MERCEDES BENZ ALTERNATORS
Alternators & Regulators Bosch with internal regulators
Alternators produced by Bosch are regular 3-period, self-rectifying form alternators.
Bosch 75 by way of 55-amp alternators use3 damaging 3 beneficial and diodes connected to stator windings to rectify current, Bosch 90 and 80-amp alternators use 14 diodes.
All alternators use 3 exciter diodes related to stator windings, while the motor is jogging these diodes turn off the alternator indicator gentle and source electric power to the voltage regulator, Bosch regulators are transistorized solid condition and integral with alternator.
(1) Manufacturer’s Section No.
190E 14/70 489 928
190D 14/70 489 897
All Many others 14/70 N/A
(1) Bosch alternator part quantities are preceded by the figures 120 or commencing with an AL lettering a amount and ending with an X.
1. You can join a voltmeter to the alternator “B+” terminal and ground, voltmeter need to indicate battery voltage, if not examine wiring among battery and alternator.
2. Switch ignition on and verify that alternator indicator mild arrives on, if light-weight does not occur on, verify wiring amongst warning light-weight and alternator, which include indicator bulb.
1. Be certain connections at battery, alternator, and starter are clean and tight, make certain alternator engine and body are adequately grounded, make certain alternator belt is restricted and in fantastic affliction.
2. Connect ammeter following manufacturer’s recommendations, join voltmeter sales opportunities to battery terminals.
3. Start out motor and operate at 3000 R.P.M. alter carbon pile to get hold of greatest alternator output, do not allow voltage to go underneath 12.6 volts.
4. Alternator output need to equal alternator rated output, minus 16-20 amps, if reading is 16-20 amps beneath alternator rating, substitute regulator and retest, if output is nonetheless way too very low, fix or change the alternator.
REGULATOR Handle VOLTAGE Test
1. Join ammeter subsequent manufacturer’s directions, link voltmeter sales opportunities to battery terminals, operate motor at 3000 R.P.M.
2. Operate engine till voltage stops soaring, voltage need to be 13.5-14.5 volts, if reading through is incorrect, eliminate regulator and make sure brushes are for a longer period than 6 m.m..
3. If brushes are all right and regulator fails to maintain voltage in specified restrictions, substitute regulator and retest, if voltage is even now incorrect, mend or switch alternator.
1. Get rid of nut, lock washer, and pulley, try to remember placement of spacers, Then take out supporter assembly and crucial, scribe mark on entrance and rear housings, remove voltage regulator and remove screws, separate entrance and rear housings.
2. Disconnect capacitor from terminal take away nut, insulators, screws and washers.
Clear away stator assembly.
3. Unsolder stator from diode assembly clear away bearing wave washer or o ring from rear of housing.
3. Aid front housing and thoroughly push out rotor, do not enable rotor to slide, get rid of screws securing bearing retainer, take away retainer front bearing and seal eliminate rear bearing from slip ring at close of rotor.
Tests & Repair service
1. Area ohmmeter scale on x100 scale join ohmmeter leads across “B+” terminal and 3 stator terminals just one at a time, reverse sales opportunities, ohmmeter really should reveal continuity in a single direction only.
2. Reconnect ohmmeter qualified prospects across damaging and 3 stator terminals one particular at a time.
Reverse leads ohmmeter need to indicate continuity in one route only.
3. Link ohmmeter potential customers throughout “D+” terminal and 3 stator terminals one at a time.
Reverse leads, ohmmeter really should indicate continuity in a person route only, if diodes are identified to be faulty, switch the diode assembly.
Fig. 3: Diode Assembly Check Diode assembly for 55 amp alternator is shown, many others are equivalent.
1. Position ohmmeter on cheapest scale, join ohmmeter across stator sales opportunities, resistance among sales opportunities ought to be 14 15 ohms for 55-amp alternator and .09 10 ohms for 65 by 90 amp alternators, if resistance is incorrect, stator has open or shorted windings and will have to be replaced.
2. Area ohmmeter on X 1000 scale. Hook up ohmmeter involving stator core and stator lead, no continuity should exist, if continuity exists, stator is grounded and have to be changed.
1. Location ohmmeter on least expensive scale, join ohmmeter throughout slip rings, resistance should be 3 4-3.75 ohms for 55 amp alternator and 2.8 3.1 ohms for 65 as a result of 90 amp alternators.
2. If resistance is too minimal, rotor has short circuit and it should be changed if resistance is infinity no continuity, rotor has open up circuit and need to be replaced.
3. Spot ohmmeter on x1000 scale, reconnect ohmmeter among either the slip ring and rotor core, no continuity should exist, if continuity exists, rotor is grounded and must be replaced.
4. Clear slip rings using a extremely great sandpaper, rings which are worn or pitted should be turned on lathe, minimal ring diameter is 1 1/16″ 26.8 m.m. if slip rings are past repair, replace slip rings as outlined in ways 5 and 6.
5. Remove rear bearing from slip ring end of rotor, unsolder wires from slip rings and bend up ends of rotor winding, pull off slip rings, make certain ends of rotor winding are not destroyed.
6. Insert the ends of rotor winding into slip ring and press new slip ring onto rotor, slip ring close have to be 9/64″ 3.5 m.m. from finish of the collar, solder rotor winding to slip ring terminals, switch rings on lathe and retest rotor, utmost slip ring operate out is 0012″.03 m.m..
Normally change bearings, if substitution front bearing is sealed on 1 aspect only, open up side will have to encounter rotor, if substitution rear bearing is sealed on just one facet only, open aspect will have to confront absent from rotor.
Guarantee brushes are for a longer time than 6 m.m. change if vital, unsolder brushes from voltage regulator, solder new brushes, and do not allow solder to operate into strands of brush leads.
Brush ought to be totally free to slide in holder with regular spring pressure of 10-14.
1. Set up the bearing, retainer, and screws in entrance housing, press rotor on to housing.
Press bearing on slip ring conclude of the rotor, solder stator to diode assembly, training treatment when soldering near diodes owing to doable warmth hurt.
2. Put in insulators on stator assembly, assemble stator assembly and rear housing, set up wave washer or O ring in rear housing, align the scribe marks and assemble entrance and rear housings.
3. Install crucial, fan assembly, and spacers, put in the pulley, lock washer and nut, tighten nut to 23-29 ft. 3-4 Nm. Assure rotor spins freely, and set up voltage regulator and capacitor.