356
Special operation and frequency control
4.25.2
Bypass-inverter switchover function (Pr. 57, Pr. 58, Pr. 135 to Pr. 139, Pr. 159)
⋅ When the motor is operated at 50Hz (or 60Hz), more efficient operation can be performed by the commercial power
supply than by the inverter. When the motor cannot be stopped for a long time for the maintenance/inspection of the
inverter, it is recommended to provide the commercial power supply circuit.
⋅ To switch between inverter operation and bypass operation, an interlock must be provided to stop the motor once
and then start it by the inverter in order to prevent the inverter from resulting in an overcurrent alarm. Using the
electronic bypass sequence function that outputs the timing signal for operation of the magnetic contactor, a
complicated commercial power supply switchover interlock can be provided by the inverter.
The complicated sequence circuit for bypass operation is built in the inverter. Hence, merely inputting the start,
stop or automatic switchover selection signal facilitates the interlock operation of the switchover magnetic
contactor.
Parameter
Number
Name
Initial
Value
Setting Range Description
57 Restart coasting time 9999
0
⋅ 00052 or less .................................................... 0.5s,
⋅ 00083 to 00250
............................................1s,
⋅ 00310 to 01800
............................................3.0s,
⋅ 02160 or more .................................................. 5.0s,
The above times are coasting time.
01800
or less
0.1 to
5s
Set the waiting time for inverter-triggered restart after an
instantaneous power failure.
02160
or more
0.1 to
30s
9999 No restart
58 Restart cushion time 1s 0 to 60s Set a voltage starting time at restart.
135
Electronic bypass
sequence selection
0
0 Without electronic bypass sequence
1 With electronic bypass sequence
136
MC switchover interlock
time
1s 0 to 100s Set the operation interlock time of MC2 and MC3.
137 Start waiting time 0.5s 0 to 100s
Set the time slightly longer (0.3 to 0.5s or so) than the time from
when the ON signal enters MC3 until it actually turns on.
138
Bypass selection at an
alarm
0
0 Inverter output is stopped (motor coast) at inverter fault.
1
Operation is automatically switched to bypass operation at
inverter fault (Not switched when an external thermal error
occurs)
139
Automatic switchover
frequency from inverter
to bypass operation
9999
0 to 60Hz
Set the frequency to switch inverter operation to bypass
operation.
Inverter operation is performed from a start until Pr. 139 is
reached, and when the output frequency is at or above Pr.
139, inverter operation is automatically switched to bypass
operation.
9999 Without automatic switchover
159
Automatic switchover
frequency range from
bypass to inverter
operation
9999
0 to 10Hz
Valid during automatic switchover operation (Pr. 139 ≠ 9999)
When the frequency command decreases below (Pr. 139
minus Pr. 159) after operation is switched from inverter
operation to bypass operation, the inverter automatically
switches operation to inverter operation and operates at the
frequency of frequency command. When the inverter start
command (STF/STR) is turned off, operation is switched to
inverter operation also.
9999
Valid during automatic switchover operation (Pr. 139 ≠ 9999)
When the inverter start command (STF/STR) is turned off
after operation is switched from inverter operation to bypass
operation, operation is switched to inverter operation and
the motor decelerates to stop.
CAUTION
Commercial operation can not be performed with the Mitsubishi vector motor (SF-V5RU).
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