ECN Forum Forums General Topics of the Trade Non-US Electrical Systems & Trades 110 volt supply, U.S. Power tools

here int he states our power can vary. you can goto House A and get a reading of 105v and 210v then go 10 houses down to house B supplied by the same power company and get 120v and 240v. it really depends on the precision of the transformers and line voltage drop here. doesn't do any damage here to things.

From University of Michigan found this:
Universal Motor Construction
Universal motors can operate on either AC or DC power. The rotor has coils that are connected to an external circuit through a commutator on the shaft, as shown in the schematic at right.

Note that the field in the rotor will oppose the field in the stator at any given moment, regardless of whether or not the polarity of the supply current changes with time. This feature gives the universal motor its unique characteristic.

The price of versatility is efficiency; universal motors are not as efficient as similarly-constructed AC and DC series motors

Hi Tinkerer, and welcome to ECN.

It's like most things -- A compromise between conflicting requirements. I seem to recall from many years ago reading that one of the adjustments made in the universal motor (as compared with a straight DC series motor) is that the commutation point is shifted a few degrees to better suit AC characteristics.

Maybe one of our guys more familiar with industrial motors can comment?

Rather than start a new thread, I thought I’d resurrect this one as it is most relevant.

As befits the familie Hutch, we are on the move once more, and this time will be heading for Blighty’s sultry shores – and yet another change in plugs in store! Plus this time I have a lot of 110-120V workshop stuff in tow that I have accumulated during my time in the USA. So I’m trying to plan ahead.

I’ve already split all the electrical stuff into “don’t bother”, “adapt it” and “no problem” sets – the workshop stuff fits into the middle category.

American TV’s fit into the former category and originally South African HiFi’s into the latter. If there’s anyone in the Denver area that would like to put in an offer on some US TV’s – PM me for a great deal!

My table and mitre saw are both rated at 15A (120V) and comprise the most thirsty of the workshop beasts. I am planning to utilize a worksite centre-tapped transformer in the interim but this strikes me as not necessarily the best in the long run. Depending on the workshop I would like to consider a fixed step-down transformer and NEMA sockets thus:


(Borrowed from www.mkelectric.co.uk )

Any ideas from the local troops on this, and whether the arrangement would be acceptable under local regs. How do radial circuits for 120V comply? Is there still a restriction on 50(?) sq. m per circuit? Your thoughts are appreciated.


[This message has been edited by Hutch (edited 02-06-2005).]

[This message has been edited by Hutch (edited 02-06-2005).]

Hi Ian!,
So you are on the move again?, Man you're hard to tie down!.
Anyhow, a socket without a switch on it, in England?.
Hmmm.

You sure get around Hutch!

Yes, the current IEE/BS7671 standard for a 20A radial circuit is a floor area not exceeding 50 sq. meters, although obviously that was designed with 240V BS1363 outlets in mind.

Whereas the ring circuit is still basically the same as it was 50 years ago (just a change from 1000 sq. ft. to 100 sq. m.) the areas and number of sockets for radial circuits have changed often and drastically over the years. It seems that the IEE has never quite been able to decide on what is "correct."

Even with the advent of the infamous part P, there's still no requirement to follow BS7671 in domestic installations anyway. (Not that you would be telling the local council about this wiring anyway, would you? ). I don't see any problem with installing a suitable transformer and running one or two 15 or 20A radial circuits for the 120V outlets. I've done the same in the past.

Switched sockets are really only an accepted convention. The (non-mandatory) IEE Regs. have only ever specified switches for sockets on D.C. supplies. There has never been any switch requirement on A.C., and unswitched BS1363 sockets are available.

[This message has been edited by pauluk (edited 02-07-2005).]

Thanks to Mike and Paul. As far as the local council is concerned I have no problem in telling them (if Part P demands it in a workshop) so long as they don’t come up with a load of unsubstantiated reasons why I should not install it thus. If there are regulations prohibiting this, it would be good to know ahead of time. I might be looking for a broad minded sparky in the Oxon/Bucks area !

I’ve seen the yellow, centre tapped 110V CEE sockets in an industrial setting up in Scotland but these look over-engineered and expensive for the domestic setting – hence me looking at the NEMA route, using MK’s Saudi Arabian sockets.

Interesting that the switches on sockets go back to the DC days. I’ve always wondered why they are so popular in Her Majesty’s current and former Dominions. I do confess that I like them and the current NEMA 6-15 in my workshop – serving the bench drill – has one.

I've seen 110V AC circuits used in Ireland for specialist purposes.

They used NEMA socket outlets fed on 16A circuits fused with standard neozed fuses rather than breakers.

I've also seen installations that used 15Amp BS546 sockets for 110V.

Definitely no chance of those overheating !


However, in any industrial or workshop installation the yellow CEEform sockets are required legally for 110V AC.

Also, they're not very expensive and are relatively easy to get. So perhaps not a bad sollution for your powertools!

you can easily buy extension cords and site transformers with those fittings.

[This message has been edited by djk (edited 02-08-2005).]