Electrical System; Alternator - Test - Perkins 1204F-E44TA Systems Operation Testing And Adjusting

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Electrical System

Electrical System

Alternator - Test

Inspect the alternator for any visible faults. The faults
could be the following items.
• Frayed wires or damaged wires
• Loose connections or damaged connections
• Loose alternator pulley
• Loose alternator or damaged alternator
1. Put the positive lead "+" of a suitable multimeter on
the "B+" terminal of the alternator. Put the negative
"-" lead on the ground terminal or on the frame of
the alternator. Put a suitable ammeter around the
positive output wire of the alternator.
a. Turn the keyswitch to the ON position but do not
start the engine.
b. The system voltage matches the specification.
Go to step 2.
c. The system voltage is less than the
specification. Check if the battery is in good
condition. Refer to Systems Operation, Testing
and Adjusting, "Battery - Test" for the correct
procedure. Go to step 5.a if the battery is in
good condition.
2. Put the positive lead "+" of a suitable multimeter on
the "B+" terminal of the alternator. Put the negative
"-" lead on the ground terminal or on the frame of
the alternator.
a. Start the engine and run the engine at least
75% of full throttle. Record the voltage on the
multimeter.
b. The voltage should be higher than the voltage in
step 1.b. The voltage is less than the maximum
voltage listed for the alternator. The alternator is
partially charging. Go to step 3. The voltage is
more than the maximum voltage listed for the
alternator. There is overcharging of the
alternator. Check the alternator wiring. Refer to
Systems Operation, Testing and Adjusting,
"Charging System - Test" for the correct
procedure.
This document has been printed from SPI2. NOT FOR RESALE
c. The value of the voltage is less than the voltage
in step 1.b. Go to step 6.
Note: Severely discharged batteries can cause low
system voltage. This can occur even while the
engine is running above idle, and the alternator is
i03635721
working properly. Correct low engine idle is
important. All alternators that are installed on this
engine are self-excited. The alternators must
exceed the turn on speed before charging will
begin.
3. Ensure that the batteries are not fully charged.
a. Fully charged batteries have open circuit
voltage above 12.5 V on 12 V systems or 25 V
on 24 V systems.
b. If the batteries are fully charged then crank the
engine for 30 seconds. This reduces the battery
voltage.
c. Connect a current probe or an ammeter to a
digital multimeter. The multimeter must have a
peak hold feature. Ensure that the probe is
zeroed. Clamp the probe around the output wire
"B+" .
d. Set the multimeter to "peak hold" or "max mode"
.
e. Turn on all electrical accessories.
f. Start the engine and run the engine at least
75% of full throttle. The peak current will appear
on the multimeter.
g. The current is at least 90% of the peak output of
the alternator. Go to step 4 or step 5.
h. The current is less than 90% of the peak
alternator output. Go to step 6.
Note: This test procedure is for applications with
a main disconnect switch.
4. Turn off all accessories. Turn the keyswitch to the
OFF position.
a. Connect a current probe or an ammeter to a
digital multimeter. Ensure that the probe is
zeroed. Clamp the current probe or an ammeter
around the ground cable. Clamp the tool with
the positive side away from the battery. Record
the value of the electrical current.
b. The current value is below 2 amperes. Go to
step 4.d.
c. The current value is above 2 amperes. Go to
step 7.
UENR4490-01