inspected
to
make sure there
are
no loose
connections. Check
particularly
in
the
con-
nection
box
to
the
motor,
that
insulation
has
not
been
worn
through, causing grounding
out
to
the
machine frame.
B.
Overload relay tripped.
If
overload
protection
for
the
motors
has
been added
to
the
machine
or
has
been special ordered and installed
b;
Harig Products, overload relay may have shut
off
motor
.
(If
an
overload relay
has
been
installed
for
the lubricating
oil
pump,
it
would
shut
off
both
spindle
motor
and
oil
pump
motor.)
Reset
overload relay
after
allowing
it
to
cool
down,
by
pushing reset bar
projecting
from
the relay.
If
the
spindle
motor
overload
is
tripping
regularly, chances are
that
too
heavy a
cut
is
being tak
en
with
the grinding wheel,
or
that
the
wheel is loading up and
putting
extra
strain on
the
motor.
A 1
HP
motor
will
have
enough power
to
take
as
heavy a
cut
as
the
operator
normally
wishes
if
table
is
crossfeed-
ing and coolant
is
not
being
used
.
If
coolant
is
used when crossfeeding
or
if
plunge grind-
ing
is
being done,
it
is
easy
to
take
a
cut
that
will
require more than 1 HP. Under these
conditions,
the
current consumption
of
the
spindle
motor
should
be
checked
to
make cer-
tain
it
is
not
drawing more than
the
full
load
motor
current shown on
the
nameplate
be
-
fore higher capacity heater overloads are
installed,
or
motor
damage may
resu
l
t.
The
oil
pump
has
an
automatically
resetting
thermo
overload in the
motor
housing itself.
If
way
oil
level in
the
sump drops
below
the
pump
intake,
motor
will
not
be able
to
pump
oil
through
its self-cooling
circuit.
The
motor
will
overheat, causing
thermo
overload
to
shut
off
the
current
until
the
motor
cools
back
to
proper temperature. The
only
indica-
tion
that
this
is
happening
will
be
that
the
oil
level in
the
sight
glass
at
the
top
of
the
column
will
not
stay above
the
middle
when
the machine
is
running.
If
oil
is
not
added
to
the
oil
filling
cup at
the
back
of
the machine,
(see
Fig
.
5)
motor
insulation
will
deteriorate
until
it
eventually shorts
out
.
C.
M?tor
burnt
out.
All
motors
used
on
your
grinder
have
a design
life
of
many years. The
motor
most
likely
to
fail
is
the
oil
pump
motor
because
it
depends
on
the
oil
level
being maintained
to
keep
it
from
overheating.
A
burnt
out
motor
will
usually
draw
an
excess
of
current and
trip
the
motor
overloads
(if
they
have been installed),
blow
fuses,
or
over-
heat in one spot.
It
may, however, overheat
an
internal connection and cause a
wire
to
break loose. Checking
motor
circuits
with
an
ohmmeter should locate
any
internal breaks.
An
ammeter check on
motor
current,
on
each
of
the
three
legs
of
a three phase
motor
will
show a shorted
out
section
of
winding
by
drawing more than the rated
full
load current.
CAUTION
:
All
electrical checks should be
made
by
qualified personnel.
The
permitted
temperature rise
that
each
motor
can
tolerate when running
at
full
load
is
shown
on
the
motor
nameplate.
The
55o
C
shown
on
the spindle
motor
means
that
the
motor
cou Id
be
99°
F
hotter
than
the
shop
air temperature and
still
be
within
the
manu-
facturer's specification. Putting
it
another
way, on a
hot
summer day, and
pulling
a
load
of
1
HP
continuously,
the
motor
could
reach a temperature
of
189°
F.
5.
OIL
DRIPPING
A.Machine
not
level. Oil
dripping
from
the
underside
of
the table ways can be caused
by
machine being
improperly
leveled. Re-check
leveling and
follow
installation instructions
if
machine
is
not
level.
B. Restricting valve opened
too
wide. Check
the
setting
of
the
restricting valve (78007
in
Figure 16). Remove
dust
guard
(part
no
.
11
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