Re: [CAD_CAM_EDM_DRO] VFD tachometer sanity check

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@...>
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:
> FAQ: http://www.ktmarketing.com/faq.html
> FILES: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/files/
> Post Messages: CAD_CAM_EDM_DRO@yahoogroups.com
>
> Subscribe: CAD_CAM_EDM_DRO-subscribe@yahoogroups.com
> Unsubscribe: CAD_CAM_EDM_DRO-unsubscribe@yahoogroups.com
> List owner: CAD_CAM_EDM_DRO-owner@yahoogroups.com, wanliker@...,
timg@...
> Moderator: pentam@... indigo_red@... [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
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>