3000W Chinese Gensets Info.

MrRchitty wrote:
Since the topic has been brought up about the 240 volt side of the Champion open synch generators, it was mentioned that it appears the AVR senses the voltage on one leg or one set of windings and if you were to use the 4 prong twist 240 volt rated plug, you could split it down the road to 2 120 volt lines/legs.

I want to take my 110 volt 3500 watt Champion which is wired in parallel and rewire it. I want to employ the same 4 pole double throw switch allowing me to have 3500 watts at 110 volt and switch to 240 volts. I know that if I use the 240 volts I won't have a problem powering my well pump. However, if leaving the switch in 240 volt and use the 240 volt 4 prong plug, split it down the line to 2 110 volt legs, am I going to have 1 leg which is regulated properly and the other leg that is not?

OK - let's back up a minute.

No, the generator DOES NOT have two voltage regulators. Actually, I am not sure how that would work without a total redesign of everything since the AVR actually regulates current required for self excitation. Without the regulator and current control the output voltage of the Chinese genny we reference would be more like 180 (give or take) volts AC.

The design of the AVR and regulator circuit does a good job of regulating both MW1 and MW2 when in series. Actually, the regulation works for one continuous coil by sampling a section and supplying around 19 to 22 volts of DC through the brushes for excitation. The excitation value is for both/all MW coils.

Now, as I noted in my first posting, OHM's law tells us that the more current we draw through a specific resistance the lower the ending voltage will be - meaning that high current drawn from either leg will create a greater voltage drop. What really concerned me in this case was the stated 30 volt differential. The difference between MW1 and MW2 with one leg fully loaded and the other lightly loaded should not be over 5 volts AC. To be higher indicates an increased resistance that should not be there. It is easy to measure resistance on both of the MW lines from the Coleman cord back - why I did not say that in the first place must have been part of a senior moment. BTW - Coleman does not automatically mean quality. It is yet another product manufactured overseas that can have problems in assembly. I have needed to fix many plugs and caps with major brand names that have developed high resistance from overheating connections and friction contact surfaces.

Now, the question of only one leg being regulated - again it is a sampling and yes it is a more accurate sampling when both MW1 and MW2 are in parallel (straight 120 VAC) because current loads on each winding will be equal. The series sampling is mainly designed for the supply of 240 volts without a center tap to split the output. All but a few 240 appliances only require "straight 240".

Use the 30 amp plug, change it to a different outlet if you wish. Unless you have a need for "straight 240" leave the other outlet alone.

But, you have yet to discover why the differential was 30 volts. That indicates there is a problem somewhere and working around it does not eliminate the problem - it only hides it. You need to determine what was causing the 30 volt drop - and it is NOT the method of regulation or an AVR fault.