Mike, the two windings on the coil got two functions: The finer winding cares for the voltage control, acting on the voltage side and also for the cut-in contact. The fat winding cares for any over-current or short in the system and from over current it will pull the field wire contact to earth so no more power will be produced in the field coils.
Traditionally the resistor is one winding in one field coil which got 4 wires for identifying it. The resistor will have like 4 ohm, the field 1-2 ohm.
Electronic regulators don´t use the resistor for a medium setting like the original - quite nice I say - but simply short the field to earth in very high switching frequency.
Below a diagram of a Bosch Z-type regulator and a picture of the very old F-Type, with only one moving lever, caring for cut-in and some linkage for the voltage control. Basically the wiring around the dynamo is same like with the later Z-type I still run in the 6 V system Horex in photo. The later type had levers and contacts at both ends for cutout and voltage control - extremely reliable. There are 4 field coils on the Horex, one with resistor winding inside as described.
Besides, there is a photo transistor ignition plus flyweights a/r device there as well. The blackbox at 10 o´clock position is the ignition , the standard coil is under the tank. So all the rest is inside the chrome cover.
Vic
Bosch Z type,
Z-type at 2 o´clock :
Traditionally the resistor is one winding in one field coil which got 4 wires for identifying it. The resistor will have like 4 ohm, the field 1-2 ohm.
Electronic regulators don´t use the resistor for a medium setting like the original - quite nice I say - but simply short the field to earth in very high switching frequency.
Below a diagram of a Bosch Z-type regulator and a picture of the very old F-Type, with only one moving lever, caring for cut-in and some linkage for the voltage control. Basically the wiring around the dynamo is same like with the later Z-type I still run in the 6 V system Horex in photo. The later type had levers and contacts at both ends for cutout and voltage control - extremely reliable. There are 4 field coils on the Horex, one with resistor winding inside as described.
Besides, there is a photo transistor ignition plus flyweights a/r device there as well. The blackbox at 10 o´clock position is the ignition , the standard coil is under the tank. So all the rest is inside the chrome cover.
Vic
Bosch Z type,
Z-type at 2 o´clock :