Before you click on any of the buttons, have a look at the basic scheme. The exciter winding rotates and induces current in the three strands,which are connected to thebattery through the plus- and minus performance diodes and the terminals B+ and B-. B+ is again connected through the (classical) ignition switch Sand the (also classical)control lamp K connected with D+. D+ is supplied by three (smaller) exciter diodes, which are switched parallel to the plus diodes. D+ forms thefeedback and current supply to theregulator, which controls the exciter windings through DF.
|Pre-exciter current circuit|
We now switch the ingnition on and start the engine. At starting RPM not enough voltage would be generated, because the excitation through the rotor would be too low. Thiswould have to get going through the remaining magnetism, which is deliberately kept low in the manufacturing/conception, to allow the complete regulation range, right up toalmost zero-regulation in normal operation. As you can see in the red-coloured circuit, the power for the exciter windings when starting, comes from the battery (externalsupply).
Don't ask the question, at which point do we have an exciter current circuit? One may assume, somewhere between starting and idling. In this situation, the exciter diodes deliver sufficient voltage forexcitation, however, for the transition to the performance diodes to charge the battery, in is not yet enough. It can be nicely seen here, how one of the strands U, V and W for two 60° angles,always gains the upper-hand in the delivery of plus-current. Of course, the same thing counts for the minus-side. Between each 60° phase, the red line alternates between the plus- and the minusdiodes.
At this point, it is sufficient to charge the battery or to send current to the consumers. This goes on, until the regulator R, due to the exceeding of the set voltage, periodically switches off, to limit this. 01/11