[sdiy] Tonewheel relics

[Roman Sowa]

And making proprietary belt wheels on a lathe is easier than making 
custom tooth gears.

Roman

W dniu 2017-10-24 o 00:48, Sarah Thompson pisze:
> Would belt drives work? They have huge advantages over gears if you need 
> smooth transfer with no cogging or backlash.
> 
> On Mon, Oct 23, 2017 at 4:34 AM, <rburnett at richieburnett.co.uk 
> <mailto:rburnett at richieburnett.co.uk>> wrote:
> 
>         @roman and Richie: thanks! From my limited experience with bldc's I
>         feel they would be costly, especially a 12-way driver system for
>         them.
>         Would they need hall sensor feedback to get the tuning accurate
>         enough?
> 
> 
>     Yes, probably not cheap.  I don't think you'd need hall sensors to
>     detect the field, but you would need to ramp the frequency up at a
>     controlled rate to allow the mechanical bits time to accelerate up
>     to operating speed.
> 
>         The pll sounds nice and classic. I'll look into that. At present I'm
>         not sure if the pick-up  coils of the generator could handle more
>         loading, e.g. As required for closing the loop. But a high impedance
>         buffer would probably be ok.
> 
> 
>     Take the feedback for the PLL from the highest frequency that you
>     can.  The loop filter in the PLL has to filter out the ripple in the
>     compared reference and positional feedback signals.  The higher you
>     can make the reference and feedback signal frequencies, the larger
>     the bandwidth of the loop filter can be, and the quicker the PLL
>     speed controller will settle.  i.e.  Don't use a reference signal
>     that is just one pulse per revolution, as this can mean you end up
>     with a very sluggish control loop!
> 
>     -Richie,
> 
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