Re: Voltage to steppers

It is considdered in good taste to reference both the author and
board it came from.

Also, I would recomend you read follow-up to make sure the
information is correct. typically in a post a slight mistake might
make it sound good, but then others will post the way it really is.
no responses means that it was either too boring to commonent upon or
correct.

in addition, some time ago there was some questions as to copywright.
many of us assigned any and all copyright to the list and public
domain. regarding my posts, all my posts are public domain.


Dave




--- 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:
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> > OFF Topic POSTS: General Machining
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reach it if

> you have trouble.
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> >
> > 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.
> >
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> > bill
> > List Mom
> > List Owner
> >
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