Rotax Alternator

[jrevens]

This is an excellent study/article on the Rotax alternator (dynamo). It was translated from French to English. I found it very interesting. It confirms that the output current is limited and associated wiring need only to be protected and able to carry 20 A maximum.


http://contrails.free.fr/elec_alt_rotax_en.php

[Delta Whisky]

Thanks John - a great find. I wondered how long it would put out the 20-21 A - now we know.

[bbs428]

Excellent find John. Thanks for this importanty info!

[henrysamson]

Very interesting. Thanks john!

I found the amps vs rpm graph especially interesting. It indicates that almost the full output of the alternator is available at 1000 rpm. I don't see that on my airplane when I have everything powered up I see a voltage of just over 12.5 volts when idling at about 1500-2000 rpm while taxiing and it fluctuates as the (old fashion xenon) strobes fire. When I check the voltage at run up with 4000 rpm I am at about 14 volts with almost no fluctuation.