1) your existing stock alternator is not working (e.g. broken wire in the winding)
2) you need more DC power for your accessories (e.g. your 1000 watt audio system). The stock 600 alternator is rated at 35 amps.
The existing system is already pretty efficient. The rotor portion of the alternator is integrated into the flywheel and becomes part of the flywheel mass..... that was a clever way to reduce overall weight of the car.
Normally, you have a flywheel which is there strictly for the mass.
In the 600, you have the flywheel doing double-duty ..... to provide the necessary inertial mass and also generating some electrical power as an alternator.
The stock 600 alternator uses a 3 phase winding containing copper wire which feeds into a rectifier containing silicon diodes ...... how much improvement can you do to that system? Copper is a good electrical conductor, what are you going to replace it with ..... silver or gold ??? The silicon diodes in the rectifier are an excellent choice and silicon is still the material of choice in the current auto rectifiers. Maybe you could find a lighter weight diode but that is only going to save you a few ounces on the vehicle weight.
You could place the diodes at the stator so you could have your "1 wire connection". I suspect the remote rectifier was used because Honda was concerned about keeping the diodes cool. Perhaps in the area of the brushes on the rotor some improvements could be made. However, the current configuration seems to go a long time before the brushes need replacement. The stock 600 voltage regulator is an electro-mechanical device which gets the job done but improvements have been made in this area since 1972.
If you decide to add an external alternator, you don't want to remove the alternator's rotor windings found on the flywheel because that is part of the necessary inertial mass that Honda calculated into the design. You could remove the stator winding, brush assembly, and rectifier since they are no longer necessary and adding weight to the vehicle (but not a part of the inertial mass). Adding the external alternator will rob additional HP from the engine than the stock system because (a) the overall vehicle weight is being increased since the alternator has weight and it is no longer part of the flywheel mass and (b) the system of drive belts and pulleys to the alternator adds mechanical losses which were not present before the modification. How much of a difference would I expect to see between the stock alternator and the external alternator if they are both outputting the same current (e.g. 15 amps)? My guess is not much...... the stock system is probably less than 1/10 hp of loss on the engine and I suspect the external system will be only slightly more than the stock loss. The big loss of hp occurs when the alternator has to start supplying some current to all the accessories in the car. To see this, take an alternator, put it on the workbench, and spin the shaft .... see how easily it spins? Now connect a load (e.g. a 12 volt lamp) between the alternator's output terminal and the case. Now try spinning the shaft ..... not so easy now. Guaranteed to make you work up a sweat if you want to see the lamp glow brightly.
happy motoring in your 600,
Dale
> Since
> the stator unit is connected to the crankshaft its technically a load just a > belt driven alternator would be. I believe the goal is remove the outdated > stator assembly and install a higher efficiency modern alternator with a > simple 1 wire connection going directly to the battery.If I remember correctly > Miles said he performed this conversion once and had mixed outcome as the > removal of the stator assembly allowed faster engine acceleration (ability to > rev) but at the cost of engine torque, making hill climbs near impossible.
> With the engine being underpowered, it uses the reciprocating mass of the > stator to produce torque. It will be interesting to see what the outcome will > be. I have a feeling it will move the power band around and increase horse > power but cost torque. I would think it would be a lot like swapping > lightweight flywheels on to engines.