Linwoodjoinery
Established Member
Evening all. How hard is it/ what’s involved/ cost of turning a standard 240v supply into 3 phase? I know that may be a massive question but just general advice would be appreciated
240v standard supply to 3 phase
- Thread starter Linwoodjoinery
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Looked into that a few years ago. We have an old farm which had split phase and the cost was huge. The supply was at that time from poles accross fields. It was going to cost thousands per pole to get three phase ran. I counted about 10 so it was going to cost me in excess of £50000 which would be a lot more now. I needed three phase for a potting machine and bought a phase convertor from power capacitors which is still working after at least 20 years. The one I have is perfect for machines that have a constant load You just set it to the correct amps and away you go but not so good for machines like saws and welders etc as the load varies. There may be more modern versions that can automatically adjust for load current. The company are still going.
Heres a link to some of there convertors
https://transwave.co.uk/Static-Converters
Heres a link to some of there convertors
https://transwave.co.uk/Static-Converters
guineafowl21
Established Member
Options are:
- As above, get a quote for 3 phase supply.
- Static and rotary phase converters, again as above try Transwave.
- Inverter drive/VFD, try Drives Direct.
- Digital phase converter.
- 3ph generator.
- False phase from a capacitor across two coils.
It really depends what you want to run, how many and for how long at a time.
- As above, get a quote for 3 phase supply.
- Static and rotary phase converters, again as above try Transwave.
- Inverter drive/VFD, try Drives Direct.
- Digital phase converter.
- 3ph generator.
- False phase from a capacitor across two coils.
It really depends what you want to run, how many and for how long at a time.
Terrytpot
Established Member
Most of us have, at some point, been tempted by the abundance of seemingly reasonable prices as far as 3 phase machinery goes. Sadly, what you would think as a fairly straightforward thing to obtain, is actually not that common and can be ridiculously expensive. Most people who opt for 3 phase stuff do so by “tweaking” their existing 240 with the aid of other equipment like vfd’s.. The snag with a 3 phase supply is not just a case of getting the extra phases (lots of trench’s may need digging from the outside of your property and onto your property) and hooking it all up ,but then also finding a power provider who will hook you up with a rather pricey tariff which are generally geared towards industrial use and don’t come cheap which when utility bills are already heading skyward may not be something you want to take on.
What is the reasoning behind this thought? A true three phase 400 volt supply has a lot more available power than any type of 230 to 400 volt conversion can deliver, blame the laws of physics so if you are wanting to power a large piece of machinery then do your sums.
If you want a supply for general workshop machinery then look at digital phase convertors but can be expensive. The easiest and often cheapest option is to run a three phase diesel generator.
If you want a supply for general workshop machinery then look at digital phase convertors but can be expensive. The easiest and often cheapest option is to run a three phase diesel generator.
Three phase power is not often that far from your property, the main cable from the 11Kv sub is three phase and houses will be wired in groups across all three phases to help keep it balanced. When I had my supply provided I had laid the duct from the edge of my property all the way to the existing meter under the stairs and provided the Isolator and JB that took the supply down to the workshop. The DNO turned up and dug the hole, luckily my side of the road and ran the 25mm four core cable through the duct and fitted a new three phase meter. All the three phases went to my JB and they ran one phase out back to my household consumer unit. The guy then sat in the hole which was wet and cut into the existing LIVE supply cable that ran up the street to remove my old supply and connect my new cable. Took about 3 hours and £1800. Had they had to cross the road then double it.
OldSchool
New member
You can get quite basic with 3 phase but remember electrical safety. A dual voltage welder can provide a transformer to take 240 voltage to 415v and carefully matched capacitors can provide starting and running for a 3 phase motor off the single 415v to make a rotary converter. A Wadkin 12" table saw, Startrite bandsaw and Cooksley planer thicknesser are all happy to run this way. You can get plans off the web for 240 rotary converters that will produce 415v 3 phase but are a little more involved. The final rotary version I made using a welder case as a housing for the capacitors and monitoring electronics with the motor mounted on top has been in use for 15 years without any problems. I have wired the workshop as 415v 3 phase with a distribution board and supplied it with the converter. I guess it all comes down to how much you want to pay and play about. 
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The issue comes down to power, I have a 400 volt TIG welder that I used when I had a three phase supply and it run between two phases. Now without my three phase supply you think all that is required is a transformer to take 230 volts up to 400 volts and it will be ok. The issue is that volts in times current in must equal volts out times current out. In more simple terms if you double the output voltage you halve the current so to get my 400 volts at 40 amps I need a transformer that will be drawing 80 amps on the primary.
