Using a transformer but still at 50Hz, of course. Doh.
Opened the box up and three transformers (and a circuit diagram)! No space to fit a toroid either.
Just have to see if the increased iron losses are tolerable.
Here's another silly idea. Go to America and buy a petrol generator supplying the correct voltage and frequency for your appliance (1.2KVA at 110VAC @60Hz). Take the microwave along with you and get the supplier to demonstrate the two running together before buying.
Edgar
Oh, I get it now ;-). Be careful of poking around inside, especially if it's been plugged in at all. Some microwave sources require quite substantial voltages.
Paul DS.
The question came up on another site, regarding a roasting oven using a
1500watt element at 110v. The suggestion was to use a 110volt Variac, as perBertie
=A0 London SW
My wife once set some sausages to cook (!) in the combined microwave / grill using the combination setting. Needless to say the hot fat created by the microwave was set alight within minutes so when she returned to the kitchen there was something of a mess. And she made me write a letter of complaint to the manufacturers that there should have been warnings about doing this sort of thing!!
Matt
Mine is a Sharp combination microwave/grille/fan/convection oven and I use all parts of it, and sometimes two of them together. The fan oven alone is a useful second oven if I need two different temperatures (most commonly if main oven is too hot for plate warming, and also when it's my turn to do Christmas for the extended family and need more oven space). I don't use it on high settings as it's not self cleaning, and whilst it heats very quickly to low/medium temperatures, it takes ages to get right up to max, longer than my main oven. Convection oven has excellent electronic temperature control down to 40C (which my main oven can't do), which is perfect for bread rising. Starting the bread off with a burst of microwave it an excellent way to get the proving started off quickly. (I can make a loaf of bread in an hour this way, although final baking is in main oven.) I do use microwave and grilling together sometimes (good for something like a macaroni cheese in 10 minutes which comes out like it was baked in the oven for much longer).
You don't find them in kitchens for worktop appliances. Hence no one sells any worktop appliances > 1400W in the US. What you find is that companies like Sharp simply don't ship their top end appliances to the US, so the non-combi version of my Microwave was available in the US, but not the Combi one which is 2650W. Even the non-combi version had a slightly reduced microwave power in the US. (You find that with things like vacuum cleaners too, although for slightly different reasons.)
"Andrew Gabriel"
In the USA they do suffer with their 112volts supply. 2650w/112v = 23amps. Whereas 2650w/220v = 12amps.
Bertie
Heating-only appliances can be used with what the Americans call a "convertor" which is basically a whopping great diode that blocks half the AC waveform. Doesn't work with anything motor driven or electronic, of course.
The message from Andy Hall contains these words:
There are certainly houses without basements, but basements are more general in the US than the absence of them is general here.
The message from "Paul D.Smith" contains these words:
All houses have 230/115 volt (or thereabouts) supplies. Two hot wires at 115 volts potential to ground and one neutral wire at 0V. 230 volts between the two hot wires. And almost every house has some appliances which use 230 volts. Dryer, air-conditioning units, electric stove, etc. etc.
However what you say is indeed true of most small domestic appliances.
The message from "Bertie Doe" contains these words:
Not too big, but expensive.
Most full-size electric stoves in the US run off 230 volts anyway. Older ones used to use complicated switching of sections of each element in their radiant hob rings between series and parallel using 230 and 115 volt supplies to give multiple heats, but most use more modern controls nowadays. Where there are clocks, however, these are almost always 115 voltt 60 Hz. Where an appliance has two elements in parallel running off 115 volts, they can be rewired to run in series off 230 volts. It isn't exactly rocket science.
Ouch -- that won't work for heating appliances either.
240VAC RMS half wave rectified is 170V RMS, not 120V RMS. That means the appliance will generate twice the heat it was designed for. This is combined with the insulation being exposed to twice the voltage it was designed for. I rather suspect it will have a very short, and possibly unsafe life.My parents still have a very nice 120V 1050W electric frying pan we bought when we lived in the US in 1960's. It (and several other US appliances which we brought back but have since been disposed of) used to be run from a large transformer. About 10 years ago, I decided to build a small switching regulator as the extra very heavy transformer was an impediment to using the frying pan. Following on from your scheme, if you half wave rectify, and you only let every other +ve cycle through, you will get the right power dissipation. However, I dismissed that partly for the reason I mentioned above about the insulation voltage being over-stressed, and also partly because I though there was some risk of the element being stressed by generating 4 times the power it was designed for on a 25% duty cycle.
So what I did instead was to take each mains cycle, and cut out the +ve and -ve going peaks. It's quite a complicated piece of Calculus working out what the phase angle is for doing the switching (particularly when you haven't used calculus for some years) to achieve 120V RMS, but ISTR it comes out around 43 degrees. This means the element is exposed to a max voltage of sin(43) x 340V (peak) = 232V instead of the 170V peak it was designed for. This is only 30% higher than it was designed for, rather than 100% higher if it were to be exposed to the 240VAC peak voltage.
This has worked fine for some 10 years now, but aware of even the 30% insulation stressing, it's always run on an RCD.
The message from "Bertie Doe" contains these words:
Yes, but in general terms there is little use domestically of 110 volt receptacles (soeckets) other than NEMA 5-15s. In other words, 15 amps tops, from 110/120 volt supplies.
You do see occasional NEMA 5-20s (one of the flat pins horizontal to prevent it going into a NEMA 5-15 receptacle) but generally if you need more than 15 amps you should go to a NEMA 6 which is a 230 volt supply.
The way their receptacles are wired it's common to find both hot wires at any wallbox, with one of the duplex sockets wired to one hot wire and the other to the other. In such an instance simply changing the NEMA
5-15 receptacle to a single NEMA 6-15 one will give you 230 volts without any rewiring at all. Neat.
Until it all falls apart, the wirenuts overheat and the place burns to the ground. Not so neat.
Thanks for that and apologies to Bill for butting in here. The Americans are quite good at designing coffee roasters. The appliance in question has good spec
Bertie
The message from Andy Hall contains these words:
Use a decent receptacle and it won't fall apart. Granted the general quality of NEMA 5-15 receptacles is dire, but good receptacles and indeed good plugs can be obtained,. NEMA 6 (230 volt) fittings are generally better quality, in my experience.
There's no particular reason for wirenuts to overheat if they're good quality wirenuts and the joints are properly made. Good wirenuts are nothing remotely like as dire as the late and completely unlamented "Scruits" if you're old enough to remember them in this country.
It'll run cooler on 230 volts :-)
Never had a building burn on me in North America. And one of the houses I lived in is still standing there at 200 years old. Fieldstone foundation and three floors of timber-frame construction above.
The message from "Bertie Doe" contains these words:
It might, but we're only guessing at the circuit and the probable answer is "Not worth trying"
Points worth noting:
That URL isn't for a variac. It's for a 55-0-55 volt site transformer
-- centre tapped and giving 55 volts from each leg to earth with 110 volts between the two live wires. Not the sort of supply expected by a US appliance, quite apart from the potential relevance of frequency differences, A good price on it, though.
A variac may refer to a VARIABLE auotransformer or may refer to an electronic "circuits," usually an SCR (silicon controlled rectifier) or Triac type circuit, which changes the waveform into a square wave so that the practical effect when it comes to dimming lights is similar to a reduction in voltage by a transformer.
The question is more one of "are they" than "can they"
They couldn't be worse that the 110v ones.
Mmm.....
I have seen some. They were deprecated over 50 years ago in the UK.
Well.... the adjusted rate of fires caused by fixed wiring in the U.S. is said to be very high in comparison with Europe. In the UK, it is virtually non existent.
Are you talking about US 3-phase or do you really mean you get +115V,
0, -115V?Paul DS
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