Mitsubishi Electric FR-A800 Series Instruction Manual page 569

NOTE
• Take power from any point between the power supply and MC1 to the terminals for control circuit power input (R1/L11 and S1/
L21). If power is taken from any point between MC1 and the inverter, the electronic bypass sequence function does not work.
• The electronic bypass sequence function is enabled only when Pr.135 = "1" and the inverter is in the External operation mode
or the PU/External combined operation mode 1 (Pr.79 = "3" (frequency command using the PU and start command using the
external signals)). When Pr.135 = "1" but the inverter is in the operation mode other than mentioned above, the MC1 and MC3
signals are ON.
• MC3 turns ON when the MRS and CS signals are ON and the STF (STR) signal is OFF. If the motor coasted to a stop from
commercial power supply operation at the previous stop, the motor starts running after the time set in Pr.137.
• Inverter operation is only available when the MRS, STF (STR), and CS signals are ON. In all other cases (when the MRS signal
is ON), commercial power supply operation is available.
• When the CS signal is OFF, the motor switches to the commercial power supply operation. However, when the STF (STR)
signal is OFF, the motor decelerates to a stop during inverter operation.
• From the point where MC2 and MC3 are both turned OFF, there is a delay time set with Pr.136, till MC2 or MC3 is turned ON.
• Even when the electronic bypass sequence is enabled (Pr.135 = "1"), the Pr.136 and Pr.137 settings are disabled in PU
operation mode.
In addition, the input terminals (STF, CS, MRS, OH) return to perform their normal functions.
• When both the electronic bypass sequence function and the PU operation interlock function are enabled at the same time
(Pr.135 = "1" and Pr.79 = "7") and the PU operation external interlock (X12) signal is not assigned to any input terminal, the
MRS signal will have another function as the X12 signal. (In this case, the inverter operation is enabled when both the MRS
signal and the CS signal are ON.)
• Set the acceleration time to the level that does not activate the stall prevention operation.
• If switching to the commercial power supply operation while a failure such as an output short circuit has occurred between the
magnetic contactor MC3 and the motor, the damage may further spread. If a failure has occurred between the MC3 and the
motor, a protection circuit such as using the OH signal input must be provided.
• Changing the terminal functions with Pr.178 to Pr.189 and Pr.190 to Pr.196 may affect other functions. Set parameters after
confirming the function of each terminal.
• Switching with the electronic bypass sequence is not available during retry. Switching occurs after the retry. When the
electronic bypass is valid at a fault (Pr.138 = "1"), switching occurs also during retry.
• When the electronic bypass sequence function and the retry function of the converter unit are used at the same time for the
separated converter type, set 101 or more in the number of retries at fault occurrence (Pr.67) on the converter unit side. When
a value less than 100 is set, the ALM signal does not turn ON until the retry count is exceeded. In this case, the electronic
bypass at a fault is not performed until the retry count is exceeded.
• To use X95 and X96 signals for the separated converter type, use a converter unit manufactured in August 2014 or later.
 Precautions for electronic bypass sequence function
• The response time of the inverter to the signals depends on the command source, NET or External.
After the communication with the inverter is established, the motor operation is performed according to the command via
NET. The commercial power supply operation with the motor is performed when the MRS signal turns ON before the
communication is established. It is recommended to turn the MRS signal ON after the communication is established.
Example: the response time of the inverter to the signals in the Network operation mode (power-ON). The command
source is External for the MRS signal and NET for the STF (STR) and CS signals.
Communication status
568
5. PARAMETERS
5.14 (A) Application parameters
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ON
Power supply
Until the communication with the inverter is established
From when the communication is established until the inverter receives a command
MRS(External)
STF(NET)
CS(NET)
Commercial
power supply
operation
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ON
ON
ON
ON
Inverter operation