# Nice mess I got in



## GK1918 (Jan 11, 2013)

The need for another larger milling machine.  I thought the hard part was moving a 3000 lb machine
behind the wife= she can see through cement.  My other lathes & mills >220 1 ph.  This mill I figured on
a vfd but the more I read it sounds like I need two vfds. because the table feed is also 3phase as well
as the coolant pump (I think) at least the work light is 110vts.  Static converter is out.  Going rotary
may be easy but I cant find a motor so thats on hold.  Like most people the purchase crippled my
pockets.  Not being in the shop now Im guessing the mill most like 1 1/2 motor and I dont know what
the table feed motor is maybe a 1/4hp. no idea about the 2 oil pumps.  So Im jammed up, she finds
out I bought another and doent work?? I know my way around any single phase, not 3.  Or just
replace motors with 110vt or something.  Then I notice vfds need to be wired direct so there goes my
nice built in controls.  Then I see vfds with 110 single input and puts out 220 3 phase so Im totally
lost?????  I will today get info off motor plates.  Maybe most logical is change mill motor and disable
power feeds      any ideas


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## Ray C (Jan 11, 2013)

Take a step back... breathe...  innnn, outttt, innnn, outttt...

Worry about the wife first.  Get her on your side and the technical glitches will seem small...


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## DaveD (Jan 11, 2013)

Just build a RPC and run it the way it was meant to be run. RPCs are fairly straight forward and you can go all the way from simple, rope start, no cap balancing to store bought controllers or complete setups and anywhere in between. Me, I bought a controller, latched on to a 10hp 3phase motor and wired it all up myself. Had to play around with the start and run caps though. 

Sent you a PM.


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## xalky (Jan 11, 2013)

A rotary converter is probably the way to go in your case. Look on craigs list, you never know. You're in massachusets, your chances are pretty good of finding one.


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## jgedde (Jan 11, 2013)

GK1918 said:


> The need for another larger milling machine.  I thought the hard part was moving a 3000 lb machine
> behind the wife= she can see through cement.  My other lathes & mills >220 1 ph.  This mill I figured on
> a vfd but the more I read it sounds like I need two vfds. because the table feed is also 3phase as well
> as the coolant pump (I think) at least the work light is 110vts.  Static converter is out.  Going rotary
> ...




Why can't you use a VFD?  I've seen stuff that says one motor to a VFD, but that's not always true.   As a designer of motor controllers I know this for certain.

I use a single VFD to power the spindle, lubricator and vacuum motors on my surface grinder (two big motors, one small one).  As long as you're not enabling the more esoteric features in the VFD (like slip compensation and the like), you'll be fine with a properly sized VFD.

A rotary phase converter is another option.  

Do not use a static phase converter for multiple motors.

John


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## xalky (Jan 11, 2013)

jgedde said:


> Why can't you use a VFD?  I've seen stuff that says one motor to a VFD, but that's not always true.   As a designer of motor controllers I know this for certain.
> 
> I use a single VFD to power the spindle, lubricator and vacuum motors on my surface grinder (two big motors, one small one).  As long as you're not enabling the more esoteric features in the VFD (like slip compensation and the like), you'll be fine with a properly sized VFD.
> 
> ...



But what about the variable speed, frequency, wouldn't that change the frequency to all the attached motors?

Sent from my SPH-L710 using Tapatalk 2


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## Hawkeye (Jan 11, 2013)

If you had a 3-phase service into your shop (or if you changed the motors to single-phase), you'd be using the gears or belts that came with the machine to change speeds. Your simplest solution may be to use a VFD to supply 3-phase at 60 Hz and not adjust the frequency. Just make it big enough to handle the total hp of all the motors, plus a bit of extra.

Once in a while, you could adjust the frequency a bit, just to get that ideal cutting speed. You'd change the speeds of the other motors, too, but small changes wouldn't hurt too much.


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## fastback (Jan 11, 2013)

I believe that you can get a VFD that converts single phase 120 volts to 3 phase, 220volts, up to 1 hp.  I have one of these on my SB lathe with a 3/4 hp and really like it.  If you set the frequency on 60 you should be all set and like already said use the gear changes that came with your machine.  The nice thing about VFD is the prices are very reasonable.


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## randyjaco (Jan 11, 2013)

Plus whatever on the RPC. It is the cheapest and easiest way to solve your secondary problem. The primary problem is smoothing things out with  SWMBO  :nono:

Randy


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## GK1918 (Jan 12, 2013)

Thanks all,  first off two days of detailing plus buffing all hand wheels even buffed the table so it really
pops.  and Friday she walks in and was impressed whew got by that hurdle.  Too bad yrs back when
I got my GK1918 it had a 3ph 10hp and I junked it.  I agree with everybodys replys I now think of
Mounting a vdf where the rev- off- fwd switch is and simply plug it into my 220.  Atleast  I will have the
spindle and worry about the table later.


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