Perkins 1106C Genset Systems Operation Testing And Adjusting page 80

80
Testing and Adjusting Section
Table 17
Maximum Acceptable Voltage Drop In The Starting
Motor Circuit During Cranking
12 Volt
Circuit
System
Battery post "-" to 0.7 volts
the starting motor
terminal "-"
Drop across the 0.5 volts
disconnect switch
Battery post "+" 0.5 volts
to the terminal of
the starting motor
solenoid "+"
Solenoid terminal 0.4 volts
"Bat" to the solenoid
terminal "Mtr"
Voltage drops that are greater than the amounts
in Table 17 are caused most often by the following
conditions:
•
Loose connections
•
Corroded connections
•
Faulty switch contacts
Diagnosis Procedure
The procedures for diagnosing the starting motor
are intended to help the technician determine if a
starting motor needs to be replaced or repaired. The
procedures are not intended to cover all possible
problems and conditions. The procedures serve only
as a guide.
NOTICE
If equipped with electric start, do not crank the engine
for more than 30 seconds. Allow the starter to cool for
two minutes before cranking again.
Never turn the disconnect switch off while the engine
is running. Serious damage to the electrical system
can result.
If the starting motor does not crank or cranks slow,
perform the following procedure:
1. Measure the voltage of the battery.
Measure the voltage across the battery posts with
the multimeter when you are cranking the engine
or attempting to crank the engine. Do not measure
the voltage across the cable post clamps.
24 Volt
System
1.4 volts
1.0 volts
1.0 volts
0.8 volts
2. Measure the current that is sent to the starting
Note: If the following conditions exist, do not perform
the test in Step 2 because the starting motor has a
problem.
3. Measure the voltage of the starting motor.
a. If the voltage is equal to or greater than the
voltage in Table 16, then go to Step 2.
b. The battery voltage is less than the voltage in
Table 16.
A low charge in a battery can be caused by
several conditions.
•
Deterioration of the battery
•
A shorted starting motor
•
A faulty alternator
•
Loose drive belts
•
Current leakage in another part of the
electrical system
motor solenoid from the positive post of the
battery.
•
The voltage at the battery post is within 2 volts
of the lowest value in the applicable temperature
range of Table 16.
•
The large starting motor cables get hot.
Use a suitable ammeter in order to measure the
current. Place the jaws of the ammeter around the
cable that is connected to the "bat" terminal. Refer
to the Specifications Module, "Starting Motor" for
the maximum current that is allowed for no load
conditions.
The current and the voltages that are specified
in the Specifications Module are measured
at a temperature of 27°C (80°F). When the
temperature is below 27°C (80°F), the voltage
will be lower through the starting motor. When
the temperature is below 27°C (80°F), the current
through the starting motor will be higher. If the
current is too great, a problem exists in the starting
motor. Repair the problem or replace the starting
motor.
If the current is within the specification, proceed
to Step 3.
a. Use the multimeter in order to measure the
voltage of the starting motor, when you are
cranking or attempting to crank the engine.
KENR6931