Atomic 4 -- generator conversion

[edwardc]

...
By output side, I am guessing you mean the output of the transmission where it hooks up to the propeller shaft? I considered that as well. It seems to have two potential drawbacks

1. it requires the transmission to be engaged -- which is more moving parts to break. Since the engine and transmission share an oil system, I do not think it is viable to remove the transmission?

2. I believe the transmission is reducing the RPM, and for the alternator we want to be increasing the RPM?
...

You'll be happy to know that both of these suppositions are incorrect. The A4 does not have a full-flegded transmission. It is more properly called a reversing gear. In reverse, a planetary gear system is engaged, and does provide a small reduction (somewhere around 1.28:1). But in forward, it is a simple friction clutch system that locks the output shaft to the crankshaft. 1:1 transfer and no moving parts.

[Dave Neptune]

Rethinking

Lord, after some consideration and conversations I don't think you will achieve your charging specs with the A-4 and an "off axis" drive. The reliability due to the strength of the set up is just to suspect.

The A-4 has the power but it needs to be transferred axially and then you seriously lack RPM's to achieve an efficient alt speed. About the only reliable way I can see harnessing the power from an A-4 is mounting a planetary drive between the engine and alt. That way the loads can be absorbed by the mounting pads and not all of the stuff hooked together.

Another possibility that may just help with space considerations is a hydraulic drive. They are quite sturdy and operate quite efficiently.

Both of these types of drives could readily be mounted to either end of the engine.

Dave Neptune

[LordGothington]

Lord, after some consideration and conversations I don't think you will achieve your charging specs with the A-4 and an "off axis" drive. The reliability due to the strength of the set up is just to suspect.

Agreed.

The A-4 has the power but it needs to be transferred axially and then you seriously lack RPM's to achieve an efficient alt speed.

So, perhaps the problem is trying to use an alternator that is designed for use with an engine. What is needed is an alternator that has peak performance in the 700-2000RPM range.

I'm thinking I need to look at alternators designed to be used with lower RPM applications such as wind power. Something like this,

http://www.windbluepower.com/Permanent_Magnet_Alternator_Wind_Blue_Motor_Wind_p/dc-512.htm

A direct drive system would be nice to minimize parasitic losses. But if I need to be able to disconnect the load, then maybe a lockup torque converter could be used?

[joe_db]

Agreed.



So, perhaps the problem is trying to use an alternator that is designed for use with an engine. What is needed is an alternator that has peak performance in the 700-2000RPM range.

I'm thinking I need to look at alternators designed to be used with lower RPM applications such as wind power. Something like this,

http://www.windbluepower.com/Permanent_Magnet_Alternator_Wind_Blue_Motor_Wind_p/dc-512.htm

A direct drive system would be nice to minimize parasitic losses. But if I need to be able to disconnect the load, then maybe a lockup torque converter could be used?

You are going to end up spending 2 times the money for something half as good as a generator designed for the purpose.
That said, the best high output DC system I know of was someone using an alternator from this company - http://www.electrodynealternators.com/e-series - directly driven off their crankshaft with an extension shaft. No way would most marine engines - and especially the A4 - take the side loads these beasts would have if they were belt driven. IIRC, the boat was getting either 200 or 400 amps at 24 volts. This company has 12, 24, 32, and 48 volt versions.