Wendelspanswick
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Woh! That's a 240v to 12v transformer, not 400v but 400va which is 400 volts x amps.
400va / 12v = 33.333amps
400va / 12v = 33.333amps
- Thread starter dan.taylor.1
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MattH
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That transformer is only 400VA so wouldn't even run a 1 HP if you could build a converter with it.
A 5 HP capable transformer is going to be huge! I had some 1KVA toroidal transformers for some mono block amps and they weighed in at over 10KGS each. You'd need at least a 7.5KVA transformer.
If you need to run a machine that has 415v control circuitry then you need a 240 1 PH to 415v 3 phase Plug and Play inverter. These are available but pricier than a 240v to 240v unit.
If you can bypass the controls and run straight to the motor and the motor is dual voltage then you can run the standard inverter.
If you run a PandP inverter then it needs to be sized for the startup current of the motor which can be three times the load current (most inverters will run an 150% output briefly). So a 5HP motor will need a 7.5HP inverter.
A 5 HP capable transformer is going to be huge! I had some 1KVA toroidal transformers for some mono block amps and they weighed in at over 10KGS each. You'd need at least a 7.5KVA transformer.
If you need to run a machine that has 415v control circuitry then you need a 240 1 PH to 415v 3 phase Plug and Play inverter. These are available but pricier than a 240v to 240v unit.
If you can bypass the controls and run straight to the motor and the motor is dual voltage then you can run the standard inverter.
If you run a PandP inverter then it needs to be sized for the startup current of the motor which can be three times the load current (most inverters will run an 150% output briefly). So a 5HP motor will need a 7.5HP inverter.
shenion
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That looks like 240 to 12VAC. 30A out though.
Kent
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On a farm, noise not an issue! Then build a generator or buy one, run it on red diesel it will be cheaper than paying the extra electric. My neighbour has a machine shop and after looking into it further its the way forward for rural properties with a 3 phase requirement. I must say going three phase to save money sounds kind of twisted about face because three phase gear will cost more to run, especially the old inefficient stuff
Wendelspanswick
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How do you work that out?
A 3 phase motors runs more efficiently than a single phase motor of the same size, is more balanced and has no start/run capacitors/windings with the associated switching.
Gents, I have posted this on another message and if it will help anyone, then come and borrow it, take it away and play. It is an up to 4 HP static converter, stick a suitable motor on it and you will have a 415 3 phase rotary converter.
I would also have though that some plasma and welders would only be going across two legs of a 3 phase supply therefore, it may be possible to use a step up transformer, guess what is in the static converter.
It is heavy, but I can pick it up OK, but would not like to post it.
It cost me £90 years ago and to be honest has sat under my bench every since as I went to 3 phase 240 volts before I picked it up. It was a, I will do that one day. Not expecting anyone to buy it off me just try and see if the solution works for you.
Adrian
I would also have though that some plasma and welders would only be going across two legs of a 3 phase supply therefore, it may be possible to use a step up transformer, guess what is in the static converter.
It is heavy, but I can pick it up OK, but would not like to post it.
It cost me £90 years ago and to be honest has sat under my bench every since as I went to 3 phase 240 volts before I picked it up. It was a, I will do that one day. Not expecting anyone to buy it off me just try and see if the solution works for you.
Adrian
brightspark
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are u talking 3 phase to the cutout fuses and only 2 phases been taken off with single phase meters fitted ??if so thats quite common years ago mainly in large victorian houses
Shox Dr
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4.0KV Motor on a Colchester Master 2500 lathe. I think I now have it all lol
The main reason I need use a CONVERTER as opposed to an INVERTER is because of the wiring on the lathe. If it was a Knacked lathe with no wiring (i.e just a case of spinning a Motor up) the 240 delta configuration on the motor would be useful. I could then use an Inverter. What the problem seems to be is the regulations regarding what INVERTER can use used on mains 240 volt. Most only go up to 3.0KV anyway.
I dont need a Rotary a static will be fine . But even then its £500 or more.
The interesting thing is some info I was told does not fully match with this http://lathes.co.uk/page28david.htm
Seems to be a minefield. lol
Regards Andy T
I don't beleive that needs to be the case, there'll be a step down transformer somewhere on the board, dropping the voltage to a safer level, 12v,24v, 110v are common, so all you need to do is replace 415v transformer to 240v supply. Swap wiring in motor.
You can then make use of the Inverters ability to electric brake the motor
normspanners
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Hi Shenion nice to read you!
havn't seen you for a while.
MattH
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You can't do that unless you have a "plug and play" capable inverter which are substantially more expensive.
This is because most inverters will be destroyed by removing the load whilst it is running. You would be doing this if you retained the lathe controls because as soon as the inverted started to "brake" the motor all the voltage on the controls would disappear.
If the controls where on a separate supply you couldn't use them as the inverter doesn't like anything but it's controls being used.
On my Boxford I stripped out all of the 415v control gear and replaced it with 24v controls wired into the inverter that replicated the old controls.
This is because most inverters will be destroyed by removing the load whilst it is running. You would be doing this if you retained the lathe controls because as soon as the inverted started to "brake" the motor all the voltage on the controls would disappear.
If the controls where on a separate supply you couldn't use them as the inverter doesn't like anything but it's controls being used.
On my Boxford I stripped out all of the 415v control gear and replaced it with 24v controls wired into the inverter that replicated the old controls.
graffian
Seer unto the end of his beard
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That looks very familiar;-)
Have you had one? Did you ever use it in anger and was it any good? I cannot actually remember where I got it from, even the £90 was a guess as I got it second hand when I got my mill, I think looking back one of the reasons I never used it was my garage supply can only handle 20 amps tops and this would require more. But now mostly guesswork.
Adrian
p.s. It is amazing what search on uk.rec.crafts.engineering can dig up. Around 2001 to 2003 I was trying to get my gear going 3 phase so around 12 to 14 years ago I must have got it, this internet is better then my memory, it proves I don’t throw much gear away, just my brain cells! Think I will continue to search I may even find when and who I got it from.
graffian
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Have you had one? Did you ever use it in anger and was it any good? I cannot actually remember where I got it from, even the £90 was a guess as I got it second hand when I got my mill, I think looking back one of the reasons I never used it was my garage supply can only handle 20 amps tops and this would require more. But now mostly guesswork.
It ran my polisher all day long at times. It was plugged into a 13A socket.
The only thing that ever went wrong was a bolt on the solenoid that disconnects the
caps comes loose every few years.
When I got my mill I ran an idler motor from the converter and then the mill from that, it
worked.
Just searched my old mail and it seems I flogged it to you in July 2003 and I sent it by dhl, it weighes 24.5kg.
Wendelspanswick
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I have the exact same inverter, made by Transwave. Mine is the 8 hp version and runs my SCM universal woodworking machine. It has 3 seperate 5kw motors for the saw, spindle moulder and planer.
My inverter has a few more switches on the side, from memory a manual boost button and a short/long boost button. On the front is 3 ammeters and a voltmeter.
So Looks like a small world, not sure now looking back as to why I ended up building my 240 Volt rotory to run my milling machine from,. think it was to require less current from the supply and hence why the unit is sat under the bench ever since, think the rubber 415 flex coming out need replacing now with age!. I don’t have emails going back to that age so how much was it at the time with the dhl?
Adrian
davida1949
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HI- I SEE YOU MENTION YOU BILT ROTARY PHASE CONVERTER CAN YOU PLEASE IN TOCH WITH ME I NEED YOUR HELP 07546357278 DAVID OR
EMAIL ME THANKS
Onoff
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Might be of interest:
Rotary Converter
A mate off another forum made and gave me this. Uses a 110V transformer re-jigged as an auto transformer to give nom 340V (230+110). He used it for ages with a 7.5HP motor and said it ran everything just fine in his shop until he got proper 3 phase. Wire missing in the photo goes from the bfo...
www.mig-welding.co.uk
I'm a bit out of touch now, but you could do a lot worse than contact Peter (if he's not retired by now or there's another younger chap with an unusual name I can't recall) at Transwave (the Co is actually Power Capacitors but Transwave is a brand name for their Phase Converter products.
They were always very knowledgeable & helpful where technical advice & selecting a unit was concerned.
(I recall using them to source for a welding application many years ago - & IIRC they suggested a Rotary unit, but with an additional "something" (can't recall what) to cope with the strike-up inrush I think).
Their transformers and kit was always good quality, & knew their stuff - so worth talking to them.
G.
Jelly_Sheffield
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I think you might have missed the original date of this thread that's just be resurrected...
But whilst you're mentioning Transwave
As I understand it, they're designed to work so the switch is flipped once the converter is running, but before the welder is powered on, and takes the start-and-run capacitors out of the circuit, as a heavy inrush current could cause them to catastrophically fail.
What I can't recall is if it switches over to run-only balancing capacitors which are rated for the inrush current or if it just takes the caps out entirely supplies one unbalanced phase to the welder...
But whilst you're mentioning Transwave
I dealt with the young chap when I spoke to them about having my existing rotary converter fitted with a "Hand Switch" to run welding plant, (before eventually going over to a genset, as the model I had wasn't suitable for the mod when they inspected it).
As I understand it, they're designed to work so the switch is flipped once the converter is running, but before the welder is powered on, and takes the start-and-run capacitors out of the circuit, as a heavy inrush current could cause them to catastrophically fail.
What I can't recall is if it switches over to run-only balancing capacitors which are rated for the inrush current or if it just takes the caps out entirely supplies one unbalanced phase to the welder...
Yeah, very good little firm, and having visited the workshop (a small well lit room buried in the bowels of their premises behind the bigger work area where they assemble and ship power-factor correction capacitor banks bigger than my pickup), they're really committed to quality and workmanship.
