Mitsubishi Electric FR-CS84-012 Instruction Manual page 64

 Checking the inverter operating status by the start signal input to the inverter and by the
Inverter running signal output from the inverter ... (c)
The Inverter running (RUN) signal is output when the inverter is running. Check if the RUN signal is output while a start signal
(the STF/STR signal for forward/reverse rotation command) is input to the inverter. Even after the start signal is turned OFF,
the RUN signal is kept output until the inverter makes the motor decelerate and stop. For the logic check, configure a sequence
considering the inverter's deceleration time.
Power ON
supply
ON
STF
RH
Pr.13 Starting
frequency
Reset
processing
ON
RY
RUN
 Checking the motor operating status by the start signal input to the inverter and by the Output
current detection signal output from the inverter ... (d)
The Output current detection (Y12) signal is output when the inverter operates and current flows into the motor.
Check if the Y12 signal is output while a start signal (the STF/STR signal for forward/reverse rotation command) is input to the
inverter. The Y12 signal is initially set to be output at 150% rated inverter current. Adjust the level to around 20% using no load
current of the motor as reference with Pr.150 Output current detection level.
Like the Inverter running (RUN) signal, even after the start signal is turned OFF, the Y12 signal is kept output until the inverter
makes the motor decelerate and stop. For the logic check, configure a sequence considering the inverter's deceleration time.
 Backup method which does not use the inverter
Even if the interlock is provided by the inverter status signal, enough failsafe is not ensured depending on the failure status of
the inverter itself. For example, if an inverter CPU fails in a system interlocked with the inverter's fault, start, and RUN signals,
the Fault signal will not be output and the RUN signal will be kept ON because the inverter CPU is down.
Provide a speed detector to detect the motor speed and current detector to detect the motor current and consider the backup
system such as performing a check as below according to the level of importance of the system.
 Start signal and actual operation check
Check the motor running and motor current while the start signal is input to the inverter by comparing the start signal to the
inverter and detected speed of the speed detector or detected current of the current detector. Note that the current is flowing
through the motor while the motor coasts to stop, even after the inverter's start signal is turned OFF. For the logic check,
configure a sequence considering the inverter's deceleration time. In addition, it is recommended to check the three-phase
current when using the current detector.
OFF
OFF
ON
DC injection brake
operation point
DC injection
brake operation
Time
OFF
ON OFF
3. PRECAUTIONS FOR USE OF THE INVERTER
3.7 Failsafe system which uses the inverter
1
2
3
5
5
6
7
8
9
10
63