MERCEDES BENZ ALTERNATORS
Alternators & Regulators Bosch with inside regulators
DESCRIPTION
Alternators made by Bosch are typical 3-phase, self-rectifying kind alternators.
Bosch 75 by way of 55-amp alternators use3 unfavourable 3 constructive and diodes related to stator windings to rectify present, Bosch 90 and 80-amp alternators use 14 diodes.
All alternators use 3 exciter diodes related to stator windings, whereas the engine is operating these diodes flip off the alternator indicator mild and provide energy to the voltage regulator, Bosch regulators are transistorized stable state and integral with alternator.
ALTERNATOR APPLICATION
Mannequin Volts/Amps
(1) Producer’s Half No.
190E 14/70 489 928
190D 14/70 489 897
All Others 14/70 N/A
(1) Bosch alternator half numbers are preceded by the numbers 0 120 or starting with an AL lettering a quantity and ending with an X.
1. You possibly can join a voltmeter to the alternator “B+” terminal and floor, voltmeter ought to point out battery voltage, if not examine wiring between battery and alternator.
2. Flip ignition on and examine that alternator indicator mild comes on, if mild doesn’t come on, examine wiring between warning mild and alternator, together with indicator bulb.
1. Guarantee connections at battery, alternator, and starter are clear and tight, guarantee alternator engine and physique are correctly grounded, guarantee alternator belt is tight and in good situation.
2. Join ammeter following producer’s directions, join voltmeter results in battery terminals.
3. Begin engine and run at 3000 R.P.M. alter carbon pile to acquire most alternator output, don’t enable voltage to go under 12.6 volts.
4. Alternator output ought to equal alternator rated output, minus 16-20 amps, if studying is 16-20 amps under alternator ranking, change regulator and retest, if output continues to be too low, restore or change the alternator.
REGULATOR CONTROL VOLTAGE TEST
1. Join ammeter following producer’s directions, join voltmeter results in battery terminals, run engine at 3000 R.P.M.
2. Run engine till voltage stops rising, voltage must be 13.5-14.5 volts, if studying is inaccurate, take away regulator and guarantee brushes are longer than 6 m.m..
3. If brushes are okay and regulator fails to maintain voltage inside specified limits, change regulator and retest, if voltage continues to be incorrect, restore or change alternator.
OVERHAUL
DISASSEMBLY
1. Take away nut, lock washer, and pulley, bear in mind place of spacers, Then take away fan meeting and key, scribe mark on entrance and rear housings, take away voltage regulator and take away screws, separate entrance and rear housings.
2. Disconnect capacitor from terminal; take away nut, insulators, screws and washers.
Take away stator meeting.
3. Unsolder stator from diode meeting; take away bearing wave washer or o ring from rear of housing.
3. Help entrance housing and punctiliously press out rotor, don’t enable rotor to fall, take away screws securing bearing retainer, take away retainer entrance bearing and seal take away rear bearing from slip ring at finish of rotor.
TESTING & REPAIR
Diode Meeting
1. Place ohmmeter scale on x100 scale join ohmmeter leads throughout “B+” terminal and three stator terminals separately, reverse leads, ohmmeter ought to point out continuity in a single path solely.
2. Reconnect ohmmeter leads throughout unfavourable and three stator terminals separately.
Reverse leads; ohmmeter ought to point out continuity in a single path solely.
3. Join ohmmeter leads throughout “D+” terminal and three stator terminals separately.
Reverse leads, ohmmeter ought to point out continuity in a single path solely, if diodes are discovered to be faulty, change the diode meeting.
Fig. 3: Diode Meeting Take a look at Diode meeting for 55 amp alternator is proven, others are related.
1. Place ohmmeter on lowest scale, join ohmmeter throughout stator leads, resistance between leads must be 14 15 ohms for 55-amp alternator and .09 10 ohms for 65 by way of 90 amp alternators, if resistance is inaccurate, stator has open or shorted windings and should be changed.
2. Place ohmmeter on X 1000 scale. Join ohmmeter between stator core and stator lead, no continuity ought to exist, if continuity exists, stator is grounded and should be changed.
1. Place ohmmeter on lowest scale, join ohmmeter throughout slip rings, resistance must be 3 4-3.75 ohms for 55 amp alternator and a couple of.8 3.1 ohms for 65 by way of 90 amp alternators.
2. If resistance is simply too low, rotor has brief circuit and it should be changed if resistance is infinity no continuity, rotor has open circuit and should be changed.
3. Place ohmmeter on x1000 scale, reconnect ohmmeter between both the slip ring and rotor core, no continuity ought to exist, if continuity exists, rotor is grounded and should be changed.
4. Clear slip rings utilizing a really tremendous sandpaper, rings that are worn or pitted must be turned on lathe, minimal ring diameter is 1 1/16″ 26.8 m.m. if slip rings are past restore, change slip rings as outlined in steps 5 and 6.
5. Take away rear bearing from slip ring finish of rotor, unsolder wires from slip rings and bend up ends of rotor winding, pull off slip rings, guarantee ends of rotor winding will not be broken.
6. Insert the ends of rotor winding into slip ring and press new slip ring onto rotor, slip ring finish should be 9/64″ 3.5 m.m. from finish of the collar, solder rotor winding to slide ring terminals, flip rings on lathe and retest rotor, most slip ring run out is 0012″.03 m.m..
The Bearings
All the time change bearings, if substitute entrance bearing is sealed on one facet solely, open facet should face rotor, if substitute rear bearing is sealed on one facet solely, open facet should face away from rotor.
Brushes
Guarantee brushes are longer than 6 m.m. change if vital, unsolder brushes from voltage regulator, solder new brushes, and don’t enable solder to run into strands of brush leads.
Brush should be free to slip in holder with regular spring stress of 10-14.
REASSEMBLY
1. Set up the bearing, retainer, and screws in entrance housing, press rotor onto housing.
Press bearing on slip ring finish of the rotor, solder stator to diode meeting, train care when soldering close to diodes as a result of attainable warmth injury.
2. Set up insulators on stator meeting, assemble stator meeting and rear housing, set up wave washer or O ring in rear housing, align the scribe marks and assemble entrance and rear housings.
3. Set up key, fan meeting, and spacers, set up the pulley, lock washer and nut, tighten nut to 23-29 ft. 3-4 Nm. Guarantee rotor spins freely, and set up voltage regulator and capacitor.
Trending Merchandise
