car alternator tester

Hello All, I am looking for some help on a homemade test device that is probably 30= years old and the transformer appears to have burned up and needs to be replaced.
It has as an input: 110V AC and 12V DC. The inputs are run through a switch and then the 110V passes through a transformer, then through diodes - as in the drawing. Then it passes on to the resistors and caps.
Could someone please explain how this suppose to work? I assume the power input from the 110V line is varied to induce a load on the alt. What I need to do is determine the size and voltage output of the transformer as it is kiplut.... Any help would be appreciated. I can tell you the large resistor is 1 ohm, the small resistor is 2 ohm the large cap is 71000mf small is 32000mf.

Thanks again for any help!

Could this be a device to get 110v FROM an alternator or maybe a diy charger for 12v. Have you seen this item in use or know that it IS an alternator tester. Just asking cause I have not seen similar,(75 yrs old)

IT actually looks like something I have downstairs. But basically it was a variac feeding a DC supply of up to 12V It was designed in the 6V ERA, so it had 6V and 12V ranges. If i have time, I could take a picture.

It's definitely an alternator tester, Ill go take some pictures of the actual machine tomorrow and post. The owner is a customer of mine, I primarily do electrical contracting work and some machine control cabinet builds with PLCs but this is more in the electronic relm. I appreciate any help.

K-I have dealt with Varacs, I have used them in hot wire cutting applications mostly just change them to SCR's now...

I am thinking that the 110V may be controlled by an SCR/Varrac to adjust the load on the alt but I'm not versed enough in electronics to be able to tell?? Ill look at what feeds the 110V going into the load bank is actually plugged into tomorrow.