Another splended and helpful page from dodge50.co.uk

 

Homepage Index

Service Index

Next Page

Starter Index

 

 

Continued From

b) Close the warning light switch (master electric
switch on dashboard) when the warning lamp
should light up.


c) Switch on a 10-15 amperes load such as lights,
fans, etc., for fifteen minutes.


d) Start engine and run at fast idle speed when


1. The warning light should go out.


2. The ammeter records a small charge depen-
dant on engine speed.


e) Increase engine speed momentarily to maximum
speed, when the charging current should be about
31 Amperes for 24 Volt, and 55 Amperes for 12
volt systems.


f) With the alternator running at approximately half
speed, (engine speed about 1,500 rev/min) switch
off electrical load. Depending on the connection
selected for the positive sensing wire LO, MED
or HI, the voltage should rise to between 26 and
28 volts on 24 volt systems and 13-14 volts on 12
volt systems and then remain constant. At the same
time the current reading should drop appreciably.
Any variance in the above data could indicate a fault
and the following procedure should be adopted before
disconnecting any components.


The regulator is a sealed unit and is non-repairable
and if found to be faulty it must be replaced.


Warning Lamp does not light up when switched "On".


Check the bulb.


If no fault


Check all wiring connections at regulator, alternator
and battery.


If no fault


Switch oft, disconnect 'F' lead at regulator and connect
it to the negative terminal.


Switch on. If warning lamp lights up, the regulator is
faulty. If lamp fails to light up, the alternator is faulty.
Warning Lamp does not go out and Ammeter shows no
output when running.


Check all regulator, alternator and battery connections.


If no fault

Switch off. disconnect 'F' lead at regulator and connect
to regulator negative terminal.


Switch on, and run at fast idle.


If no output, alternator is faulty.


If output appears, regulator is faulty.


Warning Lamp does not go out when running and
Ammeter shows reduced output with full output only at
maximum speed or Warning Lamp goes out but
Alternator delivers reduced output. Full output only at
maximum speed.


Alternator faulty. Remove from Installation and apply
open circuit diode check.


Warning Lamp flashes intermittently and Ammeter
needle oscillates when Battery Is fully charged and no
loads are switched In.


Check for excessive resistance in regulator negative
sensing lead.


If no fault, regulator is faulty.


Batteries overcharging and Ammeter indicates high or
full output all the time.


Check regulator positive sensing lead and its con-
nection at regulator.


If no fault, regulator is faulty.


Fault Finding on 11AC


If the alternator does not produce its rated output of
43 amperes for 12 volt and 23 amperes for 24 volt
circuit, the failure may be due to any unit or the
associated wiring, and the following procedure should
be followed.


Test-1
Checking the Field Isolating Relay


Disconnect the earthed battery terminal and the cable
from the alternator main output terminal. Connect a
0-60 DC ammeter between the terminal and dis-
connected cable. Link terminals 'C1' and 'C2' on the
field relay. Reconnect the battery cable. Close the
master switch and start engine and run at charging
speed. If ammeter shows a charge the relay is faulty.
or its wiring and connections.


If ammeter shows no charge, carry on with Test 2.


Test 2
Checking the Alternator and Control Box
Leave the test ammeter connected, and disconnect
cables 'F' and '-' from control unit and join them
together. Remove link from field relay terminals and
ensure they are connected to 'C1' and 'C2'. Start
engine and run at charging speed.


Ammeter should indicate current values of 35 amps or
more for 12 volt circuit or 22 amps or more for 24
volt circuit. A zero or low reading indicates a faulty
alternator.


If satisfactory output is recorded, a faulty control unit
is indicated.

Test 3
Checking or Adjusting the Voltage Setting
The regulator of the 4 TR control unit must be set on
CLOSED CIRCUIT, when the alternator is under load.
Also, the system must be stabilised before checking or
resetting Is carried out, and the battery must be in a
well charged condition. Check the battery to control
unit wiring, to ensure that the resistance of the com-
plete circuit does not exceed 0.1 ohm. Any high resist-
ance must be traced and remedied.

Connect a test DC 27.9 - 28.3 volts 13.7-14.1 volts
voltmeter (suppressed zero type) scale 12-15 volts

for 12 volt installations or 24-30 volts for 24 volt in-
stallations, between the battery terminals, and note the
reading with no electrical load. Disconnect battery
earth cable and connect test ammeter between alter-
nator main terminal and disconnected cable. Re-
connect battery earth cable, and switch on an electrical
load of approximately two amps, such as, side and tail
lights. Start engine and run at about 2000 rev/min for
at least eight minutes. If the charging current is still
greater than ten amps, continue to run engine until
this figure is reached. Then compare the voltmeter
reading with the appropriate setting limits, as specified
for the particular control unit as follows.


12V(37423)/(37449)


24V (37444)/(37502)


12V (37429)


(Part no. marked on upper edge of the moulded cover
of Control Unit).


If reading obtained is stable but outside the appropriate
limits the unit can be adjusted as follows.


ADJUSTMENT OF VOLTAGE SETTING
Stop the engine and remove the control unit from its
mounting. At the back of the unit is a sealed potentio-
meter adjuster. Carefully scrape away the sealing com-
pound. Then start the engine, and while running the
alternator at charging speed, turn the adjuster slot -
CLOCKWISE to INCREASE the setting or ANTI-
CLOCKWISE to DECREASE it - until the required set-
ting is obtained.


Recheck the setting by stopping the engine, then starl
again and slowly "run-up" to charging speed. If set-
ting is now correct, remount the control unit, dis-
connect test meters and restore original wiring con-
nections. If, after adjustment, the voltmeter reading re-
mains unchanged, or increases in an uncontrolled
manner, then the control unit is faulty and a replace-
ment must be fitted.


Test 4
Check of Alternator Output


Disconnect battery earth cable, and connect test
ammeter between the alternator main terminal and
disconnected cables. Reconnect battery earth cable,
and switch on the vehicles full electrical load and
leave on (or 3 or 4 minutes. Leave load on and start
engine and run at approximately 2000 rev/min. The
alternator output should balance the load, and at the
same time show a charge to the battery.


Check Warning Light Control
If warning light does not function either by remaining
"on" or "off", but the system is charging satisfactorily,
connect voltmeter between the alternator "AL" terminal
and earth. Reading should be 7.0-7.5 max (12 voit
alternator) or 14.0-15.0 (24 volt alternator). Con-
nect leads 'E' and 'WL' together. If warning lamp lights
the warning light control is faulty and should be re-
placed.


Fault Diagosis Procedure for 11 AC
Alternator Falls to Charge


a) Check driving belt for correct tension and wear.


b) Apply Tests 1 and 2.


Low-Unsteady Charging Rate


a) Check driving belt for correct tension and wear.


b) Check for high resistance at battery terminals
and in the circuit wiring and connection.

Check all connections made to earth.
c) Apply Test 2.


Flat Battery or Low State of Charge


a) CHECK condition of battery with hydrometer and
high rate discharge tester.


b) Check driving belt for correct tension and wear.


c) Check that the field isolating relay contacts open
when master switch is off, otherwise battery will
discharge through rotor winding.


d) Check that flat or low battery is not caused by
insufficient alternator output caused by abnormal
electrical loads by applying Test 4.


Excessive Charge Rate to a Fully Charged Battery
a) Apply Test 3.


Noisy Alternator
a) Alternator loose in mounting brackets.
b) Worn frayed or loose drive belt.
c) Worn bearings, fully out of alignment.
d) Rotor damaged or pulley fan loose on shaft.
e) Open circuited, or short circuited rectified diodes,
or stator winding open-circuit.
f) Loose pulley.


Testing the 15ACR, 17ACR, 18ACR, 23ACR,
AH 5/45, A133/55 LR, A127 and OAR series
in Position


First check the driving belt for condition and tension.
The nominal hot outputs at 6,000 rev/min (alternator
speed) are given on Page B.18. These figures may be
exceeded slightly when the alternator is running cold.
To avoid misleading results, the following test pro-
cedure should therefore be carried out with the
alternator running as near as possible to its normal
operating temperature.


Note: De-rated 17 ACR alternators may be fitted to
combine harvesters and similar applications where the
engine is operating in dusty conditions.

© Dodge50.co.uk™ 2002