George Marsh said: (quoted from post at 13:44:33 04/15/13) Helping a guy work on a MF 50 with a 12v genny. Took the genny apart and cleaned the communtator. I think we got the genny working. The Delco regulator has 3 coils. The top coil is connected to the fields, the middle coil, which is made of perhaps 10g wire, is connected to the armature. The botton coil, which is also made of 10g wire goes someplace???perhaps the switch and back to the +12v.
The wiring is a mess. I got the genny to charge by exciting the fields with a 12v tail light bulb. At an idle the armature showed 13.68 v, however the ammeter is wired backward, it showed discharge. There is no voltage getting to the fields when the switch is on. How should the voltage regulator be wired? A diagram would be nice, but not necessary. Shouldn"t there be 12v going to the fields when power is applied to the regulator? Should the armature wire be connected two the middle terminal of the regulator? Should the switch power up the bottom terminal of regulator?
Going to guess there may be two or more issues.
Is it possible the regulator needs polarized? I haven"t worked on generator in decades and have a bad case of CRS.
Any help will be appriciated. The guy is going to NAPA and try to buy a new regulator. BTW, there are no numbers on the regulator. Numbers may help too.
George
The ammeter may be OK and you may have simply polarized the fields backwards, thus causing the generator to output a polarity opposite of the battery. Most Delco are A-ckt generators, I believe.....this means that the field current is obtained from the ARM inside the generator & regulation is accomplished in that the regulator provides a switched ground to the other end of field windings, via FLD terminal. The 3 coils are voltage regulation (field control), cutout and current regulation. BATT generally comes in to an isolated contact at the cut out unit (connects to nothing else & as held in your hand these contacts will be open) Magnetic force will close this set. Field control contacts will be normally-closed as held in your hand, where the magnet force of coil will open this set of contacts. Current control contacts will be normally closed & magnetic force will open contacts. BATT and ARM will be heavy wire/high current connections and Field much smaller for only 3 or 4 amperes. That should help identify terminals. Also, Field will most likely have a resistor from FLD to case ground(case must be grounded to generator). Picture front & rear will tell me for sure whos who. If all three terminal are in a single row along one side of the VR, then the order will be B-A-F , if A-ckt type (which I believe it is). Just for future reference, if B-Ckt, the order will be A-F-B. Some have a rear terminal or 4 terminals, just to throw us off!! :) Oh, & no there is no voltage applied to fields until the generator is spinning & generating at least a little output.
This post was edited by JMOR at 11:31:39 04/15/13.
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