GMC 4000 Series Service Manual page 423

Spr* f!Y
Page 412_______________________
A/C GENERATING SYSTEM
WITH 1119507 REGULATOR
Figure 1 — Schematic Diagram of A.C. C harging Circuit with Two-Unit Type Regulator (Typical)
generator end frame and heat sink assembly. Di­
rect current is produced at output (BAT.) terminal
on generator.
On all generating system s, except those equip­
ped with the 62-amp generator, voltage is con­
trolled by a vibrating point type regulator (fig. 3).
Voltage on 62-amp generating system s is controlled
by a full transistor type regulator (fig. 4).
The regulator controls generator voltage out­
put by varying the current flow in field windings in
generator rotor assem bly. No current regulating
device is required in the regulator used with the
A.C. generator, since the generator has inherent
AMMETER
Figure 2 — Schematic D ia g ra m of A.C. C h a rg in g Circuit with Full Transistor Type Regulator (Typical)
G M C S E R V I C E M A N U A L
current regulation as long as the voltage is con­
trolled. Cut-out relay is not required with A.C.
generating system as the diodes will not conduct
an electrical current in reverse direction; i.e .,
from battery to ground through the generator.
models equipped with the 62-amp generator is
composed of transistors, diodes, capacitors, and
resistors which form a completely static electrical
unit containing no moving parts. The regulator
lim its generator voltage to a p re-set value by con­
trolling generator field current. Regulator voltage
setting can be adjusted externally by removing a
WITH 1119515 REGULATOR
The full transistor type regulator used on
VOLTMETER (IF USED)
r-------Q
W ITH 1 1 16 37 8 REGULATOR
T-5283-1