On 8 Jul 2004 12:06:26 -0700, (John Clonts) wrote:

Nathan Young wrote in message . ..
On Thu, 08 Jul 2004 03:53:23 GMT, "John Clonts"
wrote:

I am now able to reproduce my charging problem.

Engine off, Bat and Alt on:
Bus voltage: 24.8
Supply to Voltage Regulator: 22.6
Voltage Regulator Output to Alt Field: 21.6

I'm thinking maybe I should rig a jumper from Bus to the Voltage regulator
to see if the problem has to do with that 2.2v drop through the "Alt/Reg" 5A
circuit breaker, the Alt side of the master switch, and the Overvoltage
relay.

John, I didn't see your original charging problem, so cannot comment
on that, but will make a few general comments on this post.

21.6 Volts seems like a high field voltage to drive the alternator.
What kind of load was on the system during this measurement? I'm not
certain, but believe wih minimal load, the field voltage on my 14V
system was around 6-7V.

This was with the engine off and no load to speak of. Maybe I will
try monitoring it as I add load, and see what it does.

The documents at www.zeftronics.com suggested that the VR field output
of "0.5-2.0v less than the VR input" was acceptable (22.6 - 21.6 =
1.0v)


The 2.2V drop between the master bus and VR is not good and can lead
to several problems in the electrical system. I would fix this before
doing anything else.

#1. The bus voltage will be high. The VR will crank up the field
voltage until its input 'sees' 24V. Given a constant drop of 2.2V
between bus and VR, the bus will be at 26.2.


Per your logic I think I would be seeing 30.2 instead of nominal 28.0
when the engine is running? I will check that.

Crap. My bad John, 30.2 is correct. I was thinking nominal voltage
of 24, not 28.

Based upon this...

I suspect the 210 has 2 problems.

#1. You probably have a bad alternator. As long as the pulley isn't
slipping, I believe 21V field voltage would be sufficient to drive 28V
output.

#2. You still need to resolve the 2.2V drop between the bus and the
VR input. The aforementioned RC behavior could definitely cause the
pulsating ammeter you've seen. Also another cause for pulsating
ammeter is a faulty field master switch. The contacts heat up,
expand, break contact, cool down, make contact and start the cycle
over again.

-Nathan