I have a Honda E900 generator that uses a CT(Current Transformer) to vary the DC voltage to the Field Rotor. It also uses an Inductor to supply voltage when there is no 120v load on the stator. The Inductor is under the Flywheel of the Motor so there is always some voltage on the rotor when there is no load on the stator. Problem is the motor is shot and I would like to use the generator portion with out the CT. I need a circuit designed to regulate the voltage to the field to maintain 120v ac on the stator under varying loads. I have determined that I need about 21 VDC .41A at no load and 60 VDC 1.12A at full load. I would like to add a transformer to the 120v supply to run the circuit and to get things started use a 12 or 24 v battery. I also need a circuit to charge the battery. I have some electronics experience but never designed circuits. Any help would be appreciated.

 

Just buy a universal AVR on eBay or Amazon. They are around $10 - $15.

 

tcmtech

I understand your thought however I cannot find any manual or wiring diagram for the universal avr's on ebay. From what I can decipher the universal avr's use a dpe winding in the stator for excitation supply to the avr. I do not have a dpe winding.

I would rather not waist the money. I would like to design a circuit that could be tweaked if needed. I have access to a scope, function generator, power supplies, dmm, components, etc. I just need a design to get me started. I have searched this forum but I cannot find a circuit that doesn't depend on a dpe (excitor) winding.

 

See this and modify as needed to use the main output windings as both the exciter and voltage reference sources.

At worst, you may need to add a small transformer configured as an autotransformer to buck the AC voltage down a bit for whatever circuit you chose to build.

http://portable.generatorguide.net/avr.html

 

Here is the basic circuit, from a previous project, for what you need. Some values may need tweaking for your purposes.

Ifixit