Designing a HT oven

Whewwwwwwwwwww that sounds REEEEEEEEEEEALY dangerous.

At first I thought it was kind of a slick work around for doubling the amperage without a major routine. Silly me.

Syn
 
Originally Posted by Kiwi303 View Post
I've known a tradesman get around that problem by whipping up a little fused box with one socket hooked to two plugs on heavy duty extransion cords. Check the fusebox of the house and pull the fuse on a power socket loop, and find which sockets arent working, plug the fuse back in and pull another one out and find which sets of power sockets use that fuse. run the extension cords in to those separatly fused sockets and hey presto, a 35A machine can run off two 20A domestic 240V circuits instead of needing a dedicated line. or effectively 17.5A on each line.

Cheaper for him to use the customers power than haul around a generator.
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Not a good idea. First of all you have to know the power system of the country you live in. U.S. standard household power is twin (split phase) 110 VAC lines. Line to line gives us 220 VAC, line to ground is 110 VAC. Most European, Asian, and many other countries have straight 230 VAC (single phase) line to ground systems. On an American system doing the trick mentioned might lead to twin 20 amp 110VAC and it might give you a single 20 amp 220 VAC circuit, depending on if the outlets chosen were fed by the same 110 VAC leg in the breaker panel.

Even when done properly it would be hazardous as has been mentioned. There are a lot of 'tradesman' tricks that really aren't for the faint of heart, others are downright dangerous! I work in industrial instrumentation and controls and see crap like this hurt people all the time...
 
This is a great thread................ a few weirdnesses along the way but I do believe it will end up with a well-designed, and readily built, DIY, HT oven, something I had thought about buying down the road a ways.

The freely dispensed, collective experience and wisdom that comes together in forums like this never ceases to amaze me. In this thread alone there are EE software types, electricians, instrumentation pros, and many others who've already broken the trail saving lots of time and potentially hazardous mistakes for those of us following behind.

Thank you all for taking the time to share.

Syn
 
110 AND 220 VAC from the same plug? hmm... thats new to me, I was thinking that the discussions on here about using 110V and 220V machines were involving current converters wired into the main house board running a dedicated plug.

Here it's 240V 50Hz single phase. and the 110/220 twin/single doesn't happen.

I haden't thought about the live plug, How hard is it to run each wire into the junction box where both extension cords enter the box to become the single outlet cord, through a one way current diode? Trying to remember fiddling with DC electronics kits as a kid, theres a diode, colouration standrd as black with one end silver, that only allows current one way round the curcuit, normally integrated into the battery lead so a battery the wrong way round won't fry the curcuit board. do those owrk on AC?
 
Kiwi303 said:
I haden't thought about the live plug, How hard is it to run each wire into the junction box where both extension cords enter the box to become the single outlet cord, through a one way current diode? Trying to remember fiddling with DC electronics kits as a kid, theres a diode, colouration standrd as black with one end silver, that only allows current one way round the curcuit, normally integrated into the battery lead so a battery the wrong way round won't fry the curcuit board. do those owrk on AC?
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Quite ironic that many countries have 220v supply as from my interactions with electrical engineers, many of them feel that its a very dangerous voltage range: "Lower voltages are not enough to be a huge fatality risk, and higher voltages will 'kick' you away" 220v is just perfect to hold you there while frying you! ... I have a healthy respect for energetic little electrons!

Similar to what you are suggesting there Kiwi, there are definately ways you could make it safe.. However you would probably need to use relays due to the higher amperage, and diodes would not directly work on AC. You should really let your artisan mate have a look at this thread!

Syn is right in that I love reading these threads cos a lot of the guys are very giving of technical knowledge that the rest of us dont have. I have never heard of twinning of phases and always thought that US power supply was 110V throughout... something more for me to go and learn about!!

What was the original topic of this thread again?????
 
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