Not a problem at all, my friend.
I can provide you with as much detail as you wish - but I will also need a bit more.
Exactly what is or isn't your genset doing?
Too much voltage, too little voltage, no voltage at all?
The DPE winding (excitation) is definitely needed for voltage production.
Here is a brief overview of how your set produces voltage.
A genset is composed of 2 major components - an engine and a generator, commonly referred to as an alternator. hf
A generator is composed of 2 major components - a rotor, commonly referred to as an armature, and a stator. The stator typically has 2 or more windings - 1 or more power windings, and a smaller exciter winding.
There are 3 things required for the production of electricity - a magnetic field, a conductor (wire), and movement between the field and conductor. Since the field has no physical mass, it is much easier to move it than to move the conductor. We move the field by spinning it with the engine. This is why most gensets are known as revolving field gensets.hf
When you start the engine, the rotor starts spinning (it is connected directly to the crankshaft of the engine).
The rotor is a giant electromagnet.
When not running, the rotor retains a small bit of magnetism, known as residual magnetism.
As it spins, the magnetic field around the rotor is passed through the windings of the stator (conductor). The magnetic field aligns the electrons in the wire and makes them move. This flow of electrons is electricity.
However, the amount of electricity flowing is not very much, so the voltage regulator takes the AC power coming in from the DPE winding and converts it to a DC current, and feeds it back to the rotor through the brushes. This increases the strength of the magnetic field - which, in turn, increases the amount of electricity produced - until the VR senses that there is 120 volts (give or take) available.
Remember, a magnet has 2 poles - north and south, or positive and negative. As the positive pole passes the windings, it moves the electrons in one direction (the positive pulse). As the negative pole passes by, it moves the electrons in the opposite direction (the negative pulse). One positive pulse and one negative pulse are one cycle, or Hertz. Since US power is 60 Hz, this process must happen 60 times per second (50 times per second (50 Hz) in much of the world).hf
We now have nominal voltage flowing (120 V in the US).
When a load is applied to the genset, this voltage drops correspondingly to the size of the load.
The voltage regulator senses this power drop from the exciter winding and says ‘Hey, I've got a load on and the power is dropping. I'd better make more power'. It does this by increasing the DC voltage to the rotor, which creates a stronger magnetic field, which pushes even more electrons into movement.
The VR constantly monitors this voltage and adjusts the field accordingly.
We now have electricity.hf
From what you are describing here, it sounds as if your DPE winding is bad, and that the windings of the stator may be shorted together.
Is the reading of the DPE winding actually 0 (no resistance), or open (no continuity)?
Another quick test of the stator is to remove all leads from the stator, and isolate them so they can not touch each other. Also disconnect all wires from the VR.
Set your meter to ohms, on the lowest scale possible.
Test each winding -
Main power 1 (wires 11 and 22) should actually be 0.16 - 0.19 ohms
Main power 2 (wires 33 and 44) should be the same
DPE winding should be 2.01 - 2.39 ohms
Now test one wire of each winding to ground - there should be no continuity on any of them.
Now test one wire from each winding to one wire of the other windings - none of them should show any continuity.
If you show ground or continuity between any windings, the stator is shorted.
If these are good, but the DPE is open, the stator is burnt.
This stator will run you over $500 - so be sure to test carefully.
If all of these are good, ohm across the slip rings of the rotor - it should read 7.7 - 9.6 ohms.