Testing And Repairing: Rotor

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Test claw pole rotor for short circuits to ground using 40V AC tester. Measure resistance of exciter (field coil) in rotor with ohmmeter across slip rings. Resistance should be 4.0-4.4 ohms. If necessary, turn slip rings in a lathe, noting maximum runout of 0.001" (0.03 mm) and minimum diameter of 1.25" (31.5 mm). Maximum pole wheel runout should not exceed 0.002" (0.05 mm).