn't have the standard UK plug for a start...

Really? My cooker is rated at 12500W, it has a 60A feed at 240V, quite normal in the UK

I did not say it wasn't.

And either thermostat will turn them both off, and they definitely won't voltage-share properly, so it will blow up the control electronics in both.

IOW, a very very very bad idea.

Thanks, Rich

You of all people should have spotted I was pulling the OPs leg!

On double insulated appliances maybe, definitely *not* on a cooker which is no doubt meant to be earthed. The robustness of the unit is secondary.

Dave

Maybe so, but I'm willing to bet you are in North America, *not* the UK, which is where the OP is based. Earthed metal bodied kitchen appliances like bench top cookers are commonplace here.

Different country, continent for that matter- different regulations to conform to.

dave

Aren't we talking a small portable cooker? A fullsized kitchen range is normally 50A in the US, but I thought we were discussing a single burner hotplate type thing or toaster oven?

But isn't the cooker a NA model? Otherwise he wouldn't be needing a converter in the first place.

On Fri, 31 Mar 2006 13:28:54 +0200, "frischmoutt" Gave us:

The device he showed a pic of has NO transformer in it, you top posting, Usenet retard.

Any

like

Which of course leads to the obvious comment that it would be illegal to use in UK anyway, just in case someone thinks that's worth considering. Coroners do......

Ken

Which leg? The hot or neutral? :)

I have a similar gadget here, which also says 1600W, and I opened it up. There is a big heatsink with a TO220 Triac(15A?) on it, a 18k 5W gate resistor and a small cap which has no marking. There is also a bimetall switch mounted on the heat sink with a heater where the load current runs thru. Me think this is quite smart for an over-temperature and over-current protection. I even used it to operate an American blender 50-s style, rated for 800W. In the upper speed ranges it was working very well, but that was all mechanical. If your oven has a small transformer in it for the electronic timer it will probably function as well. Another question is the safety. Without PE/earth the cooker is not considered safe in England, which might be of concern if there is an insurance event happening.

Yes, precisely why triac based converter kludges on unearthed metal cased appliances are a recipe for disaster, possibly even a case for compensation claims should a third party be injured/killed. These converters worry me- they imply to the lay purchaser that as long as the wattage and voltage requirements are met, then it's safe to use. This is not necessarily the case.

There is the matter of spacing between live PCB traces/wiring and chassis to consider- 240V is far more likely than 120V to create a potentially fatal situation if steam/moisture settles on live components and creates a path to chassis.

Therefore, without examining the OP's equipment, and indeed the converter, there's no way in hell I would advocate connecting either to a UK supply.

Dave

Hi James, The ferromagnetic core has developed a lot it seems. Just try using a simple load like heater. See if the cb breaker goes on or what. Good Luck Nitin

Yes, heard of Ni-Chrome, and a _lot_ of modern equipment, does not use it (cost).... Many of the devices like the one being shown, use ceramic printed elements, which have over 2:1 resistance change from cold to hot. Not as large as things like Tungsten filament lamps, which typically have over

Best Wishes

That's only because there's still no one to pick up the challenge of designing a heater-based appliance to withstand a 4.24kV(p) (@ both prongs) insulation test (which is required for non grounded appliances sold in the EU). ;-)

I can't believe that there are still end-users AND designers out there, who are willing to find that out, the hard way :-P