Barry,
The voltage regulator monitors the output voltage of the alt and attempts to keep it at a preset voltage. It does this by adjusting the voltage across the rotor coils. The difference with high amp regs is they are just able to give a higher voltage across the rotor coil. The low amp ones just reach a certain voltage and then flat line. The higher the primary voltage ( rotor coil) the higher the output of the alt.

__________________
Grumpy Old Diesel Owners Club group

I no longer question authority, I annoy authority. More effect, less effort....

1967 230-6 auto parts car. rust bucket.
1980 300D now parts car 800k miles
1984 300D 500k miles
1987 250td 160k miles English import
2001 jeep turbo diesel 130k miles
1998 jeep tdi ~ followed me home. Needs a turbo.
1968 Ford F750 truck. 6-354 diesel conversion.
Other toys ~J.D.,Cat & GM ~ mainly earth moving