Bypass-Inverter Switchover Function (Pr. 135 To Pr. 139, Pr. 159) - Mitsubishi Electric F700 Instruction Manual

4.20.2 Bypass-inverter switchover function (Pr. 135 to Pr. 139, Pr. 159)

The complicated sequence circuit for bypass-inverter switchover 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
Electronic bypass sequence
135
selection
136 MC switchover interlock time
137 Start waiting time
138 Bypass selection at an alarm
Automatic switchover frequency
139
from inverter to bypass operation
Automatic switchover frequency
159 range from bypass to inverter
operation
The above parameters can be set when Pr. 160 User group read selection = "0". (Refer to page 156.)
⋅ When the motor is operated at 60Hz (or 50Hz), 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.
Initial
Name
Value
0
1s
0.5s
0
9999
9999
Special operation and frequency control
Setting
Range
0 Without electronic bypass sequence
1 With electronic bypass sequence
0 to 100s Set the operation interlock time of MC2 and MC3.
Set the time slightly longer (0.3 to 0.5s or so) than the
0 to 100s time from when the ON signal enters MC3 until it
actually turns on.
Inverter output is stopped (motor coast) at inverter
0
fault.
Operation is automatically switched to bypass
1 operation at inverter fault (Not switched when an
external thermal error occurs)
Set the frequency to switch inverter operation to
bypass operation.
Inverter operation is performed from a start until Pr.
0 to 60Hz
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
Valid during automatic switchover operation (Pr. 139 ≠
9999)
When the frequency command decreases below (Pr.
139 to Pr. 159) after operation is switched from
inverter operation to bypass operation, the inverter
0 to 10Hz
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.
Valid during automatic switchover operation (Pr. 139 ≠
9999)
When the inverter start command (STF/STR) is
9999
turned off after operation is switched from inverter
operation to bypass inverter operation, operation is
switched to inverter operation and the motor
decelerates to stop.
Description
209
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