C.E. Niehoff & Co. C627/C628/C631/C656/C657/C658/C671/C680 Troubleshooting Guides - Manual (Page 2)

Page 2
TG30G
Section A: Alternator Description and Operation
Figure 1 — Alternator with A2-149 Regulator
CEN C656, C657, C658, C671, and C680
Alternator Description and Operation
C656, C657, C658, and C671 14 V (400 A) and
C680 14 V (430 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.
When C656 is controlled by the
A2-149 regulator,
this alternator becomes self-energizing through inter-
nal diode trios in the drive end housing. Residual
magnetic field induces small voltage in stator and
energizes field coil. Field coil continues receiving
incremental voltage until full voltage is achieved.
See Figure 1. AC is rectified into DC output through
diodes. Regulator controls voltage output. A2-149
regulator has a D+ terminal to provide a signal to
vehicle electrical system, confirming alternator
operation, and an R terminal to provide an optional
AC voltage tap.
When C656, C657, C658, and C680 are controlled by
the A2-155 regulator, these alternators become exter-
nally energized through the IGN terminal connected
to a switched power source to turn on regulator. See
Figure 2. A2-155 regulator has a P terminal to pro-
vide an optional AC voltage tap.
CEN C627, C628, and C631
Alternator Description and Operation
C627 14 V (340A), C628 14 V (290 A), and C631 14 V
(350 A) alternators are self-rectifying. All windings
and current-transmitting components are non-mov-
ing, so there are no brushes or slip rings to wear out.
When C627, C628, and C631 are controlled by the
A2-155 regulator, these alternators become externally
energized through the IGN terminal connected to a
switched power source to turn on regulator. See
Figure 2. A2-155 regulator has a P terminal to
provide an optional AC voltage tap. Regulator can be
mounted on the drive end or anti-drive end housing.
REGULATOR
Figure 2 — Alternator with A2-155 Regulator