C.E. Niehoff & Co. C726 Troubleshooting Guides User Manual

Page 2

Page 2

TG69A

Section A: Wiring Diagram

CEN C726 Alternator
Description and Operation

C726 42 V 380 A alternator is internally rectified. All

windings and current-conducting components are
non-moving, so there are no brushes or slip rings to
wear out.
After engine is running,

A2-339 regulator receives

energize signal. Regulator monitors alternator rota-
tion and provides field current only when it detects
alternator shaft rotating at or above idle speed.
After regulator detects alternator rotation, it gradual-
ly applies field current, preventing an abrupt me-
chanical load on accessory drive system. The soft
start may take up to 20 seconds.
A2-339 regulator used with these units also
• is negative temperature compensated. Setpoint is

42.0 V at 72 F.

• provides overvoltage cutout (OVCO). Regulator

will trip OVCO when system voltage rises above
46 volts for longer than 3 seconds. OVCO feature
detects high voltage and reacts by opening alter-
nator field circuit and turning off alternator.
Removing and reapplying energize signal at IGN
terminal will reset OVCO circuit.

• maintains alternator steady-state output voltage

at regulated settings as vehicle electrical loads are
switched on and off.

Figure 2 — Wiring Diagram

Figure 1 — C726 Alternator and

A2-339 Regulator Terminals

B+ terminal



IGN terminal

B–

terminal



P terminal