2007 ISUZU KB P190 Circuit

STARTING AND CHARGING SYSTEM 6D3-9



Generator Power
1. Adjust load resistor, if the required load currents are not attained.
2. The shape of the voltage curves on oscilloscope curve should be regular.
3. Test value: 5 to 7A.
4. If the required minimum current intensity is not attained, o
r
if the oscilloscope picture shows variations, the alternator
should be overhauled.

Regulated Voltage Circuit Diagram

Legend
1 Battery
2 Ignition Lock
3 Charge Telltale
4 Resistor, for attainment of load current with the battery set in series
5 Voltmeter
6 Ammeter
7 Generator




Installation
1. Install generator assembly and bring generator assembly to the position to be installed.
2. Install generator assembly and tighten to the specified torque.
Torque:
Long bolt: 35 N ⋅
⋅⋅
⋅
m (3.6 kgf ⋅
⋅⋅
⋅
m)
Short bolt: 20 N ⋅
⋅⋅
⋅
m (2.0 kgf ⋅
⋅⋅
⋅
m)
3. Connect wiring harness connector.
4. Move drive belt tensioner to loose side using a wrench, then install drive belt to normal position.
5. Reconnect battery ground cable.


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ISUZU KB P190 2007

6D3-10 STARTING AND CHARGING SYSTEM
The generator has four external connections; the "B+" lead to
battery positive, "L" lead to the warning lamp circuit(max. 2
watts), "S" lead to battery positive terminal for battery sensing
and an earth connection.

Explanation of type inscripiton
Example:KC-A--> 14V 50-90A.

K = Code for Stator OD(126mm OD).
C = Compact Generator.
A = Ausland (countries other than Germany)
> = Direction of rotation(clockwise).
14V = Generator Operating Voltage.
50A = Stabilised output at 25 C at 1800 RPM./13.5
Volts.
90A = Stabilised output at 25 C at 1800 RPM./13.5
Volts.

Generator Connetions.
B+ : Battery Main Connection (battery positive)
S : Battery Sense Connection(battery positive)
L : W aring lamp(via warning lamp to Ignition switch)


BATT.SENSE
REGULATOR ASSEMBLYHYBR10 ALTERNATOR ASSEMBLY
12V BATT. 1GN.SW .
300a*
W ARN.LAMP
1.2 W ATT L
S 8+
SUPPRESSOR
CAPACITOR
0.5 µf
NOTE: * RESISTOR IS RECOMMENDED TO
ENSURE THAT THE GENERATOR
REMAINS FUNCTIONAL IN CASE OF
W ARNING LAMP FAILURE


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ISUZU KB P190 2007

STARTING AND CHARGING SYSTEM 6D3-11
Warning
Do not reverse S and L connections as this will destroy the
warning lamp circuit of the regulator.
Ensure good electrical contact beween generator earth and
battery negative,

Operation
W ith the Iginiton switch turnded "ON", current is supplied via
the warning lamp to the "L" terminal of the regulator. Base
current is fed to T15 causing it to turn on, current then flows
from B+ through the rotor winding via the regulator brushes
and the collector emitter junction of T15 to earth completing
the circuit. The current in the rotor causes a magnetic field
between adjacent poles to be created, this field is rotated and
cuts the windings of the stator at right angles inducing a
voltage into them.
As the speed is increased this induced voltage increases and
results in curent being rectified in the 3 phase diode bridge and
supplied as DC to the B+ output and hence to the battery.
W hen the voltage at the B+ terminal of the battery reaches
around 14.2 volts, this voltage is monitored by the "S" lead and
turns the regulator Hybrid base current to T15 OFF removing
rotor current, resulting in a decrease in output voltage to below
the regulating voltage, T15 base current turns ON and the
whole cycle is repeated very rapidly.
D38 protects T15 and the regulator against the back voltage
developed across the rotor winding when T15 turns OFF.
The new generated EP regulators incorporate current limiting
in the warning lamp circuit.

Backup Regulation
The EP regulator will limit the output voltage to a safe level
should either the main B+ cable or the battery sense wire
become decoupled, the output voltage will be slightly above the
normal setting(1-3 volts).

Start up phase
W hen the Iginition switch is turned on and the engine is not
running, the current to the rotor is reduced by switching it on
and off at a 50% duty cycle, the frequency is approximately 4
KHz and may be audible at times.
This is quite normal, once the engine is started normal
regulation commences.

Warning lamp failure
Should the warning lamp fail, the generator will self excite by
deriving a small current from the phase connecion allowing the
voltage to build up to regulating level.
Note: no filed current will flow when the engine is cranking.


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ISUZU KB P190 2007

6D3-12 STARTING AND CHARGING SYSTEM
Diagnosis
The EP regulator incorporates diagnostics which will illuminate
the warning lamp as a result of fault conditions in the generator
and external circuitry.

These conditions include:
1.
An open circuit in the regulator battery sensing wire (S
Terninal)
2. An open circuit or excessive voltage drop in the B+ cable.
3. An open circuit in the generator phase connection.
4. Overcharging of the battery.
5. Regulator output stage short circuit.
6. Open circuit rotor.

The regulator compares the voltage at B+ with the voltage at
the "S" terminal connceted to battery positive. If the voltage
differential exceeds a predetermined threshold, the regulator
will operate in backup mode to limit the output voltage to a safe
level. The warning lamp; will remain illuminated as along as
these conditions prevail.
Sources of high resistance which will trigger the warning lamp
are:

a. Poor contact in wiring harness connectors.
b. Poor contact between rectifier and regulator.
c. High resistance in fusible link assembly.

Caution:
When bench testing the generator it is important that the
warning lamp wattage of 2 watts is not exceeded.
Reversal of the "S" and "L" on the regulator will damage
the regulator.
The correct plug for the regulator is a 9 122 067 011 for the
Bosch tye and for the Shinagawa connector the number is
X02FW.

See appendix 1 for daignostic matrix.
Before testing or disassembling the generator please observe
the following points.

1. W hen testing the diodes with AC type testers the RMS.
Vlotage output must not exceed 12.0 volts, it is
recommended that the stator should be disconnected
during this test.
2. W here zener power diodes are used, the breakdown voltage should be tested to ensure all diodes have the
same zener voltage.
3. Insulation tests on the rotor and stator should use a voltage not exceeding 110v for a series test lamp. The rectifie
r
must be disconnected from the stator prior to testing.
4. W hen carrying out repairs to the charging system always disconnected the battery negative first, and reconnect it
last.


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STARTING AND CHARGING SYSTEM 6D3-13
5. During current output tests please make sure that the
ammeter is securely connceted into the charge circuit.
6. Some battery powered timing lights can produce high transient voltages when connected or disconnected. Onl
y
disconnect or connect timing lights when the engine is
switched off.
7. Make sure the warning lamp circuit is functioning normall
y
before commencing tests.
8. Battery isolation switches must only be operated when the engine is stopped.
9. To protect the charging system when using 240 volt chargers it is recommeneded that the battery is
disconnected whilst charging.
10. Due to the very low resistance value of the stator winding it may not be possible to obtain accurate readings without
special equipment.
11. 12 volts must never be connected to the "L" terminal of the regulator as this will damage the lamp driver circuit.
12. No loads apart from the warning lamp can be connected to the "L" termainal. The "W " terminal is provided for this
purpose.

Disassembly
1. Mark the relative positions of the end housings in relation to the stator assembly to aid reassembly. Use a permanent
marking pen do not use centre punched as this can cause
misalignmnet of the housings.
2. Remove the EP regulator from the slipring end housing b
y
removing the two screws. Tilt the regulator slightly from the
plug connection until the regulator clears the housing, then
lift clear.
3. Remove the four through bolts.
4. Carefully remove the stator assembly along with the slipring end housing taking care not to put strain on the stator wires.
5. To disconnect the stator from the rectifier assembly, grasp the stator wires close to the wire loop with a pair of long
nosed pliers, heat the joint with a soldering iron, when the
point becomes plastic apply a slight twisting motion to the
wires, then pull upwards to release the wires. Remove the
stator.
This procedure opens the wire loop to release the stato
r
connections easily.
6. To remove the rectifier remove the three retaining scre
w
and the B+ terminal nut and washers.

Note: the B+ bolt and the positive heatsink retaining screw are
fitted with mica insulating washers.
These must be discarded and replaced with new washers and
heatsink compound.


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6D3-14 STARTING AND CHARGING SYSTEM
7. To remove the pulley, mount an 8mm Allen key in the vice
with the short end upwards, place a 24mm ring spanner on
the puley nut, position the internal hexagon of the roto
r
shaft onto the Allen ken, loosen the nut and remove the
pulley.

Note: the pulley has an integral boss which locks up against
the bearing,
therefore no thrust collar is provided.
8. Removing the rotor assembly. Remove the four retaining screws from the drive end housing, withdraw the roto
r
complete with the bearing.

Note: the rotor must not be pressed from the drive end housing
using a press as the bearing retaining plate and drive end
housing will be damaged or distorted. Parts removed in this
way must be replaced if the integrity of the generator is to be
maintained.
9. Remove the drive end bearing from the rotor shaft using a
chuck type puler, take care not to distort the fan assembl
y
during this process.
10. Remove the slipring end bearing using the same meghod as in 9.

Clean
Thoroughly clean all components except the rotor and stator
with an approved cleaning agent. Ensure that all traced of oil
and dirt are removed. If an abrasive cleaner is used to remove
scale and paint from the housings take care not to abrade the
bearing and mounting spigot surfaces. The rotor and stator
must be cleaned with compressed air only, the use of solvents
could cause damage to the insulating materials.

Inspection
1. Rectifier assembly
The following test equipment is required.
The recitifier assembly is not repairable and must be replaced
if a faulty diode is detected during inspection.

(a)
Adiode tester where the DC output at the test probes does
not exceed 14 volts or in the case of AC testers 12 volts
RMS. This is to ensue that when inspection rectifiers fitted
with zener power diodes the forward and reverse checks
are completer and are not masked by the diode turning on
due to the zener breakdown voltage.
(b) A zenere diode tester with a DC output in excess of 30 volts, the tester should also incorporate internal current
limiting set to 5 Ma. to prevent high currents during
inspection.
(c) Diodes can be destroyed during service due to high temperature and overload, open circuits are usually a result
of excessive voltage.

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STARTING AND CHARGING SYSTEM 6D3-17
fan.
4. Replacing the brushes (inbuilt regulator)
Check the brushes for length, this is measured from the brush
holder to the end of the brush along it's centre line. Also
inspect for any sideways wear. If worn replace both brushes.
The minimum length is 3.8mm. Inspect the brush springs for
signs of corrosion or loss of tension or uneven tension.

Replacing the brushes, using a soldering iron apply heat to the
soldered joints on the rear of the brush holder of the regulator,
using a small lever prise up the retaining tabs to release the
brush lead and spring. Thread the new brush lead up the
brush holder along with the spring, pull the lead through the
tabs until the brush is protruding 12mm from the holder.
Bend down the tabs and solder the brush lead taking care not
to allow the solder to run up the lead which will reduce
flexibility. Use 60/40 resin cored solder.

5. Ball bearing
Please note the bearings used in this KCA generator are a
high
tolerance type, only fully sealed bearings of the same
specification are to be used as replacements. It is
recommended that the bearings be replaced during the
reconditioning process to restore the unit to original
specification.







6. Regulator
The regulator can only be tested when fitted into an altenator.

Warning: do not reverse"S" and "L" connections or put 12
volt supply to "L" terminal, this connection must not be
used as a supply source other than to supply the
requirements of the warning lamp 2(watts).
Such action will destroy the regulator warning lamp
circuit.

For test voltages refer to Generator output testing section.
See also additional information on regulator function earlier in
this instruction.


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ISUZU KB P190 2007

STARTING AND CHARGING SYSTEM 6D3-19
Inspection
Generator
Before any in field testing can be undertaken it is important
that the battery's conditions is established and the terminals
are clean and tight.

Check the condition of the generator drive belt and ensure that
it is adjusted in accordance with the engine manufacturer's
recommnedations.

Battery conditions:
Note: This assessment may be difficult with maintenance free
assemblies.

Test the specific gravity of the individual cells the readings
should be within 10 points of each other, it is recommended
that the average SG should be 1.260 or higher.
A load test should be carried out to determine the ability of the
battery to supply and accept current. This is a good indicator
as to the general condition of the battery.
A load equal to the normal starting current should be placed
across the battery, the duration of this load test should not
exceed 10 seconds, during this time the terminal voltage
across the battery should not drop below 9.6 volts. Observe
each cell for signs of excessive gas liberation, usuall an
indication of cell failure.
If the battery test is clear proceed with the Generator tests as
follows.

Care should be taken when making the following connections.
It is recommended that the battery negative terminal be
disconnected before the test meters are connected, and
reconnecting the negative terminal when the meters are
inserted into the circuit under test. The warning lamp in the D+
circuit should not exceed 2 watts.

Regulating voltage test on the vehicle.
Connect a voltmeter to the generator, the positive lead to the
B+ terminal and the nagative lead to the generator casing.
Select the voltage range to suit the system, i.e. 20v for 12 volt
sysytems or 40v for 24 volt systems. Connect an ammeter in
series with the main output cable from the B+ terminal on the
generator, the range selected must be capable of reading the
maximum output from the generator.

Note the voltmeter reading before starting the engine. This
reading should increase when the engine is running indicating
generator output, start the engine and increase the engine
speed until the generator is running at 4000 rpm, switch on
vehicle loads of 5-10 A is indcated on the ammeter, the
voltmeter shoud read 14.0-14.2 v for a 12 volt system, for a 24
volt system the readings should be 5-10 A and 27.7-28.5 volts.


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ISUZU KB P190 2007