Can I test the amps from my alternator like this?

[jinman]

Can you scan to something besides a PDF file? I'd try a .jpg or .png. Even if you scan to a .tif or .bmp file, they could be converted to a .jpg. The problem with your pdf is that the resolution is too low. It almost looks like the image was scanned to be postage stamp size and then blown up to fill a whole page. It's almost as if a thumbnail image was blown up to a full page. To maintain resolution, you can always scale down, but rarely scale up.

 

[Treemonkey1000]

I was thinking a sense resister. We use them all the time at work, to measure milliamps on computer memory. But, that's it, milliamps. To get a high power one is not hard, it is just $$$.

Use a couple of 100 watt light bulbs in series. Cheap shunt resistor

 

[rsmith02184]

i found a friend who is going to lend me his clamp on ammeter (or whatever it is called).

what should i test? the amps coming from the alternator?

 

[Transit]

Use a couple of 100 watt light bulbs in series. Cheap shunt resistor

Good try, but NO cigar. The whole idea behind using a shunt resistor is that it has a fixed, constant and stable value. The resistance of any light bulb will change with temperature making it useless as current measuring devices.
To build a load bank to test a power supply, thats ok.

 

[Transit]

i found a friend who is going to lend me his clamp on ammeter (or whatever it is called).

what should i test? the amps coming from the alternator?

For starters, you mention that you have a number of wires that get hot. Thats where I would look first.
I would also measure the output current of the alternator and compare it to the current into the battery.
BTW, record the values.

 

[rsmith02184]

here is another attempt at posting the schematic....keep your fingers crossed.

 

[Soundguy]

no need to school me on an alt.. I'm quite familiar with electrical generation principles.

My point was that if it is a permanent field dynamo.. it is going to be playing by different rules than a field current controlled vreg..

soundguy

True, but I'm thinking "real" alternator as we have in road vehicles.
We used alternators with built in diode/regulator packs in underground vehicles many years back.
One main problem was dust getting into the main battery isolators, one good jar over a rough patch of road, and the dust became an insulator under the isolator contacts. One dead alternator and four burnt out light bulbs.
I came up with a solution tested it and saved my employer a lot of money over the years with less down time on the scooptrams.
Just part of an electricians job, to save himself work!!

Essentially what happens when you disconnect an alternator from the battery, is the reference voltage is lost, the regulator is screwed!! It doesn't know how to regulate anymore in laymans terms. So the output voltage goes up to many hundreds of volts, smoking the diode pack and regulator.
Yes even a low battery voltage presents some sort of reference!! Albiet it below 12 when a battery is discharged, but it's better than nothing!!!!
Forget linear power supplies where the reference is a zener diode!!! The battery replaces the zener in a charging circuit.

When you have a bad back and the batteries weigh in at around 90 plus pounds, you soon start to THINK!!!

 

[Soundguy]

If all else fails, replace the alternator with a 50 amp, one wire unit with a built-in regulator. Not stock, kind of crude but it will get the job done.

EWWWE...

I'd go with a common delco 10SI 37a job, 3 wire... about 45$ at napa ( 4110 ).. no need for al that excess power generation capability.. or the extra money for that high rpm/self excite vreg module, when you can get a 3 wire to charge at 400 rpm...

soundguy

 

[jinman]

here is another attempt at posting the schematic....keep your fingers crossed.

Thanks! I'm working on some color highlighted illustrations. It will take me awhile, but I'm hoping my illustrations will explain things enough that you'll be able to get some quality troubleshooting. In the meantime, if anyone else wants to explain the circuit, go ahead. I welcome your help.

 

[Transit]

First I see a FUSEABLE LINK in the circuit between the battery, alternator and key switch to limit current. What is its current value? The two lines from the VG to the Alt. I an not sure what they do without knowing what is in the black box. I can assume that the VG is acting like a voltage regulator holding the output constant with an oversupply of voltage and current from the alt, or i may assume that the Alt case is grounded [not shown] and one of the two lines is the rotor winding feed and the other is the AC output current from the alt to VG rectifier. Need to know how the alt is wired and more about the VG innards.