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Old 11th Feb 2013, 15:12
  #628 (permalink)  
syseng68k
 
Join Date: Jun 2009
Location: Oxford, England
Posts: 297
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saptzae, #623
Resonant currents on the bus would be an interesting scenario. I experienced
load dependent oscillation during charger development.
Had a the same problem with a one off rotary inverter speed and voltage
control for a lab power supply. With any mechanical devoce in the loop, it
can be quite difficult to model / analyse from basic servo theory and there's usually
some hand tweaking of the lead / lag networks to get it right, especially
if your maths is a bit rusty, like mine. My excuse was / is that too many years
of software have partially dissolved the higher facilities, but ymmv .

Resonant currents might be a possibility, but resonant with what ?. The apu
starter conditions might be the worst case, but the pwm driver for the
starter motor must be well filtered to prevent interference with radio and
other sensitive avionics. Any transient effects will be in the 10's or
hundreds of milliseconds range, not microseconds and you can't have those
effects without considerable inductance in the line. Transmission line theory
applies and all that...
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