[TowerTalk] SteppIR

[W0MU Mike Fatchett]

The driver chips are a weak link.  The older boxes they were surface 
mounted.  The new controller they are in sockets.  The driver chips are 
cheap.  I have a tube of them on hand, just in case.

Mike W0MU

On 3/1/2015 6:42 AM, Jim Lux wrote:
> On 2/28/15 8:33 PM, Richard (Rick) Karlquist wrote:
>>
>>
>> On 2/28/2015 5:46 PM, Jim Thomson wrote:
>>
>>> ##  whats wrong with installing a shaft encoder on the plane jane
>>> DC..or AC
>>> motor?    That’s what K7NV  does on his prop pitch conversions..and 
>>> works
>>> slick..simple concept, easy mod to any motor.  Its all fed to the
>>> Green Heron
>>> box...which is a modified RT-21.
>>>
>>> Jim  VE7RF
>>
>> What is wrong with it is unnecessary complexity.
>> The SteppIR stepper motor scheme works perfectly, with
>> occasional recalibration.  Don't fix it if it ain't
>> broke.  The SteppIR antennas have had their share
>> of reliability problems, but the stepper motor isn't
>> one of them.  They just work, even if other stuff
>> in the antenna may not always work.
>
>
> This is why steppers (or their close cousins brushless DC motors) 
> dominate in industrial applications, particular where you need slow 
> and stop speeds.  For "continuous run at variable speed", variable 
> frequency drive induction motors are popular.
>
>
>
>
>  If there is
>> a weak point, it is the controller that operates
>> the stepper motor.
>
> I would think that the stepper drivers are vulnerable. Particularly 
> with long runs: a lot of inductance, and very sensitive to lightning 
> and transients.  The SteppIR remote driver box probably fixes this.. 
> put the driver close to the antenna, and use RS485 as the comm link.
>
> A previous TT post (in 2007) said that they use a L6219 chip as the 
> driver.
>
>
>
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