Myford super 7 lathe

[klaus gerhard]

I happened to buy a Myford Super 7 from a friend. It was made in 1973. All there and in good condition but I struggle to conect the electric wiring incl the Drewhurst switch. As a solution I am considering to buy a new 400V electric motor which seems to be available from Myford. Is that a useful modification? What is your experience?
Thanks Klaus

[Bob.Murphy]

A 400 volt motor will require a three-phase electrical supply - either straight from the mains (which might be difficult to arrange) or via a Variable Frequency Drive (VFD) which turns single phase into three.

It's a whole world of pain as there are different methods of producing a phase converter - solid state or motor-driven. You would have to know which capacity you would require. More Amps = more cost.

Fortunately I have three-phase from the mains!

Bob.

[simon.holyfield]

Is this any use Klaus?

https://www.instructables.com/Wiring-up ... lathe-mot/

[klaus gerhard]

Bob, I forgot to mention that my little garage has a 400V socket. So this would be fine.
Simes, thanks for that. I will try to follow that.

Thanks
Klaus

[Julian Murphy]

These guys are good for converters and inverters. Always very helpful.

https://transwave.co.uk/

[Bob.Murphy]

"Bob, I forgot to mention that my little garage has a 400V socket."

Ha Ha! Sorry Klaus, I didn't mean to 'teach Granny'. I have 415v 32A three-phase for my 50" Colchester Triumph 2000" lathe and my Bridgeport Mill. I believe three-phase on the continent is 380v as your line voltage is 230v (ours here is 240v). I'm sure it will be fine for your Myford - no worries about failing starter condensers that happens with single-phase (three-phase is self starting!).

[klaus gerhard]

Bob, of course you are right!!
While thinking about the best alternative motorwise, I was considering this: https://www.myford.co.uk/product/motor- ... 4hp-1ph-2/

[Roger Gwynn]

I have used a digital 3 phase to single phase converter for years on my lathe, infinitely variable speed, works well.

[Bob.Murphy]

While thinking about the best alternative motorwise, I was considering this: https://www.myford.co.uk/product/motor- ... 4hp-1ph-2/

3/4 hp single phase seems a little light, I have a 1.5hp single phase motor in my 1950s 'Denford Viceroy' lathe (a Boxford-type, not dissimilar to a Myford).

My Warco 230 lathe is single phase but has a built-in VFD and variable speed, it loses torque at slow speed and for that reason I prefer a gear drive.

My Colchester is 7.5hp and has 16 speeds, at low speed (23 rpm) nothing will stop it

I would go for the three phase option.

Bob.

[Paul Slootheer]

I never did regret the purchase of my little 1976 Myford ML10 a couple of years ago!