Re: Check my math and reasoning....

I have no idea as the nameplate on the Sigma stepper is buried (only
shows wiring schematic). I was told by a very reputable source on
driving steppers that the Nema42 motors need the higher voltage &
that this would push the torque curve up a little higher than stock
configuration. The original supply, I believe is 60v for these
steppers...I sincerely doubt that an increase of 10v would have any
negative effect.

-Brady

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Robert Campbell" <bob@c...>
wrote:

> Brady,
>
> Just one more question. What is the name plate voltage on your

stepper

> motors?
>
> Bob Campbell
> Bob@c...
> www.campbelldesigns.com
> Breakout board
> THC board sets
> CNC router plans
> Stepper Motors
> VisualMill Basic
> ----- Original Message -----
> From: "braidmeister" <braidmeister@y...>
> To: <CAD_CAM_EDM_DRO@yahoogroups.com>
> Sent: Monday, June 27, 2005 5:28 PM
> Subject: [CAD_CAM_EDM_DRO] Re: Check my math and reasoning....
>
>
> > Thanks Bob. What would be the result of running the larger

ampacity

> > supply (@70v) over one that had less amps for the steppers?
> >
> > Drives will be 202s for the steppers and 320/340s for the
> > servos...same 70v requirements just different ampacities.
> >
> > -Brady
> >
> > --- In CAD_CAM_EDM_DRO@yahoogroups.com, "Robert Campbell"

<bob@c...>

> > wrote:
> >> Brady,
> >>
> >> You need to separate the calculations for stepper motors and

servo

> > motors.
> >>
> >> I would suggest that you build two power supplies. One for the
> > stepper
> >> motors and one for the servo motors.
> >>
> >> One of the limiting voltage factors will be the drivers that you
> > are going
> >> to use. The Gecko drives have an 80 volt limit. I would keep it

at

> > about 70
> >> volts.
> >>
> >> I would recommend that you look for 100 volt capacitors. You can
> > always hook
> >> them in parallel to get more capacitance.
> >>
> >> Bob Campbell
> >> Bob@c...
> >> www.campbelldesigns.com
> >> Breakout board
> >> THC board sets
> >> CNC router plans
> >> Stepper Motors
> >> VisualMill Basic
> >> ----- Original Message -----
> >> From: "braidmeister" <braidmeister@y...>
> >> To: <CAD_CAM_EDM_DRO@yahoogroups.com>
> >> Sent: Monday, June 27, 2005 5:04 PM
> >> Subject: [CAD_CAM_EDM_DRO] Check my math and reasoning....
> >>
> >>
> >> > OK gang,
> >> > I am trying to piece together my power supply and have a few
> >> > questions regarding the rated voltage for a capacitor. I am
> > finding
> >> > that most use 50v caps and they are cheap and available...I am
> >> > wondering at this point if I am missing something...here's

where

> > I am
> >> > and where I want to go with the PS:
> >> >
> >> > I am running Sigma N42 motors on the Bridgeport and the manual
> > says
> >> > that they are 6.8A. I would like to build a power supply with
> > enough
> >> > juice to power these 3 steppers AND an 11A Servo for the 4th

axis

> >> > down the road. I will eventually need to run 4 of these 11A
> > servos @
> >> > 70v ~ so I am thinking why not just build one supply and be

done

> > with
> >> > it?
> >> >
> >> > Right now I have 2 50v (what decal says on each...but

advertised

> > as
> >> > 55v when I bought them) 800VA torid transformers. I bought 2 at
> > the
> >> > time so that I would have enough amperage to run the 4 servos.

Now

> >> > comes the question of capacitors...I need caps are rated by
> > voltage
> >> > after being rectified, right?...In this case at least 80v...not
> > 50v,
> >> > right??? I searched around on here and didn't see any

reference to

> >> > this.
> >> >
> >> > So...If my math is correct, I will need (using the servo motor
> > draw
> >> > as a guideline) Assuming 50v rectified to 70v by the 2 torids:
> >> >
> >> > 44Amps * 67% (from Campbell's pdf) = 29.5A
> >> >
> >> > C= (80,000 * I) / V)
> >> > (80000 * 29.5) / 70 = 33691 uF
> >> >
> >> > Could I get away with 3 P10653-ND from DigiKey? They are 12,000
> > uF @
> >> > 100v +/-20%.
> >> >
> >> > Did I do my math right...or am I missing something???
> >> >
> >> > Thanks!!!
> >> > -Brady
> >> >
> >> >
> >> >
> >> >
> >> > Addresses:
> >> > FAQ: http://www.ktmarketing.com/faq.html
> >> > FILES: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/files/
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> > wanliker@a...,
> >> > timg@k...
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> >> > [Moderators]
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> >> >
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> > Addresses:
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> > FILES: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/files/
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wanliker@a...,

> > timg@k...
> > Moderator: pentam@c... indigo_red@q... davemucha@j...
> > [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
> >
> >
> >
> >
> >
> >