Fred O. wrote:

Here I go again. Has anyone ever considered using the alternator as a brushless motor
to start an engine ? It would seem that a 70 amp. alternator could get you into the
1hp. range. It would require some high current switching with some pulley mods. but I
have been thinking about it for a single rotor engine.

Fred O.

Generator and DC motors are more or less the same but I don't think
an alternator will work as a motor when confronted with DC.

Paul Lamar

An alternator will not run as a motor. As stated it is not a generator.
In the alternator the alternating current produced is rectified by the
diodes before getting out at the terminal as a direct current voltage.
It is actually a 3 phases alternator, that is why 6 diodes are used.
The process cannot be reversed by applying a voltage at the terminal.
The fact is that the battery 12 volts is always applied to that terminal
and nothing happens because of the diodes that blocks a reverse current
flow.

Rino

I should have provided more detail in my "high current switching". Forget about the diode
rectifiers and DC for a moment. A 3 phase permanent magnet AC motor and a 3 phase permanent
magnet alternator are identical animals. The motor drives from a 3 phase AC power source,
the alternator generates 3 phase AC power when driven. With the addition of an angle sensor
for commutation information and some high current switching transistors one can drive a 3
phase permanent magnet alternator as a 3 phase motor from a DC source very nicely. Right
Butch ? And all that can be done, including the switching to convert from alternator to
starter, at less weight than a starter and solenoid. I have not considered reliability as
yet, as I said I was just thinking about it.

Hand propping would be much simpler but I only have one hand.

Fred O.

The AirCraft Rotary Engine NewsLetter.              Powered by Linux.
ACRE NL web site. Copyright 1998-2002 All world wide rights reserved.
http://home.earthlink.net/~rotaryeng/            http://www.linux.org