At the present state of the art that is actually very bad practice. The
solenoids are pretty weak sisters reliablity wise. What one should do is
use a little solid state amplifier to isolate the switch and the starter
solenoid. I suspect they don't do it because, while the basic design is
superficial - 2 transistors max. - the hardening of the transistors against
the transients present in this sort of application is too big a nuisance. A
half dozen caps and diodes I would guess and, if you don't get it right they
die pretty quick - so you gotta do it right. Nice place to put a manual by
pass to start the engine if ignition switch or wiring die.
Jim
Most marine applications use a second solenoid to energize the starter
solenoid. The starter solenoid needs a few more amps to activate
it than the
second one does. Most Lehmans I have seen used this set up. I
just finished
a repower using Cummins latest QSM 11s and they used a second solenoid to
energize the starter solenoid. I have even seen it used in the automotive
world.
Rodger Wrona
Rollsdoc
MT49PH
At the present state of the art that is actually very bad practice. The
solenoids are pretty weak sisters reliablity wise. What one should do is
use a little solid state amplifier to isolate the switch and the starter
solenoid. I suspect they don't do it because, while the basic design is
superficial - 2 transistors max. - the hardening of the transistors against
the transients present in this sort of application is too big a nuisance. A
half dozen caps and diodes I would guess and, if you don't get it right they
die pretty quick - so you gotta do it right. Nice place to put a manual by
pass to start the engine if ignition switch or wiring die.
Jim
>
> Most marine applications use a second solenoid to energize the starter
> solenoid. The starter solenoid needs a few more amps to activate
> it than the
> second one does. Most Lehmans I have seen used this set up. I
> just finished
> a repower using Cummins latest QSM 11s and they used a second solenoid to
> energize the starter solenoid. I have even seen it used in the automotive
> world.
> Rodger Wrona
> Rollsdoc
> MT49PH
>
