YASKAWA Varispeed-505WII - Maintenance; Periodic Inspection; Parts Replacement; Field Thyristor Replacement

MAINTENANCE
VS-505WIl requires almost
no daily inspection .
To keep the
correct and successful operation,
periodic
maintenance operations should be
per-
formed . The users should prepare
their own
maintenance programs based on the following
guidelines
.
PERIODICINSPECTION
Table 8 shows the minimum
inspection items and
the procedures
.
Table 8
Periodic Inspection
PARTS REPLACEMENT
. Replace the
parts required after
checking the
trouble
and correcting it
according to TROUBLE-
SHOOTING GUIDE .
. Turn off the power before
part removal or
mounting .
10
Fig . 11 Field
Thyrsitor Assembly
Field Thyristor Replacement
With all the Models, thyristor modules
consisting
of a thyristor
and a diode are used as the field
thyristor . Replace them as follows .
1 . Remove the
four mounting screws of field
snubber board (3PCB), lead
clamping screws,
control power
connector . Then, remove snubber
board . See
Fig . 11 .
2 . Remove lead clamping
screws connecting
to
thyristor, and
remove the leads from
thyristor .
In
this case, mark all terminals
for identification .
See Fig . 12 .
3 . Remove
thyristor mounting
screws (2) and
remove thyristor module .
4 .
Check tY ;Ie type and capacity of
new thyristor
module against the
requirements . Install it by
reversing the removal procedure,
making con-
nections to the terminals
identified by the
marks
made before
removing the old thyristor
module .
Coat the thyristor mounting surface with joint
compound,
JOINTAL Z madeby Nippon Light
Metal Co . , Ltd .
Main Circuit Thyristor Replacement
VS-505W 1, 230 V at 25 A
The unit
uses a thyristor
module
consisting of
two
thyristors . Replace
it as follows
.
1 . Remove snubber
board (4PCB) mounting
screws (5) and lead clamping
screws . Remove
snubber board . (Fig
. 13)
2 .
Remove bus bar mounting screws
and lead
clamping screws
connected to thyristor . Remove
bus bar and leads . (Fig
. 14) In this case, mark
the terminals
for identification .
3
. Remove two
thyristor clamping screws and
thyristor .
4 . Check the
replacement module for type
and
capacity, and reinstall it by
reversing the dis-
assembly procedure,
identifying the terminals by
means
of the marks made prior to
disassembling .
THYRISTOR
MTGSCREWS
Fig . 12
With SnubberBoard Removed
Inspection
Part
Inspection
Item
Inspection
Procedure
What to do Remarks
Thyristor "
Noise " Check for Replace .
Rule of thumb
cooling any inter-
for cooling fan
fan
mittent or
replacement :
unusual
15,000 hours
noise . of
operation .
" Vibration " Feel by
hand . -
General " Dust or
. Check for
Clean with
dirt
dust clogging
an electri-
or
dirt
cal cleaner
" Loose
ter-
adhesion .
,
Tighten .
minal
" Check
for
screws or
loose screws
nuts
or nuts .