US to UK 'transformer'

[LiamPope]

Hi folks,

Wife has her eyes on the Rolls Royce of electric rice cookers - more functions than grains of rice in the world , but it's only available in the US. Rated at 700W. I've shown her the size/cost/appearance of a suitable step-down transformer and said pretty much forget about it, but she's hit me back with this...

Ebay link

Huh? 1600W from a wall-wart sized thing that costs peanuts? Well I guess surely it must be an SMPS of sorts with some horrible switched ac output waveform, but then if it works it works. Even mentions 'heating-related' appliances specifically. Anyone reckon it can possibly do what it says on the tin? What's going on with the 50W and 1600W settings - why would that be needed? Maybe it'll do 1600W for 10 seconds then tell you to come back much later ?

Cheers

 

[davelx]

What's going on with the 50W and 1600W settings - why would that be needed?

M guess would be that the 50W setting gives a better waveform.

 

[ban-all-sheds]

Wife has her eyes on the Rolls Royce of electric rice cookers - more functions than grains of rice in the world

How many functions do you need?

1) Cooking rice.

2) Keeping rice warm (and you shouldn't do that for long, as it's not safe.

And with respect to (1), you still have to wash the rice, you still have to measure the water, and it still takes just as long to cook as it does in a saucepan.

They are a complete waste of space.

 

[LiamPope]

Well,

You turn them on and forget about them until you want to serve. No watching a pan come to the boil, monitoring it simmer etc. Perfect results every time despite lack of required intervention. Impossible to burn base. Never end up with a mass of sticky stodge. Easy to clean. Can keep rice warm safely for a long time. Does not take up a ring on the stove. Is an insulated vessel that applies the optimum heat so uses a fraction of the energy of boiling a kettle then simmering away on a hob ring.

No no no! You're of course right and the whole of Asia is wrong. They're a pointless waste of space

 

[ban-all-sheds]

You turn them on and forget about them until you want to serve.

For how long?

No watching a pan come to the boil,

That takes all of 1-2 minutes.

monitoring it simmer etc.

No monitoring needed if you do it properly.

Perfect results every time despite lack of required intervention.

Perfect results every time using a saucepan with zero intervention.

Impossible to burn base.

Impossible to burn the base if you can work a timer.

Never end up with a mass of sticky stodge.

Never end up with a mass of sticky stodge when using a saucepan with zero intervention.

Easy to clean.

So is a saucepan.

Can keep rice warm safely for a long time.

Is that something you need to do?

Does not take up a ring on the stove.

Is that genuinely a problem often enough to be a real one? Bear in mind that a rice cooker does take up storage and worktop space.

Is an insulated vessel that applies the optimum heat so uses a fraction of the energy of boiling a kettle then simmering away on a hob ring.

Simmering rice in a closed pan doesn't use a huge amount of energy - how much rice do you cook and how often that you will appreciate the savings from using a rice cooker, and how long before you recoup your investment?

No no no! You're of course right and the whole of Asia is wrong. They're a pointless waste of space

A lot of Asia is characterised by a very different level of rice consumption (like all day, every day), and different space constraints on general purpose cooking appliances.

 

[LiamPope]

I forgot to mention my wife is Malaysian . She can't go very long without rice. The benefits apply to us and the convenience is well appreciated. Of course more primitive/traditional methods are acceptable, but why shouldn't anyone use technology to improve their quality of life? It is no different in that respect to a washing machine, dishwasher, electric kettle, central heating system, automatic gearbox, etc, etc. I imagine you have one or two of the above unneccessary 'wastes of space'? If you wont appreciate the benefits of an electric rice cooker, I suggest you simply dont purchase one. Many thanks for the criticism though, really .

 

[ericmark]

I used a rice cooker in Hong Kong and understand why she would want one. The adaptor seems too cheap. On internet a 1000va transformer costs between £30 and £45 likely need to add vat but could be same if sent from USA plus could have other customs duty.

For heating appliances the frequency is unlikely to be a problem but the centre tapped earth may be and you may need to add fuses.

However have you not tried Hong Kong for same cooker they have same 230vac at 50Hz as we have.

 

[OwainDIYer]

Ebay link

Huh? 1600W from a wall-wart sized thing that costs peanuts? Well I guess surely it must be an SMPS of sorts with some horrible switched ac output waveform, but then if it works it works. Even mentions 'heating-related' appliances specifically.

This will have a transformer for the 50W setting and a diode for the 'heating' setting, so it blocks half the AC waveform. It doesn't actually transform the electricity down to 110V, so you are still have the safety risks of exposing a 110V appliance to UK mains voltage. The joys of US electrics.

The modified waveform might kill anything electronic.

 

[ban-all-sheds]

why shouldn't anyone use technology to improve their quality of life?

No reason at all.

But I've owned a rice cooker, and I found that it provided zero improvement.

If you wont appreciate the benefits of an electric rice cooker, I suggest you simply dont purchase one.

I did purchase one, and used it for a while.

I found that it did not save me any time, it did not save me any effort, it did not save me any measuring and it did not produce better results. But it did take up space in order to provide no benefits whatsoever.

Many thanks for the criticism though, really .

From some of your comments earlier it seems that you have difficulty in cooking rice properly, so I can see how a rice cooker could benefit you, but I wasn't aware of that at first - what I was doing was to give you the benefit of my first-hand experience of one. For all I knew you could well have thought (as I did) "one of those could be handy", and then find (as I did) that it wasn't.

 

[plugwash]

This will have a transformer for the 50W setting and a diode for the 'heating' setting, so it blocks half the AC waveform.

It will need to be more than just a diode (a diode will only reduce the RMS voltage by the square root of two, to reduce the RMS voltage to half would require removing three of the four quarter cycles so you are talking a device more like a dimmer in operaiont.

The modified waveform might kill anything electronic.

mmm, anything with a transformer upfront isn't going to like a waveform that likely has a substatial DC component.

 

[ban-all-sheds]

RMS value for a half-wave rectified supply is Vpk/2, i.e. 170v in practice, 163v nominally.

So if all this thing does is half-wave rectification then it's no good for 110v appliances. The chances of finding out how it works without buying one and testing/dissecting are probably about zero, but on the face of it it's a fraction of the price, size and weight that a real 1600W step-down transformer would be, so I'm suspicious.

No good for the rice cooker anyway, as it can only be used for 15 minutes at a time.

 

[OwainDIYer]

AFAIK they're just diodes.

The RMS calculation would explain why people on Tripadvisor have found themselves setting things (or themselves) on fire, or frying their appliances, with these things.

 

[ban-all-sheds]

I've shown her the size/cost/appearance of a suitable step-down transformer

As Eric says, HK uses 230V, and so is awash with rice cookers of the right voltage.

Are there any Chinese supermarkets near you?

 

[FDJ]

If you are willing to do some work. I.e putting it in a box etc. Have a look here
http://www.airlinktransformers.com/stepupstepdown-transformers.asp

These are auto-transformers that do not provide any isolation between input/output as most do. They are smaller, cheaper and more efficient than an isolating transformer would be. The AT1000 would be more than adequate for the rice cooker.

Frank

 

[ban-all-sheds]