Onan LTC Series - Page 17

MAINTE}IANCE
PERIODIC
SERVICE
At
regular
intervals
inspect inside
the
cabinet
for
dust.
Clean
as
required.
Always
keep the
cabinet
clean.
Dust
and
dirt
can
cause hum, irregular
operation,
or even a
com-
plete
breakdown
of the
system.
At
the
same
time,
inspect
wiring for
loose
or
dirty
connections.
OX&{
WIRING
DIAGRAITS
The
wiring
diagram
fumished with
every
lmd
bansfer
control
is
your
key to the
control.
Keep
it
vith
the
onhol.
Use
the
wiring diagram:
1.
To
explain control
operation
2.
To
obtain
part
nunbers
for
ordering repair
parts
3.
To
deternine the
function
of
all components
4.
To
aid
in coatrol
repair
Here
are some hints on
reading wiring
diagrams.
The Onan
wiring diagram
is a semi-pictorial.
[t shows all
components
in
their approximate
position
and named by
function,
i.e.,
time delay on
starting
relay
and
the start-stop
relay. The
relative
positions
of the terminals
on
each component
are
the
same
as
you
see them
in the
control.
All relays are
shown
d*arct(ized unless
otherwise
noted.
The outside
enclosure
metal
is
shown
in dotted
lines.
Each view is
tabeled
to
indicate
the
direction
of
viewing and location.
For example: Panel
Rear
View
(inside
panel
as
seen
from
the
rear).
FtG.
l5
ADJUSTMENT
0F
VOLTAGE
SENSITIVF
RELAY
(Oprionol)
Undcr-Volfogc
Rcloy:
Determines
the voltage
at which
the
the
load
transfer
switches
the load
from
line
to
generating
plant
and
back
again. This
relay
was
accurately
set
at the
factory.
Settings
are
marked.
Do not
chn(e
the adjustments
without
taking the
proper
precautions.
NOTE: Sone contrcIs have
a
non*djustable
voltage
sen-
sifive rcIay
(no
@ver
or
adjasdnent
unttols,
Fig.
16).
Do
not
attempt to
adjast
this relay.
If
the rcIay becomes
inopetative,refum
it to thedealer
or
m
ONAil
serwce center.
Do
not
changethe setting on
adjustable
relays
until
you
are
sure
it
requires
readjustment.
Undetected
line voltage
drops
in
the supply
line may be causing
the
relay
to
oper-
ate, in
which
case,
the
relay
is
sewing
its
purpose.
A recmd
of line voltage readings
(taken
at
times
of
suspected
improper
operation)
rnay isolate
the
trouble
in
the
supply
[ine.
Following is the
ad;ustment
procedure:
1.
Provide
an acqtrate
acvoltmeter(not
less than
100Ct-ohms
per
volt) of
0
to
l5Srange.
To
simulate
a ljne volt-
age drop,
provide
a
tOffFohm
wire wound
rheostat(2-watts
or larger).
2.
Install a temporary
jumper
wire
from the
relays
N'O
to
C
terminals
(see
Fig.
16).
3.
Connect the voltmeter across
the
L1
and
L2
terminals.
Connect
the rheostat in
series with
the
Ll
terminal and
wire which normally connected to
this
terminal.
4. Turn the
temporary rheostat
to
its minimum resistance
position,
giving
a
high
reading
on
the temporaryvoltneter.
5.
Remove the
protective
caps from the
two
adjusdng
con-
trols of
the relay. Note
the factory marking
of
the
con-
tml
adjustments.
6
Tum the
pickup
control to
its
clockwise
limit. Turn
the
drapoat
control to
its
counterclockwise
limit,
then
1
'4
tum
clockwise.
7.
Turn the
picfup
control
slowly
counterclockwise
until
a click is heard.
The
relay
points
have now closed.
8.
Turn
the temporary rheostat to drop
the
voltmeter reading
until the relay contacts
open.
q.
Turn
the
temporary
rheostat to raise the voltmeter
reading
slowly.
Note
the
voltage at which
the
relay
closes.
This
is the
pickup
voltage
at which
the load
will
transfer
back to the normal source.
10.
If
the
pickup
does
not ocrur at
the desired simulated
voltage,
turn
the relay
pickup
control
rn
the
proper
l4