Connecting SX460

[walker]

I just got an Sx460 AVR for my MB-19. The wiring diagram leaves a bit to be desired, and refers you to the generator wiring diagram, which I don't have. Essentially I a scrapping the old AF stuff, as the operation is intermittent at best.
So it looks like I simply connect fx to the positive field, and fxx to the negative field. Does polarity matter on this connection?
When connecting terminals 7 and 8, the diagram shows them connected to S and N(I assume neutral) for 120v operation, and S and T for 220v operation. What wires in a 12wire alternator are RSTN, or does it matter, and just connect it to neutral and a hot, or two hots?
Also, I am planning on rebuilding the rest of the generator controls shortly, do you see any problems with just disconnecting them now, aside from engine controls and test running it (engine runs fine, no low O
P, over temp, etc) I can set Htz manually, check voltage with a VOM.

 

[Isaac-1]

I think you may be getting ahead of yourself, how did you go about determining that an SX-460 was an appropriate voltage regulator for the MB-19? Is the MB-19 a brushless design, do you have resistance and excitation values for the exciter?, etc??

Ike

 

[walker]

I have little or no info on this head. Everywhere that I have posted, including here, gets little or no response. The alternator is a 12 wire on a 15kw Air Force generator built in 1967. It has the Hercules 198 diesel. It is a 50-60 hertz generator, not the 400hertz model. It actually runs and works, but the electronics are flaky, and I am forever chasing something down to make it work, hence the new AVR.
I spoke with Tom over at Central Ga Generator, and he had me check the voltage at the VR input to determine DC polarity and recommended the SX460.
So that is how I arrived at getting this particular AVR.

 

[Isaac-1]

The SX-460 is a good generic choice most of the time, I just wanted to ask because there is potential for damaging the regulator or possibly the generator if it is not a good match on field resistance or excitation current. To try to answer your questions, keeping in mind there are a number of SX-460 clones out there and markings on them may vary slightly, but generally have the European X,XX, RSTN nomenclature, instead of the American F1, F2, etc.. F1 (X) is positive, and F2 (XX) is negative, although getting them backwards generally only means demagnetizing the field, and magnetism can be restored, usually in either polarity. As to the reference input, you need to think about it as voltage range, not as Line to Line or Line to Neutral, as this will depend on how you connect the 12 leads, and your desired voltage output. If connecting 120/240 single phase you can pick either one on their appropriate jumper connections for the point 3 to 4 jumper, if wiring up for 120/208 3 phase you will likely want to pick 120V, if a higher voltage then things get a little more complicated.

Your question, What wires in a 12wire alternator are RSTN, or does it matter, and just connect it to neutral and a hot, or two hots? Has me concerned that you are not fully understanding the concepts of wiring a 12 lead generator, but this may just be a terminology confusion, think of RSTN as a 3 phase representation the same as L1,L2,L3 and L0 when referring to 3 phase power. The 12 leads are probably T1-T12 if using common U.S. naming, note not all companies use the same naming scheme, T-1 through T-12 are combined in various patterns to form the L outputs, either 1 or 3 phase depending on desired voltage.

Ike

 

[walker]

Mine are all numbered with the T designations. I just didn't understand the RSTN or what it designated, it makes a lot more sense now. I understand enough about the 12 wire to be able to change the voltages on the reconnection board, but when multiple schemes for naming things come up it is not quite as easy.