Lincoln Electric SVM194-A service manual 43TROUBLESHOOTING and REPAIRF-43

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F-43TROUBLESHOOTING AND REPAIRF-43

EXCITER ROTOR RESISTANCE AND GROUND TESTS PROCEDURE

(Exciter / Auxiliary Power Alternator) (continued)

7. Insulate the lead wires that had been discon- nected from the brushes during the static rotor resistance test. Position and secure them so they cannot become damaged by the spinning rotor. It is recommended that the ohmmeter leads be securely attached to the brush termi- nals, using clips or terminals BEFORE starting the engine.

8. Start the engine and run it at high idle speed (1800 RPM). The resistance should read approximately 42* ohms at 770F (250C).

9. Shut off engine, and move one of the ohmmeter leads to a good clean chassis ground connec- tion.

10. Restart the engine and run it at high idle speed (1800 RPM). The resistance should be very high, at least 500,000 (500k) ohms.

11. If the resistance readings differ significantly from the values indicated, recheck the brushes and the brush spring tension. If the brushes and slip rings are good, replace the rotor.

12. Securely connect the leads to the brush termi- nals (see wiring Diagram) and replace the alternator cover if testing and service is com- plete.

*NOTE: The resistance of the copper windings will change with temperature. Higher temperatures will produce higher resistance, and lower temperatures will produce lower resistance.

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CLASSIC® 300D & 300G