Onan LTC Series - Page 19

operation.
Two
or three
settings may
be required
to {ind
the
exact value.
Hogen
Timc
Dcloy
Rcloy
Adiurfncnt: This
synchronous
motor-driven
time delay-relay
(F'ig.
19)
has a dial on its
face
to
aid in
setting
the
correct time delay.
A
black
poi
nter
indicates
the
pre-set
time
delay;
a
red
pointer
indicates
the time
delay
left
in each operation.
To set
the
relay,
simply turn the
adjusting knob in the center
of
the
dial.
Time
delay can
be
changed with
power
on or o[t.
PILOT RELAY
VARIABLE
RESISTOR
This
slide arm
adjustable resistor determines
the
voltage
at which
the
pilot
relay
pulls
in as the
generating plant
builds up speed. It should not
require
adjustment unless it
(or
the
relay)
is
replaced.
It
was
factory
adjusted
to
pull
in
at 80
to 85% of
voltage as
the
generating plant
builds
up
speed.
For
example, on
a
240-volt
generator,
the
relay
should
pull
in when
the
voltage
reaches
190 to
2ff)-volts.
TROUBLE.SHOOTING
AND
REPAIR
Troubl,:.shooting
(or
repalr)
is
a
job
for a competent
elec-
trician
Hifh
voltajos
are
present
throughout
the control
during
normal
and
standby operation.
Because the engine
generator,
load
transfer control,
commercial
power
and
load,
are
all
interdependent,
trouble-shooting
requires checking
BATTERY
CHARGING
CURRENT
ADJUSTMENT
BATTERY
CHARGING
TRANSFORMER
.i-\
(o'
out
the
various
systems.
You
must
decide whether
the load
transfer,
commercial
power
or
generating
plant, is
causing
the trouble.
Before
doing
anything, determine
exactly
whet
the
trouble is.
A troubleshooting
chart
at
the
end of
this section
gives
typical
causes
of
the most
common
contml
problems.
By checking
out the
systems,
trouble often
canbe
isolated.
Operate the
generating
plant
from its
own
conhols"
If
the
plant
operates properly
alone, the
trouble is
probably
in
the
load
transfer
control.
Next,
determine which
load
transfer
control component
is
at
fault.
Observing
relay
action during operation is
an
important
tech-
niquo....it
helps
determine
how
far
an operation
gets
before
running into
trouble.
For
instance,
if
the
plant
will not
start
when
the line
fails, watch
voltage
sensitive relays,
time
delay-relays,
and
tlre
start-stop relay.
When
optional
equipment
(time
delays,
voltage sensitive
relays,
etc.) is believed
to be
defective, they
can often
be
checked by
elrmrnating
their contacts
from the
circuit with
a
jumper
wire.
Example: If
a
time delay
on
a stopping
relay
appears defectrve,
short
across the
contact
terminals
to eliminate
the
relay from the
circuit.
lVhen commercial
BATTERY
CHARGING
CURRENT
HETER
RECTIFIER
FUSE
TRA
NSFORMERS
(For
Voltage
Sensltlve
=Relays
-
Optional)
o
TRANSFER
swlTcH
PILOT
RELAY
--
-
.
_=-
STA
RT-STOP
RE
LAY
TIHE
DELAY
RELAY
RETRANSF
ER
INSTANT
TRANSFER RELAY
TRANSFER
SWTTCH
(Optional)
FIG
20
l6