RE: [CAD_CAM_EDM_DRO] Torque Units-WAS Re: What makes a motor a s ervo? calculating power

I didn't know I could inspire so much fear-:) If only my kids felt the same
way.....

Ron, I agree, as long as we all know what it means, it's not a problem. But
you can see from Randy's post that he DOESN'T really know what it means-he
says that the torque is written as oz/in, which means you divide it by the
distance to get the force. This may get him where he wants to go, but it is
not the correct way to do it, and can only serve to confuse others.

I do think it is important to know that the force and the moment arm
distance, as well as their units, are multiplied, not divided, to get
torque. That way when you try to use it in other equations, you will get
sensible results.

A common language only works when we all try to obey the (important) rules.

Andy Wander
Verrex Corporation

-----Original Message-----
From: R Rogers [mailto:rogersmach@...]
Sent: Thursday, May 12, 2005 12:58 PM
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: Re: [CAD_CAM_EDM_DRO] Torque Units-WAS Re: What makes a
motor a s ervo? calculating power

LOL...I don't think you'll get him to budge. We had this very same debate a
year ago. The important thing is that one realizes what oz-in represents.
Imagine a 2 inch diameter wheel having a radius of 1" and 1 ounce of weight
suspended from the circumference on a horizontal plane from the axis. That
is 1 oz-in of rotational torque. Suspend 2 ounces of weight and that is 2
oz-in etc. For those who don't know.

Without risking the wrath of Andy, I'll forgo saying something sensible like
"As long as we understand what it means" :-). All servo manufacturers that
I've seen do display it as lb-in with a dash. It's not an equation rather a
specification of torque.
Ron

m0nkey0ne <m0nkey0ne@...> wrote:
Andy,
Not sure what picayune is, hope you can find a doctor ....
If they are multiplied wouldn't that be OZxIn or INxOZ or OX*IN or
IN*OZ? You actually are writing OZ minus IN. (OZ-IN) I read all
these posts because I dont know much, however I did know exactly what
they mean by OZ/IN. If you had a 400 oz/in situation and wanted to
determine what that is per 2 inches, you would in fact divide by 2.
400 oz at 1 inch is equivilent to 200 oz at 2 inches.

Back atcha
Randy


--- In CAD_CAM_EDM_DRO@yahoogroups.com, Andy Wander
wrote:

> At the risk of being labeled as "picayune", I will repeat:
>
> It is NOT oz/in, it is OZ-IN or IN-OZ>
>
> They are MULTIPLIED, not DIVIDED!
>
> Had to get that off of my chest........
>
> Andy Wander
> Verrex Corporation
>
> -----Original Message-----
> From: Alan Marconett [mailto:KM6VV@a...]
> Sent: Wednesday, May 11, 2005 2:48 PM
> To: CAD_CAM_EDM_DRO@yahoogroups.com
> Subject: RE: [CAD_CAM_EDM_DRO] Re: What makes a motor a servo?
> calculating power
>
> Thanks Mariss,
>
> I didn't find it, but the stepper is probably 550 oz/in?
>
> Interesting, but not surprising that a servo is about 2X more

powerful for

> its size/weight. I'd noticed that steppers seem to be bigger for

the same

> power (building robots). More wattage in a smaller/lighter package
> because...?
>
> If I take half of 170 oz/in for the servo, then about 85 oz/in servo
> (possibly less) would be similar to a 550 oz/in stepper in machines

they

> could drive (gearing needed for servo).
>
> Can I assume that the "300 Watts" printed on my servos is

continuous? I

> don't have them in front of me, and I didn't find them on a Google

search.

> Target machine is an RF-31 mill. The 1000 (or was it 2000) line

encoders on

> them are over kill, I'll have to reduce that. Or does one of your

new servo

> drivers do that for me?
>
> Thanks for the comparison.

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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........
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