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oil pan 4 12-09-2015 10:52 PM

Schottky diode alternator
For this project I will be taking my old alternator and rebuilding the 3 phase bridge rectifier and trio voltage regulator rectifier with ultra high efficiency solar panel Schottky diodes.

But this isn't an alternator for any old vehicle electrical system.
This vehicle electrical system has a Lithium Iron Phosphate battery, 1000w pure sine inverter, 12v air compressor, lots of LED lights, electric coolant pump, electric fuel pump, solar panels, electric power steering and more.
So it has to be very hard working and efficient.
Common vehicle alternators are 1950s tech. Nothing it powers was even thought of as having 12v automotive application in the 1950s.

The alternator I am using is our of my suburban. I changed it out a few years ago because the alt wasn't really charging the battery. I think the voltage regulator was going bad. I just replaced it with a spare and put it on a shelf and didn't think about it for 8 years.

I am going to take it from this:
Typical GM alternator.

And turn it into this:
External rectifiers
Voltage adjustment
Exciter kill switch
Convert from 3 wire wye to 4 wire wye
Voltage sense going all the way to the relocated battery.

Why? Just to see what happens.

The original ideal to have an vehicle alternator use these ultra low forward voltage drop diodes came from serialk11r here:

me and my metro 12-09-2015 11:16 PM

Looks like a great project. Back about 20 years ago my city had an ambulance with a 200 amp Leese-Neville alternator. Only the rotor and the stator were in the case, all the diodes were mounted up front with big heat sinks. That was the only one we never had any problems with. Keep us posted.

DragBean 12-10-2015 02:35 AM

Turning Alternator into a motor to drive power steering
Nice car.
Are all the electric sub systems stock or aftermarket?

I'm doing something similar. Basically I'm unbelting the alternator and water pump from the engine. Then I'm going to drive the water pump with the alternator.

At this point i was just going to keep the field current constant, but I'm wondering if i can manipulate the already existing field voltage regulator on an alternator to improve the efficiency of the alternator motor?

Basically I'm going to have a potentiometer control the speef of the alternator.. Wonder if i can feed that or into to the field voltage to reduce it's voltage as rpms go up?

oil pan 4 12-10-2015 11:28 AM

I think it would be a lot easier to get a DC motor powered coolant pump and just run it off a PWM controller. I am using a $5 ebay PWM controller off ebay to power my big 7amp, 55gpm coolant pump.

oil pan 4 12-10-2015 03:01 PM

1 Attachment(s)
This is what the old GM alternators typically look like.

oil pan 4 12-10-2015 03:30 PM

1 Attachment(s)
Here is the alt with the diode trio and bridge rectifier removed. Alternator coils installed, new voltage regulator installed, old brushes reused, 4 wire conversion done, purple wire brings in power to the voltage rectifier from the remote schottky trio, gland seal strain relief installed.
I used 10 gauge wire for the lines and neutral because I bought 4 more partial 500 foot rolls of black and white 10 gauge for pennies on the dollar so for the foreseeable future I will be using 10 gauge wire as opposed to 12 gauge.
The motor brushes are being held back with a pin.

The purple wire will allow me to cut power to the exciter.

All the crimp connections are soldered because that's how it came from the factory and it seems to have worked well.

oil pan 4 12-19-2015 12:18 AM

The master plan is to install a 2000w samlex pure sine and 1000w Xantrex pure sine inverter into my suburban for remote build projects. This 2000w continuous, 4000watt surge inverter should be able power my mig welder, skill saw, pretty much everything but my plasma cutter and largest air compressors.
Finally got the deal I wanted on that samlex pure sine inverter.
Main problem was the 1000w would not power a skill saw well and had no where near the power to run the welder or 7 inch grinder.

Daox 09-29-2016 03:58 PM

How is this working out?

What was the reason you went to the 4 wye design vs 3 wye?

What diodes did you use for your setup?

I may be modifying an alternator soonish...

oil pan 4 09-30-2016 09:55 AM

According to my lineman's handbook going from a 3 wire wye to 4 wire wye system will allow a system to move something like 74% more power just by adding a neutral wire.

California98Civic 09-30-2016 10:26 AM

Way. Over. My. Head. ... subscribed.

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