Re: Voltage to steppers

Hi Richard,

out of curousity, what boards ?



--- In CAD_CAM_EDM_DRO@yahoogroups.com, Falcon2 <rittermann1@c...>
wrote:

> this is the basic info that people need
> can i post this on two other boards??
>
> richard
> ----- Original Message -----
> From: <david_mucha@y...>
> To: <CAD_CAM_EDM_DRO@yahoogroups.com>
> Sent: Thursday, January 16, 2003 9:08 PM
> Subject: [CAD_CAM_EDM_DRO] Re: Voltage to steppers
>
>
> > Hi,
> >
> > and I'm glad your interest brought you over here from the

BasicStamps

> > list.
> >
> > What I posted over there was something that many first time

stepper

> > users don't know about.
> >
> > Stepper motors have nameplates that list some basic information

for

> > calculations which is unlike standard electric motors which put
> > maximums on the motor nameplates.
> >
> > using ohms law, you need to know some basics. resistance, amps,
> > volts, watts, and inductance. with the basic lising of just a
> > voltage and current, you can figure out all the rest.
> >
> > to charge the motor coil you need to pump current into it. higher
> > voltage means that current gets there faster. higher voltage

means

> > faster motor speeds.
> >
> > double the voltage and you double the speed. your 12 volt motor

will

> > spin at 12 volts, it will do slightly more work at 24 and really
> > start to come into the power band at 70 volts. or 5 times the

rated

> > voltage. If you want to run at 30 volts, a 1.5 volt motor would

be a

> > better choice.
> >
> > Power output increases proportionally with supply voltage. Losses

in

> > the motor increase with the square of the voltage. At some point

the

> > motor just gets too hot. This occurs at about 25 times nameplate
> > voltage. most hobbiests think a 5 volt motor needs to run at 5

volts

> > and 6 volts is too much.
> >
> > also, stepper motor output power is independent of speed. Since

power

> > is speed times torque, this means every time you double motor

speed,

> > torque is halved. steppers appear to loose power at higher

speeds as

> > on some machines the torque needed to move the assembly exceeds

the

> > delivered torque and the motor starts missing steps.
> >
> > One thing on the nameplate that should not be exceeded is the

amps.

> > if you connect both sides of one coil of a 6 wire motor so they

are

> > in parallel you use the full motor amperage. if you connect

those in

> > series, then you half the current as you doubled the resistance

and

> > 4x'ed the inductance. this also means you get the same power, but
> > lose top end speed.
> >
> > i'm sure others will comment on this or other questions you might
> > have.
> >
> > Dave Mucha
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > --- In CAD_CAM_EDM_DRO@yahoogroups.com, "pwrcntrl <info@c...>"
> > <info@c...> wrote:
> > > I have a home-grown machine that uses small 55mm 12V steppers. I
> > have
> > > driven them with an embedded controler & Allegro driver chips,
> > which
> > > make it fairly straightforward. The setup uses round ground
> > thompson
> > > shafting and linear bearings and moves quite freely, however,

the

> > > little motors only have enough torque to drive consistently in
> > either
> > > 1/2 or wave drive. I would more importantly like to see some

more

> > > speed. during free moves...it doesn't need torque beyond what is
> > > required to move itself around.
> > >
> > > From what I have been reading here while lurking (from people

like

> > > Dave M, of the Basic Stamp list - Hi Dave!) it seems that it is
> > > common practice to drive steppers above their rated voltage, is
> > that
> > > correct?
> > >
> > > If so, what will driving my 12V motors at say 24V do? It seems

you

> > > guys were talking about 10X rated V, so I'm wondering what 2X

will

> > > do....
> > >
> > > Perhaps I should just change motors. Of course they will have

to be

> > > inexpensive say $20- and with 1/4 inch shaft. If I need to go

over

> > > the V rating of the driver chips, I may have to re-think
> > everything...
> >
> >
> > 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@a...
> > Moderator: jmelson@a... timg@k... [Moderator]
> > 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/

> >
> >