Delco 27SI – Specifications

Table 1
27-SI Alternators
Part Number Nominal Voltage Nominal Current
9L-5938 Alternator Gp 12 V 58 A
3T-7070 Alternator Gp 12 V 58 A
9W-1082 Alternator Gp 12V 83 A
Table 2
Specifications for 27-SI Alternators (1)
CAT Part Number 9L5938 3T7070 9W1082
Torque of Pulley Nut (4) 100 ± 7 N·m (75 ± 5 lb ft) 100 ± 7 N·m (75 ± 5 lb ft) 100 ± 7 N·m (75 ± 5 lb ft)
Torque of Four Through Bolts (3) 6.2 ± 0.6 N·m (5.5 ± 5 lb in) 6.2 ± 0.6 N·m (5.5 ± 5 lb in) 6.2 ± 0.6 N·m (5.5 ± 5 lb in)
Torque of “B+” Terminal (Nut) (1) 7.1 ± 0.9 N·m (63 ± 8.0 lb in) 7.1 ± 0.9 N·m (63 ± 8.0 lb in) 7.1 ± 0.9 N·m (63 ± 8.0 lb in)
Torque of “B-” Terminal (Bolt) (2) 2.3 ± 0.6 N·m (20 ± 5 lb in) 2.3 ± 0.6 N·m (20 ± 5 lb in) 2.3 ± 0.6 N·m (20 ± 5 lb in)
Voltage Rating 12 V 12 V 12 V
Rated Output Current 58 A 58 A 83 A
Polarity Negative Ground Negative Ground Negative Ground
Rotation CW or CCW CW or CCW CW
Test Speed 5000 rpm 5000 rpm 7000 rpm
Rated Output Current at the Test Speed 37.0 A 47.8 A 61.1 A
Output Voltage at
25 °C (77 °F)
27.4 ± 0.6 V 27.4 ± 0.6 V 14.0 ± 0.3 V
Resistance of Rotor Field Winding at
27 °C (81 °F)
2.4 to 2.7 ê 2.4 to 2.7 ê 2.2 to 2.7 ê
Current of Rotor Field Winding at the Voltage Rating and
27 °C (81 °F)
3.3 to 3.8 A 2.5 to 2.8 A 5.7 to 7.1 A
Turn-On Speed at
25 °C (77 °F)
2000 rpm 2000 rpm 2000 rpm
( 1 ) Refer to Illustration 1.

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