YASKAWA YASNAC 3000G - Page 154

5.
Commutator
surface
A.
Check
visually
surface
roughness
of
commutator
throughout
inspecting
window.
The
commutator
should
take
on
light
brown
or
chocolate
color
after
100-200
operating
hours
in
the
process
the
motor
ideal
development
of
the
commutator
film.
Such
commutator
needs
no
attention
other
than
to
be
kept
clean.
3.
Clearance
of
ventilation
window
blockage
the
Check
the
ventilation
window
of
DC
spindle
motor.
If
it
is
clogged
with
duet
or
dirt,
in¬
spect
DC
spindle
motor
removing
the machine
cover.
manual.
a
polished
Refer
to
the
machine
tool
builder
'6
Inspection
of
commutators
and
brushes
is
essen¬
tial
for
keeping
the
excellent
performance
of
the
control.
Inspection
work
to
be executed
is
de¬
scribed
in
the
following
three
items.
For
detailed
instructions,
refer
to
YASNAC
MAINTENANCE
MANUAL.
B.
See
if
blackened
bar,
threading
(or
groov¬
ing)
is
on
the
commutator.
If
any
of
them
is
detected,
investigate
the
cause
of
trouble.
Threading
or
grooving
on
the
commutator
surface
may
be
due
to
too
small
motor
load.
Blackened
bar is
responsible
to
carbon
dust
in
commutator
slots,
or
incidentally
produced
sparkings.
If
it
appears
that
the carbon
dust
is
a
cause
of
blackened
bar,
finish
the
com¬
mutator
with
a
clean
dry
cloth
to
smooth
the
surface.
If
the
cause
seems
to
be
responsi¬
ble
for
sparking,
consult
the
company.
Three-Month
Inspection
of
Commutators
and
Brushes
The
carbon
dust
from
brushes,
scattered
around
the
commutator
inside
the
motor,
may
cause
motor
troubles
such
as
the
layer
short
of
arma¬
ture
and the
flashover of
commutator.
worst
case,
it
may
lead
the
control
to
a
fatal
damage.
To
avoid
this,
be
sure
to
give
an
in¬
spection
on
the
commutators
and
brushes
at
least
every
three
months.
In
the
6.
Motor
inside
(dirty)
A.
Check
visually
the
motor
interior
through
inspection
window.
Though
the
dried
carbon
dust
is
not
virtually
harmful
to
the
correct motor
running,
clean
the inner
parts
such
as
commutator,
brush-
holders
and
brushes
with
compressed
air
(air
pressure:
2-4
kg/cm2).
4.
Carbon
brushes
A.
Under
normal
operating
conditions,
brush
wears
by
2
to
4
mm
per
1000
operating
hours.
If
wear
is
excessive,
checktosee
if
oil
contaminates
armature
surface,
or
abnormal
overcurrent
flows
motor
circuit.
B.
Where
oily
carbon
dust
exists
inside the
mo¬
tor
due
to
poor
oil
seal
or
defective
enclo¬
sure,
consult
the
company.
B.
When
brush
length
becomes
shorter
than
those
shown
below,
replace
the
brush
with
new
one.
Minertia
motor
junior
series:
6
mm
or
below
DO
motor
for
spindle:
17
mm
or
below
7.
Servomotor
with
oil
seal
As
the
life
expectancy
of
oil
seal
and brush is
5000
hours
(about
five
years),
the
inspection
and
maintenance
by
the
company
should
be
done
every
5
years
as
well
as
the
control.
If
possible,
yearly
inspection
taking
less
than
8
hours
is
re¬
commended.
C.
If
either
of
brush
or
pigtail
is
broken,
brush
assembly
must
be
replaced
as
a
whole unit
with
new
one.
«.
1.4
BATTERY
j
w
Make
sure
that
the
battery
lamp
on
operator's
panel
is turned
off.
If
it
is
turning
on,
consult
maintenance
personnel.
The
battery
must
be
replaced
with
new one
within
a
month.
PIGTAIL
Fig.
8.
1.3
NOTE:
When
replacing
the
brush
assembly,
consult
the
company.
147
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