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Wisconsin THD - regulator YJ-59: How does it work?


I have a THD with a 12 V 10 amp alternator. There are four wires connected to the alternator. Two black wires are connected to the rectifier YJ-58, which is simply to diodes connected to engine ground. The white wire (center tap of windings) from the alternator is connected to the battery via the amp-meter. The red wire from the alternator is connected to the regulator YJ-59, and the white wire from the regulator is connected to the battery via the white wire (center tap from alternator) and the amp-meter. My question is about the working principle of the regulator. I have checked the manual, and the check procedure tells that the resistance should be infinity between all combinations of the wires to the regulator, and also between the wires and ground (in both directions). This tells me that there is something more than a simple diode inside the regulator YJ-59. Buying a new expensive regulator seems a waste of money if I can easily build a new one. Can anyone tell me how the regulator works, and what’s inside YJ-59?


Yes, I to would like to convert my VH4D, both regulator and rectifier are bad in mine, however I only have 3 wires exiting my stator which is 25 amp, I'm trying to figure out how to use a standard 3 terminal combined regulator and rectifier, guessing certain wires must be combined on a 3 wire style, reg.dont want to use trial and error method! Cant seem to get any replies on how to.


I have two suggestions for you, you can remove your flywheel and examine the stator and magnets to see what is going on, or else you can put an oscilloscope on the output leads to see for sure what the thing is putting out. But from here it would be my GUESS that this thing is putting out three phase AC. If this proves to be the case you can, if you are really cheap, scrap the rectifiers out of an old Delcotron alternator or else buy a new set from a rebuilder. That will get you DC of whatever voltage the unit is putting out. Since you can't tinker with the field strength you get what you get, but one would have to guess that Wisconsin or whoever they bought that system from designed the generator to provide optimal output at rated speed since it is most likely the engine will be operating most often at that speed. Since you can't really change the machine's output you will have to add a current relay of some sort, either make or buy one.

The causal observer may question, "Why would anyone go to such a fuss? Why not simply buy the parts from Wisconsin?" This is of course a good question, but assuming the parts are even available (a big IF) the prices would be absurd and the electronics associated with these systems were not exactly known for their robustness. So coming up with an alternative is a good idea.