Re: [CAD_CAM_EDM_DRO] Servo drivers ?

R Rogers wrote:

>Stephen Wille Padnos <spadnos@...> wrote:
>[snip]
>
>Max Current: This will determine the maximum torque that the motor can
>deliver. Servos are rated with a torque constant (Kt), which tells the
>amount of torque per amp of current. If you have a motor that can take
>10A continuous, then any drive that can supply 10A continuously
>(regardless of the operating voltage) will be able to get full torque
>from the motor. The total voltage across a servo is (neglecting losses)
>the back EMF, and the IR drop across the winding resistance. So, the
>winding resistance will cause a reduction in maximum speed proportional
>to the amount of torque you're getting from the motor. For my motors,
>the Geckos will happily pump the max. continuous current into them, and
>I have roughly double that in reserve, for high acceleration
>situations. Again, the high-current Rutexes could drive the motor at
>its full peak current, giving a total of 112 in-Lb of torque(!), whereas
>the Geckos will be limited to only 60 or so (poor me :) ).
>
>////If I understand what you are saying correctly, operating a servo at less voltage however supplying the required amperage will result in lower top speed AND less torque is contrary to what I've learned. Marriss stated that Limiting a servos voltage and still supplying the required amperage will not result in lower torque output. Only a lesser top speed will be encountered. If I understood him correctly :-) ////
>
>[snip]
>

Hmmm - I don't think I said there would be less torque...

What I was trying to say is that the torque output also decreases the
maximum speed available at that moment. The Gecko limitation is that it
can't provide the peak current for my servo (37A), so in a sense, I
don't have a driver that can supply full current, and therefore also not
full torque. It's still capable of double the continuous torque, however.

- Steve