Soundguy
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A circuit and B circuit are COMMON generator/voltage regulator circuit types.
they refer to how the field is powered.
In A circuit, the field coil in the generator has one side hooked to the armature, and the other side goes to the insulated stud on the genny body. the vreg on an A circuit system has a field tab that is hooked to the genny field stud.. from there ( and this is a simplification ) it goes thru a bias resistor and to ground. there is also a set of relay contacts 'ACROSS' the bias resistor. when the contacts are open, field current flows from ground thru resistor, thru field coil, to armature ( electron current flow, assuming negative ground.. etc.. etc.. ). When the relay contacts are closed, the bias resistor is shorted, and current thus bypasses it, .. thus when the contacts are closed, field current is higher, having only the resistance of the field coils themselves in the circuit.
power is supplied by the armature.. etc. these regulators are called mechanical vibrating regulators, as the field contacts open and close to regulat field current, and thus charge voltage.. thus charge current.
in B circuit systems, one side of the field coil is grounded in the generator, and the other side exits the insulated stud, at the vreg, the field stud is tied to the armature stud via a bias resistor. there is also a set of relay contacts across this bias resistor. same deal.. armature supplies power.. which directly powers field thru a resistor / or shorted resistor.. etc... etc..
that was an oversimplification of the vreg itself, as there are other parts in play such as the cutout, the purpose of the air gap in respect to cut in voltage, current limiting..e tc.. etc.
a circuit basically tells you that the genny needs external ground to the field.. B circuit needs power to the field.
soundguy
they refer to how the field is powered.
In A circuit, the field coil in the generator has one side hooked to the armature, and the other side goes to the insulated stud on the genny body. the vreg on an A circuit system has a field tab that is hooked to the genny field stud.. from there ( and this is a simplification ) it goes thru a bias resistor and to ground. there is also a set of relay contacts 'ACROSS' the bias resistor. when the contacts are open, field current flows from ground thru resistor, thru field coil, to armature ( electron current flow, assuming negative ground.. etc.. etc.. ). When the relay contacts are closed, the bias resistor is shorted, and current thus bypasses it, .. thus when the contacts are closed, field current is higher, having only the resistance of the field coils themselves in the circuit.
power is supplied by the armature.. etc. these regulators are called mechanical vibrating regulators, as the field contacts open and close to regulat field current, and thus charge voltage.. thus charge current.
in B circuit systems, one side of the field coil is grounded in the generator, and the other side exits the insulated stud, at the vreg, the field stud is tied to the armature stud via a bias resistor. there is also a set of relay contacts across this bias resistor. same deal.. armature supplies power.. which directly powers field thru a resistor / or shorted resistor.. etc... etc..
that was an oversimplification of the vreg itself, as there are other parts in play such as the cutout, the purpose of the air gap in respect to cut in voltage, current limiting..e tc.. etc.
a circuit basically tells you that the genny needs external ground to the field.. B circuit needs power to the field.
soundguy