[alberg30] Alternator Question ?

[Mpete53 at aol.com]

From: Mpete53 at aol.com

    Charging systems basic test

    I have found that most charging problems can be diagnosed using a cheep 
volt meter. Often only one bad connection causes the problem.
Test 1  Batt terminal voltage 
    Check the batt voltage at the batt posts not the wire terminals when the 
engine is off. This gives you the lowest batt voltage that you should find 
during the rest of your testing.

Test 2  Alternator voltage Vs batt voltage
    Start the engine then take a voltage reading across the Alternator output 
terminal and the Alternator main case. This is the output voltage of the 
Alternator.
    Recheck the Batt post voltage with the engine running
Compare the two voltages, they should both be the same and about 1.5 volts 
higher than the voltage in test 1 (13.5 to 14 volts is good, but deeply 
discharged batt might cause it to be lower)

    If Alt. voltage is OK but Batt voltage is low, look for broken wire, bad 
amp meters, corroded terminals and wires between alt and batt. 

    If all voltages in test 1 and 2 are the same (no voltage increase engine 
running), the alt is not working. Go to test 3


Test 3 Power to voltage regulator

    Depending on the alt that you have, you may or may not be able to check 
the voltage regulator input supply. If your voltage regulator has a wire from 
the key switch, or the + side of the spark coil, with the key in the run 
position check the voltage there. The voltage should be the same as the rest 
of the system. 
    If voltage is not the same, find out why. Is there a bad wire, connection 
and double check that it is really a 12 V supply wire not a feed for the 
tack. 
    If the voltages checks it is time to take the alt and reg to a repair 
shop and let them bench test them.
        
Mark
Jocelyn 585

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