ORGANIZATIONAL MAINTENANCE OF THE GENERATOR
The generator electrical system also con-
tains a 125 V, 15 amp duplex convenience receptacle
which is equipped with a spring-loaded protective
cover and protected by a 15-amp circuit breaker.
e. Generator output voltage is controlled by a
The generator set shall be shutdown prior
solid state type regulator which is adjusted by the
to performing maintenance on the generator
voltage adjust rheostat on the control cubicle panel.
e l e c t r i c a l system. Serious injury or death
Voltage sensing may be local (at the generator set)
by electrocution may result from failure to
or from a remote location. The voltage regulator
o b s e r v e this warning.
p e r m i t s parallel operation of generator sets by cross
precise generator sets. Utility sets are not intercon-
a . One lead of each of the two coils of each
nected but the dummy plugs must be installed.
generator phase (30 KW, 50/60 Hz Precise and
Utility Sets) is connected directly to the voltage
reconnection board. The remaining two leads of
If operating on 240/416 V and remote
each phase pass through the windows of a three-
s e n s i n g is required, a 2:1 transformer
w i n d o w current transformer which serves as a cur-
must be supplied.
rent pickup for generator exciter voltage regulation.
A second three-window current transformer serves
f. The tactical relay box, which is common to all
a s a sensor for control cubicle instruments. The
three models, contains relays to shut down the gen-
leads make two passes through the windows of this
erator set upon actuation of the over voltage, short
c i r c u i t , overloaded, and reverse power protective de-
make one pass through a single-window cross-
v i c e s . It also houses the current transformer load re-
a c t i v e power measurement. Local voltage sensing
g. The special relay box, which is found on all
a n d adjustment are accomplished across a single
t h r e e models of the generator sets, contains the re-
c o i l of the remaining phase. (See FO-1.)
mainder of the protective devices and the voltage
r e g u l a t o r paralleling controls.
h. The precise relay box, which is found only on
p r e c i s e models of the generator set, contains the
On 30 KW, 400 Hz Precise Sets, two leads
paralleling controls for the electric governor and the
of one of the phases, instead of being
f i x e d resistors of the frequency adjustment system.
connected directly to the voltage recon-
The precise relay box of the 50/60 Hz precise model
nection board, are routed to pass through
is equipped with a frequency selector switch.
t h e window of the cross-current trans-
VOLTAGE RECONNECTION BOARD.
b. The voltage reconnection board consists of
a stationary terminal board and a movable link-type
move voltage reconnection board and spacers.
board. This arrangement provides a means of con-
necting the two coils of each phase in series or
( 2 ) Tag and disconnect electrical leads to volt-
parallel to provide 120/208 or 240/416 Vac genera-
t o r output. Simultaneously, the voltage reconnection
board provides reconnection of any other circuits
necessary to convert the generator set from 120/208
Cleaning and Inspection.
Vac to 240/416 Vac operation.
( 1 ) Clean reconnection board assembly with
f i l t e r e d compressed air and a soft bristle brush or
c . The reconnection board is connected to the
load terminal board through a three pole, three
wipe with a clean, lint-free cloth lightly moistened
phase main load contactor which is electrically con-
with an approved solvent.
trolled by the circuit breaker switch on the control
cubicle panel. The main load contactor will open
( 2 ) Visually inspect terminal board for burned
automatically when anv of the protective devices
o r corroded terminals and links. cracked or broken
actuates or when the START-RUN-STOP switch on
i n s u l a t i o n , links and terminals, and stripped or
the control cubicle panel is placed in the STOP
o t h e r w i s e damaged threads.