YASKAWA Varispeed-505WII - Control Circuit Board Replacement; Troubleshooting Guide

MAINTENANCE
(Cont'd )
Control Circuit Board Replacement
Disconnect
all the leads from
the terminals .
Then,
unplug the connectors
shown in
Fig .
24,
and remove the
6 control circuit board mounting screws .
Mount the
new
board by reversing the disassembling
procedure .
Plug-in
the connectors firmly .
CAUTIONS
IN REPLACING CONTROL
CIRCUIT BOARD
TROUBLESHOOTING GUIDE
1 4
EXTERNAL
CONTROL
TERMINALS
FUSE-BLOWN
DETECTION
CONNECTOR
CURRENT
DETECTION
CONNECTOR
Make sure that the type of the new control circuit board agrees
with
the nameplate and potentiometer settings of
new
control
circuit board are the same as the old one . Refer to the
nameplate "Cautions in Operation" posted on the inside of the
control circuit board door of VS-505WII . See Table 6 "Adjuster
Locations on the Control Circuit Board and Functions" .

Fig . 24
Control Board
Table
9
Troubleshooting
Guide
Note : If the
reading is not
m
. accurate measurement with a 500 V megger is required .

Reading must
be 3 megohms
or above .
Trouble Possible cause Check method
What to do
PREP
lamp Control Failure indicating
OFF printed lamp ON .
board
Operation sequence Check the external operation sequence .
_
Replace the control board . See Replace-
failure . ment of Control Board .
OCL lamp
Control Too low setting of Is setting dial at the positions indicated Set the setting dial to the
ON
printed "OL%," "OLT" . b lock "
dint?
position of lock
dint .
board Too high setting of
"FLIMIT," "RLIMIT"
Refer to Tables 6and 7 .
Incorrect setting of
Readjust .
"IFB' :
Thyristor Defective deterto- Check thyristor (Fig . 25) . Replace thyrtstor . (See Main
rated) . Circuit Th rtstor
on
page
9 . )
Motor and Overloaded . Check load current . A iust loa .
Reset .
driven Locking . Run motor without load, and see if it locks Repair motor .
machine Check load for locking .
Layer shorting in Run motor with terminals P and N dis- Repair motor .
motor . connected . If OCL lamp does not light,
the motor and its circuit
are defective .
Grounding of
motor Measure resistance between terminal P) " Repair motor .
circuit . (or N) and ground (E) with a multitester . " Correct wiring .
If the
reading
is nearly
-
on
the largest
scale of the tester, the circuit is normal .
U lamp Thyristor Defective deterto- Check thyrtstor (Fig . 25) Replace thyrtstor
.
(See Main Circuit
ON r ated) .
Th rtstor on page 9 .
Motor Layer shorting in Operate only board with (P) and (NT - 1 - s- Repair motor .
motor . connected . If fuse is not blown, motor
circuit is
defective .
Grounding of motor Measure resistance across terminal I' or " repair motor . To replace
circuit . N) and ground (E) with a multitester, and " Correct wiring .
fuses (1FU,
if the reading is nearly
m on
the largest
ZFU . 5FU),
scale of the tester, the circuit is normal . refer to
o (See
Note
.)
Replacement
t ;
Control
Defective phase Ifthemotor isnormal . replace
of Thyristor
circuit
control circuit) . control circsut board . Refer
Protection
" O board
to Replacement of Control Fuse .
c
Circuit Board on page 13 .
c
Fuse Defective deterio-
rated) .
_
FL lamp Motor Layer shorting in
Measure resistance across terminal J and
" Repair motor .
ON field winding . K with converter terminal J and K dis- " Replace fuse
.
(3FU
or
4FU) .
connected with a tester . If it
indicates
m, it means- field circuit is disconnected .
Grounding of field Measure
resistance across terminal (
.I
or K
circuit . andground (E) with a multitester, and if
the reading is nearly
m
on the largest
scale of the tester, the circuit is normal .
Control Defective . If the motor is normal, replace control
[board
circuit
board . See Replacement of Control
Board on pa
_
e 13 .
THG
lamp Motor Over Main circuit Check load current . ' Ad ust load .
ON loading . Field circuit Check field current
. Head ust . See Adjustment
on page
7 .
Locking . Run motor without load, and see if it locks . Re it motor .
Check load for lockmf- .-, . A .'
_'J
.
Blocked air filter .
Refer to the instructions for Industrial
DC Motors (TOE-C435-3) .
Insufficient cooling Check the blower for correct
running Correct wiring .
with blower . direction .
MCF lamp Motor Cooling blower
stop . Check fan for locking or overloadinE ; . Repairor replace fan .
ON
_Check thermal relay for tri . .in
TCF lamp Thyristor cooling an stop . Check
fan for
locking or
overloading . Replace the thyristor cooling fan . See
ON
Where the fan is provided with
Replacement of
Thyristor Cooling Fan,
failure
sensor on page 12 .
Surge Main CKT
Excessive surge . Check fuses 3FU, 4FU . Eliminate cause of surge . Replace surge
absorber
and fuse . See Replacement of Surge of
fuse blown
Absorber Fuse and Replacement
of
Sure Absorber
.