Rick,
I've seen some good info and some misinformation in the thread. I don't
know the Toshiba model numbers well enough to know if this is native
single phase or not. I think I have a VFS7 manual pdf at work. If it is
it will say it on a tag on the side of the drive and list something
like input 8A 1 phase. If it only lists 3 phase on the tag, you probly
have to derate it. If it has a 1 phase rating, the manual will state it
somewhere. (If you can find the toshiba drives website (tic something,
but a bit hard to track down, look for legacy drive), they have
downloads you can search for the word single.

If you have to derate, you get about 60% of the 4.0 Amps, or 2.4A
continuous. It will start your motor by itself, probably start the
motor and Reeves drive, and may even power the lathe for continuous
moderate cuts. It will put out 2.4 X 150% =3.6A for a minute at a time,
which will cover the full 1hp for any 1hp 1750 rpm motor I've seen. A
bit wimpy for you lathe, but probly passable. If you don't have to
derate, its fine. I don't remember any Toshiba's having undefeatable
input phase loss detection, though they might. If a drive does have
phase loss detection, and you can't defeat it, then it will not run on
single phase. Often manuals don't say whether you can run single phase,
but you can anyways.

Toshiba is one of the few manufacturers to include recommendations to
overspeed your motor; in an earlier VFD manual (VFSX) they mention for
a 1750 motor it is okay to double the speed. 80hz is conservative. If
your motor is a standard frame (56 or 143T/145T), then its easy to
replace, abuse it as you like, a 3 phase replacement is not too pricy.
The comment about the lathe not liking doubling the Reeves high speed
is accurate, but if you don't exceed the lathe's top speed you're okay
at 80, 90, or 100, or even 120 hz, though 80 is "safest". To access
anything over 60, you probably need the remote pot.

If it was made in 1997, then it may have sat around for a while, and
the capacitors need reforming. The best way is with a 240 volt Variac.
slowly ramp up the voltage, then keep it at 240V for 3-4 hours before
hooking a motor to it. Equal is 120 variac + transformer. I think
Variac w/o transformer to 120V,hold a bit, then switch to 240V is next
best. Simply plugging it in for 4 hours at 240V will still do plenty
good. If you don't do this, and it has sat around, it may die quickly
on you. This might be in your manual.

Its only a 1 hp drive, don't worry about the circuit and inrush. The
basic idea is to cover the listed input single phase amps + a safety
factor. But still an easier load on the circuit breaker than a motor
with the same amps, where you have to oversize by more. It will stop
your lathe pretty quickly, I'd try 3-4 seconds min or you start losing
faceplates. You can add a braking resistor if you want LOTS of quick
stops close together. Some you have to add a module for, $$$, justa
resistor, then not bad, though you gotta house it. If you frequently
overheat the drive into a trip from breaking, then get a resistor.

Wade

Rick Cox wrote:
Frank,
Would the "Inrush" be listed in a typical Manual.
The VFD I have is a Toshiba model vfs7s 2007up. It was manufactured in '97.
It is rated at 4.0 amps at 1.6kva 0.5-80hz.

Thanks for the heads up.


"Frank Ketchum" wrote in message
ink.net...

"butch burton" wrote in message
oups.com...
If you use a VFD to convert 220 to 3 phase, will the motor it is
powering loose any power or is a 10 HP 3 phase motor powered with a VFD
still 10 HP.

Thanks


It won't loose power, but you still need a circuit capable of powering a
10hp motor to power a 10hp drive. Hope that makes sense.