Check First When You Have A Trouble; Motor Does Not Start - Mitsubishi Electric FR-A720-00030-NA Instruction Manual

5.5

Check first when you have a trouble

Refer to troubleshooting on
addition to the following check points.
POINT
· If the cause is still unknown after every check, it is recommended to initialize the parameters (initial value) then reset the
required parameter values and check again.
5.5.1

Motor does not start

Check
points
Appropriate power supply voltage is not applied.
(Operation panel display is not provided.)
Main
Circuit
Motor is not connected properly.
The jumper across P/+ and P1 is disconnected.
(FR-A720-02150 (FR-A740-01100) or less)
Start signal is not input.
Both the forward and reverse rotation start signals (STF,
STR) are input simultaneously.
Frequency command is zero.
(FWD or REV LED on the operation panel is flickering.)
AU signal is not ON when terminal 4 is used for
frequency setting.
(FWD or REV LED on the operation panel is flickering.)
Input
Output stop signal (MRS) or reset signal (RES) is ON.
signal
(FWD or REV LED on the operation panel is flickering.)
CS signal is OFF when automatic restart after
instantaneous power failure function is selected (Pr. 57 
"9999").
(FWD or REV LED on the operation panel is flickering. )
Jumper connector of sink - source is wrongly selected.
(FWD or REV LED on the operation panel is flickering.)
Wiring of encoder is incorrect.
(Under encoder feedback control or vector control)
Voltage/current input switch is not correctly set for analog
input signal (0 to 5V/0 to 10V, 4 to 20mA).
(FWD or REV LED on the operation panel is flickering.)
page 109 (speed control), page 130 (torque control) and page 142 (position control) in
Possible Cause
Check first when you have a trouble
Countermeasures
Power ON a moulded 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 commercial power supply-inverter switchover function is
active, check the wiring of the magnetic contactor
connected between the inverter and the motor.
Securely fit a jumper across P/+ and P1.
When using a DC reactor (FR-HEL), remove the jumper
across P/+ and P1, and then connect the DC reactor.
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).
If 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 CS signal.
Restart operation is enabled when restart after
instantaneous power signal (CS) is ON.
Check that the control logic switchover jumper connector is
correctly installed.
If it is not installed correctly, input signal is not recognized.
Check the wiring of encoder.
Set Pr. 73, Pr. 267, and a voltage/current input switch
correctly, then input an analog signal in accordance with
the setting.
Refer
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