Step by Step Check List
1. Check alternator shaft speed. Should be 3600 RPM, 60 hertz at full load.
2. Check voltage output at terminal ends of Lines L1 and L2. If volt-age is correct at this point, make a progressive
check from this point through the wiring system.
3. Check brush contact to rings. Brushes and holders should be free from dirt. Brush should snap back when lifted and
released. Using caution to prevent scratching the ring or chipping the brush, a thin knife edge can be inserted for
lifting the brush.
4. Inspect all wiring for loose or broken connection. Look for loose or broken solder joints. If a solder joint needs
repairing on a diode, use a hot iron to accomplish repair quickly. Blow on the joint for quick cooling. Diodes can be
destroyed by prolonged heat.
5. Check diodes. (See method outlined under Bridge Assemblies). Isolate all brushes from the rings by inserting heavy
paper under the brush. Remove one quick disconnect clip from the base field bridge. This will isolate all parallel
6. Before removing the paper insulation from under brushes, check out the rotor as outlined under Field Assembly. If
voltage is correct at no load but drops excessively on load, and correct speed is maintained, suspect the control field
or the control field connections.
7. When the voltage at correct speed is very low at no load and approximately 50% of rating on load, the base stator
winding may be open. Check for a circuit between the brown leads connected to the base field bridge. Disconnect
one lead before making check.