T.O. 35 C2-3-442-2
P -9 -TM-457 -35
TM 5-6115-457-34
TM-07464A-35
Section VI. MODE I RELAY BOX ASSEMBLY
clockwise, will cause the corresponding
6-85. GENERAL.
set to increase its share of the total re-
active KVA.
The Mode I relay box assembly
(A27) is a junction box which is utilized to
c. The shorting plug connected to
interconnect certain electronic compon-
Mode I relay box connector J31 converts
entry, for 50/60 hertz precise and utility
the Mode I relay box from precise to utility
generator set operation. The relay box
contains a DC relay assembly, cross cur-
set operation. Removing this shorting plug
rent transformer, a variable resistor, a
allows the precise relay box harness to be
connected to J31, thus connecting from
shorting plug, the engine crank relay (K3 ),
the battery charging ammeter shunt (R13)
utility to precise set operation.
and interconnecting harnesses.
6-86. DC RELAY ASSEMBLY (A5).
a. The dc relay assembly (A5) is a compo-
nent mounted printed circuit board. It con-
6-87. TEST ON EQUIPMENT.
tains the field flash relay K5 (figure 1-14),
parallel operation voltage sensor rectifier
a. Symptoms and Isolation of Malfunc-
bridge CR4 and relay K7, fuel level relay
tion. A malfunction of the DC relay assem-
K8, start circuit diode CR3, fuel pumps
bly (A5) is usually indicated by failure of
diode CR6, and paralleling lights resistors
one or more of the following circuits to
function normally: the generator field
R6 through R9. Resistor R3, rectifier
flashing circuit, synchronizing lights cir-
bridge CR4, and relay K7 are connected in
parallel with winding T6-T9 of the generator
cuit, engine fuel pump circuit, engine
assembly. When the generator output is
cranking circuit, or the low fuel level
connected for 120/208 VAC output; T9 is
fault circuit. To isolate the malfunction,
reconnected to T3 and T6 is connected to
refer to figure 1-14 and proceed as follows:
T12. The voltage across this phase coil is
WARNING
rectified by CR4 and then applied to relay
K7. This causes its contacts to short out
Exercise extreme care not to
resistors R9 and R6 in series with the
touch electrical connections when
synchronizing lights DS4 and DS5. When
working on the electrical compon-
the generator output voltage is reconnected
ents with generator set operating.
for 240/416 VAC; terminals T6 and T9 are
connected together. This de-energizes
NOTE
relay K7, and resistors R6 and R9 are
connected in series with synchronizing
lights DS4 and DS5.
Remove cover from mode I relay
box to gain access to the test points,
see figures 6-15 and 6-22.
b. The variable resistor (R29) is a
potentiometer which permits adjustment of
1. Start engine , as engine comes up
reactive KVA between sets operating in
p a r a l l e l . Its slotted shaft, when rotated
to speed, measure voltage across terminals
6-59
