🚀 go-pugleaf

In article <100500010@datacube> dje@datacube.UUCP writes:

->Does anyone have experience with amplifiers  driving inductive loads?
->I am building a small syncho system  that needs  to run  off +12V DC.
->It  currently  uses  a  400  Hz  sine  wave  oscillator (Wien Bridge)
->followed by an automotive type amplifier  chip (LM383)  followed by a
->1:4 step up transformer to get enough voltage to drive the synchros.

->Here's the problem.  A synchros presents an  inductive load.   When a
->class  A  or  AB amplifier  drives an  inductive load  the current is
->maximum  when load  voltage is  lowest (zero).   This  causes lots of
->power dissipation in the amplifier.  This kills the batteries quickly
->and gets the amp *hot*.  The synchros run cool as cukes.

Put an capacitor parallel with your synchro. You can compensate your
inductieve load part and run with a very low dissipation in your
amplifier. :-) Drift of the resonant circuit does not change the
fase more then without capacitor. For the best result you must connect
the capacitor to the secundaire side of your step up transformer.

->How about a capacitor  in series  to create  a resonant  circuit?  It
->would have to be fairly large and stable.  Any drift in the  L, C, or
->F would throw off resonance though.

Don't make a series resonant circuit: The voltage and the phase
are very difficult to controll.

henkp peek, henkp@nihefk  ..!seismo!mcvax!nikhefk!henkp.UUCP