New toy.

[DavidA]

VT,

Thanks for that link.

It certainly adds to my growing pile of info on generating the third phase.

But it falls down at the first fence; I need 415 Volt.

Dave.

[Arbalist]

Have you checked the motor plate Dave? The motor on my old mill could be run on 415 or 240V.

[vtsteam]

David the principles are the same, though.

You would need start and run capacitors rated for 415V motors (which I I'm sure are available in the UK), and if you use a single phase starter motor it would be the type used at your usual mains voltage.

The method of checking voltage across the legs to balance the capacitor values is the same.

So unless you don't have 415 at all, you could basically follow the same procedure.

hmmmm.....maybe that's what you're saying...

[mattinker]

But it falls down at the first fence; I need 415 Volt.

So, you need a 240/415 step up transformer to put in front of you three phase creating set up!

Regards, Matthew

[awemawson]

When I was making phase converters (and I've made a few) I would find a 240 isolating transformer with multiple input a output tappings. Most have a pair of nominal 120vwindings in series with +/- 10% adjusting tappings

Wire all four in series. Bung 240 across the middle pair and take your 415 off the ends having selected suitable tappings to get 415 ish volts not 480.

[DavidA]

I think firstly I will go check the voltage plate on the milling attachment as I already have this in the shed.

The lathe wont be here until the end of the month as I have to make some sort of access for it.

But armed with the mill, and assuming for the moment that it can be run of 230 Volt, I may have a play around with the capacitor idea.  I do have some 415 Volt capacitors somewhere.

Dave.

[Andrew Wildman]

I am currently building a rotary phase converter to run my omnimil.  I have a static one but for the 4+1.5+0.25 hp motors it is not big enough.

I purchased a cyntringam arc welder to use as a 5Kva auto transformer.  It also lays down a mean bead of weld!  The welder has 220, 240 and 415 taps so you can connect to 240 and get 415 from the other tap.  Cost me £30

[DavidA]

Andrew,

Looks interesting.  Keep us informed on your progress and the end results.

Dave

[DavidA]

Well,  the Denford arrived yesterday.  I had a local guy wiht a HIAB bring it to the house and dump it as far down the drive as the HIAB would reach. Cost me £50 for about 15 minutes work,  but was worth the money. It then took my brother and I another two hours to move it the remaining twenty foot into the shed.

Main problem was due to the drive being around a foot higher than the shed floor.

So we had to make a gently sloping 'roadway' of six inch concrete blocks before we could use the pallet truck I had borrowed from my daughter's works to (very slowly and carefully) ease the machine down. We tied the lathe to the front of brothers car and used that to ensure that it didn't get away from us.

Having placed it in it's new home I had a good look at it.  I hadn't seen it for months.  Sadly the people who took it over after it's original machinist retired didn't look after it at all. It was simply placed on a pallet and left in a damp storage room.

Both chucks are rusty. and so was the tail stock end of the bedway.  Fortunately,  in a twisted sense,  they had left the tray full of sud oil. They also left lots of the tooling in the tray. So it was all slimy and wet.  But not too damaged.

But it will rise,  Phoenix like from the ashes of it's neglect.

Tony,  the guy who used to cherish it,  would have wept at the sight.

All I need need now is a rotary convertor (the plate says 1.5 Amp at 415 Volt). But that will have to wait a while.  The wife want to go for a week in Greece.  And I can hardly refuse now.

Dave,

[Jonny]

Where abouts are you Dave you could have my Transwave rotary think its 5.5kw, should just about run the 1.5kw 3ph 440v
Just kept as a backup the last four years while I use a single to 3ph 440v digital invertor plug and play.

[DavidA]

Jonny,

I'm way up in West Yorkshire.  But thanks for the offer.

Also I wondered if your converter may be a bit over kill.

The plate on the motor says 1.5 Amp FLC . I assume that means Full Load Current.

Looking at the calculations for three phase motor power power consumption I get,  using an average Voltage of 415 and an assumed power factor of 0.8,  a power draw of only 0.863 Kw.

So a little 2.5 Kw unit would do fine.


I'd be happy for anyone to confirm these figures.

Dave.