Alternator & Regulator Buick Estate Wagon

DESCRIPTION

The CS series alternators are available in 74, 85, 100, 105 and 120-amp output. The alternators use a delta stator, rectifier bridge, and rotor with slip rings and brushes. A built-in regulator incorporates fault detection circuitry. Conventional pulley and cooling fan are used.

CS series alternators operate with 2 wire connections and a ground path through the mounting bracket. The first wire connection is the battery positive "BAT" terminal. This terminal must be connected to the battery during operation. The second wire connection is through the indicator or suitable external resistor to the "L" terminal of the regulator. This connection serves to turn the unit on at start-up.

Three other regulator terminals, "P", "I" and "S", are provided for optional use. The "P" terminal is connected to the stator and may be connected to a tachometer. The "I" terminal provides an alternate method for turning on the alternator without going through the indicator light or external resistor and is often used in parallel with the "L" terminal connection. The "S" terminal may be used to sense electrical system voltage somewhere else on the vehicle for voltage control. If the "S" terminal is not used, the regulator uses an internal voltage sense for control.

No periodic maintenance of CS alternators is necessary. CS144 alternator can be disassembled and repaired. All CS121 and CS130 alternators are non-serviceable and must be replaced as complete assemblies. See the ALTERNATOR SPECIFICATIONS to determine model number and amperage of individual units.

ADJUSTMENTS

No adjustment or maintenance is required on alternator assembly. Regulator voltage is preset and no adjustment is possible.

ALTERNATOR WARNING LIGHT

1. Visually check alternator belt and wiring. On models without charge light, proceed to «UNDER OR OVERCHARGED BATTERY»(/buick/estate-wagon/1990-1990/remont/charging-system/#alternator-regulator__under-or-overcharged-battery) . On models with charge light, proceed to step 2).
2. Turn ignition switch to the ON position (engine not running). Charge light should come on. If charge light is not on, disconnect alternator harness connector at alternator. Using a jumper wire, connect one end of jumper wire to alternator harness connector terminal "L". Connect the other end to ground. If charge light comes on, repair or replace alternator.
3. If charge light did not come on in step 2) with jumper wire connected, locate open circuit between grounding lead and ignition switch. Charge light may be open. If charge light was on in step 2), go to next step.
4. Start engine and run at moderate speed. Charge light should go off. If charge light stays on, disconnect alternator wiring connector. If light goes off, repair or replace alternator. If light stays on, check for grounded wire to alternator wiring connector terminal "L".

UNDER OR OVERCHARGED BATTERY

1. If battery is undercharged or overcharged, disconnect alternator wiring connector from alternator.
2. Using a voltmeter, connect positive voltmeter lead to "L" terminal of alternator wiring connector and negative lead to ground. Turn ignition switch to ON position (engine not running).
3. If voltmeter reads zero volts, an open between "L" terminal and battery is indicated. Repair as required. Reconnect alternator wiring connector.
4. Using a voltmeter, connect positive voltmeter lead to positive battery post. Connect negative lead to negative battery post. Start engine and run at moderate speed. If voltage reads more than 16 volts, repair or replace alternator.

CURRENT OUTPUT

1. Connect an ammeter in series with positive battery cable. Connect positive voltmeter lead to positive battery post and negative lead to negative battery post. CAUTION: Carbon pile testing is part of this procedure. To avoid explosion, turn carbon pile OFF before connecting it to or disconnecting it from vehicle battery.
2. Connect carbon pile rheostat to battery, ensuring carbon pile rheostat is in the OFF position before connecting to battery.
3. Start engine and reduce speed to idle. Turn on all accessories. Load battery with carbon pile rheostat to obtain maximum amperage. Maintain voltage at 13 volts or more.
4. If ammeter reads within 15 amps of rated output, alternator is okay. If ammeter does not read within 15 amps of rated output, replace alternator. See «ALTERNATOR SPECIFICATIONS»(/buick/estate-wagon/1990-1990/remont/charging-system/#alternator-regulator) at the end of this article.

ALTERNATOR OUTPUT

Scheme 1

1. Mount alternator on test stand. Be sure ground polarity of alternator and battery are the same. Ensure battery is fully charged. Connect voltmeter, ammeter, carbon pile (in OFF position) and 30-500 ohm resistor between the battery and the terminal "L" of alternator. (Scheme 1)
2. Rotate alternator by hand in clockwise direction. Slowly increase alternator speed and observe voltage. If voltage is uncontrolled and increases to more than 16 volts, rotor field is shorted and/or regulator is defective. A shorted rotor field coil can cause regulator to become defective.
3. If voltage is less than 16 volts, increase speed and adjust carbon pile to obtain maximum amperage output. Maintain voltage at 13 volts. If output is within 15 amps of rated output, alternator is okay. If output is not within 15 amps of rated output, repair or replace alternator. See «ALTERNATOR SPECIFICATIONS»(/buick/estate-wagon/1990-1990/remont/charging-system/#alternator-regulator) at the end of this article.

Scheme 2

1. Scribe end frames to facilitate reassembly. Remove through-bolts and separate end frames. Using an ohmmeter, check for grounds. (Scheme 2) Reading should be very high or infinite. If reading is not as specified, replace rotor.
2. With an ohmmeter, check rotor for shorts and opens. (Scheme 2) Replace rotor if reading is not 1.7-2.1 ohms at 70°F (21.1°C).
3. To reassemble alternator, reverse disassembly procedure. Retain brushes with brush retaining pin during reassembly. (Scheme 5) Remove retaining pin after tightening through-bolts.

Note. Manufacturer recommends using a new bearing whenever end frames are separated.

Scheme 3

1. Scribe end frames to facilitate reassembly. Remove through-bolts and separate end frames. Remove stator lead attaching nuts and remove stator. Using an ohmmeter, check stator grounds. (Scheme 3) Connect one ohmmeter probe to one stator lead and the other probe to the stator core.
2. Ohmmeter should read infinite. If ohmmeter does not read infinite, replace stator. Repeat test with remaining stator leads. Stator cannot be checked for opens and shorts with ohmmeter.
3. To reassemble alternator, reverse disassembly procedure. Retain brushes with brush retaining pin during reassembly. (Scheme 5) Remove retaining pin after tightening through-bolts.

Note. Manufacturer recommends using a new bearing whenever end frames are separated.

Scheme 4

1. Scribe end frames to facilitate reassembly. Remove through-bolts and separate end frames. Connect an ohmmeter from grounded heat sink to one (of the 3) grounded flat metal rectifier bridge terminal connectors and note reading. (Scheme 4)
2. Reverse leads. If both readings are the same, replace rectifier bridge. Repeat test between grounded heat sink and the other 2 flat metal terminal connectors. If reading is the same when leads are reversed at either connection, replace rectifier bridge.
3. Repeat test between insulated heat sink and its 3 flat rectifier bridge metal connectors. Replace rectifier bridge if test reading is the same when leads are reversed at any test connection.
4. To reassemble alternator, reverse disassembly procedure. Retain brushes with brush retaining pin during reassembly. (Scheme 5) Remove retaining pin after tightening through-bolts.

Scheme 5

Note. Manufacturer recommends using a new bearing whenever end frames are separated.

TROUBLE SHOOTING

Note. See the TROUBLE SHOOTING - BASIC PROCEDURES article in the GENERAL TROUBLE SHOOTING section.

OVERHAUL

Note. Replacement parts are not available for CS121 and CS130 alternator. If alternator is defective, a new unit must be installed. CS144 alternator may be disassembled for repair.

BRUSHES & REGULATOR OVERHAUL - CS144

1. Scribe end frames to facilitate reassembly. Remove through-bolts and separate end frames. Remove solder from brush connections and remove attaching screws and connectors. Separate regulator and brush holder from end frame. Clean new brushes with soft dry cloth.
2. Put brushes in holder and hold with brush retaining pin. (Scheme 5) Install brush holder into alternator by reversing removal procedure. To reassemble alternator, reverse disassembly procedure. Remove brush retainer pin after tightening through-bolts.

Note. Manufacturer recommends using a new bearing whenever end frames are separated.

DRIVE END BEARING OVERHAUL - CS144

1. Scribe end frames to facilitate reassembly. Remove through-bolts and separate end frames. Remove shaft nut while holding rotor with a hex wrench inserted into shaft end. Push rotor from housing. Remove plate and push bearing out.
2. To insert new bearing, press against outer race and push bearing in until stop is felt. Bearing is double sealed, no added lubricant is required. Assemble retainer and press rotor into end frame. Torque shaft nut to 40-80 ft. lbs. (54-108 N.m).
3. To reassemble alternator, reverse disassembly procedure. Retain brushes with brush retaining pin during reassembly. (Scheme 5) Remove retaining pin after tightening through-bolts.

Note. Manufacturer recommends using a new bearing whenever end frames are separated.

ALTERNATOR SPECIFICATIONS

ALTERNATOR SPECIFICATIONS

See also:
• TROUBLE SHOOTING - BASIC PROCEDURES
• ALTERNATOR SPECIFICATIONS
• UNDER OR OVERCHARGED BATTERY