power
returns, the
control
sbould then operate in
e
normal
manner
(except
without
the time delay). If this
happens,
check
the relay.
NOTE:
The start
time delay cannot b tested
in
lf,is manner.
Whan if
is
linclsM
in
tha
circait,
ff,e slarf-sbp
rcIay
is
elininated
and tho tine delay
contacts
qntrol
lhe
plant
directly.
RELAY
REPAIR
Except for the
transfer
switch
and
transfer
switch
pilot-relay,
Onan does not recommend repairing relays.
If defective,
replace
them.
However,
relays with
dirty
contacts
can
be
cleaned
with hard
paper
or
gauze
tape soaked in
carbon
tetrachloride.
U
contacts are
pitted,
replace
the relay.
TRANSFER
SWITCH
REPAIR
All
transfer
switches
have
replaceable
contacts
and
coils.
CAUTION:
Do
not touch the
tl.rlnsler
svitch
unless
notmal
Iine
pover
is
o|f. Se/
lle
Operation
Se/ector Sc/irdr
(what
used)
to
STOP
position
or
disqnnect statin! batteies
Transler srvircJr
coils
are rated
according to
voltage.
Coils
used
at rated voltage
(stamped
on
coil) should
last
indefi-
nitely.
If
magnet
does
not close
freely
(as
when
dirty)
the
coil
overheats
and
could
burn
up
(coils
can also
burn
from
excessively
high
or low voltages).
To
remove
coils
see
Table
3.
TABLE
3.
COIL REMOVAL
Contacls never
require cleaning
(or
refacing)
for
the life of
the equipment.
Dis-colored
silver
contacts
operate
effi-
ciently. Filing
the contact
f aces destroys
their
matingsur-
face.
If
contact
points
become
badly burned
or
pitted,
replace
them as follows:
1.
Remove
plastic
hood.
2.
Remove spring and
washer
frorn
each
contact
guide
post.
3. Lift
contacts from
guide post.
Curved silver
contact
surfaces
face
inward.
4.
Take out stationary
contacts
by removing
screws
holding
them to
the
transfer switch
olastic
bodv.
Tronslcr Switch
Hur: Whena
Imd is
connected
to the
normal
povet
source,
the
switch
may
be mechanically
held
which
eliminates hum.
When
the transfer
switch connects
the
load
to
the
(eneratin(
plant,
the
switch is
electrically
hetd and
a
hum
condition can occut.
Hum
may
occur in ncchanically-
held
switches
because of incorrect
adjustment of
the coil-
disconnect micro-switch.
To
minimize
contact
hum,
magnet
sealing faces
were
ground
and
polished
(some
switches
include
shading
coils). Ercessive hum can be
caused
by
dirt
between
the
magnet
sealing faces. Clean
them
with
cerbon
tetrachloride.
Use
mediunrfine
grade
emery
paper
on ntsted sealing
faces.
Remove
all
traces of
emergy dust.
At
some
titne,
the
transfer
switch
lineside
latching
mech-
anism may
require
adjustment.
Transfer switch chattering
can be caused
by a latching mechanism that
does not
lock
the
contacts closed
which
causes
the
mechanism
to
pickup
and
drcp
out
repeatedly.
Transfer
switches
featuring
mechanically
held
line con-
tacts
or
electrically
held
getterator contacts,
operate
as
follows:
The
line
contacts
are
closed and
locked
in
the following
manner
(see
Fig.22).
The lineside
main
coil
pulls
the
contacts
closed. While
the contacts
ane closing, the
mechanical latch
engages
the contact control md and
locks
the contacts
closcri.
At
the
same time,
an
arm
on
the mech-
anical latch
actuates
the coil
disconnect switch
(micro-
switch)
which
opens
the
main
coil
circuit.
The line
contacts
are
now closed
and
lcnked
in
place
and
power
is removed
from
the
main
coil
simultaneously. Removal
of
power
fmm
the ma-rn
coil eliminates
any
electrical
noise
(hum)
from the
transfer
switch.
To
open the line contacts,
the latching
coi I m ust
be
energized which disconnects the latching
mechanism
allowing the
linc
contacts
to
open.
The
latching mechanism and
the coil disconnect
switch
must be adfusted
to open the
main
circuit
just
as
the
con-
tacts reach the closed
position.
tf
the
main coil
circuit
is not
broken,
hum may result.
tf the
coil disconnect
switch
opens
the coil circuit
before
the
contacts are seated,
the
contacts
will
chatter. Each
transfer switch
has several
electrical interlock
switches
(see
Fig. 21) which are
oper-
ated
by the mechanical movements
of
the
line
and
generator
contact
control
rods.
ADJUSTING
MECHANICALLY HELD SWITCHES
To
adjust
the
latching
mechanism
for
positive
locking,
loosen
the
locking
screws
whichsecure
thelatching
brackets.
Adjust
the
bracket
for
l,/16"
clearance between
the latching
lever
and
the
contact
operating rod
when
the main coil
armature
is
fully seated
(Fig.
20). On
units
with
roll
pins
locking
the latching
coil,
remove
the
noll
pins
to
make the
adjustment.
After
the adjustment
is
complete,
drill new
holes and
install new
roll
pins.
MECHANICALLY HELD
S}VITCH
2OG'4OO
A1.IP
(FIG.
22)
l.
llisconnect coil
lead
wlres.
2.
Remove
cap screws
(4)
mountlng
thc
coll and
stationary
magnet
as semb ly
to
the cas
e.
3.
Pull out
assembly
4.
Remove coil
f rom
magnet
assembly.
MECHANICALLY
HELO
SWITCH
IOO AMP
(FIG.
2I)
l. Disconnect
the coil
lead wires.
2.
Snap
off
the
hairpln-shaped
retainlng clips
holding
the
control rod
and slide out
the
control
rod.
3.
Slide out the stationar/ armature
and
coll assembly.
4.
Remove the coil from the stationary
armature.
t7
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