Mitsubishi Electric 800 Series Instruction Manual page 587

6.5
Check first when you have a trouble
NOTE
• If the cause is still unknown after every check, it is recommended to initialize the parameters, set the required parameter
values and check again.
6.5.1 Motor does not start
Check
points
Main circuit Appropriate power supply voltage is not
applied.
(Operation panel display is not provided.)
Motor is not connected properly.
The jumper across P/+ to P1 is disconnected.
A DC reactor is not connected.
Input signal Start signal is not input.
Both the forward and reverse rotation start
signals (STF, STR) are input simultaneously.
Frequency command is zero.
AU signal is not ON when terminal 4 is used for
frequency setting.
Output stop signal (MRS) or reset signal
(RES) is ON.
CS signal is OFF while the automatic restart
after instantaneous power failure function is
selected (Pr.57 Restart coasting time 
9999).
Jumper connector of sink - source is
incorrectly selected.
Voltage/current input switch is not correctly set
for analog input signal (0 to 5 V/0 to 10 V, 4 to
20 mA).
(Operation panel indication is [PS].)
For the separated converter type, terminals
RDA and SE of the converter unit are not
connected to terminals MRS (X10 signal) and
SD (PC for source logic) of the inverter
respectively.
Two-wire or three-wire type connection is
incorrect.
586
6. PROTECTIVE FUNCTIONS
6.5 Check first when you have a trouble
Possible cause
was pressed.
Countermeasure
Power on a molded case circuit breaker (MCCB), an earth
leakage circuit breaker (ELB), or a magnetic contactor (MC).
Check for the decreased input voltage, input phase loss, and
wiring.
If only the control power is ON when using a separate power
source for the control circuit, turn ON the main circuit power.
Check the wiring between the inverter and the motor.
If the electronic bypass function is active, check the wiring of
the magnetic contactor (MC) between the inverter and the
motor.
Securely fit a jumper across P/+ and P1. When using a DC
reactor, remove the jumper across P/+ to P1, and then connect
the DC reactor.
Connect the DC reactor securely when required according to
the capacity.
Check the start command source, and input a start signal.
PU operation mode: /
External operation mode: STF/STR signal
Turn ON only one of the forward and reverse rotation start
signals (STF or STR).
When the STF and STR signals are turned ON simultaneously
in the initial setting, a stop command is given.
Check the frequency command source and enter a frequency
command.
Turn ON the AU signal.
Turning ON the AU signal activates terminal 4 input.
Turn MRS or RES signal OFF.
Inverter starts the operation with a given start command and a
frequency command after turning OFF MRS or RES signal.
Before turning OFF, ensure the safety.
Turn ON the automatic restart after instantaneous power
failure/flying start (CS) signal.
When the CS signal is assigned to an input terminal, automatic
restart operation is enabled when the CS signal is turned ON.
Check that the control logic switchover jumper connector is
correctly installed.
If it is not installed correctly, input signal is not recognized.
Set Pr.73 Analog input selection, Pr.267 Terminal 4 input
selection, and a voltage/current input switch correctly, then
input an analog signal in accordance with the setting.
During the External operation mode, check the method of
restarting from a input stop from PU.
Check for the wiring.
Check the wiring.
Use the Start self-holding selection (STP (STOP)) signal when
the three-wire type is used.
Refer to
page
―
―
60
42
42, 69
207
50
207
318
50
448
54
318
164, 574
Refer to the
Instruction
Manual
(Hardware)
of the FR-
F862.
550