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Electrical Service Question. What voltages do you have?

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IronMonger

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I am wondering about the voltages used over there. I am accross the pond and use a phase converter so I have 240 volts three phase. I also have a used 30 KVA three phase transformer to get me 440 volts three phase. My shop is looking more like Dr. Frankenstien's lab!

So what are the standard voltages used over there in terms of voltages and cycles? Do any of you guys use phase converters and if so, what kind of power do you get out of them?

Thanks...
 

PowerTool

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Standard UK voltage is 230v/50Hz - used to be 240v,but has been reduced to a more European 230 (although it still varies slightly depending on area/supply)
Not certain,but believe three-phase is 415v,and the cost of getting a three-phase supply into a domestic premises is normally very expensive,so tends to be limited to industrial useage.

Andrew
 

IronMonger

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Hmmm, I see this got moved to general chat. I did not post this question to find out how to run vacuum cleaners or tooth brushes. I am interested in how english made woodworking machines run and what you guys over there are doing to get the heavy iron running in your shop. Over here, many of us are interested not only in how these machines run but how to get them to run in our shops. I personally dont know many folks who bought new table saws and jointers from the local store new. We got smokin good deals on them at auctions. So understanding how the electrical issues work is often the first step in getting that old Oliver table saw or Porter 20 inch wide jointer to run. In fact, I spent tonight working out details on my allen bradley series 709 - A starter attached to my jointer. Had to locate a new coil and resize the overload relays to convert from 440 volts down to 220 volts. Also had to reconfigure the motor leads accordingly. When you run the old iron, you will be dealing with this.
 

Scrit

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Three phase in the UK is 415volts @ 50Hz and generally supply companies won't put in to domestic properties in my experience (or if they do they'll charge an arm and a leg and you'll then need to get an industrial contractor to do the wiring as three phase doesn't come under Part P according to my local BCO). That means you either need to use a phase converter or convert the machine to single phase.

With older motors the best type of phase converters tend to be the rotary type with a single phase motor at one end and a three phase at the other running as an alternator, however taking into account the power loss in rotary conversion it becomes difficult to power much above about 10HP (7.5kW) as the start load will then be around 50 amps (worked on a 60% overload at startup) - about half the consumer unit capacity of many domestic supplies in the UK.

Static converters are OK, but they tend to be limited to about 7 or 8HP (5 to 6kW) and they invariably generate a reduced voltage on L2 and L3 (the second and third lives) with the L3 being as much as 35% down on L1 in voltage terms. This translates to problems starting motors under load or overheating of the motors in continuous usage - and as we all know heat kills the windings of motors. Having tried both static and rotary converters in the past I think that the point at which you need to go to a rotary is somewhere around 3 to 4HP.

The third route is to replace the motor and contactor sets with single phase gear. Fortunately a lot of table saws, etc were well over engineered (for example Wadkin seemed to have put the same wiring set into AGS/BGS/BGP saws regardless of whether they were 2HP or 7HP) so it's mainly a case of finding a suitable capacitor start single phase motor then replacing the contactor set. That, however, does tend to limit you to 3HP (2.2kW) as your maximum motor size and above that (15 to 20Amp contactor set) you need to start installing low voltage AC or DC coil contactor sets, etc which are a lot more expensive. The other point is that with certain machines it is exceedingly difficult, sometimes impossible, to install replacement motors onto - for example you couldn't get a bolt on motor for most of the British-made industrial chisel/chisel mortisers like the White NJ, Wadin MF, Robinson SL/E, Brookman etc or even the more recent and more modest Wadkin DM square chisel mortiser, nor for a single end tenoner like the Dominion BXA (which in any case would need no less than 5 x 2HP motors)

However, the biggest single limiting factor is moving these machines. Whilst a Wadkin AGSP weighs about 1/2 tonne, the Wadkin PK (that one's another local one to me, Dev) weighs in at 1 tonne, a Robinson SL/E at a staggering 1-1/2 tonnes (and from past experience is very top-heavy) and the Dominion BX single-ended I used to have was just short of 2 tonnes all-up. Getting a machine into a hired Transit Luton may be easy enough at the pickup end, but is your drive flat enough to offload and will the 1/2tonne taillift take that gleaming (?) piece of cast iron you've just bought? That means for anything over 1/2tonne you probably need specialist transport with a Hiab crane who will want to get their 16tonne flat bed lorry down your drive (and can the tarmac take the weight?)....... I'd forget about the local haulage company as they only pay about £30/tonne on RHA insurance if they drop your machine - and they sometimes do :cry: With a lot of British housing and the tiny workshops most people these machines aren't an easy option, Dev :shock:

BTW I would like to point out to any budding electricians that 230volt phase to earth hurts and can sometimes kill - but 415volt phase to phase is nowhere near as forgiving and will probably just kill you straight off.... So if you don't absolutely know how to wire one of these machines GET AN ELECTRICIAN.

Scrit
 

porcupinewood

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I though I would add my experience here. I have a home build phase converter that runs a 10hp motor. In Canada 550/600 3phase is more common and 208 being more normal in schools equipment because it is safer, but is not as commonly used anymore. I bought an SCM jointer/planer/mortiser that the motor was impossible to change on so that started me off building the converter. Now I have several machines running off it, the largest being a 7.5 hp panel saw.
I has not been without its problems, keeping the load balanced on my homes 200 amp service, the transformer on the pole undersize for the amout I am of current I am drawing. I have hydro now coming to change it one of these months!
The low starting torque by the developed third phase made my 24" planer impossible to start, even with added extra capacitors. So I changed it to 7.5hp single phase ouch!
It does seem to shortened life span of the T8 lights and electronics and causes flickering. And then there is the constant dimming of all the house lights!
aah well, It is better than paying separate business taxes, +++. And I am out the back door to work!.
Mark[/quote]
 
A

Anonymous

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PowerTool":1qzlen1x said:
Standard UK voltage is 230v/50Hz - used to be 240v,but has been reduced to a more European 230 (although it still varies slightly depending on area/supply)
Andrew
Actually, this isn't quite what happened (although it is the official version). Basically, the european standard was 220V and the UK 240V. We all agreed to have a common voltage and so the tolerances were changed and so we run at 240V and they run at 220V but all are in the tolerance range for a 230V supply. Thus all equipment works fine whetether in europe or UK


Measuring the mains will invariably read near 240V in UK - been an electrical/electronics engineer for over 20 years and never measured 230V at a socket yet :wink:
 

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