turbocharger repair - ripped off!

[Bill Shaw]

That is the old analog Stewart Warner balancer.  It was tough to trim all the
op-amps in those units for calibration.  I worked on the development of
their new (7 or 8 years ago) digital balancer.  Same old leaf spring sensors
and some fancy math in an 80C196 giving a digital readout of the imbalance.

Digitize the imbalance over time,  fft it,  calculate the difference in the phase
angles between the two sensors,  and you're almost there.


Bill


Dave Williams wrote:

>
>  The common type uses two leaf springs.  One end is fixed to the frame,
> the other has a block with a pair of ball bearings.  From that end a rod
> runs down to a voice coil arrangement to measure displacement.  The
> shaft spins up to its critical speed, displacement is shown on an analog
> meter, and the strobe is triggered, phase-shifted to show at maximum
> displacement.  I spent several days poring over the manuals for my big
> Stewart Warner machine; I couldn't believe how simple it was, and kept
> looking for the gotchas...

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