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
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
