C.E. Niehoff & Co. C803D Troubleshooting Guides - Manual (Page 2)

Page 2 TG32D
Section A: Description/Operation
CEN C803D Alternator/Regulator Description and Operation
C803D 28 V, 500 A alternator is internally rectified. All windings and current-transmitting components are non-moving,
so there are no brushes or slip rings to wear out. C803D alternator is furnished with an open duct in the anti-drive end
cover plate, which accommodates a 4” duct.
This alternator is externally energized when the battery master switch on the vehicle is turned on and provides power
to the regulator through the IGN circuit (A2-346 regulator can also operate without vehicle connection to IGN, and
instead provide power by sensing rotation through the regulator’s AC circuit). Field coil is then energized. AC is rectified
into DC output through diodes in anti-drive end rectifier housing and supplied to the battery from the alternator B+
terminal. See Figure 7 on page 3. Alternator output current is self-limiting and will not exceed rated capacity of alterna-
tor. Regulator maintains alternator output voltage at pre-determined regulated setting (see below for setpoints) as vehicle
electrical loads are switched on and off.
A2-330, A2-336, and A2-361 regulators furnished with some units include:
• External IGN terminal for energize connection.
• (A2-330 & A2-336 only) P terminal that can provide optional AC voltage tap. P terminal signal frequency (Hz) x 10 =
alternator shaft rpm.
• (A2-330 & A2-336 only) D+ terminal that can provide DC voltage signal to vehicle electrical system, confirming alter-
nator operation.
• Overvoltage cutout (OVCO) function. See page 4.
• (A2-330 & A2-336 only) Tricolored LED. See page 4.
• (A2-330 only) Current-limiting function.
• Regulator fixed (flat temperature compensation) setpoints shown in Table 1 are selected based on battery type. Battery
type selection and battery maintenance/function are the sole responsibilities of the customer.
Figure 2—Voltage Setpoints
Table 1— A2-330, A2-336, & A2-361 Regulator Setpoint Switch Position
Voltage Setpoints (±0.2 V) Battery Type
Position 1 27.5 V Maintenance
Position 2 28.0 V Maintenance
Position 3 28.5 V Maintenance-free
Position 4 29.0 V Maintenance-free
Note on Group 31 batteries: If boiling or excessive gassing occurs with high voltage
setpoint (position 3), change to medium voltage setpoint (position 2).
A2-346 and A2-363 regulators furnished with some units include:
• (A2-346 only) Optional external IGN terminal for energize connection. This regulator can function with or without
vehicle ignition. When necessary, IGN terminal on regulator is connected to vehicle ignition to provide battery voltage
when engine is running. Circuit should be off (no voltage present) when vehicle ignition is off or engine is not running.
• (A2-346 only) P terminal that can provide optional AC voltage tap. P terminal signal frequency (Hz) x 10 = alternator shaft
rpm.
• (A2-346 only) D+ terminal that can provide DC voltage signal to vehicle electrical system, confirming alternator
operation.
• (A2-363 only) No external terminals, only a special 3-pin vehicle harness connector providing one pin for optional AC
voltage tap (PHASE OUT), one pin for DC voltage signal to vehicle electrical system confirming alternator operation
(D+), and one pin for the energize connection (ENG).
• Overvoltage cutout (OVCO). See page 4.
• Tricolored LED. See page 4.
• Battery type selection and battery maintenance/function are the sole responsibilities of the customer.
• J1939 connector to be used with optional A9-4036 harness.
— When A9-4036 temperature/voltage sense harness is not connected, regulator will operate in fixed voltage setting
determined by the select switch position on the bottom of the regulator. See Column 2 in Table 2.
— When A9-4036 temperature/voltage sense harness is connected, regulator will automatically optimize the charge
voltage for battery type based on temperature. Also, vehicle manufacturer-requested functions of 1939 interface
are available through connector. See Column 3 in Table 2.
Figure 3—Voltage/Battery Switch
Table 2— A2-346 & A2-363 Regulator Voltage/Battery Switch Position
Switch Position
A9-4036 Harness Not Connected
(Voltage Select)
A9-4036 Harness Connected
(Battery Select)
Position 1 27.5 V Maintenance (D Category)
Position 2 28.0 V Maintenance-free (Group 31)
Position 3 28.5 V AGM
Position 4 29.0 V DO NOT USE POSITION # 4