EXP-925
Midtronics B.V. Hoofdveste 6 - 8 Houten NL
www.midtronics.com
20
Chapter 5: System Test
Alternator Decisions and Recommendations
Decision
Action
NO PROBLEMS
The system is showing normal output from the alternator. No problem detected.
NO OUTPUT
The alternator is not providing charging current to the battery.
•
Check the belts to ensure the alternator is rotating with the engine running. Replace
broken or slipping belts and retest.
•
Check all connections to and from the alternator, especially the connection to the battery.
If the connection is loose or heavily corroded, clean or replace the cable and retest.
•
If the belts and connections are in good working condition, replace the alternator. (Older
vehicles use external voltage regulators, which may require only replacement of the
voltage regulator.)
LOW OUTPUT
The alternator is not providing enough current to power the system’s electrical loads and
charge the battery.
•
Check the belts to ensure the alternator is rotating with the engine running. Replace
broken or slipping belts and retest.
•
Check the connections from the alternator to the battery. If the connection is loose or
heavily corroded, clean or replace the cable and retest.
HIGH OUTPUT
The voltage output from the alternator to the battery exceeds the normal limits of a
functioning regulator.
•
Check to ensure there are no loose connections and that the ground connection is
normal. If there are no connection problems, replace the regulator. (Most alternators
have a built-in regulator requiring you to replace the alternator. In older vehicles that use
external voltage regulators, you may need to replace only the voltage regulator.)
Diode Decisions and Recommendations
Decision
Action
EXCESSIVE RIPPLE
One or more diodes in the alternator aren’t functioning or there’s stator damage, which is
shown by an excessive amount of AC ripple current supplied to the battery.
•
Make sure the alternator mounting is sturdy and that the belts are in good shape and
functioning properly. If the mounting and belts are good, replace the alternator.
OPEN PHASE
The Tester has detected an open phase within the alternator. Replace the alternator.
OPEN DIODE
The Tester has detected a open diode within the alternator. Replace the alternator.
SHORTED DIODE
The Tester has detected an shorted diode within the alternator. Replace the alternator.
