Charging help needed please

[glennpm]

Hi,


My three brush generator is not working properly. The generator is on a 59A and has been converted to 12 volts. It was rebuilt by a company in Rhode Island years ago from whom I also bought a new voltage regulator.


When running, my 1932 ammeter is just slightly to the plus side without any lights on. Any load and the ammeter is quite negative. Voltage running is 12.5V but if the headlights are switched on, or horn blown, etc.; the voltage is only 12.1V.


Details:

- rebuilt generator, three brushes
- 12V negative ground
- new regulator (GM type)
- new battery with full charge
- Good ground for voltage regulator and generator
- regulator has been polarized
- new wiring throughout
- volt meter connected directly to battery for these tests.
- Ford generator I think is internally grounded so bypassing the regulator is not an acceptable way to test the generator alone. (http://www.bowersflybaby.com/tech/spark2.html under, "Is It the Generator or Regulator?"


I found a good article this morning, http://myclassicthunderbird.net/?page_id=584.

This section is helpful. The red highlighting is by me:

"When the engine is not operating, the contact points on the cut out relay (Fig. 20), are held open by spring tension. In this way, the cut out relay prevents the battery from being discharged through the low-resistance generator armature to ground. When the engine starts, the voltage, induced in the generator armature, forces current through the energizing coils of the cut out relay. At approximately 12 volts, the coils are energized sufficiently to overcome the spring tension and close the cut out points. With the points closed, the current can now flow from the generator to the external load. When the generator voltage drops sufficiently below the battery voltage to de-energize the cut out relay coils, the spring tension again opens the points to disconnect the generator from the external load, and prevents the battery from discharging through the generator. Before the cut out contacts open, a small amount of reverse current will flow from the battery to the generator.

The voltage limiter holds the generator voltage below a predetermined setting by controlling the amount of voltage applied to the field coils. This can be accomplished only as long as the voltage of the generator is high enough to operate the voltage limiter. When the engine is not operating, the contact points in both the voltage and current limiter units (Fig. 20), are held closed by spring tension. When the engine starts, voltage, induced in the generator armature, causes current to flow through both sets of points to the field coils. The greater the field strength, resulting from this current, the greater is the generator output voltage from the armature. When this increased output voltage energizes the voltage limiter coil, sufficiently to open the points, the current to the field coils is cut off. The resulting weakening of the field decreases the generator output voltage. As the generator voltage decreases sufficiently to de-energize the voltage limiter coil, spring tension again closes the points to provide current for the field. The voltage limiter contacts open and close at a rate of about 60 to 200 times a second to accomplish control of the generator voltage, and thus protects the system from high voltage when the system load demand is low.

The current limiter protects the generator armature windings by limiting the maximum amount of current supplied by the generator. Any increase in current above the current limit setting, results in a decrease in voltage, but if the voltage decreases, the voltage limiter will not operate. Therefore, when the current from the generator reaches the current limit setting, the voltage limiter no longer functions. At this point, the current limiter assumes control. Like the voltage limiter, the current limiter performs its function by controlling the amount of current that is supplied to the generator field coils. When the generator output current becomes excessive, it energizes the current limiter coil sufficiently to open the points and, thereby, cuts off the voltage and resulting current going to the field. The resulting decline in field strength reduces the generator output and prevents excessive current from being produced by the generator, and thus protects the generator when the system load demand is high.
When the current limiter is operating, the voltage limiter contacts remain closed, and the current limiter contacts open and close at a rate of about 30 or 40 times a second."

With my engine running, the "cut out relay" points are not contacting. Both the voltage and current limiters are contacting. I manually closed the cut out relay and alternately opened the voltage and current point with finger pressure. None of this made any difference in the output voltage.


Hoping to get some guidance please.