TM 9-6115-604-34
NAVFAC P-8-633-34
SECTION IX. PARALLEL CABLE ASSEMBLIES
5-48. GENERAL. The reactive circuit and governor circuit cable assemblies are used to interconnect the sensing
circuits of two or more generator sets working in parallel. During parallel operation, the phase sequence, frequency, and
voltage of each generator set output must be made to coincide with the others. The reactive circuit and governor circuit
cable assemblies provide a means of connecting the governor and voltage regulator circuits.
5-49. REPAIR OF PARALLEL CABLE ASSEMBLIES. See Figure 5-37.
a.
Remove screws to remove clamps (2 or 8).
b.
Unsolder and remove plug connector (3 or 9) from shielded cable (6 or 12).
c.
Remove bushings (4 or 10) and band markers (5 or 11) from shielded cable (6 or 12).
d.
Replace damaged or defective components.
e.
Position band markers (5 or 11) on shielded cable (6 or 12).
f.
Slide bushings (4 or 10) onto shielded cable (6 or 12) and solder plug connectors (3 or 9) onto cable (6 or 12).
g.
Position bushings (4 or 10) over sleeve of plug connectors (3 or 9) and secure with clamps (2 or 8).
SECTION X. CURRENT BOOST MODULE A101
5-50. GENERAL. See Figure 5-38 and Figure 5-39. The purpose of the current boost module Al 01 (CBM) is to assist
the voltage regulator VR1 01 during generator overload conditions such as engine starting, and to independently supply
the generator exciter field current during generator short circuit faults. Operating power for the CBM is provided by two
associated current transformers located in the conduit box assembly attached to the rear of the generator. The CBM
consists of five functional circuits.
a.
DC Output Circuit. The DC output circuit contains a power bridge rectifier and two silicon controlled rectifiers
(SCR's) in series with the AC input. When the SCR's are turned off, the power bridge rectifier supplies boost
current to the exciter field. If the SCR's are turned on continuously, the AC input will be shorted, thus removing
the DC output voltage. The DC output circuit is controlled by two associated circuits, the firing circuit and the
voltage limiting circuit.
b.
Firing Circuit. During normal generator operation the firing circuit will ensure continuous conduction of the DC
output circuit SCR's (the continuous conduction of the SCR's removes the DC output). If the generator output
voltage decreases below the comparator circuit's preset limit, the firing circuit will turn off. This causes the DC
output circuit to turn on and supply boost current.
c.
Voltage Sensing Circuit. The AC generator voltage is stepped down to the required level and rectified, and the
resultant DC signal is applied to the comparator circuit.
d.
Comparator Circuit. This circuit compares the sensing voltage with a preset reference voltage established by the
operation point adjustment control R13. If the generator voltage decreases below the value set by R13, the
comparator circuit enables the firing circuit. When the generator voltage increases above the value set by R13,
the comparator circuit disables the firing circuit to remove the boost current.
e.
Voltage Limiting Circuit. The voltage limiting circuit monitors the DC output voltage and adjusts the firing angle
of the DC output circuit SCR's to limit the DC output to 180 V dc.
5-90
