Thread: 2A 2.25 Military polarity.

Originally Posted by JDNSW

<snip>; unlike the latter, alternators cannot be easily used with either polarity.

John

John I do however when I first joined the LROC in Sydney (1972), there were a number of members (Bobslandies being one) who had 24V aircraft starter motor winches.

To generate the 24V they used one regular -ve ground 35Amp externally regulated Bosch alternator and a second 35Amp Bosch with it's diodes reversed in the alternator chassis giving a +ve ground alternator. The 24V winch feed being generated across the two batteries with the vehicle ground as the series connection.

I don't know how this would go today with the solid state internally regulated alternators.

Diana

Originally Posted by Lotz-A-Landies

John I do however when I first joined the LROC in Sydney (1972), there were a number of members (Bobslandies being one) who had 24V aircraft starter motor winches.

To generate the 24V they used one regular -ve ground 35Amp externally regulated Bosch alternator and a second 35Amp Bosch with it's diodes reversed in the alternator chassis giving a +ve ground alternator. The 24V winch feed being generated across the two batteries with the vehicle ground as the series connection.

I don't know how this would go today with the solid state internally regulated alternators.

Diana

It would depend on the alternator. The positive earth alternator would have to have its internal wiring altered so that what was previously the earth became the output and vice versa. Just how easy this would be would depend on the construction of the alternator, but I expect it would be possible, even if it involved the fitting of thin mica insulating washers in some places. In some cases it would be feasible to simply insulate the alternator from the engine, but this obviously would invite accidental shorts!

John