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Alternator & Regulator Isuzu Impulse II

Charging System 2 illustrations ~682 words

DESCRIPTION

Alternator is a Nippondenso 75-amp type. Alternator is non-serviceable and requires no periodic maintenance. Replace alternator if defective.

A solid state, nonadjustable voltage regulator is mounted inside the alternator. Regulator components are enclosed in a solid mold. Voltage regulator and brush holder assemblies are attached to slip ring end frame.

Two brushes carry current through 2 slip rings to a field coil mounted on rotor. Stator windings, assembled inside a laminated core, form part of alternator frame assembly. A rectifier bridge containing 6 diodes is connected to stator windings.

ALTERNATOR BELT

Application(1) Belt Tension Lbs. (kg)
All Models70-110 (32-50)
(1) Belt tension is checked with belt tension gauge.
(1)Belt tension is checked with belt tension gauge.

ALTERNATOR BELT ADJUSTMENT

ALTERNATOR WARNING LIGHT

  1. Visually check alternator belt and wiring. On vehicles without charge indicator light, go to «UNDERCHARGED OR OVERCHARGED BATTERY TEST»(/isuzu/impulse/ii-1990-1993/remont/charging-system/#alternator-regulator__undercharged-or-overcharged-battery-test). On vehicles with charge indicator light, go to next step.
  2. Turn ignition switch on, with engine off. Indicator light should come on. If indicator light comes on, go to step 4). If indicator light does not come on, disconnect alternator harness connector at alternator. Using a fused jumper wire, connect one end of jumper wire to alternator harness connector terminal "L" and other end to ground. (Scheme 1)
  3. If indicator light comes on when jumper wire is connected, replace alternator. If indicator light does not come on when jumper wire is connected, locate open between grounding lead and ignition switch. Charge indicator light bulb may be open.
  4. Start engine and operate at moderate speed. Charge indicator light should go off. If indicator light stays on, disconnect alternator wiring harness connector and check light. If indicator light goes off, replace alternator. If indicator light stays on, check for grounded wire to alternator wiring connector terminal "L".

UNDERCHARGED OR OVERCHARGED BATTERY TEST

  1. If battery is undercharged or overcharged, disconnect alternator wiring harness connector from alternator. Turn ignition switch on, with engine off.
  2. Connect voltmeter from ground to terminal "L" and, if used, terminal IG in wiring harness. If voltmeter reads zero volt, check for an open between terminal "L" and battery. Repair as required. Reconnect alternator wiring harness connector.
  3. Start and operate engine at moderate speed with accessories off. Using a voltmeter, measure voltage across battery posts. If voltage reads greater than 16 volts, replace alternator.

Scheme 1

Scheme 1: CURRENT OUTPUT TEST
Scheme 1: CURRENT OUTPUT TEST
  1. Connect an ammeter in series between positive battery terminal and alternator terminal "B". (Scheme 1) Connect positive voltmeter lead to positive battery post and negative lead to negative battery post. To avoid a battery explosion, ensure carbon pile rheostat is OFF position before connecting to battery.
  2. Ensure carbon pile rheostat is in OFF position. Connect carbon pile rheostat to battery. Start engine and allow to idle.
  3. Turn on all accessories. Load battery with carbon pile rheostat to obtain maximum amp output. Maintain voltage at 13 volts or more. If ammeter reads within 15 amps of rated amp output, alternator is okay. See «ALTERNATOR SPECIFICATIONS»(/isuzu/impulse/ii-1990-1993/remont/charging-system/#alternator-regulator) table. If ammeter does not read within 15 amps of rated amp output, replace alternator.
ApplicationRated Amp Output
All Models75

ALTERNATOR SPECIFICATIONS

ALTERNATOR OUTPUT TEST

WARNINGTo avoid a battery explosion, ensure carbon pile rheostat is OFF position before connecting to battery.

Scheme 2

Scheme 2
Scheme 2
  1. Mount alternator on test stand. Ensure ground polarity of alternator and battery are the same. Connect alternator to a fully charged 12-volt battery. Connect voltmeter, ammeter, carbon pile (in OFF position) and 30-500 ohm resistor between battery and alternator terminal "L". (Scheme 2)
  2. Slowly increase alternator speed and observe voltmeter reading. If voltage is less than 16 volts, go to next step. If voltage is uncontrolled and increases to more than 16 volts, rotor field is shorted and/or voltage regulator is defective. A shorted rotor field can cause voltage regulator to become defective. Repair as required.
  3. If voltage is less than 16 volts, increase alternator speed and adjust carbon pile as required to obtain maximum current output. Maintain voltage at 13 volts. If maximum current output is within 15 amps of alternator rated amp output, alternator is okay. See «ALTERNATOR SPECIFICATIONS»(/isuzu/impulse/ii-1990-1993/remont/charging-system/#alternator-regulator) table. If maximum current output is not within 15 amps of rated output, repair or replace alternator.

TROUBLE SHOOTING

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