I am the one that posted the information about converting the ammeter to
use a later 280Z unit in a 67.5.
One thing that everyone has overlooked in replying to this thread is the
connections to the ammeter. That is, the two 1/4" quick disconnects that
connect the wires to the back of the ammeter. When I bought my 67.5 it had
a 63 Amp alternator installed. The connections on the ammeter showed signs
of being overheated. The connectors had lost all temper and the insulation
was melted back over 1" on each lead! This overheating could have been
caused by just being old, but my previous 67.5 didn't have this problem.
The upgraded ammeter has studs on it, rather than the quick discnnects,
which make much more reliable connections.
The heat generated in these connections was caused by the voltage drop
across the connections. Voltage drop is related to the current flowing
through the connection. The voltage drop is calculated by the equation
E=I/R, where E is the voltage, expressed in volts, I is the current,
expressed in amps, and R is the resistance expressed in ohms.
Power, or heat, is the sum of volts and amps, so as the current doubles,
with the voltage and resistance staying the same, the power disipated in
the connection will also double.
>From this you can see that any poor connections can be tolerable at low
currents, but can cause real problems at higher currents.
I am currently running a 63A alternator and 60A alternator. The wiring is
the stock harness. I have not seen any sign of the wiring overheating,
just the connections. I am in the process of building a replacement wiring
harness and will upgrade the alternator wiring at that time.
If anyone wants information on how to replace the 67.5 ammeter with a
higher current one please let me know.
Peace,
Pat
- Support Habitat for Humanity, A "hand up", not a "hand out" -
Pat Horne, Network Manager, Shop Supervisor, Future planner
CS Dept, University of Texas, Austin, Tx. 78712 USA
voice (512)471-9730, fax (512)471-8885, horne@cs.utexas.edu
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