T M - 0 5 6 8 4 C / 0 5 6 8 5 B - 12
4-38. CONTROL CUBICLE ASSEMBLY.
a. Test, On Equipment (see figure 4-33).
When disconnecting leads from terminals, tape
leads to prevent electrical shorts.
(1) Control Cubicle. Perform operational test on
control cubicle, checking for proper operation in each of the
Generator Sets three modes using a voltmeter of known
accuracy. Check that ac output voltage indicated on control
panel matches output voltage at terminal board. Check that
Generator Set does come to an EMERGENCY STOP when
dc control circuit breaker (figure 2-3) is pulled. Test individ-
ual components of the control cubicle as given below. See
figure 4-33 for location of components.
(2) With the generator operating at rated fre-
quency, flash the generator field by placing the master switch
on the control cubicle in the start position. If the generator
voltage fails to build up after flashing, the control cubicle
may be defective.
(3) Voltage Adjust Rheostat (R1). Turn the
Ammeter Voltmeter transfer switch to its various positions.
For each position of the switch, turn voltage adjust rheostat
to its extreme positions. Voltage reading should be as fol-
lows. Voltage adjust range shall be between 205 and 220V
for the 120/208V, 3 phase, 4 wire connection. Between 114
and 126V for the 120V, 1 phase, 2 wire connection. Between
228 and 252V for the 120/240V, 1 phase, 3 wire connection.
(DS2). With a good incandescent lamp in place and 24 vdc
present at terminals of panel light (panel light switch ON),
check that lamps do light.
Be certain panel light switch is OFF before
installing or replacing panel light assembly.
(5) Hour Meter (M2). Operate Generator Set.
Check hour meter against a known accurate time source.
Replace meter if necessary.
(6) Battery Charging Indicator (M1). Connect
meter capable of reading at least 35 volts DC from terminal
on battery charging indicator to ground. Operate Generator
Set. With the needle in the yellow area, the meter should read
between 18 and 27.5 volts. With the needle in the green area,
the meter should read between 24.5 and 31.5 volts. NOTE:
The apparent overlap in voltage between the yellow high and
green low is the result of a plus or minus 1.5 volt meter
(7) DC Control Circuit Breaker (CB2). Operate
Generator Set. Pull circuit breaker (CB2). If generator does
not come to an emergency stop, stop the unit using master
switch and replace breaker.
Disconnect battery cable before making checks,
unless otherwise noted.
(8) Master Switch (S1). Disconnect battery. Tag
and disconnect seven leads to master switch. Using an ohm-
meter, check for continuity between terminals for each of the
five switch positions as given in table 4-3. If the continuity is
not found for each set of terminals listed, replace master
(9) Panel Light Switch (S2). Tag and disconnect
two leads to panel light switch. Using an ohmmeter, test for
continuity between terminals on switch. With the switch in
the OFF position, there should be no continuity. With the
switch in the ON position, there should be continuity.
Replace switch if necessary.
Table 4-3. Master Switch Continuity Check
RUN AUX FUEL
Check for Continuity