Phase converter for a nardini 14x40

K

kylec

Guest
Hello,

A good gunsmith friend of mine has decided to part with his nardini. Since its a 3 phase machine, and I dont have 3 phase, what is the best option to convert 220v single to 3 phase? The machine has a 6 h.p. motor. Any and all suggestions are appreciated!

Thanks,

Kyle
 
Besides the rotary phase converter option, you might consider a VFD- Variable Frequency Drive. Many can be single phase in, 3 phase out. The advantage is that you will have infinately variable speed control of the spindle when finished. It's been some time since I bought mine (also on a Nardini 1440) but the price premium over the rotary converter was about $200. Seems like I paid about $650 for the VFD, which is a Yaskawa brand. Let me know if I can help further.

John Whidden
 
Thanks John,

Do I need to run a separate 3 phase motor with the VFD before power goes to the lathe?

Kyle
 
I have 2 VFDs and I love them. I added a cheap braking resistor to one of them and it stops the spindle instantly. A rotary phase converter does require a 3ph. idler motor. Do not consider a static converter.
 
Vfd

The modern VFD is the most cost effective method of of pruducing true 3 phase from single phase. It converts single phase 240 AC to DC and back 3 phase of a specified voltage based on the unit purchased. The cost goes up with the increase in horsepower. Older VFD lost torq with the reduction of cycles. The new VFD are much better regulated and the new NEMA motors are made to be run with a VFD. My VFD a Westinghouse 215 has many extra features including digital controls, and motor breaking.

There are several threads on Home Shop Machinist and Practical Machinist web sites. There is a web site called "Dealers Direct" where new and used VFDs are sold. There are some deals out there.

When I replace the 3 hp single phases (metric) motor on my Tiawan Lathe. The NEMA American motor with the same foot print and Metiric with the same shaft size wa a 5 1/2 horse power motor. I have never encountered any torq problems down to 10 cycles or 12 rpms. Rarely do I use my VFD turned down lower than 30 cycles 1/2 norm 60 cycle load.

Nat Lambeth
 
Kyle,

As stated, nothing else is needed. I just looked and mine is a Yaskawa GPD 315/V7 rated at 7.5kW. Hope this helps.

John Whidden
 
I have a rotary phase converter on my Nardini 1440. My VFD experience is a grand total of one. I hooked it up according to the instructions and smoke poured out of it. I wouldn't do another one unless I got someone else to hook it up! It was an expensive lesson. The RPC works just fine but it is noisy. I am going to move it outside my shop I think. Mine is a 7.5 HP rated unit.
 
Kyle,

I don't know. Whatever 7.5 kW equates to- sorry I don't have the formula in front of me.

John
 
As Butch said, the static converters are worthless on a lathe. About thirty years ago I wired one for a 16" South Bend with a 12" four jaw. All I got for my money was smoke and oil. The rotary converters are noisey, and waste a lot of power to create the third leg. I have a 20hp, and a 10 hp unit in my shop. In the winter they will heat the shop. Summer time................ :-(
I have experience with VFD's on Bridgeports. That I liked.
Regards,
Bob
 
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