Re: VFD Selection

How much is a sherline spindle? What is the difference with a
spindle, motor, and headstock? Sherline mills are very small and the
mill I plan to build is about 4' x 4'.

Thanks,

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "ballendo" <ballendo@y...>
wrote:

> George,
>
> Have you considered using a Sherline Spindle? It could be mounted

in

> place of your router and its speed control would take the place of

the

> VFD... I use it this way on a couple of my gantry machines...
>
> Hope this helps,
>
> Ballendo
>
> P.S. Using Peter Homann's Digispeed controller with Mach2 you can
> have the spindle rpm under gcode control.
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "george_barr"
> <george_barr@y...> wrote:
> > Leslie,
> > It appears that I cannot use a VFD or Variac to reduce my

router

> to
> > 1k rpm. What type of motor can I use with a VFD (input: 120VAC,
> > output: 120VAC or DC) without getting too expensive or without
> using
> > servo drives? Is there a specific phase specification. Does the
> > motor have to be AC or can it be DC? What I am planning to do is
> cut
> > mild steel (which requires low rpm speed)?
> >
> > Thanks,
> >
> > --- In CAD_CAM_EDM_DRO@yahoogroups.com, "Leslie M. Watts"
> > <leswatts@a...> wrote:
> > > Your Bosch apparently has a phase control already built in
> > > as do my Porter Cables. So you don't need another.
> > >
> > > These speed controllers don't do too well at low RPM due
> > > to the lack of a tach or encoder rpm feedback. In any case
> > > 1000 rpm would be rough running. Series and compound wound
> > > motors just don't have low end torque. That is why the low
> > > end is designed to be 8k.There is just not much left below

that.

> > >
> > > A VFD will not work with a universal wound brushed motor.
> > > Speed is voltage related in these, which is why Variacs
> > > were often used before phase control was cheap.
> > >
> > > Sounds like you need to drill holes in plastic, etc.
> > >
> > > I use a modular head where I can quickly bolt on another motor.
> > > A PM dc motor makes a pretty good light duty low speed spindle
> > > when driven by a dc servo amp, and doesn't cost so much if
> > > purchased surplus.
> > >
> > > A dc servo amp MIGHT work with a router
> > > if a tach was added and the phase control bypassed, but it
> > > would be a hassle-and although most router motors would work
> > > on dc they might not be rated for it. They are definitely
> > > not designed for heavy spindle loads either.
> > >
> > > I work a bit with portable power tool engineering, and we are
> > > all looking forward to the day when all of them use brushless
> > polyphase
> > > induction motors with frequency control. It will happen- but
> right
> > now
> > > commutators are still used due to the cost of brushless drive
> power
> > > electronics.
> > >
> > > Les
> > >
> > >
> > > Leslie M.Watts
> > > L M Watts Furniture
> > > Tiger Georgia USA
> > > (706) 212-0242
> > > http://www.lmwatts.com
> > > Engineering page:
> > > http://www.lmwatts.com/shop.html
> > > CNC surplus for sale:
> > > http://www.lmwatts.com/forsale.html
> > > CNC carved signs:
> > > http://www.lmwatts.com/signwp.html
> > >
> > >
> > >
> > >
> > > -----Original Message-----
> > > From: george_barr [mailto:george_barr@y...]
> > > Sent: Tuesday, April 13, 2004 3:17 PM
> > > To: CAD_CAM_EDM_DRO@yahoogroups.com
> > > Subject: [CAD_CAM_EDM_DRO] Re: VFD Selection
> > >
> > >
> > > Leslie,
> > > It seems to me a Variac only limits the voltage going out. I
> > > already tried a variable router speed controller found at:
> > > http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?
> > itemnumber=43584
> > >
> > > This router speed controller does not work since my rouers

normal

> > > speed range is 8k - 20k rpm and I need to have a speed of about

1k

> > > rpm. The speed controller cannot slow this router below 8k it
> > > seems.
> > >
> > > Are you saying that a VFD cannot work with my router?
> > >
> > > Thanks,
> > >
> > > --- In CAD_CAM_EDM_DRO@yahoogroups.com, "Leslie M. Watts"
> > > <leswatts@a...> wrote:
> > > > George,
> > > >
> > > > You don't need a VFD for a unversal wound router motor.
> > > > It's speed is not dependent on line frequency.
> > > > Typically a phase control triac system is used. It is similar
> > > > to a light dimmer but has IR comped backemf or tach feedback
> > > > to contol the speed.
> > > >
> > > > Granger, MSC, etc have many of these, and some are well under
> > > > $100.
> > > >
> > > > A variac works as well, but with poorer speed control.
> > > >
> > > >
> > > > Leslie M.Watts
> > > > L M Watts Furniture
> > > > Tiger Georgia USA
> > > > (706) 212-0242
> > > > http://www.lmwatts.com
> > > > Engineering page:
> > > > http://www.lmwatts.com/shop.html
> > > > CNC surplus for sale:
> > > > http://www.lmwatts.com/forsale.html
> > > > CNC carved signs:
> > > > http://www.lmwatts.com/signwp.html
> > > >
> > > >
> > > >
> > > >
> > > > -----Original Message-----
> > > > From: george_barr [mailto:george_barr@y...]
> > > > Sent: Tuesday, April 13, 2004 2:34 PM
> > > > To: CAD_CAM_EDM_DRO@yahoogroups.com
> > > > Subject: [CAD_CAM_EDM_DRO] VFD Selection
> > > >
> > > >
> > > > I want to get a VFD for my Hitachi M12V router so I can vary

the

> > > > speed for metal, aluminum, and wood milling. The M12V is a
> > single-
> > > > phase series commutator motor, 115VAC, 60HZ, 15 Amps router.

I

> > > would
> > > > like to use my 120VAC outlet for the VFD. Can someone tell

me

> > what
> > > > kind of VFD I should get? I have noticed some VFD have 3 to

1

> > phase
> > > > conversion and all sort of specifications. I certainly do

not

> > want
> > > > to buy the wrong one. Also, it should interface to my

pmdx.com

> > > break
> > > > out board.
> > > >
> > > > Thanks,
> > > >
> > > >
> > > >
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to

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EXCEPTIONS........

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> > > > List Mom
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> wanliker@a...,
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> > > [Moderators]
> > > URL to this group: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO
> > >
> > > OFF Topic POSTS: General Machining
> > > If you wish to post on unlimited OT subjects goto:
> > > aol://5863:126/rec.crafts.metalworking or go thru Google.com to
> > reach it if
> > > you have trouble.
> > > http://www.metalworking.com/news_servers.html
> > >
> > > http://groups.yahoo.com/group/jobshophomeshop I consider this
> to
> > be a
> > > sister site to the CCED group, as many of the same members are
> > there, for OT
> > > subjects, that are not allowed on the CCED list.
> > >
> > > NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY
> POSTING
> > THEM.
> > > DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........
> > > bill
> > > List Mom
> > > List Owner
> > >
> > >
> > > Yahoo! Groups Links