Re: [CAD_CAM_EDM_DRO] Frozen stepper motor shaft

Hi Andy,

I agree that it's not oz divided by inches, but it's not oz MINUS inches
either! I'll probably be OK when it comes to the equations. Each to
his/her own! ;>)

The RUST on the shaft/end bells would surely be an indication of a
serious problem! The shafts I've seen on steppers seem to be of a
pretty good steel, I've seldom (if ever?) seen any rust there. Bent
shaft, dented end bells (different name?) as others have mentioned,
would also be serious. But I just took it that they were new/used, and
might actually be OK (hope so!).

Alan KM6VV
Déjà Vu!


Andy Wander wrote:

> Alan:
>
> Yes, I have brought it up before. Some will say I am too picky(I guess
> you are one of them) but it is NOT a division, it is a multiplication,
> that becomes the "unit". If you look into WHY we use "ounce inches" or
> similar terms for torque, you will quickly understand why(1 oz-in of
> torque equates to a 1 ounce force at an inch from the center of
> rotation, but to only 1/2 ounce of force at 2 inches from the center of
> rotation-do the math-you MULTIPLY the ounce by the inches).
>
> If you ever start trying to use these units in a mathematical
> formula(which is not that far out a proposition, considering we are
> attempting to design and build machines that use torque) you will get
> hopelessly confused, as the units won't "cancel" properly.
>
> The worst part is, that the folks who KNOW it is "ounce-inches", and not
> "ounces per inch", and can shrug off the improper use, won't get caught,
> because they KNOW how to use the formulas and calculations. But those
> who DON'T know the proper terminology are the ones who most likely won't
> be able to make sense out of it.
>
> That's why I think it is important, and will keep bringing it up, as
> long as I think it is important.
>
> Back to the subject at hand, I think your advice to do an ohmmeter check
> on the windings was good, as was that of the other poster who
> recommended making sure none of the leads were touching when trying to
> turn the motors. Until Mike gets back to us on what else he has tried, I
> don't think we can go much further in solving his problem, unless it
> would be to recommend that he checks the shafts where theey exit the
> bearings and motor case for any evidence of corrosion. If they are
> rusted or pitted to the point where that is what is causing sticking,
> theen a good penetrating oil might do the truick.
>
> Andy Wander
> Verrex Corporation
>
> P.S. By the way, I am sure that you know that just because a Google
> search turns up a bunch of mistakes, that doesn't make them suddenly
> become correct.
>