22 Jan
2011
22 Jan
'11
6:37 p.m.
On 22/01/2011 20:50, Tony Duell wrote:
Yes, it's only portable tools that have to be 110V. Anything mounted on
a bench or floor-fixed, and not on a building site, is likely to be 230V
single-phase (with neutral at approximately ground potential) if it's
small, say 1HP or less, or 415V three-phase if larger. 110V is used for
portable lighting and other things as well.
> On Sat, Jan 22, 2011 at 11:55 AM, Tony Duell
<ard at p850ug1.demon.co.uk> wrote:
>> In the UK, all 'portable' power tools
used industirally (for example an
>> electric dril lused ona buildingsite) must be 110V units, powered from an
>> isolating transformer with the outptu centre-tapped to ground. The idea
>> is that if there's an insulation failuer, the worst shock the user could
>> receive is 55V, which is unlikely to be fatal.
So if you were
to go to a store that sells routers or maybe a benchtop
drill press with a 1hp induction motor, that would be 115 volts?
I would think a bench drill press wouldn't be classed as a 'portable'
power tool, and thus would be 230V. Certainly small lathes have 230V
motors (and larger ones have 415V 3 phase motors). There is a 32A version of the connextor (and I beleive
63A and 125A ones,
but I have never seen them, at any votlage rating). It's less common, and
I've never seen a portable transforemr with it fitted. There are larger
transformers, 5kVA rating or more, but I doubt you'd be able to feed the
input of that.
The biggest I have in use is 32A and I do have quite a few of them, but
our Estates Department have 63A ones. IEC60309 is the standards number
Tony was thinking of; the connectors are sometimes called "Commando"
plugs, because that's a trade name owned by one of the most common makes.
>> Even if you're `just' an enthusiast,
scuh a transformer is worth having.
>> Some power tools, particularly, the industrial-spcification ones only
>> come in 110V versions. And although the output is centre-tapped to earth
>> rather than having one side earthed, the transformer is useful for
>> running US stuff over here, at least for testing (I made up a cable with
>> a BS4343 plug on one end and a US socket on the other).
>> These transfoemrs are not particuarly cheap (I would guess perhaps $200
>> or so), and they are not light, so shipping might be expensive. But they
>> are designed to run power tools.
> This sounds like what I'm after. Can you point me at one online somewhere?
Yes, they are useful; I have one at home. Prices range from about UKP50
to several times that (and much more for large site transformers, which
can be almost a metre cube).
Take a look at
http://uk.farnell.com/pro-elec/p20-2/transformer-site-2-x-16a-2kva/dp/13550…
or
http://uk.farnell.com/clairtronic/10260/transformer-isolation-2250va/dp/149…
and you'll see some fairly small examples (the second one is similar to
my one at home, except mine's 3kVA). Click on "Product range" to see
more. The "Technical Data Sheet" is no help if you want to know how
heavy they are, but mine is heavy enough that I'd not normally try to
carry anything else at the same time :-)
Or look up "site transformers" on Amazon.co.uk (not on amazon.com).
--
Pete Peter Turnbull
Network Manager
University of York