Re: [CAD_CAM_EDM_DRO] Does a VFD do the trick?

you might reconsider steppers as they are cheap to
control.
you can get steppers with double shaft and put crank
on it. my cnc mill is like that. no trouble to work it
manually at all.

--- Familia Peter Arce & TAD <peteryco@...>
wrote:

>
> Hello friends,
> I fell over my own words yesterday and have to make
> the best out of it.
>
> A (2,5-3tons) beauty of surface grinder from 1957 I
> have to get again to
> work. Complete new electrics with a PLC.
> What I thought were reduction motors are plain three
> fase motors (1700
> revs, 125W) inside 1 to 1 geared.
> Out side reduction Y 1:3 makes 1,7mm per motor turn
> and Z 1:7,5 makes 0,13mm per motor turn.
> With solid state relays I will get the Y movement
> reasonable well to work.
> But for the Z movement not. I would like to have an
> automatic down feed
> graduable from 0,001 to 0,04mm until I am close to
> the final measurement
> and still be able to manage the machine by hand.
> That makes me exclude steppers as option.
>
> Does a VFD on standard three fase motors do the
> trick that I can turn it
> just something like 2 degree or more per impuls and
> later leave it free
> spinning?
>
> As you know me, I work on all kind of machines, but
> I hadn´t to convert
> any with this kind of task and have no hands on
> experience with VFD's.
> The PLC has encoder inputs so if necesary I can hook
> some on the motors,
> screw or nut.
>
> The owner first of all needs the machine running,
> keeping future options
> open, but a automatic use and position feed back
> will be greatly
> apreciated. And tiny VFD's aren´t that much out of
> financial reach.
>
> Who has played with VFD's and standard threefase
> motors (240V Delta
> generated with slave motor) and can give me a
> reference if it is feasonable?
>
> Best regards from Costa Rica, where clocks work
> diferent.
>
> Sven Peter
>
>
>
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