Re: VFD tachometer sanity check

Oh, what the heck. I just bought this on E-Bay:

http://cgi.ebay.com/ws/eBayISAPI.dll?
ViewItem&item=2573683479&ssPageName=ADME:B:EOAB:US:6

I'm not 100% sure that its what I'm looking for, but its promising
and cheap enough to give it a shot.

Jeff


--- In CAD_CAM_EDM_DRO@yahoogroups.com, "James Cullins"
<jcullins@c...> wrote:

> You may be able to use a digital panel meter the calibrate it to

read what

> you want.
> Jim
> ----- Original Message -----
> From: "andyolney" <andy@o...>
> To: <CAD_CAM_EDM_DRO@yahoogroups.com>
> Sent: Saturday, November 22, 2003 1:54 PM
> Subject: [CAD_CAM_EDM_DRO] Re: VFD tachometer sanity check
>
>
> > Harbor Freight has some digital multimeters for $3 at the momont

and

> > it occurred to me that at that price you could afford to hack

one of

> > these up for a tachometer display. Andy
> >
> > --- In CAD_CAM_EDM_DRO@yahoogroups.com, "James Cullins"
> > <jcullins@c...> wrote:
> > > Jeff
> > > Ok, you are reading the RPM as a voltage of 0 to 10v and
> > converting it to
> > > RPM reading, should work fine, are you using a digital

display?

> > > Jim
> > >
> > >
> > > Jim
> > > ----- Original Message -----
> > > From: "washcomp" <jeff@w...>
> > > To: <CAD_CAM_EDM_DRO@yahoogroups.com>
> > > Sent: Saturday, November 22, 2003 1:09 PM
> > > Subject: [CAD_CAM_EDM_DRO] Re: VFD tachometer sanity check
> > >
> > >
> > > > Jim:
> > > >
> > > > Yes. I was figuring on using the max RPM reading (on a

voltmeter)

> > > > to be calibrated to 10 volts analog output which is linked

to the

> > > > frequency.
> > > >
> > > > Jeff
> > > >
> > > > --- In CAD_CAM_EDM_DRO@yahoogroups.com, "James Cullins"
> > > > <jcullins@c...> wrote:
> > > > > Jeff
> > > > > I have been thinking about that myself. Wouldn't you

need a

> > way
> > > > to set up
> > > > > the max RPM
> > > > > to indicate the RPM correctly?
> > > > > Thanks
> > > > > Jim
> > > > > ----- Original Message -----
> > > > > From: "washcomp" <jeff@w...>
> > > > > To: <CAD_CAM_EDM_DRO@yahoogroups.com>
> > > > > Sent: Saturday, November 22, 2003 7:40 AM
> > > > > Subject: [CAD_CAM_EDM_DRO] VFD tachometer sanity check
> > > > >
> > > > >
> > > > > >
> > > > > > I'm thinking of buying a variable frequency drive for my
> > > > Bridgeport.
> > > > > >
> > > > > > The 10 Volts off the analog contacts of the VFD can be

set to

> > be
> > > > > > proportional to the frequency.
> > > > > >
> > > > > > If the RPM is linear to the frequency (after slip has

been

> > taken
> > > > > > into account), and if the voltage is linear to the

frequency,

> > > > then
> > > > > > shouldn't the voltage be linear to the speed?
> > > > > >
> > > > > > If this is the case (the real question I'm asking), once

the

> > > > setup
> > > > > > is calibrated, this should give the ability to have an
> > accurate
> > > > > > electronic analog tachometer on the control pendant I'm
> > designing
> > > > > > without resorting to an additional optical encoder.
> > > > > >
> > > > > > I figure a tachometer would be useful for "manual"

machining

> > and
> > > > > > sanity checks on CNC milling.
> > > > > >
> > > > > > Any thoughts, comments or suggestions would be

appreciated.

> > > > > >
> > > > > > Jeff
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > > Addresses:
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wanliker@a...,

> timg@k...
> > Moderator: pentam@c... indigo_red@q... [Moderators]
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> >
> > 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
> >
> >
> >
> > Your use of Yahoo! Groups is subject to

http://docs.yahoo.com/info/terms/

> >
> >
> >