Mitsubishi Electric Freqrol-A100 Instruction Manual page 169

5.2 TROUBLESHOOTING
If any function of the inverter is lost due to occurrence of a fault, establish the
cause and make correction in accordance with the following inspection proce-
dure. Contact your sales representative if the corresponding fault is not found
below, the inverter has failed, the part has been damaged, or any other fault
has occurred.
\
5.2.1 .Checking the Parameter Unit Display
The display of the parameter unit is switched as follows to indicate the cause of a faulty operation.
-
Display
Parameter Unlt
1
Inverter LED
OC During
OC1 :Overcurrent during
I
-
acceleration
I
Stedy Spd Oc
OCZ : Overcurrent during
constant speed
Ov During
OV1 : Overvoltage during
acceleration
Stedy Spd Ov
0 V 2 : Overvoltage during
constant speed
0 V 3
:
Overvoltage durlng
1
During
/
deceleration
Motor Overload
1
THM: overload alarm
I
I
Under Voltage UVT :Undervoltage
I
OHT: External thermal
Sill Prev STP
OLT :Stall prevention
I
I
Option Faull
OPT: Inboard option
connection alarm
Corrupt Memry
PE :Parameter storage
device alarm
I
Retry No. Over
I
RET
:
Retry count exceede~
1
CPU Fault
1
CPU:CPU error
comms. Error
Cause of Fault Check P o l n l Remedy
Main circuit device overheat
Deceleration too fast?
Check for output short circuit or
ground fault.
Check for cooling fan stop.
I
Increase decelerat~on tlrne.
Change fan. Remove obstacle to
coollng fan. (Note)
Check brake operation.
l ~ c c e l e r a t i o n too fast?
1
Increase acceleration time.
Overvoltage on DC bus (terminals p-
Sudden load change? Keep load stable.
N)
lncrease deceleratlon tlme. (Set de-
Decelerat~on too fast?
celeratton tune w h ~ c h matches load
G D ~ \
. .
Reduce braking duty.
Thermal relay for motor
Reduce load.
Motor used under overload? Increase motor and inverter capaci-
Thermal relay for inverter ties.
Instantaneous power failure
Check the cause of instantaneous
power failure.
*Large-capacity motor started?
C h e c k power system equipment
.Drop of power supply voltage *Is a jumper or DC reactor
such as power supply capacity.
-Terminals P and P i are open. connected across terminals P and
*Connect a jumper or DC reactor
Pl?
across terminals P and P I .
$round fault occurred in output cir- Check motor and cables for ground
suit. fault. Remedy ground fault area.
External thermal relay operated. Check motor for overheat.
Reduce load and frequency of opera
t i , . . .
Stall prevention or current limit func-
lion activated too long.
Motor used under overload?
- - - - - - -
Reduce load.
lncrease motor and inverter capaci-
. .
~
.
3ption and inverter connected im-
properly. Check for loose connector.
Securely connect.
Storage device (EEPROM) faulty.
Number of parameter write times too
many?
Change inverter.
Operation could not be resumed
within the number of retry times set.
Check cause
Of
alarm
CPU malfunction
Check for loose connector.
Change inverter.
Securely connect.
The PU has been disconnected from
Check that the PU is connected se-
the connector. curely.
Securely install the PU.
*Reset signal ON
.Loose connection between PU and
OCheck
miswlring to reset *Turn the reset signal off.
inverter'l
terminal. *Securely connect.
Communication circuit fault
*Check for loose connector.
.Change inverter.
- 2
Note: This alarm does not occur due to the cooling fan stop, but it will occur to prevent the main circuit
devices from overheating by the fan failure.
*Switch power off, then on.
CPU malfunction '2 *Switch reset signal on, then off.
*Change inverter.
*1: The parameter unit display remains unchanged but operation may be performed in the external
operation mode.
*2:
If the alarm is kept displayed on the parameter unit and unit LED after remedy, the internal
circuit may be faulty. Consult your sales representative.