Alternator

An alternator is a form of electrical generator in which a magnetized field called a rotor revolves within a set of stationary coils called a stator. As the rotor revolves, alternating current is induced in the stator. The current is then rectified and used to operate the electrical accessories on the motorcycle and for charging the battery. The rotor may be either permanently magnetized, or magnetized by a separate winding in the rotor. Kawasaki machines use both types.

Alternators with permanently magnetized rotors are controlled by a solid state regulator. Alternators with externally excited field windings require a regulator similar to that in an automobile. Rotors on some models are permanently magnetized; others require separate excitation.

If alternator or regulator problems are suspected, as in the case of a chronically undercharged battery or dim headlights, first check the alternator output voltage:

1. Connect a 0-20 DC voltmeter across the battery terminals. Be sure that you connect the positive voltmeter lead to the positive battery terminal, and the negative voltmeter lead to the negative battery terminal.

2.Start the engine and run it at 5,000 rpm. If the voltmeter indicates 14 to 15 volts, you may assume that the alternator and regulator are OK.

3.If the voltmeter does not indicate 14 to 15 volts, further checking will be required. Trouble may lie in the alternator, regulator, or wiring.

Figure 19B

KH250, KH400, and S Series (Without CDI) Alternator Troubleshooting

1. There are 3 leads from the alternator. Check for continuity between the following leads, as shown in Figure 19A.

a. Pink to yellow

b. Pink to white

c. Yellow to white

2.Set the ohmmeter to its highest range. Connect one lead to any stator wire, and the other to the alternator housing (Figure 19B). The meter should indicate infinite resistance.

3.Replace the stator if the unit fails either of the preceding tests.

KH400 Alternator (with CDI) Troubleshooting

1. There are 3 leads from the alternator to the voltage regulator.

2. Set the ohmmeter to the R x 1 range. Measure the resistance between the 2 yellow leads; it should be 0.45-0.7 ohms. If the reading is less, the coils are probably shorted. A higher reading or no reading at all indicates the coils are open.

3. Set the ohmmeter to the highest range. Connect one lead to a yellow lead and one to the chassis (frame, engine, etc.); repeat for the other yellow lead. The meter should indicate infinity. If there is any meter reading, it indicates a short.

4. If the windings indicate normal resistance, but voltage and current tests indicate that the alternator is defective, then the magnets in the rotor are probably weak and must be replaced.

5. Replace the stator if the unit fails any of the preceding tests.

KH500 and H1 Alternator Troubleshooting

1. Measure field winding resistance between the slip rings, as shown in Figure 21. If the resistance is not 3.5 to 5.5 ohms, replace the rotor.

2. Measure insulation resistance of the field winding. Set the ohmmeter to its highest range, then measure resistance between either slip ring and the rotor shaft. Insulation resistance must be essentially infinite.

3. Inspect the brushes. Replace them if they are worn to 3/8 inch (9.3 millimeters). Standard length for new brushes is 9/16 inch (14 millimeters).

4. Check for continuity between each pair of yellow wires coming from the alternator stator.

5. Set the ohmmeter to its highest range, then measure insulation resistance between the stator housing and the three yellow leads. Insulation resistance must be essentially infinite.

H2 Alternator Troubleshooting

1. Measure resistance between both yellow leads. Resistance should be approximately 0.4 ohm.

2. With the ohmmeter set to its highest range, measure insulation resistance between either yellow lead and ground. Insulation resistance must be essentially infinite.

3. Measure resistance between the blue and the green leads. Resistance should be approximate1y 5 ohms.

4. Measure resistance between the black lead and each white lead. Resistance should be approximately 200 ohms.

5. Measure resistance between the white and green leads. Resistance should be approximately 200 ohms.