Re: I want to upgrade to servors

Luis,

What you are calling "locking up" is usually called "stalling". This
happens when the rotor in the motor gets out of sync with the
incoming pulse train. There are a number of reasons that this can
happen...

Are your motors the "pancake" style with 15 degrees per step? These
look like they are made out of stamped sheetmetal, and are bigger
around (diameter) than they are long/tall?

It has been awhile since I looked at Eastern Air's catalog, but they
used to "specialise" in this type motor. This pancake type is not
generally a good match for a Sherline type setup...

Alternatively, the "hybrid" type motors have a machined face and
generally look to be higher quality construction compared to the
pancake type. They usually have a die cast and machined faceplate,
with a 1.500 inch "locating" boss inside the 4 bolt holes(23 size
motor).

Anyway, there are two possible problems if you have these pancake
motors. One is that the rotor moves a large amount each step, which
takes time. This will tend to make these motors slower overall, IME.
Second is the concept of "matching" the motor to the load. We often
get away with less than ideal choices here, but the sherline setup
can lead to problems.
The leadscrew of a sherline has very little mass, and the 15 degree
motor will have more "ringing"(overshoot and settling to the
magnetically correct position) than a 1.8 degree motor, since the
rotor is moving farther with each step. Add these two factors
together, and you WILL have the type of problems you are experiencing.

Now while I have assumed that you do have the pancake motors, the
problem can also be seen with the hybrid type motors, when used with
a sherline. If you have a double shaft motor, try "gripping" it
lightly to add some "drag" (damping) to its movement. If this
improves your situation, you can add friction to the system a few
ways. Tighten up the backlash nut adjustment. Add grease to the
leadscrew liberally. Adjust the plastic gibs on the axes for
a "tighter" fit. REDUCE the current to the motor (you may be "over-
driving your setup. Are these 6 wire motors? Are you using the "full"
coil? If so, your amperage is set too high. Try switching the motor
connections to 1/2 coil).

Finally, there are devices sold for steppers to "damp" the output.
One type is called a Lanchester dampener. These have a metal disk
spinning inside of a fluid filled plastic housing.

If any of my assumptions are correct, you will have more problems
when the motor is alternating direction, than if it is driving one
direction only.

Lastly, what is your power supply voltage and amperage?

Hope this helps.

Ballendo


--- In CAD_CAM_EDM_DRO@y..., "luisguillermo98" <luisguillermo98@y...>
wrote:

> I have camtronic controller and its deliver 2amp which is the same
> current as the motor.. so I do not understand why they run too

slow..

> if you try to run them faster the axis of the stepper will not

move,

> I think that is what people called "LOCKING UP"..
>
>