When installing a new or rebuilt generator or after overhaul of a unit, it must be polarized prior to starting the engine. This is done by letting the generator run briefly as a motor to give pole shoes the necessary residual magnetism of the correct polarity for excitation. Polarize the generator using one of the following methods (with fan belt removed):

Connect lead from negative battery post to D- terminal on generator (see Fig 1). Momentarily contact lead from positive battery post to D + terminal on generator. Generator is now polarized and ready for testing.
With regulator connected to generator, momentarily contact lead from positive battery post to D+ terminal on regulator.
NOTE: Never polarize by connecting B+ terminal on regulator to D+ terminal on regulator as damage may result to regulator and generator.

Generator is now polarized and ready for testing.

Fig 1: Polarizing Generator
Courtesy of NOT AVAILABLE

EARLY BOSCH GENERATOR SPECIFICATIONS

Former Designation

Type Inscription

RPM Specifications for

Load Setting

Field Winding

Abbrev. Type Symbol

Rating

Output Test

Rated Voltage at No-load RPM

cold RPM

hot RPM

Amps.

Watts

Ohms + 10%

LJ/GE(M)
LJ/GEF (M)
LJ/GEG(M), (S)
LJ/GEH
RED
REE
LJ/RED
LJ/REF
LJ/REG
LJ/REH

E
ED
EF
EG
EH
EW

160/6/2500
7V 40 A 26

1450

2450

2600

.....

160

1.2

180/6/2300

1500

2200

2300

.....

180

1.0

180/6/2500 (F) ⁽¹⁾

1750

2500

2600

.....

180

0.8

7V 45 A 27

1850

2600

2800

....

0.8

200/6/2400 (F) ⁽¹⁾

1550

2300

2400

.....

200

0.8

7V50 A 25

1700

2450

2600

33.5

.....

0.8

200/6/2600

1750

2550

2650

.....

200

1.0

7V 50 A 28

1850

2650

2850

33.5

.....

1.0

200/12/2400(F) ⁽¹⁾

1650

2250

2500

.....

200

3.5

14V 25 A 25

1850

2400

2600

.....

3.5

200/12/2600(F) ⁽¹⁾

1800

2500

2700

.....

200

3.5

14 V 25 A 27

1890

2500

2750

17.0

.....

3.5

200/12/2700(F) ⁽¹⁾

1850

2600

2750

.....

200

3.5

14 V 25 A 29

2050

2700

2950

17.0

.....

3.5

240/12/2800 (F) ⁽¹⁾

2150

2750

2900

.....

240

3.5

14 V 25 A 31

2050

2900

3150

17.0

.....

3.5

450M12/3700 (F) ⁽¹⁾

2200

2950

3100

.....

300

3.5

14 V38 A 32

2300

3050

3250

25.0

.....

3.5

LJ/CGE
LJ/GG(V)
LJ/GGVR

G
GV

200/12/2400

1700

2400

2500

.....

200

4.8

240/12/2100

1450

2050

2200

....

240

4.8

240/12/2400

1700

2300

2500

....

240

4.8

14V30 A 25

1630

2400

2550

.....

4.8

RKC
LJ/GK(M)
LJ/GKW

KC
K

300/12/1450
14 V 38 A 15

1100

1450

1500

.....

300

5.2

400/12/1500
14 V 50 A 16

1100

1450

1550

.....

400

5.2

450 M 12/2600
14V 38A 24

1950

2350

2400

.....

300

5.2

⁽¹⁾	Low-ohmic field, use regulator with P.T.C. compensation resistor only (A-type).

LATE BOSCH GENERATOR SPECIFICATIONS

Bosch Part No.	Rating	No Load RPM For Voltage Rating	Output Test		Load Setting Amps.	Field Winding Ohms+10%
Bosch Part No.	Rating	No Load RPM For Voltage Rating	Cold RPM	Hot RPM	Load Setting Amps.	Field Winding Ohms+10%
0101302084	14V38A19	1300	1850	1950	25	3.4
0101302086	14V30A20	1450	1900	2100	20	3.5
0101302090	14V30A20	1450	1900	2100	20	3.5
0101302103	14V30A25	1650	2450	2600	20	3.5
0101302111	14V30A20	1450	1900	2100	20	3.5
0101302113	14V30A20	1450	1900	2100	20	3.5
0101302117	14V30A20	1450	1900	2100	20	3.5

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.

• Brakes feel soft, pull hard to one side, or make grinding noises.

• The engine overheats, stalls repeatedly, or misfires under load.

• You are missing required tools, torque specs, or safe lifting equipment.

• You are not confident in the next step or safety outcome.

Safety Warning

Polarizing Generator

Use the Manual With the Right Hardware

When to See a Mechanic

Rather have a pro handle this?