Fwd: eddy current brake

[Mark Eidson]

It's my understanding that the dynamic range, 20:1, is difficult for a
simple PLL.  I think the confuser would have to adjust the feedback based on
the current RPM range to keep it locked.  me

At 04:37 PM 12/11/96 -0600, you wrote:
>>Hi there,
>>
>>think the Eddy.effect is exlained enough, so lets go back where the idea came 
>>from (can't remember who it was, but what it was):
>>reducing/removing backlash of the ignition rotor!
>
>Help me understand ..... (I've listened to related discussions re
>ignition control for a while)
>
>I hear the 4 pointed star crank pickup isn't good enough to use
>a PLL to develop nth degree resolution.
>
>Same for the distributor pickup.
>
>So, seems everyone wants to use either the flywheel teeth or a gear
>attached to the cam (maybe even the cam gear??).  Is that right?
>
>I know n-nothing -- at least not practically.  Seems to me the crank
>pickup with PLL would work.  Any variation due to speed of the tooth
>approaching the pickup giving faster rise time ergo changing reference
>could be compensated for either in an analog circuit or in a confuser
>using either a lookup table or (probably) a simple trig function.
>I don't think the crank's gonna have much backlash :-)
>
>As far as backlash, why wouldn't an averaging function take care of
>that?  After all, how fast can an engine change speed? and the delta-speed
>seems to me to be the most egregious factor (pun) in successfully
>implementing some kind of smoothing circuit (maybe even an f-v convertor ??)
>
>Now, there's an idea I absolutely haven't explored .... Do an f-v conversion
>and filter it ??? would that work?
>
>
>Tom Cloud <cloud at peaches.ph.utexas.edu>
>
>
>
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