Topic: Generator output


silverchief    -- 10-16-2011 @ 1:06 PM
  With engnine not running, voltmeter at battery shows 6 Volts.

Engine running, generator shows 6 volts charge, low or
fast idle, no appreciable difference. Lights on and fast idle will pull reading back to 6 volts.

Connecting voltmeter to alternator "batt" and to ground,
shows same - 6 volts.

Is my generator doing it's job? Shouldn't it read something above 6 volts at fast idle?




37RAGTOPMAN    -- 10-16-2011 @ 4:44 PM
  silverchief
it should be putting out over 7 volts,
but not knowing what year presents a problem to know exactly what the problem is,
how old is the battery,?
does the cells test OK, with a hydrometer ?
what is the reading,
did you charge the battery first.and it only reads 6 volts,
did you try a 2nd voltmeter? to see the one you are using is working correctly?
get back to us with more info.
37RAGTOPMAN and keep on FORDIN,,,!!!


LanceD    -- 10-16-2011 @ 4:46 PM
  With the engine running around 1k rpm's you should read around 6.75v to 7v on the battery. So I think you're not giving enough info because I doubt you're getting exactly 6v for a reading.

Also is there a battery gauge in the dash? If so what is it doing?

-I know I have an old car, that's where my knowledge ends, Lance


supereal    -- 10-16-2011 @ 7:35 PM
  Voltage across the battery when engine speed is above idle should be about seven and a half volts. I'd suspect either the generator quit, or the voltage regulator is at fault. Check all connections at both units to see that they are clean and tight. My bet is that one of the generator brushes is not making contact, either from wear or from being stuck in the holder. If the generator is old, I'd opt for a rebuilt.


TomO    -- 10-17-2011 @ 6:38 AM
  I am confused. Do you have an alternator or generator? If you have an alternator, does it have an internal regulator or use the one on the firewall?

I like to measure the generator voltage at the regulator. That way any connection resistance will not affect the reading.

To check out the generator, jumper the field wire to the armature terminal at the regulator. Raise the engine rpm to about 1,000 and measure the voltage at the battery terminal of the regulator. It should be at least 7 volts.

Tom


supereal    -- 10-17-2011 @ 9:54 AM
  If I recall correctly, I believe Don has a generator. For those with a "one wire" alternator, you may have to race the engine to get it to come on. They rely on residual magnetism in the rotor to excite the unit. A much better system uses a second wire connected to the ignition switch to "wake up" the alternator. In general. on a slow turning flathead, an alternator usually doesn't produce better results than a generator in good condition.


silverchief    -- 10-18-2011 @ 11:42 AM
  Sorry guys - here is more information.
1949 flathead engine, with Optima battery, original equipment, 6 volt setup. Believe generator probably rebuilt with "restoration," about 10 years and 30,000
miles ago. At about 30mph ampmeter shows very slight charge. Batt about 18 months old, recently came up to full charge in about 3 hours at 2amp charge, so I believe it is in good condition. Original clock works,
so I guess is a parasite. Driven about 3 miles, several times a week.



silverchief    -- 10-18-2011 @ 5:02 PM
  Dropped my generator off at a reliable rebuild shop this afternoon. Will let you know if that solves the problem.

Thanks for the help.


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