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.

[koates]

Hi there Glen...…..Your voltage reading at the regulator battery terminal should be approx. 14.2 volts with the engine revs at plus 1000 RPM. Generators do not charge at engine idle speed. A fully charged battery at rest should read approx 12.6 volts. For a Ford system test the generator output first by removing the field wire from the regulator and connecting it across to the ARM terminal. Rev engine up to approx. 2000 RPM and generator should be charging quite high at around 30 amps on your ammeter because the voltage regulator is bypassed except for the cutout contacts which should be closed. If you still have no charge and the cutout contacts are not closing then the generator is most likely at fault and would have to be removed and opened up for repairs. Because your generator has been converted to 12 volts I am assuming the field coils are connected as per the original Ford system which controls the field windings to the Armature connection through the regulator. The other system controls the field windings to ground through the regulator. Do the test and report back. Regards, Kevin.

[JSeery]

Generator should be putting out over 14 volts (the voltage regulator terminal B). Well, see Kevin post a good description!

[glennpm]

Thanks Kevin and JSeery,

Yes, I know that my voltage is way too low. I also didn't mention that the output goes up only .2-.4V even at higher RPM, like 2,000 or so.

I thought I could test as Kevin mentions, "For a Ford system test the generator output first by removing the field wire from the regulator and connecting it across to the ARM terminal." but was reluctant to try it today after reading the warning in the URL I linked in my post,

"- 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?"

Assuming this is wrong, I'll test as Kevin suggests tomorrow.

Thanks for your help!

[JSeery]

What your reading is not correct for a Ford generator, Kevin gave you the correct way to check it. I'm on a Rumbleseat kick today, here is one of his old post.

[glennpm]

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Good, I'll test it as Kevin says.


Thanks

[glennpm]

Hi,


I removed the generator end band to check the wiring. On the left side there are two brushes visible. The top appears to be to the field coils. The bottom brush exits the case directly and I assume this is the armature connection? On the right side the brush has a braided ground wire attached to it and appears to be internally grounded.


Are these three brush connections correct?


Thanks

[koates]

Glen, It appears there are three brushes in there which would not be a normal set up when using a three unit regulator. The ground brush originally had a copper braided cable connecting to a rivet inside the end housing. Another unusual feature is the wiring harness appears to go directly inside the generator without connecting to any terminals on the gen case. Not the way I would do it. I suggest that you don't touch the internals of the generator and do the test that I outlined in my last post first. Because this generator is not STANDARD or ORIGINAL its hard to know whats been done inside there unless I had it in my hands. Regards, Kevin.

[glennpm]

Okay Kevin. I just started it and pushed the 3rd brush down, i.e., rotated clockwise when looking from the front, and it made no difference. Tomorrow I'll switch the regulator wiring as you say.


Thanks!
Glenn

[Init1]

You may want to check if the regulator is functioning properly. Even new ones may be out of adjustment and cause issues.
And be sure it's a Ford one. GM won't work.

[koates]

Originally Posted by Init1

You may want to check if the regulator is functioning properly. Even new ones may be out of adjustment and cause issues.
And be sure it's a Ford one. GM won't work.

There is a correct procedure for testing generator charging systems. The voltage regulator cant be tested or adjusted unless the generator has the correct voltage output. Establish that the generator is good first and if it is then the regulator can be tested, adjusted or repaired if required. Most GM systems operate in a field to ground control circuit through the regulator. Most Ford systems operate in a field to generator or armature control circuit. There are some exceptions to that. Regards, Kevin.

[flatheadmurre]

If they converted a 3-brush to voltage regulator...it works like a GM generator !!
The 3rd brush gives you current and the regulator grounds the other end of that winding...
First you have to find out what they have actually done when converting the generator...any numbers on the reguator that can give you a clue if it´s using an A or B type regulation (ford or GM).
If it´s using a GM style grounding the Field wire will do the same as Kevin states for a ford unit.

[glennpm]

Hi flatheadmurre,


I went back through my old receipts and although there is not marking visible on the regulator, perhaps on the back of the base, the instruction sheet says its for a GM or American Motors generator.



I did a lot of searching last night and found mention of converting a three brush genearator by removing the third brush connection and then connecting this wiring from the fields to the FLD connection on the regulator. Is this what you are referring to? For example,



"The conversion just involves removing the third brush and wiring the two fields in series, and then using the -47 Delco regulator"


... and Harley instructions here:



http://3.bp.blogspot.com/-EYFlr2eozn...enerator13.jpg


I will test my generator in an hour or two this morning per Kevin's post.


Thanks,

[JSeery]

Anything I posted has no bearing on your generator! Was assuming it was a Ford 2-brush!! Not sure what it is or how it has been converted, so very difficult to know how to trouble shoot it.

[glennpm]

Okay Kevin, moving the FLD wire to the ARM and running at more than 1,000 RPM or better, showed no great positive amperage, in fact a little negatrive.



The battery is fully charged. With the FLD wire back to its position the cut out relay is fluttering and I measured voltage at the regulator terminals as:


FLD ~4V
ARM ~ 11.1V
BAT ~12.5V


I measured resistance from brush three to ground at about .6 ohms.


I also temporarily disconnected the lead to brush three, ran it at 1K plus and no difference in ammeter needle, i.e slightly negative.


Guess its time to pull the generator and take it apart to see what I have. BTW the generator mod for 12 volts was done in 1990 by DJ's Alternator and Starter Service in Harwinton, CT.

[glennpm]

Now looking for a wring diagram and help for how to convert a three brush to a two brush using a GM type regulator.


Thanks,
Glenn

[flatheadmurre]

If your generator is still 3-brush i would buy a fun project 12v regulator.
It looks stock.
It´s solid state so no more issues with regulator adjusting.
Just my 2c.

[glennpm]

I would buy from "fun projects" in a minute if it would work. The site says this though, "Designed for the standard 6 volt positive ground system, both a 6 volt and a 12 volt model are available and both are designed to work with the unmodified 6V generator"


My generator looks stock so maybe I paid for nothing or perhaps I have 12V field coils and a new GM regulator and nothing else.


I'll see if maybe they can tell me some checks to do without a disassembly.


Thanks

[flatheadmurre]

Measure the resistance of the field winding.
Lift the third brush and stick something between it and the armature.
Then measure between the brush and the field wire at the regulator.
This will tell you if you have a std field winding.

[glennpm]

I measure 5.4 ohms.


What do I have and what are you using for the specs please?


Glenn