UK to US transformer

[David P]

I have just bought a whole load of 240v to 110v transformers to power an art installation that has come from the states.
when they arrived It occured to me that they look just like the transformers inside those yellow boxes that everone uses on site to power 110v equipment.
does anyone know if it would be ok to run US appliances through a standard site transormer? it could save me a small fortune next time.

 

[securespark]

Only if the frequency and voltage match. And, of course, that the load is suited to the tx.

 

[David P]

Only if the frequency and voltage match. And, of course, that the load is suited to the tx.

well i suppose that that is my question securespark.
The frequency is set for the national grid isn't it? at around 50 Hz? (the transformers that I have bought dont have anything other than windings, so no frequency change there).
The voltage is stepped down to 110v from 240v and the rated max load on both my bought transformers and cheap site transformers is 2kva.

can it really be that simple to get american equipment running on UK mains?

 

[securespark]

Isn't US stuff 120V, 60Hz?

 

[David P]

Dunno. thats why I was asking.
like the uk 220 to 240 perhaps the us is 110 to 120?
dunno what frequency the us uses.
for that matter is UK power 50Hz?
just a vaguely remembered guess on my part.

someone said that the voltage is always dropped at a local substation from the generated voltage and amperage - which would be the same in the uk as it is in the us - the higher the voltage (lower amps) the further it can be transmitted through cables, so it is sent through the grid at x,000 volts (over long distances) then stepped down to 450v at regional substations.
in the uk these are situated every few miles, but in the states every few houses seems to have a small transformer (making sense of the distance issue with lower voltages). just a theory, but it seems to make some sort of sense to me.
anyone confirm or correct?

 

[ban-all-sheds]

can it really be that simple to get american equipment running on UK mains?

Depends what it is.

Anything with a switched-mode power supply could well be fine with no conversion (but do check the specs!).

Lights, heating etc will need a step-down transformer, and a site one will be fine.

Anything with a mains motor will not be fine.

 

[David P]

thanks for the concise answer ban all.

 

[Spark123]

Another thing, depending on what you are using them for you need to check the transformer is suitable i.e. you say your site transformer has a max rating of 2KVA which is fine if it is driving a motor which only runs for short periods (i.e. as in power tools.) If using it for lighting which can be on for a prolonged period the continuous rating of the transformer needs to be used.

 

[ebee]

If your running a clock it couldbe 20% ish off time but that might be an advantage either way

It`s about time we decimalised timescales anyway

 

[breezer]

America 's supply is 120v @ 60hz, here in the uk it is 230v @ 50hz

But dont forget that site transfromers are 2 x 55v (they are centre tapped)

 

[ban-all-sheds]

Yes, but that's just to ensure that the voltage w.o earth never exceeds 55V.

Between the two phase wires is 110V.

 

[breezer]

i know that, but my main point was confirming the voltage frequecy

 

[Steve]

does it not matter, then, that the neutral isn't earthed at the TX? And what if these appliances need an earth?

They do seem to use a lot of local transformers in America. Many commercial buildings there take in power at high voltage and step it down with their own transformers (of course many do this here, but it is much more common there). Many neighbourhoods there have one transformer per street - here, there might be one for every 10 streets. Our transformers are better hidden though, in little green buildings down back alleys. They seem to like having their transformers and power distribution networks on poles in America.

Having transformers at ground level, in little buildings allows our local distribution system to be better - we use a "ring main" system, where a huge cable leaves the substation, goes around the streets with taps off it to houses, and then back to the substation. I believe they use radials from transformers in America - since its hard to form a ring in mid-air. And I love those mid-air joints they are oh-so fond of. They just look sooo safe!

 

[plugwash]

site transformers have the earth on a center tap rather than on the neutral but this shouldn't bother most appliances and unless the cable runs are unreasonablly long shouldn't pose any safety issues (and any safety issues it would pose would be just as bad with site tools), there is still an earth wire present for earthing the case.

some equipment may be bothered by the UK frequency but its pretty rare and almost none of the converters sold for use with US appliances convert the frequency anyway.

oh and site transformers being safety isolation units are far less likely to die in ways that are harmfull to your appliances than many of the cheaper units sold for running US equipment.