Quote:
Originally Posted by Capt Kirk
It seems to me that the cutout is designed to interrupt the generator when battery voltage is at whatever the voltage setting of the cutout is...correct?
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Nope - the Cutout Couldn't care less about Battery voltage, or electrical system load. It simply Disconnects the generator completely when the generator OUTPUT voltage falls below the battery voltage, and reconnects the generator when the generator output voltage rises ABOVE about 6.2 volts, or so.
The Model "A" generator is "Third brush regulated" to deliver a "CONSTANT AMPERAGE" to the Electrical system of the car Regardless of what the battery voltage, or the generator speed happens to be. It does this because of the "Bending of the magnetic lines" is directly proportional to the rotational speed of the generator at the point where the field excitation is picked off by the "third brush".
When the generator speeds up, the Third brush delivers LESS power to the FIELD COILS. This automatically reduces the Field coil excitation, and keeps the AMPERAGE (not the voltage) delivered to the electrical system relatively constant. The Model "A" generator is only capable of about 10 amps constantly supplied, and will overheat and "throw solder" out of the commutator if you stress it higher.
A "Voltage regulator" is an entirely different breed of cat. It has a "Cutout relay" which functions exactly the same as an "A" cutout, but there are two additional relays which both control the Field Excitation,
The Second relay limits the VOLTAGE that the generator puts out, and is why the Charging rate after a startup will be HIGH, to replenish the energy used by the starter, and then fall to a low value as the battery voltage rises to avoid overcharging the Battery.
The third relay is a Current control, which won't let the generator exceed it's thermal capability, when current draw on the electrical system is high.