Re[2]: ATM A Cage as Secondary Holder

[Dwight Elvey <elvey@hal.com>]

Al Kelly <akelly@ghg.net> wrote:
> 
> At 10:05 PM 7/21/98 +0200, you wrote:
> >
> >I have to agree on this issue about stepper vibration being
> >a bigger problem. In my work, I need very smoothe motion 
> >for microinjection......<snip>...
> 
> I believe your requirements are much more demanding than even smooth
> arc-second astronomical tracking accuracy, but it is certainly true that
> even large, heavy telescopes may suffer from stepper vibration amplification
> if stepper mounting is not cushioned or otherwise properly damped. 

Hi
 I not sure if I mentioned this before but here it is again.
The vibration from steppers can be significantly reduced
by reducing the current to the coils. With gear ratios of
1000:1 or more the load of the telescope has little effect
on the stepper. One can use one of many methods to reduce
the current, including a variable resistor, of sufficient
current and wattage rating, inline with the coils power lead.
Adjust the current so that there is just enough to keep
the stepper moving and a little bit move to give a safety
window.
Dwight