lonnwood wrote:

During the last 2 ground test runs my voltage has been
creeping lower. It started out at 14.2 volts but now it is
around 13.5.  It is from an 87 RX7.
What are the failure modes on these?
Do I just need to change the internal regulator or is there
any testing I can do first?
Lonnie

That certainly sounds like it is at the lower limit.
Is it a built in voltage regulator. Assuming the belt is not
slipping. Got a picture of your alternator mounting scheme Lonnie?

Try changing the battery. Can you rig up an amp meter?

Paul Lamar

The belts are good and tight. It is the stock alternator mounting. Yes it is
an internal alternator.

Darn! I knew that! Sorry.  

 I am running 2
batteries, same voltage on either battery. I will rig up
an ammeter tomorrow.  Here is a picture before dual belts and before
modified engine mounts.
Lonnie

Two batteries? That might have something to do with it.
Two low batteries have half the resistance calling on the alternator
to put out twice the charging current. That may damage the alternator. 

Also where are you measuring the voltage? At the output of
the alternator or at the battery terminals? If the wire is
too small for the charging current there will be a small voltage
drop from the alternator end of the wire to the battery if
the alternator is actually charging the batteries.


Paul Lamar
 
The AirCraft Rotary Engine NewsLetter.  Powered by Linux.
ACRE NL web site. http://home.earthlink.net/~rotaryeng/            
Copyright 1998-2002 All world wide rights reserved.