fusible link questions

Clarence L.Snyder clare.snyder.on.ca at ibm.net
Sat Feb 6 04:40:34 GMT 1999


Jim Davies wrote:
> 
> On Thu, 4 Feb 1999 AL8001 at aol.com wrote:
> 
> >
> > A alternator is current limited by the size of the stator windings and , to a
> > lesser extent, the size of the rotor ( field ) windings.
> >
> And by the max amperage to the rotor.
The only difference between a 55 and 60 amp alternator in most cases is
the amount of copper in the rotor. The "upgrade " kits that were
available for both Delcotron and Chryco alternators a few years back
were just heavier rotors. The stators and diodes, as well as the
regulators, remained the same.
Alternator power output is determined entirely by field current up to
the point where the stator windings overheat or the diodes let go. This
power would cause voltage to go sky high if not controlled either by
load (ohm's law) or a voltage sensing regulator. This regulator can
control output by varying the field current or by turning it off and on.
The cruder systems work by providing full, half, or no feild current,
switching between them. The more sophisticated use a PWM type system,
varying either the frequency or pulse width to adjust duty cycle.
A very few alternator systems used current regulators like a DC
generator used. Among them was the Leece Neville of the seventies. Some
GM and Chryco units used 2 unit regulators, but the second unit in their
case was a field relay.



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