C.E. Niehoff & Co. C722, C724 Troubleshooting Guides
C722 and C724 Alternator
Troubleshooting Guide
Hazard Definitions
These terms are used to bring attention to presence of hazards of various risk levels or to important information concerning product life.
Indicates presence of hazards that
CAUTION
will or can cause minor personal
injury or property damage.
Indicates special instructions on
NOTICE
installation, operation or mainte nance that are important but not
related to personal injury hazards.
Table of Contents
Section A: Wiring Diagram ................................................2
Section B: Basic Troubleshooting ......................................3
Section C: Advanced Troubleshooting .........................4 – 6
Battery Conditions
Until temperatures of electrical
NOTICE
system components stabilize, these
conditions may be observed during
cold-start voltage tests.
• Maintenance/Low Maintenance Battery
— Immediately after engine starts, system volts are
lower than regulator setpoint, amps are medium.
— 3–5 minutes into charge cycle, system volts
increase, amps decrease.
— 5–10 minutes into charge cycle, system volts
increase to, or near, regulator setpoint and amps
decrease to a minimum.
— Low maintenance battery has same characteristics
with slightly longer recharge times.
• Maintenance-free Battery
— Immediately after engine starts, system volts are
lower than regulator setpoint, low charging amps.
— Once charge cycle begins, low volts and low amps
are still present.
— After alternator energizes, voltage w ill increase
several tenths. Amps will increase gradually, then
quickly, to medium to high amps.
— Finally, volts will increase to setpoint and amps
will decrease.
The time it takes to reach optimum voltage and
amperage will vary with engine speed, load, and
ambient temperature.
• High-cycle Maintenance-free Battery
These batteries respond better than standard maintenance-free. Charge acceptance of these batteries may
display characteristics similar to maintenance batteries.
• AGM (Absorbed Glass Mat) Maintenance-free Battery
These dry-cell batteries respond better than standard
maintenance-free. If battery state of charge drops to
75% or less, batteries should be recharged to 95% or
higher separately from the engine’s charging system to
avoid damaging charging system components and to
provide best overall performance. Charge acceptance of
these batteries may display
maintenance batteries.
characteristics similar to
Battery Charge Volt and Amp Values
Volt and amp levels fluctuate depending on the battery state
of charge. If batteries are in a state of discharge—as after
extended cranking time to start the engine—system volts
will measure lower than the regulator setpoint after the engine is restarted and system amps will measure higher.
This is a normal condition for the charging system; the
greater the battery discharge level, the lower the system
volts and the higher the system amps. The volt and amp
readings will change as batteries recover and become fully
charged: system volts will increase to regulator setpoint
and system amps will decrease to low level (depending on
other loads).
• Low Amps: Minimum or lowest charging system amp
value required to maintain battery state of charge,
obtained when testing the charging system with a fully
charged battery and no other loads applied. This value
will vary with battery type.
• Medium Amps: System amps value which can cause
the battery temperature to rise above adequate charging
temperature within 4-8 hours of charge time. To prevent battery damage, the charge amps should be
reduced when battery temperature rises. Check battery
manufacturer’s recommendations for proper charge
amp rates.
• High Amps: System amps value which can cause
the battery temperature to rise above adequate charging
temperature within 2-3 hours of charge time. To prevent battery damage, the charge amps should be
reduced when battery temperature rises. Check battery
manufacturer’s recommendations for proper charge
amp rates.
• Battery Voltage: Steady-state voltage value as mea-
sured with battery in open circuit with no battery load.
This value relates to battery state of charge.
• Charge Voltage: Voltage value obtained when the
charging system is operating. This value will be higher
than battery voltage and must never exceed the regulator voltage setpoint.
• B+ Voltage: Voltage value obtained when measuring
voltage at battery positive terminal or alternator B+
terminal.
• Surface Charge: Higher than normal battery voltage
occurring when the battery is disconnected from
battery charger. The surface charge must be removed
to determine true battery voltage and state of charge.
• Significant Magnetism: Change in strength or intensi-
ty of a magnetic field present in alternator rotor shaft
when the field coil is energized. The magnetic field
strength when the field coil is energized should feel
stronger than when the field is not energized.
• Voltage Droop or Sag: Normal condition occurring
when the load demand on alternator is greater than
rated alternator output at given rotor shaft RPM.
TG71A
Page 1
Section A: Wiring Diagrams
CEN C722 Alternator
Description and Operation
C722 28 V (350 A) alternators are self-rectifying. All
windings and current-transmitting components are
non-moving, so there are no brushes or slip rings to
wear out. These alternators become externally energized
through the E terminal, connected to a switched power
source to turn on regulator.
Features of A2-212 regulator furnished with some C722
units include:
• R (or W) terminal with voltage limiter
that limits output voltage to
8V peak. Output voltage
frequency (Hz) =
alternator rpm/10.
• D+ terminal to provide signal
to vehicle electrical system,
confirming alternator
operation.
• overvoltage cutout (OVCO).
STATOR
See page 4.
CEN C724 Alternator
Description and Operation
C724 28 V (350 A) alternators are
self-rectifying. All windings and
current-transmitting components are
non-moving, so there are no brushes
or slip rings to wear out. These
alternators become externally
energized through the IGN terminal,
connected to a switched power source
to turn on regulator.
RECTIFIER
STATOR
*Thermal switch is not factoryinstalled on all models.
Features of A2-214 regulator furnished with some C724
units include:
• P terminal that can provide
optional AC voltage tap.
• D+ terminal that can provide DC voltage signal to
vehicle electrical system, confirming alternator
operation.
• Overvoltage cutout (OVCO). See page 4.
• Green lens LED. See page 4.
B+
BR
R
R
CHARGE
WARNING
LIGHT OR
CONTROLLER
IGN
DUAL
DIODE TRIO
BK
FIELD
W
*
THERMAL
SWITCH
F
E
D
C
B
A
G
Bñ
B–
ALTERNATOR
Figure 1 — C722 and C724 Wiring Diagrams
IGNITION
SWITCH
E
A2-212
REGULATOR
REGULATOR
RECEPTACLE
LOAD
BATTERY
D+
R
P
R (or W)
terminal
E terminal
Page 2
C722 ADE View
B+ bolt terminal
B– bolt terminal
D+ terminal
Figure 2 — C722 Alternator Terminals
C724 ADE View
IGN terminal
D+ terminal
B+ bolt terminal
B– bolt terminal
Figure 3 — C724 Alternator Terminals
P terminal
TG71A
Loading...