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Stepper Motor Question

K

Karthik Ravikanti

Jan 1, 1970
0
Hi all,
Say I have a stepper motor whose ratings say that it rotates
1.8deg/step.
Does that mean 1.8 degs as in Full Step mode or as in Half Step Mode?
I mean: Will it rotate at 3.6 deg/step in Full-step mode or will it
rotate at 0.9deg/step in Half-Step Mode?


Another question:
I know that in order to get a stepper motor rotating u need to give it
a sequence of pulses as input. Say I just connect one phase to a
battery(that is, only one pulse). Will it just rotate by one step and
stop?



Thanx,

Karthik Ravikanti
http://students.iiit.net/~karthik_ravikanti
 
L

Larry Brasfield

Jan 1, 1970
0
Karthik Ravikanti said:
Hi all, Hi.
Say I have a stepper motor whose ratings say that it rotates
1.8deg/step.
Does that mean 1.8 degs as in Full Step mode or as in Half Step Mode?

It means 1.8 degrees per full step.
I mean: Will it rotate at 3.6 deg/step in Full-step mode or will it
rotate at 0.9deg/step in Half-Step Mode?

The latter.
Another question:
I know that in order to get a stepper motor rotating u need to give it
a sequence of pulses as input.

It is more useful to think of the motor as responding
to electrical phase changes. The motor will tend to
follow those changes, which occur in steps, not pulses.
Say I just connect one phase to a
battery(that is, only one pulse). Will it just rotate by one step and
stop?

It might not rotate at all, or it could rotate most of
two full steps. It would depend on what the rotor
position was before you energized the single coil.
That energization would define one of the electrical
phase positions midway between some adjacent full
step positions. The rotor will settle at that position.
Whether it has to move to settle there would depend
on the starting position.

Welcome.
 
R

Rich Grise

Jan 1, 1970
0
Hi all,
Say I have a stepper motor whose ratings say that it rotates
1.8deg/step.
Does that mean 1.8 degs as in Full Step mode or as in Half Step Mode?
I mean: Will it rotate at 3.6 deg/step in Full-step mode or will it
rotate at 0.9deg/step in Half-Step Mode?


Another question:
I know that in order to get a stepper motor rotating u need to give it
a sequence of pulses as input. Say I just connect one phase to a
battery(that is, only one pulse). Will it just rotate by one step and
stop?

This page isn't bad:
http://www.interq.or.jp/japan/se-inoue/e_step1.htm
It's the first hit here:
http://www.google.com/search?q="stepper+motor"+principle+of+operation

Good Luck!
Rich
 
J

John Popelish

Jan 1, 1970
0
And if the motor moves, the generated EMF also takes part in limiting
the current
 
As an editor, you seem to have mastered the nit-picking about the
choice of words, but you don't seem to be able to produce an
alternative sentence, which would seem to be the more important task in
the business of providing constructive criticism.
 
J

John Fields

Jan 1, 1970
0
As an editor, you seem to have mastered the nit-picking about the
choice of words, but you don't seem to be able to produce an
alternative sentence, which would seem to be the more important task in
the business of providing constructive criticism.

---
Thanks, Bill. It seems that in your eyes and in one swell foop I've
been upgraded from a Texan ignoramus to a master editor, of sorts...

But, with regard to your critique, I'm surprised you didn't notice
that the correction which I made to the original sentence did, in
fact, produce an alternative sentence which was, with reference to the
subject matter, technically more accurate than the original sentence
yet didn't lead the reader away from the subject matter, stepping
motors. Since there was no denigration in the correction, I fail to
see why you don't consider the criticism constructive, since the
criticism pointed to an error and gave a way to correct it.

I also sent the criticism along to Jones, so if he replies and gives
his permission for me to post his reply here I will and then, perhaps,
I'll suggest that you head for your dictionary and look up 'gracious'.
 
B

Bill Sloman

Jan 1, 1970
0
If you were of the stuff which editors are made of, you'd have recognised
that I wasn't too impressed with your editorial skills.
But, with regard to your critique, I'm surprised you didn't notice
that the correction which I made to the original sentence did, in
fact, produce an alternative sentence which was, with reference to the
subject matter, technically more accurate than the original sentence
yet didn't lead the reader away from the subject matter, stepping
motors.

If you had, in fact, posted a complete sentence, I might have been able to
work this out. All that was obvious from what you posted was that you
preferred "impedance" to "reactance" which is fair enough as trivial
nit-picking goes, but scarcely worth posting.
Since there was no denigration in the correction, I fail to
see why you don't consider the criticism constructive, since the
criticism pointed to an error and gave a way to correct it.

The "error" - such as it is - doesn't impair the usefulness of the web-page,
and thus doesn't justify a public comment.
I also sent the criticism along to Jones, so if he replies and gives
his permission for me to post his reply here I will and then, perhaps,
I'll suggest that you head for your dictionary and look up 'gracious'.

If you'd confined yourself to sending your criticism to Jones, you might
just aspire to be in a position to lecture me about the meaning of the word
"gracious".
 
J

John Fields

Jan 1, 1970
0
If you were of the stuff which editors are made of, you'd have recognised
that I wasn't too impressed with your editorial skills.

---
Be that as it may, Sams Technical Publications seems to to have a
different impression since I recently finished, and was paid for,
editing one of their books. And you? Still sitting at home twiddling
your thumbs?
---
If you had, in fact, posted a complete sentence, I might have been able to
work this out.

---
Since I did, in fact, post a complete sentence, you _should_ have been
able to work it out. Also, if the meaning of the sentence was
unclear, you could easily have gone back to the web page (you posted
the link, remember?) in order for clarification.
---
All that was obvious from what you posted was that you
preferred "impedance" to "reactance" which is fair enough as trivial
nit-picking goes, but scarcely worth posting.

---
So, you don't realize that there's a difference between impedance and
reactance?
---
The "error" - such as it is - doesn't impair the usefulness of the web-page,
and thus doesn't justify a public comment.

---
The usefulness of the web page isn't what's being discussed, a
technical error on that web page is, and since the article is
technical in nature the error should be corrected. You certainly
don't seem to have any aversion to commenting on what you consider to
be errors you find publicly, so your stance on the "impropriety" of my
doing the same smacks of hypocrisy. What a surprise...
---
 
B

Bill Sloman

Jan 1, 1970
0
John Fields said:
---
Be that as it may, Sams Technical Publications seems to to have a
different impression since I recently finished, and was paid for,
editing one of their books. And you? Still sitting at home twiddling
your thumbs?
---

---
Since I did, in fact, post a complete sentence, you _should_ have been
able to work it out. Also, if the meaning of the sentence was
unclear, you could easily have gone back to the web page (you posted
the link, remember?) in order for clarification.
---

On reading this I checked your posting via my providers news server and I
found that you had indeed posted a complete sentence. I'd responded to what
I'd seen on Google Groups, where the last half of the sentence wasn't
displayed. I apologise for blaming you for a fault in Google Groups.

Sure there's a difference, but it isn't an error that misleads the reader.
---
The usefulness of the web page isn't what's being discussed, a
technical error on that web page is, and since the article is
technical in nature the error should be corrected. You certainly
don't seem to have any aversion to commenting on what you consider to
be errors you find publicly, so your stance on the "impropriety" of my
doing the same smacks of hypocrisy. What a surprise...
---

I distinguish between errors that misdirect the reader, and those which only
need to be corrected for reasons of technical pride.
Misleading information has to be corrected - typos and similar errors can be
left to the author to correct, if they can be bothered.
---
There's no need for me to 'aspire' to a position I already hold, and
whether you consider my actions to be ungratious isn't the point. If
you hadn't found it necessary to be offensive when I replied to your
question, no lecture on graciousness would be necessary.

I must say that I regret being offensive to you when I should have been
offensive about Google Groups - a clear case of misdirected efort.
 
K

Karthik Ravikanti

Jan 1, 1970
0
My God,
This thread was supposed be about my teeny-weeny question on stepper
motors.
But now when I return to it, the topic switches over to editing,Google
Groups, and all.
I am really new to newsgroups and forums, seriously I wonder how do you
guys find the time to respond to complete strangers so *illustratively*
on even apparently unrelated topics!

newways....;)

Karthik Ravikanti
http://students.iiit.net/~karthik_ravikanti
 
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