Voltage Converter

[PullUpTulip]

Hi, I need a step down converter for US to UK voltage and am unsure what Wattage I will need. It's a coffee maker by the way. Most converters I have seen are around the 45 mark, would this be sufficient?

Many thanks in advance

[Buenchico]

It's probably going to be cheaper to buy a new coffee maker than to buy a transformer for your existing one.

A 45W transformer would probably overheat and burn-out within a few seconds if you tried to use it with a coffee maker.

The power consumption of coffee makers varies between models. I'd expect there to be a label somewhere on your coffee maker quoting its power rating but, as you can see from this page, typical power ratings are usually around 1000W:
http://www.kenwoodworld.com/uk/product_categor y.php?cat=239http://www.cholmondeleyarms.co.uk /

The highest power rating of a UK-to-USA transformer sold by Maplin Electronics is only 300W. This costs about �40. One of the customer questions on their information page specifically asks if they sell a transformer suitable for use with a coffee maker. The reply states that they don't and also that the customer would need an 'industrial strength' transformer. These usually cost well into three figures so I think that you'll need to buy a new coffee maker (or start drinking instant coffee!).
Source:
http://www.maplin.co.uk/Module.aspx?ModuleNo=1 3358&&source=14&doy=28m4

Chris

[theprof]

I really think we need to clarify something here before we go any further.

I take it you are thinking of operating a USA manufactured 110v coffee maker in the UK, PullUpTulip?

If this is the case, you need a step-up transformer and not a step-down one.

I'm fascinated by that Maplin converter Chris - it's quite something. The second paragraph below the picture states:

200VA Step-Down Transformer
Input voltage: 214.8W
Output voltage: 110V

Hands up those that can tell me when we began to measure voltage in the UK in Watts! Alternatively can anyone tell me the name of the country that has a domestic mains voltage of 214.8V?

[stanleyman]

You can use a power tool transformer, not too expensive but I can't see the point in using appliances out of the country of origin with very different voltages and standards. It will cost you more to get it working than buying new in the country of use.

I've also seen strange voltage markings in catalogues, it probably comes from trying to unify with the whole world.

[Buenchico]

Not that it's particularly important, but I've just noticed that my first link, above, seems to have got mixed up with a link from a completely different post. It should be:
http://www.kenwoodworld.com/uk/product_categor y.php?cat=239

The Prof is more observant than me, in regard to the Maplin link.

All the same, as Stanleyman points out, the cost of an appropriate transformer will still exceed the cost of a new coffee maker.

Chris

[Fitzer]

Best Stuff sell a variety of step down converters here and go up to one rated to 3000w at �125, it's as ugly as sin though and you'd definitely be better off with a new coffee machine.

[theprof]

Thanks for the compliment Chris. Like you and stanleyman, I agree that the cost of one of these transformers would be prohibitive and I wouldn't even consider buying one for something like a coffee maker.

The beststuff site suggested by Fitzer is again about as logical as the Maplin site. The boxed section states "Step Down voltage converters are for using equipment from the USA in the UK or Ireland" whilst "Step Up voltage converters are for using equipment from the UK or Ireland in the USA"

This cannot be true as its the opposite of what's required in each circumstance. Curiously, despite this, the pin/socket configurations are correct.

However, the specifications of each individual converter for sale are all correct ie if they increase the input voltage they are called step-up and if they decrease the input voltage, they are called step-down.

What a shambles!

Finally Fitzer, if PullUp Tulip is prepared to go to the expense of a converter to use a USA coffemaker in the UK, he needs a step-up converter not a step-down one.

[Andy Boz]

What Mr Prof????

A step up steps up, a step down steps down.

240 volts to 110 volts is step down, ie UK to US.

I would bang the machine on ebay, and buy another. Or I would pull the back off and see if there is a switch internally to change the input voltage to the transformer, unlikely but possible.

3kw power tool transformers cost about 70 quid plus vat, and they would provide the volts needed

[Fitzer]

As per Boz, if PullUp Tulip wants to use a US coffee maker in the UK he needs a step down converter ie. he needs to convert UK 240v to US110v. In addition to the Best Stuff site being completely correct in their descriptions they also point out that the converters can be altered to step up by switching the jumper on the back of the machine and using the 3 pin to US 2 pin adaptor that they supply with the unit.

[PullUpTulip]

Thanks all. To replace this machine, which was a gift, would cost over �250 so probably worth my while getting a converter and not risk burning the house down.

Why is the Wattage so important anyway? I never really gave Wattage much thought before apart from lightbulbs!

[theprof]

Thank you all for your comments.

The voltage in the USA is 110v while the voltage in the UK is 240v, although the figures are immaterial as we only need to accept that the USA domestic voltage is less than the UK domestic voltage.

It follows that in order to use a USA manufactured appliance in the UK, we need to reduce the UK mains voltage from 240v to 110v.

The reduction in voltage is facilitated by the simple means of connecting UK mains voltage to the primary core of a step-down transformer whilst the appliance is powered via the secondary core of the same transformer. In other words, the input voltage is 240v, whilst the output voltage is 110v.


Now Andy Boz is absolutely correct when he says that �a step up, steps up, a step down, steps down� and �240v to 110volts is step down ie UK to US�. My last paragraph also demonstrates this.

It follows that a step-down convertor is a transformer that in this case, would reduce 240v to 110v and likewise, a step-up convertor is a transformer that would increase the voltage from 110v to 240v. In practice, this is easily achieved by switching the input/output to the primary/secondary respectively as Fitzer has kindly pointed out.

However, I would at this point ask you to read carefully the original posting of PullUpTulip. He/She asks:

�Hi, I need a step down converter for US to UK voltage and am unsure what Wattage I will need�. Now we can put this another way:

�Hi, I need a step down converter for US voltage to UK voltage and am unsure what Wattage I will need�.

Why would the poster wish to use a step-down transformer to convert 110 volts to 240 volts. Surely this would be a step-up transformer? Which country is this coffemaker in?

All suggestions pointing out the error in this logic gratefully received.

[gumboil]

What a great site! Well, I'm with theprof on this one. No matter how I look at this, I can't fault the logic in his last posting.I can see what Andy Boz and Fitzer are on about, but it seems to me that theprof is also correct in what he says.

[PullUpTulip]

To clarify, the coffee maker is a US product which I'd like to use in UK.

All sugestions pointing out the error in this logic are probably pedantic so should probably be left alone ;o)

[Pete1956]

PullUp Tulip, in answer to your question about the wattage i.e. the power:

Any transformer that you use must be rated (in watts) at least the same power rating as the appliance otherwise it will overheat.

Not especially relevant, but anyone wanting to know what voltage/freq and connector type used in a particular country may like to visit:

http://kropla.com/electric2.htm

[mibn2cweus]

Warning! Never step-up voltage in the UK! Danger!

Some definitions may be in order:
The input of a transformer is the primary winding receiving power (from the mains).
The output of a transformer is the secondary winding delivering power (to the appliance).

When voltage is specified:
A step-up converter enables the use of a lower mains voltage for powering devices that require a higher supply voltage.
A step-down converter enables the use of a higher mains voltage for powering devices that require a lower supply voltage.

Although this at first may seem pedantic, improper use of a converter in the UK could result in delivering four times the proper operating voltage to a US appliance. Quadrupling the voltage can potentially quadruple the current as well and thereby deliver SIXTEEN TIMES THE POWER!!!

A step-up transformer would be used in the US for UK equipment.
A step-down transformer would be used in the UK for US equipment.

[SeaJayPea]

I'd suggest ringing the manufacturer's helpline and see if there's a converter within the machine itself. �250 is an expensive coffee maker, and you may find that, in order to export to this country, there is already a function to change the voltage. Many US electrical products do have this facility.

[Spug]

On some electrical items it doesn't give the Wattage but there is a way in which you can work out the Watts if you know the ampage. You multiply the amps by the volts. So, for a US item used in the UK the voltage would be 120 and if the amps were say 4 amps the wattage would be 480. Also, it pays to allow some margin for error and indeed voltage surges of at least 10 percent.

[SisterSue]

My partner informs me that if you go to a builders merchant and buy a 110v transformer as used on building sites, this will power almost anything and costs about �45.

A new coffee maker would be my preferred option.