Generators and Regulators: Other BMW 7 series E38 facelift

Bosch

1. Place DVOM on lowest scale. Measure resistance between 2 of the 3 sets of wires. Move one DVOM lead to the other set of wires. Check resistance between the remaining set of wires. Resistance values must be identical. If resistance is incorrect, stator has open or shorted windings and must be replaced.
2. Place DVOM on x1000 scale. Connect DVOM between stator core and each stator lead. Continuity should not exist. If continuity exists, stator is grounded and must be replaced.

Motorola

Connect DVOM between stator core and each stator lead. Continuity should not exist. If continuity exists, stator is grounded and must be replaced.

1. Place DVOM on lowest scale. Connect DVOM across slip rings. Ensure resistance is within specification. See «ROTOR RESISTANCE»(ref-4028-S20511946642000060900000) table.
2. If resistance is too low, rotor has short circuit and must be replaced. If resistance is infinite (no continuity), rotor has an open circuit and must be replaced.
3. Place DVOM on x1000 scale. Connect DVOM between rotor core and either slip ring. Continuity should not exist. If continuity exists, rotor is grounded and must be replaced.
4. Measure slip rings for wear and eccentricity. If wear is visible, fine grind and polish slip rings. Maximum runout for slip rings is 0.11" (0.03 mm).

ROTOR RESISTANCE

Place DVOM on lowest scale. Connect DVOM across slip rings. Ensure resistance is approximately 4 ohms within specification. See ROTOR RESISTANCE table. If resistance is too low, rotor has short circuit and must be replaced. If resistance is infinite (no continuity), rotor has open circuit and must be replaced. Measure slip rings for wear and eccentricity. If wear is visible, fine grind and polish slip rings. Maximum runout for slip rings is 0.11" (0.03 mm).