- multimeter;
- power supply with adjustable voltage up to 20 V or battery charger;
- three or two-jaw puller;
- mandrel from the cup puller kit for pressing out the front bearing.
Disassembly
1. Remove the generator from the car.
2. Having pressed the three spring clips, remove the protective cover of the generator rectifier unit.
3. Using a Phillips screwdriver, unscrew the two screws securing the voltage regulator.
4. Disconnect the wire connector from the output of the voltage regulator and remove the voltage regulator from the generator.
5. Using an 8 mm spanner, unscrew the three bolts connecting the terminals of the stator windings to the rectifier unit (1), and another bolt securing the rectifier unit (2) (note how the insulating and thrust washers are installed).
6. Carefully bend the wire of the generator stator winding leads to the side.
7. Using a Phillips screwdriver, unscrew the screw securing the capacitor.
8. Remove the rectifier unit from the generator together with the capacitor. Using a 10 mm socket wrench, unscrew the two nuts of the contact bolt. We remove the remote and insulating bushings from the bolt, remove the bolt from the rectifier unit and remove the capacitor tip from the contact bolt.
9. Mark with a marker the relative position of the front and rear covers of the generator (to simplify assembly).
10. Using an 8 mm socket wrench, unscrew the four bolts that tighten the front and rear covers of the generator.
11. With a slotted screwdriver, gently push the generator covers apart.
12. Disconnect the rear cover along with the stator winding from the front cover of the generator.
Recommendation. To determine the technical condition of the rear bearing, shake from side to side and vigorously rotate its outer ring. The generator bearing should not have significant play, and the ring should rotate freely without jamming and extraneous noise. A defective alternator bearing must be replaced.
13. Mark the stator with a marker (to indicate its position relative to the rear cover of the generator).
14. We take out the stator from the rear cover of the generator.
Recommendation. To determine the technical condition of the front bearing of the generator, hold the pulley with your hand, shake it from side to side and rotate the front cover of the generator. If the bearing seizes, has significant play, or makes noise when the cover is vigorously rotated, then it must be replaced.
Helpful advice. The manufacturer recommends changing the front rotor bearing along with the front cover of the generator, as it is rolled into the cover. But, given that the cost of the bearing is much lower than the cost of a new front cover and, especially, the generator assembly, it is advisable to press out and replace the faulty bearing.
15. If it is necessary to replace the front bearing of the generator with a 24 mm socket wrench, unscrew the pulley fastening nut, holding the pulley with sliding pliers.
16. Remove the pulley with spring from the rotor shaft (3) and flat washer (2), spacer (1).
17. We screw the nut of the generator pulley onto the threads of the rotor shaft (flush with end). By blows of a hammer with a rubber striker on the nut, we press the rotor out of the front bearing.
18. If it is necessary to replace the front bearing of the generator, install the front cover in a vise (The jaws of the vise must be fitted with soft metal pads).
19. Having selected suitable mandrels from a set of cup puller, we press the bearing out of the seat in the front cover of the generator.
20. If it is necessary to replace the rear bearing of the generator, we fix the rotor in a vice with soft pads on the jaws. Using a universal puller, we press the rear bearing from the rotor shaft.
Examination
1. Check the generator rotor windings: a) applying the ohmmeter probes to the slip rings of the rotor, we check the excitation winding for an open circuit. The resistance of a healthy excitation winding should be 5-10 ohms;
b) connecting the ohmmeter probes to any slip ring and to the rotor, we check the excitation winding for a short circuit to «mass». With a good rotor winding, the ohmmeter should show an infinitely large resistance.
2. Check the generator stator windings:
A) alternately connecting the ohmmeter probes to the terminals of the stator winding, we check the winding for an open circuit. In the absence of a break, the ohmmeter will show a small electrical resistance (about 10 ohm);
b) by connecting the ohmmeter probes to any terminal of the winding and to the stator, we check the stator winding for a short circuit to «mass». If there is no short circuit, then the ohmmeter should show infinite resistance.
3. Check the generator rectifier unit:
Note. A good semiconductor diode conducts electricity in only one direction. A diode is faulty if it does not conduct current or conducts current in both directions.
A) connect the positive lead of the ohmmeter (in diode test mode) to common bus of auxiliary diodes (1), and the negative terminal probe - to the output of the tested diode (2). A good diode should not pass current (resistance tends to infinity);
b) change the probes of the tester in places. If the diode is good, the ohmmeter should show resistance (several hundred ohms). Similarly, we check the other two auxiliary diodes;
V) we connect the probe of the negative output of the ohmmeter to the plate of the rectifier block of the generator, into which the tested diode is pressed, and the probe of the positive output to the diode output. A good diode should not
pass current (resistance tends to infinity);
G) swap tester probes. If the diode is good, then the ohmmeter should show a resistance of several hundred (Ohm).
Similarly, we check other power diodes of the generator.
4. Check the generator voltage regulator:
A) we inspect the brushes of the generator voltage regulator, we are convinced of their mobility. If the brushes are broken or badly worn (protrude from the brush holder by no more than 5 mm), or the brushes wedged in the brush holder in this case, the voltage regulator must be replaced;
b) to check the voltage regulator, we assemble the simplest circuit (see below). TO «mass» voltage regulator wire connect the negative terminal of the power source, and to its output - positive. We connect the test lamp to the brushes of the generator voltage regulator.
Warning. When connecting wires supplying voltage to the voltage regulator of the generator, strictly observe the polarity. Incorrect wiring will destroy a working voltage regulator.
With a voltmeter we control the voltage supplied to the voltage regulator;
Generator voltage regulator relay test circuit: 1 - multimeter (in voltmeter mode); 2 - control lamp; 3- «weight» voltage regulator; 4 - output of the generator voltage regulator; 5 - brushes
V) turn on the power supply and apply 13 V to the voltage regulator. The control lamp should light up, indicating that at such a voltage in the vehicle's on-board network, the excitation current will flow to the generator rotor winding;
G) gradually increase the voltage until the control lamp goes out. The voltage at which the control lamp goes out should be 14.5-14.7 V.
d) reduce the applied voltage until the control lamp lights up again. The voltage at which the control lamp turned on should not be lower than 13.2 V. 5. Capacitor check:
Note. It is possible to measure the capacitance of the generator capacitor only with a special device. You can verify the failure of the capacitor using an ohmmeter with a measurement limit of at least 1000 kOhm.
We connect an ohmmeter to the terminals of the capacitor and observe its readings. If the capacitor is not broken, then when the device leads are connected to it, the ohmmeter will at first show a small resistance, then this resistance will increase rapidly until it stabilizes. A similar change in the readings of the ohmmeter should be repeated when the polarity of the device is changed.
A defective rotor, stator, capacitor or voltage regulator must be replaced. If one or more of the diodes in the rectifier unit of the generator is defective, the unit must be replaced as an assembly.
Assembly
Warning. Before pressing the front bearing of the generator into place, it is necessary to check the seat of the bearing and, if necessary, restore the chamfer with a knife or scraper where the edges of the hole have remained jammed. When pressing the front bearing into the generator cover, the force must be transferred only to the outer ring of the bearing.
1. Having selected suitable mandrels from the cup puller set, we press the new front bearing of the generator into the seat in the front cover until it stops.
Warning. When doing the following work, apply only light blows with a hammer. Strong blows can crack the generator cover, which is made of brittle aluminum alloy.
2. Using a steel drift of a suitable diameter and a hammer, we restore the rolling of the bearing in the generator cover.
Warning. Before installing the alternator rear bearing, make sure that the rotor shaft is securely clamped in a vise. Place a wooden block of a suitable size under the rotor shaft so that the front impeller of the rotor is not damaged during pressing. To avoid damage to the bearing, strikes should only be applied to the inner ring.
3. Using a piece of pipe of suitable diameter (19mm deep socket can be used) until it stops, we press the new bearing of the generator onto the rotor shaft.
Further assembly of the generator is carried out in the reverse order of disassembly. At the same time, we combine the marks applied to the covers and the generator stator. We finally tighten the coupling bolts evenly, crosswise, in several stages of half a turn. After tightening the bolts, we make sure that the rotor rotates easily (the rotor task may be due to the skew of the covers). Before tightening the stator winding bolts, make sure that insulating washers are installed under their heads.
Warning. When installing the generator voltage regulator, do not apply side forces to the brushes.