Lincoln Electric SAE-300 HE, Service Manual, Page: 34 / 84

LINCOLN ELECTRIC SAE-300® HE Service Manual
29
9. Check the wiring, fuse and terminals connecting the field bridge rectifier to the exciter stator
winding. See Wiring Diagram.
10. Perform the Exciter Stator Short Circuit and Ground Test Procedure .
11. Perform the
Exciter Rotor Resistance and Ground Test Procedure (Exciter / Auxiliary Power
Alternator)
.
When the Exciter Stator Short Circuit and Ground Test Procedures have been completed, reconnect
the leads to the AC terminals of the field bridge rectifier.
Be sure that there are no loads of any kind across any of the stator windings. The exciter winding
should be the only stator winding connected at this time. Examine stator wiring for damage,
pinched leads, chafed insulation, etc. If necessary, disconnect and insulate the stator output leads
as close to the stator winding as possible. If any leads were disconnected, secure them to prevent
damage from moving parts. See Wiring Diagram.
12. Re-start the machine and measure the rotor voltage.
If the rotor voltage continues to read significantly lower than 124 VDC, the stator is probably
defective and should be replaced.
NOTE: The field bridge rectifier may appear to function normally when tested independently, but
may malfunction when placed under the stress of normal operation. For this reason, it is
recommended that the bridge rectifier be replaced with a known good component before replacing
the stator.
* Voltages shown in this document are for a machine operating at normal temperature. Voltage
readings may be slightly higher if the machine is cold.
Figure F.8 – Exciter rotor voltage test