ALTERNATOR AND VOLTAGE REGULATOR

Transcription

1 / 1 SECTION ALTERNATOR AND VOLTAGE REGULATOR GENERAL INFORMATION The alternator system is composed of a belt-driven, oilcooled, brushless alternator and an electronic voltage regulator. These components are controlled by the vehicle s multiplexing system. The alternator generates an alternating current, which is then rectified to direct current. The voltage regulator limits the maximum voltage produced at the alternator s output terminal by controlling the rotor s magnetic field by excitation. WARNING: The electrical wiring on the vehicle is NEGATIVE- GROUNDED. If the batteries are not connected appropriately for a NEGATIVE-GROUNDED system, serious damage to the alternator, voltage regulator, batteries and cabling will result. DO NOT short-circuit any terminal on the alternator or regulator. OPERATION See Figure 1. The alternating current generated by the alternator is rectified through a diode rectifier bridge. See Figures 2 and 3. The completely sealed alternator is cooled and lubricated by the engine oil. The oil is distributed via internal conduits and descends by gravity to the drain outlet. The alternator must never be operated without a supply of engine oil. The alternator has a maximum capacity of 270 A of direct current at maximum engine speed (approximately 6500 rpm at the drive shaft) and 160 A when idling. The alternator has three terminals (see Figure 3): a direct current terminal, an excitation terminal (field) and a relay terminal (alternator start). The relay terminal sends a direct current signal of 24 volts to the multiplexing system, which retransmits information to various systems throughout the vehicle. T-CONNECTOR AND OIL INLET AIR SPACES STATOR ROTOR NON MAGNETIC RING OIL INLET STATIONARY FIELD WINDING DIODE DRAIN O-RING STATOR TERMINAL O-RING Figure 1 - Sectional View of Alternator

2 2 / FIELD CURRENT SUPPLIED BY VOLTAGE REGULATOR FIELD TERMINAL MOUNTING SCREW RELAY TERMINAL DIODE DC TERMINAL GROUND TERMINAL DIODE OUTLET DC GROUND TO POSITIVE TERMINAL OF BATTERY AND STATOR STUD R DIODE AND HOLDER DIODE MOUNTING SCREW Figure 2 - Electrical Diagram of Alternator Figure 3 - Rectifier with Cap Removed The voltage regulator monitors the voltage to the battery terminals. When the battery voltage is lower than regulated by the regulator, the latter transmits an excitation current to the alternator s field winding assembly. The excitation current allows the altenator to produce as much output voltage as possible. Whenever the battery voltage is greater or equal to the voltage regulated by the regulator, the excitation current is decreased, the windings are thus deactivated and the output voltage of the regulator begins to drop. ALTERNATOR PRECAUTIONS To avoid damaging the alternator system, always take the following precautions during maintenance and verification operations: WARNING: On T-Drive vehicles, the starter and alternator cables are continuously live, even when the switch on the power distribution box is off. 3. Whenever the batteries are connected, the alternator output terminal is live. When working near the alternator, disconnect the negative battery cable to prevent accidental grounding to the alternator output terminal. 4. Never ground the field terminal to check for the presence of an alternator field current. MAINTENANCE Because there are no brushes, slip rings or moving seals, the alternator needs no periodic maintenance. However, the following checks must be performed regularly: 1. Check for loose assembly bolts between the engine and the alternator, and tighten as necessary. 2. Check all wiring for loose connections or corrosion. Clean and tighten as needed. Make sure all cable insulation is in good condition and that all cables are firmly attached to prevent shearing of the insulation. 3. With the engine running, listen for noises and check the alternator for any vibrations. If it is noisy or vibrates excessively, remove it for inspection and repairs. 4. Check the level and density of the battery electrolyte. Restore the level as required. For more information, see section : BATTERIES in this manual. 1. The electric wiring is NEGATIVE-GROUNDED. Connecting the batteries or a battery charger to a positive-grounded terminal will put a high current through the alternator diodes and vehicle wiring, resulting in burned open circuit diodes and a burned wiring harness. 2. Never operate the alternator with the field terminal connected and the output terminal disconnected. With no battery or electric charge in the circuit (ruptured contact), excessive voltage may build up in the alternator. Make sure all contacts in the load circuit are well connected.

3 / 3 CHECKS In the event of a malfunction in the alternator system, a dashboard light will go on on the dashboard to indicate that the alternator is not charging. The light normally goes on when the MASTER CONTROL SWITCH is in the ON position each time the engine is started. If it lights up during operation, it indicates a generating system malfunction. The checks explained under the headings CHECKING THE ALTERNATOR OUTPUT ON THE VEHICULE and CHECKING THE ALTERNATOR RELAY TERMINAL in this section can be made to determine whether the problem is in the alternator or the alternator relay terminal. If the problem is in neither of these, see the section entitled VOLTAGE REGULATOR further in this section for other points to check. Any defective unit must be replaced. Following is a list of the most common alternator malfunctions: 1. Alternator diodes open or short-circuited. 2. Stator windings short-circuited, grounded or open. 3. Field windings short-circuited, grounded or open. 4. Excessive alternator noise. RELAY FIELD ALTERNATOR DC TERMINAL GROUND VOLT- METER Figure 4 - Typical Test Setup BATTERY CARBON PILE AMMETER CHECKING THE ALTERNATOR OUTPUT ON THE VEHICLE See Figure 4 for a typical test setup. 1. Disconnect the negative battery cable. 2. Disconnect all wires on the voltage regulator and field terminal. WARNING: DO NOT let the wires touch ground; damage to equipment may result. 3. Connect a voltmeter and an ammeter to the circuit as shown in Figure 4. a. Connect one wire of the ammeter to the positive battery terminal and the other to the DC terminal of the alternator. b. Connect the positive wire of the voltmeter to the DC terminal of the alternator and ground the other on the alternator body. 4. Run a connecting wire from the DC terminal to the field terminal as shown. 5. Connect a charge (carbon pile) to the battery as shown. Make sure the carbon pile is not energized. 6. Reconnect the negative cable to the battery. 7. Start the engine and run it at about 1300 rpm. 8. Turn on all the vehicle accessories and adjust the carbon pile until the ammeter indicates a current of 270 A. 9. Check the voltmeter; a minimum reading of 28.2 V should be obtained. 10. If the alternator fails to operate as stated in steps 8 and 9, it is defective. Check the components as explained under the TROUBLESHOOTING GUIDE further in this manual.

4 4 / CHECKING THE ALTERNATOR OUTPUT ON A TEST BENCH See Figure 5. Once the alternator has been removed from the engine, it can be inspected on a test bench with no oil circulation, as long as the output is limited to 100 A. A higher amperage may be used, but only for a maximum of 15 seconds. Operating the alternator at more than 100 A for more than 15 seconds will cause it to overheat, resulting in damage to the coils and diodes. If the unit is to operate longer than 15 seconds at more than 100 A, an oil circulating system must be installed. An SAE No. 30 oil must be used at a pressure of 35 psi (241 kpa) and a temperature of 180 to 220 F (82 to 104 C). This will allow the oil to circulate at about 1 gal/min (4 l/min). The setup shown in Figure 5 will make it possible to obtain this result. A spiral tube connected to a water supply can be submerged in the oil for cooling. Before performing the tests, heat the oil to 180 F (82 C) by immersing a 110-V heating element in it. To check the alternator on a test bench, make the electrical connections shown in Figure 5, operate at a given speed. Recommended output readings are available in the manufacturer's documentation Adjust the carbon pile to obtain the desired output level. CHECKING THE ALTERNATOR RELAY TERMINAL When the engine is running and the alternator is charging, current is sent to the multiplexing system from the relay terminal. 1. Connect the voltmeter wires to the relay terminal and to the vehicle ground. 2. Start the engine. A reading of about 13.5 to 27 V is normal and indicates an appropriate supply to the relay. 3. Connect the voltmeter wires to No. 2 terminal of JCT 24 junction and to the vehicle ground. The voltmeter should indicate the battery voltage when the alternator is charging. A zero voltage reading indicates a defective relay. CHECKING THE DIODES See Figure 6. While checking the diodes for short-circuits and ruptured contacts, use an ohmmeter with a 1-V cell. Select a scale on which a reading of 300 ohms corresponds to about the one-third mark. WARNING: DO NOT use any high voltage, such as a 110-V test lamp, to check the diodes. OIL INTAKE CATHODE (-) MOUNTED ON SUPPORT CATHODE (-) MOUNTED IN END BELL WATER LINE VALVE DRAIN OIL OIL TANK HEATER ANODE (+) ANODE (+) Figure 5 - Hot Testing of Alternator Figure 6 - Checking the Diodes with an Ohmmeter

5 / 5 Remove the mounting screws and lock washers attaching the diode cap to the end bell. Remove the cap from the end bell and, at the same time, take the terminal bolts out of the diode cap. HOLDER-MOUNTED DIODES See Figure 5. To check the diodes mounted in holders, connect the positive ohmmeter wire to each anode and the negative ohmmeter wire to the cathode of the diode and take the reading. Reverse the connections and take the reading again. If both readings are under or over 300 ohms, the diode is defective. If one reading is high and one low, the diode is in good condition. Defective diodes must be replaced as described under the heading REPLACING THE ALTERNATOR INTERNAL COMPONENTS in this section. END-BELL-MOUNTED DIODES Check the diodes mounted in the end bell. If one reading is high and one low, the diode is in good condition. CHECKING THE FIELD WINDINGS See Figure 7. Inspect the alternator field windings for ruptured contacts, grounds and short-circuits by using an ohmmeter or by checking the amperage as follows: 1. Connect an ammeter and a 24-V power supply in series with field terminal and the ground (on the diode end bell). 2. Alternator excitation should increase the reading from 7 to 7.2 amps with 24 V connected in series. 3. Any other reading indicates a short-circuited, open or grounded inductor. CHECKING THE STATOR WINDINGS OPEN CIRCUITS To check the stator windings for open circuits, connect an ohmmeter to two pairs of diode holders as shown in Figure 7, taking care to maintain the polarity of the wires. Check the holders according to this sequence: 1-2, 1-3, 2-3. See Figure 8. The ohmmeter should indicate low resistance. If the reading indicates infinite or high resistance, the stator windings are open. Defective diodes must be replaced as described under the heading REPLACING THE ALTERNATOR INTERNAL COMPONENTS in this section. READINGS INCREASE FROM 7 to 7.2 AMPS WITH 24V CONNECTED IN SERIES V POWER SUPPLY AMMETER FIELD TERMINAL Figure 7 - Checking the Stator Windings

6 6 / GROUNDS To check the stator windings for grounding, connect an ohmmeter to the diode holder and the diode end bell, as shown in Figure 9. The ohmmeter should indicate infinite or very high resistance. If the reading indicates low or zero resistance, the stator windings are grounded. SHORT-CIRCUITS Because of their extremely low resistance, stator windings are difficult to check for short-circuits without special laboratory equipment. If all other alternator tests are satisfactory, but the alternator still does not operate according to the specifications, it may indicate the presence of short-circuited stator windings. As an alternative method, the windings may be checked for grounding through the use of a MEGGER device, or equivalent. Before proceeding, ensure that all equipment and electronic circuit components are well insulated. To use the power unit, connect one test wire to a stator terminal and the other to the stator body. Leave the power on for five seconds and watch the light on the unit. If the light goes on, the stator is grounded. Repeat the test for the two remaining stator wires. REPLACING THE ALTERNATOR REMOVAL 1. Open the rear engine access door and remove the guard plate at the front of the engine. If equipped, open the inside engine access door, near the passenger seat at the back of the bus (V-Drive vehicles only). 2. Remove the drain plug and empty the oil into a container. Put the drain plug back into place. 3. Disconnect the F and RLY terminal wires and the battery cables on the DC terminal of the diode cap. Place electrical tape on the cable ends to prevent short-circuiting, and label the wires removed from the other terminals to facilitate identification at the time of installation. 4. Disconnect the oil lines (supply, return and equalizing). Stator windings appear in a star configuration and the end of each phase is attached to a common terminal. HOLDER 1 HOLDER 2 HOLDER 3 CHECKING SEQUENCE: 1-2, 1-3, 2-3 (+) (-) INFINITE OHMMETER Figure 8 - Rupture Test in Stator Winding Figure 9 - Grounding Test in Stator Winding

7 / 7 5. Lift up the retractor arm and pulley to remove the drive belt from the alternator. REPLACING THE ALTERNATOR INTERNAL COMPONENTS WARNING: Before unbolting the alternator from its bracket, make sure it is held in place by a safety clip. 6. Remove the bolts attaching the alternator to the enginemounting bracket. 7. Remove the four nuts and lock washers and lift the alternator from its assembly rack. INSTALLATION 1. Install the alternator on its assembly rack. Install the four nuts (1/ inch) and lock washers (1/2 inch). 2. Lift up the retractor arm and pulley to install the alternator drive belt. See Figure Connect the oil lines. WARNING: Dirt can block the oil inlet in the diode cap. When replacing or connecting the oil lines, do not allow any dirt to enter. 4. Connect the wires to the FLD and RLY terminals. Apply a torque of 3.4N m (30lb-in.). Connect the terminals and connect the battery cables to the DC terminal, applying a torque of 24N m (18lb-ft). Tighten all terminal nuts. 5. Make sure the drain plug is installed and fitted tightly into the diode cap. Once the oil has been drained from the diode cap, there will be about one quart less of oil circulating in the engine. After starting the engine and putting the diode cap back into place, check the oil level and top it up if necessary. 6. If equipped, close the inside engine access door (V-Drive vehicles only). Install the guard plate in front of the engine and close the rear engine access door. In the following replacement methods, it is assumed that the diode cap is still off and that the diode wires have been disconnected, as required during the preceding tests. WARNING: When replacing a diode, make sure it is designed for a NEGATIVE-GROUNDED system. The diode can be identified by the symbol stamped on the housing. The arrow must point towards the flexible wire of the diode. To replace any of the three diodes mounted on holders attached to the stator wire studs (See Figure 2), remove the diode and its holder. The two outer diodes and their holders are identical and may be installed on either side. The middle diode has a different holder: its mounting holes are 2 in. (50.8 mm) c/c apart, as opposed to 2-1/4 in. (57.2 mm) c/c for the outer diodes. REPLACING HOLDER-MOUNTED DIODES See Figure Remove the nut, together with the diode holder, from the lock washer attaching the holder to the stator wire stud. 2. Remove the nut, lock washer and flat washer attaching the holder to the small stud in the end bell. 3. Remove the diode and holder, then remove the insert from the small hole in the holder or from the small stud in the end bell. 4. Remove the nut and flat washer from the diode assembly stud, then remove the diode from its holder. 5. Place the new diode in the holder and install the flat washer and nut on the diode assembly stud. While holding the diode with a wrench against its flats, tighten the nut on the assembly stud with a torque of 160 to 180 lb-in. (18.1 to 20.4 N m). 6. Place the diode and its holder on the stator wire stud and the small assembly stud. Place the insert on the small stud inside the orifice in the diode holder. Install the flat washer, lock washer and nut on the small stud and tighten with a torque of 22 to 25 lb-in. ( N m). Install the nut with the lock washer on the stator wire stud and tighten well.

8 8 / REPLACING END-BELL MOUNTED DIODES See Figure 10. To remove a diode, take a thin wrench, open it to 1 inch (25.4 mm) and place it on the flats of the diode housing to unscrew it from the end bell. Coat the threading of the new diode with silicone grease, screw it into the end bell, and tighten it with a torque of 160 to 180 lb-in. (18.1 to 20.4 N m). If no other part needs to be replaced, see the heading INSTALLING THE DIODE CAP, to complete the assembly. REPLACING INDUCTORS See Figure 10. REMOVAL 1. Remove three diodes and their holders from the end bell to gain access to the two lower bolts between the end bell and the inductors. 2. Remove the nut, flat washer and lock washer from the three stator wire studs. 3. Remove the six bolts and lock washers holding the diode end bell to the stator body. 4. Separate the end bell from the stator body and remove the end bell and inductors from the rotor, while pushing the stator wire studs out of the end bell. 5. Remove the nut, lock washer, flat washer and insulating washer holding the exciter terminal stud inside the end bell. Push the stud out of the end bell. 6. Remove the insulating bushing from the exciter terminal stud and the o-rings from the end bell. 7. Remove the four bolts and lock washers attaching the inductor to the end bell. 8. To separate the inductor from the end bell, put four 24 3" bolts in the place of the 24 2" assembly bolts removed in Step 7. Screw the bolts to equal heights. Place the end bell in the mandrel press and use an appropriate puller to exert force on each of the four bolt heads and push the inductor out of the end bell. INSTALLATION 1. Place the inductors inside the end bell, insert four 24 3" bolts and screw them into the inductors to keep the holes lined up. 2. Support the end bell on the mandrel press housing so as to prevent damage to the diodes, and press the inductor into the end bell. 3. Push until the shoulder of the induction coil reaches the bottom against the end bell. 4. Remove the four guide rods. Install the four 24 2" bolts with new lock washers, attach the inductor to the end bell, and tighten well. 5. Place the insulating bushing in the hole of the exciter terminal stud in the end bell and insert the terminal stud through the bushing. 6. Place two o-rings and the bushing on the terminal stud and insert it into the hole in the end bell. 7. Install the insulating washer, flat washer, tooth lock washer and nut on the terminal stud and tighten well. 1. OUTPUT TERMINAL STUD 2. TOOTH LOCK WASHER 3. FLAT WASHER 4. INSULATING WASHER 5. DIODE (IN END BELL) 6. DIODE AND HOLDER 7. STATOR TERMINAL STUDS 8. RELAY TERMINAL WIRE STUDS 9. INSULATING WASHER 10. FLAT WASHER 11. TOOTH LOCK WASHER 12. INDUCTOR TERMINAL STUD Figure 10 - Alternator Components

9 / 9 8. Install each of the three stator wire studs in the end bell as follows: place the insulating washer on the stud and insert the stud into the end bell. 9. Place the insulating bushing on the stud and place the stud in the orifice in the end bell. 10. Install the flat washer, nut and lock washer on the stud and tighten well. 11. Install three diodes and their holders on the end bell as described earlier under the heading REPLACING END-BELL MOUNTED DIODES. 12. Install a new o-ring in the groove around the end of the stator body. Insert the inductor into the rotor and place the end bell against the stator body. 13. Attach the end bell to the stator body with six bolts and lock washers. Tighten well. 14. If no other part needs to be replaced, see the heading INSTALLING THE DIODE CAP to complete the assembly. INSTALLING THE DIODE CAP See Figure Make sure all diodes are correctly installed and well tightened. The diode wires screwed into the end bell must be firmly attached to the diode holders. The relay terminal wire must also be attached to the left diode holder as shown in Figure Once the three diodes are mounted on their holders, connect the wires to the output terminal stud as shown in Figure 2. Tighten the mounting screw. Place insulating bushings on the studs of the output terminal stud and the relay terminal. 3. Place a new o-ring in the diode end bell. 4. Once the diode cap is placed on the end bell, the studs on the output and relay terminals must be inserted through the holes in the top of the cap. A flexible steel wire installed on the stud threads and the wires passed through the holes will make it easier to get the studs through the holes. Make sure the insulating bushings are installed on the terminal studs. 5. Once the cap is in place against the end bell, install seven mounting screws and lock washers. Tighten the screws firmly and equally. 6. Referring to Figure 2, install the insulating bushings and o-rings on the studs of the output and relay terminals, and push them into the cap. Make sure the bushings are positioned in the counter-bores on the top of the cap. Hold each stud in place with an insulating washer, flat washer, tooth lock washer and nut. Tighten the nuts. 7. Make sure the drain plug is installed and well tightened in the bottom of the cap. To prevent dirt from entering the oil inlet in the top of the cap, block the orifice until the alternator is installed. REPLACING THE STATOR See Figure 11. If the test indicates a ruptured contact or short-circuit in the stator, both the stator and its body must be replaced. REMOVAL 1. Remove the diode end bell and inductors as described previously in steps 1 to 4 under REMOVAL in the section REPLACING INDUCTORS. 2. Remove the six bolts and lock washers attaching the stator body to the drive-side end bell. 3. Separate the stator body from the drive-side end bell and remove it from the end bell and the rotor. WELDING THE STATOR TERMINALS To weld the stator terminals, follow these steps: 1. Thoroughly clean the wire and the terminal with a wire brush. 2. Using a gas welding torch and silver solder, weld the stator wire to the terminal. 3. Clean the weld thoroughly with a wire brush. 4. Using a high-quality, resin-based soldering flux, coat the silver weld with an 80% tin/20% lead weld, or a pure tin weld, to protect the silver weld from being damaged by motor oil. The silver weld will provide the necessary mechanical strength and will not be affected by temperature. The lead-tin weld will protect the silver weld against damage from exposure to motor oil.

10 10 / Figure 11a - Alternator -Exploded View

11 / SCREW 2 - WASHER 3 - CAP 4 - WASHER 5 - SCREW 6 - LOCK WASHER 7 - SCREW 8 - LOCK WASHER 9 - NUT 10 - WASHER 11 - STATOR TERMINAL STUD 12 - NUT 13 - LOCK WASHER 14 - DIODE HOLDER STUD 15 - DIODE HOLDER 16 - ANCHOR 17 - DIODE SCREEN 18 - NUT BEAM 19 - LOCK WASHER 20 - BOLT 21 - LOCK WASHER 22 - RECTIFIER CHASSIS 23 - STATOR 24 - ROTOR 25 - DC TERMINAL 26 - RELAY TERMINAL 27 - ROTOR TERMINAL ROTOR TERMINAL BOLT 30 - LOCK WASHER 31 - GEAR CHASSIS 32 - O-RING 33 - RETAINER NUT 34 - WASHER 35 - ROTOR 36 - BEARING RETAINER 37 - SCREW 38 - BEARING SPACER 39 - DOUBLE-ROW BEARING 40 - SINGLE-ROW BEARING 41 - BEARING COLLAR 42 - INSULATING RING 43 - O-RING 44 - INSULATING WASHER 45 - INSULATING WASHER 46 - FLAT WASHER 47 - TOOTH LOCK WASHER 48 - NUT 49 - LOCK WASHER SPRING 50 - INSULATING RING 51 - INSULATING WASHER 52 - INSULATING FITTING 53 - INSULATING RING 54 - O-RING 55 - INSULATING WASHER 56 - WASHER 57 - TOOTH LOCK WASHER 58 - LOCKNUT 59 - LOCK WASHER SPRING 60 - ISOLATOR PAD 61 - INSULATING RING 62 - O-RING 63 - INSULATING WASHER 64 - WASHER 65 - TOOTH LOCK WASHER 66 - LOCKNUT 67 - LOCK WASHER SPRING 68 - BOLT Figure 11b - Alternator Components List INSTALLATION 1. Place the new o-ring in the groove around the drive side of the stator body. 2. Place the stator and body on the rotor against the drive-side end bell. Attach the stator body to the drive-side end bell with six bolts and lock washers. Tighten well. 3. Install the diode end bell and inductors as described in steps 5, 6 and 7 under Installation in the section REPLACING INDUCTORS. 4. Install the closing cap on the current rectifier as described further. REPLACING THE BEARING OR ROTOR See Figures 11 and 12. Whenever the rotor and drive-side end bell are dismantled for any reason, the single-row bearing must be replaced because of the possibility of damage during dismantling. REMOVAL AND DISASSEMBLY 1. If the counter-driven gear was not removed from the rotor shaft when the alternator was taken out, remove it now by removing the nut and flat washer from the shaft. 2. Remove the six bolts and lock washers holding the driveside end bell to the stator body. Separate the drive-side end bell from the stator body and remove it along with the rotor. 3. Support the drive-side end bell in the mandrel press so that the rotor can be pushed out. Using an appropriate adapter positioned against the end of the rotor shaft (which will pass through the inner bearing raceway), push on the rotor and remove it from the end bell and double-row bearings. (Because the outer raceway of the single-row bearing is held in the end bell by the bearing cup and the inner raceway is pressed against the rotor shaft, the bearing may be damaged when the shaft is removed and replaced.) 4. Remove the six screws attaching the bearing cup to the drive-side end bell. Remove the bearing cup, single-row bearing and bearing spacer from the end bell. 5. Support the drive-side end bell in the mandrel press with the double-row bearing at the bottom so it can be pushed out. Using an appropriate screwdriver to exert force on the outer bearing raceway, push the bearing out of the end bell. 6. Remove the rubber bearing collar from the end bell groove.

12 12 / ASSEMBLY AND INSTALLATION See Figure Install a new single-row bearing inside the drive-side end bell. Install the bearing cup and attach it with six screws. Fix the screws into place after tightening. 2. Place the rubber bearing collar in the groove of the bearing bore in the drive-side end bell. Lubricate the collar so that the bearing can be pushed in without dislocating or damaging the collar. 3. Place the rotor in the mandrel press with the shaft end up. Install the drive-side end bell and single-row bearing on the rotor. Using a screwdriver placed on the rotor shaft to exert force on the inner bearing raceway, push the bearing against the shaft until it reaches the bottom against the rotor. 4. Install the bearing spacer on the rotor shaft. Place the double-row bearing on the rotor shaft at the bore of the end bell. Using an adapter that will exert force on both the inner and outer bearing raceways, push the bearing against the shaft and into the end bell until the inner raceway reaches the bottom against the bearing spacer. 5. Place a new o-ring in the groove around the drive side of the stator body. 6. Insert the rotor between the stator and the inductor and place the drive-side end bell against the stator body, attaching it with six bolts and lock washers. Tighten the bolts with a torque of 60 to 65 lb-in. (6.78 to 7.32 N m). WARNING: When replacing the alternator on this vehicle, be sure to use an alternator with the same drive ratio. Use of any other drive ratio will cause severe and costly damage to the alternator and engine. CLEANING AFTER DISASSEMBLY Whenever the alternator is disassembled, check if grease has built up on the stator. If so, use light mineral oil to clean it. INSPECTION AFTER DISASSEMBLY When the alternator has been disassembled to the point where the stator is exposed, it should be checked for the following: 1. Appropriate varnish. 2. Conductors appropriately spaced to prevent quasi shortcircuits. 3. Appropriate positioning of the phase wire. 4. Intense conductor and double-vee butt-welds. BEARING RETAINER SCREW BEARING O-RING SPACER PLATE SEAL BEARING SPACER Figure 12 - Pulley-Side Components of Alternator

13 / 13 ALTERNATOR BELT AND TENSIONER See Figures 13 and MAINTENANCE The alternator drive belt must be inspected regularly. Examine the belt ribbing for any signs of cracking or damage. Figure 14 shows the types of cracks that are acceptable. Measure the belt deflection at the point where the span is longest normally, between 3/8" and 1/2" (9.5 to 12.7 mm). The belt tensioner requires no maintenance and cannot be repaired. However, both the tensioner and the belt tension should be inspected every 24,000 miles (38,000 km) or every 1,000 hours. Use a tension gauge to check the belt tension. For a new, eight-ribbed belt, the recommended tension is 200 lbf (890 N). For a used belt, a tension of 80 to 160 lbf (360 to 710 N) is recommended A belt is considered used if it has been in service for more than 10 minutes. REPLACING THE BELT 1. Use a 3/8" (13 mm) carriage nut wrench to hold the tensioner. 2. Remove the belt. 1. TENSIONER (ALTERNATOR BELT) 2. ALTERNATOR BELT 3. ALTERNATOR PULLEY 4. TENSIONER (WATER PUMP BELT) 5. BELT (WATER PUMP) 6. ALTERNATOR MOUNTING RACK Figure 13 - Typical Belt Installation The pulley bearings should turn freely. 3. Check the tightening torque of the tensioner bolts; it should be 32 lb-ft (43 N m). Figure 14 - Criteria for Belt Inspection

14 14 / VOLTAGE REGULATOR GENERAL INFORMATION The voltage regulator is located in the battery compartment. The Voltage Regulator is a maintenance-free, electronic component sealed in an aluminum case. It is designed to protect against over-voltage and short circuits. The function of the regulator is to maintain the same voltage, although there are wide fluctuations in alternator speed and load, thus preventing battery undercharge or overcharge. Two types are available, depending whether the vehicle is a V-Drive configuration (see Figure 15) or a T-Drive configuration (see Figure 16). TROUBLESHOOTING Trouble in the regulator circuit will cause symptoms of undercharged or overcharged batteries. See Table 1 to determine the nature of the problem. Adjust according to ADJUSTMENT heading below. CHECKING THE REGULATOR This procedure only applies to regulators installed on V-Drive configurated vehicles. 1. Install the clamp ammeter on the alternators DC output cable. (The cable connected to the battery). 2. Connect a voltmeter with negative lead to GND and positive lead to the BAT terminal on the regulator. The reading of the voltmeter should be approximately the battery voltage. If not, repair the ground or battery-to-regulator wiring and recheck to verify the repairs. 3. Turn the MASTER CONTROL SWITCH to the RUN position and place the positive voltmeter lead on the regulator IGN terminal. The reading should be within 2 volts of BAT voltage. If so, go on to step 4. If voltage is low or zero, check switches and wiring between batteries and regulator IGN terminal for open and loose connections and repair the defect. Recheck to verify the repair. 4. With voltage at IGN, place voltmeter positive lead at FLD. The reading should be ± 3 volts of BAT voltage. If so, check the voltage between alternator F terminal and ground (case). If alternator F voltage is near zero, look for an open circuit in the wire from the regulator FLD terminal to the alternator F terminal and repair it. 5. Recheck to verify repair. If the voltage at regulator FLD is still less than 5 volts, remove the wire from FLD terminal and recheck. STREET SIDE STREET SIDE NOVA LFS T-DRIVE 40 FT NOVA LFS V-DRIVE 40 FT ADJUSTING SCREW NOVA LFS ARTIC T-DRIVE ADJUSTING SCREW GROUND FIELD (-) BATTERIES (+) IGNITION SENSE Figure 15 - Voltage Regulator (Nova LFS V-Drive) Figure 16 - Voltage Regulator (Nova LFS T-Drive)

15 / 15 Dim lights UNDERCHARGED BATTERIES Low dash voltmeter reading (only if dash voltmeter option is installed) Slow or no cranking Starter solenoid chatter CHARGE BATTERY Tell tale on with engine running REGULATOR TROUBLE SYMPTOMS OVERCHARGED BATTERIES Lights very bright or burned out High dash voltmeter reading (only if dash voltmeter option is installed) Hot battery - Above 120 F (50 C) Unpleasant odor emission from the batteries Table 1 - Trouble Symptoms 6. Recheck to verify repair. If the voltage is still less than 5 V, replace the regulator. 7. If an overcharged battery symptom exists, and the voltage cannot be adjusted into the normal range (27 to 29 V at the alternator) by turning the adjusting screw (Figures 15 and 16), start the engine and turn on electrical loads to take about 50 to 100 A from the alternator. Check voltage between regulator BAT and GND terminals. Compare this reading with voltage across the battery. If the regulator voltage is more than 1 V below the battery s voltage, check and repair connection and ground wires between the battery and the regulator. If the voltage still cannot be adjusted, replace the regulator and check alternator field for shorts or grounds. ADJUSTING THE REGULATOR In order to execute the following procedure, a numeric voltmeter with at least 1.5% precision and 10 kiloohm/volt impedance and a clamp ammeter capable of measuring 300 amperes are required. 1. Start the engine and let it run at fast idle. 2. Activate the heating system and open the exterior lights or any other combination of electrical accessories to obtain a current of 20 to 200 A. 3. Make the following connections, depending on the configuration of the vehicle: a. On a V-Drive vehicle, connect the voltmeter directly to the voltage regulator: the negative lead on the negative terminal and the positive lead on the positive terminal. b. On a T-Drive vehicle, connect the voltmeter directly to the batteries: the negative lead on the negative terminal and the positive lead on the positive terminal. 4. The voltage must be constant at 27.6 ± 0.1 volts. 5. Adjust this voltage if necessary using the adjusting screw. See Figures 15 or 16. To increase the voltage, turn the screw clockwise. To reduce the voltage, turn the screw counterclockwise. 6. After adjusting the voltage, the adjusting screw must be secured with an anti-tamper seal.

16 16 / SPECIFICATIONS ALTERNATOR Model...See Parts Manual Manufacturer... Delco-Remy Series DN Type Drive... Belt Drive ratio...2.7:1 Resistance (80 o F [27 o C]) Ω FIELD CURRENT AT 80 F (27 C) Current... 7 to 7.2A Voltage... 24V REGULATOR Model...See Parts Manual Manufacturer... Delco-Remy Series...according to option Type...Integrated Circuit Polarity... Negative ground Voltage regulation... 27V SYMPTOM Low Voltage Output High Voltage Output No Voltage Output TROUBLESHOOTING GUIDE SOLUTION a. Check: loose drive belt; low battery state of charge. b. Check: current load on system is greater than alternator can produce. c. Check: defective wiring or poor ground path; low regulator set point. d. Check: defective alternator and/or voltage regulator. a. Check: wrong regulator. b. Check: high regulator set point. c. Check: defective regulator. d. Check: alternator. a. Check: broken drive belt. b. Check: battery voltage at alternator output terminal. c. Check: defective alternator or regulator. Table 2 - Troubleshooting Guide