Mitsubishi Electric FR-E720-0.4K Instruction Manual page 17

The line voltage drop can be calculated by the following formula:
3 × wire resistance [mΩ/m] × wiring distance [m] × current [A]
Line voltage drop [V]=
Use a larger diameter cable when the wiring distance is long or when it is desired to decrease the voltage drop (torque
reduction) in the low speed range.
(2) Total wiring length
The overall wiring length for connection of a single motor or multiple motors should be within the value in the table below.
Pr. 72 Setting
Cable Type
(carrier frequency)
1 (1kHz) or lower
Unshielded
cable
2 (2kHz) or higher
1 (1kHz) or lower
Shielded
cable
2 (2kHz) or higher
When driving a 400V class motor by the inverter, surge voltages attributable to the wiring constants may occur at the
motor terminals, deteriorating the insulation of the motor. Take the following measures 1) or 2) in this case.
1) Use a "400V class inverter-driven insulation-enhanced motor" and set frequency in Pr. 72 PWM frequency selection
according to wiring length.
Carrier frequency
2) Connect the surge voltage suppression filter (FR-ASF-H/FR-BMF-H) on the inverter output side.
NOTE
 Especially for long-distance wiring, the inverter may be affected by a charging current caused by the stray
capacitances of the wiring, leading to a malfunction of the overcurrent protective function, fast response current limit
function, or stall prevention function or a malfunction or fault of the equipment connected on the inverter output side.
If malfunction of fast-response current limit function occurs, disable this function. If malfunction of stall prevention
function occurs, increase the stall level. (
operation selection in Chapter 4 of the Instruction Manual (Applied).)
 When using the automatic restart after instantaneous power failure function with the wiring length exceeding 100m,
select without frequency search (Pr. 162 = "1, 11"). (
1000
Voltage
0.1K 0.2K
Class
100V/200V 200m 200m
400V -
100V/200V 30m 100m
400V -
100V/200V 50m 50m
400V -
100V/200V 10m 25m
400V -
Wiring Length
50m or less 50m to 100m
14.5kHz or less 8kHz or less
Refer to Pr. 22 Stall prevention operation level and Pr. 156 Stall prevention
0.4K 0.75K
300m 500m
- 200m 200m
200m 300m
- 30m 100m
75m 100m
- 50m 50m
50m 75m
- 10m 25m
Exceeding 100m
2kHz or less
Refer to Chapter 4 of the Instruction Manual (Applied).)
Wiring
3.7K
1.5K 2.2K
or Higher
500m 500m 500m
300m 500m 500m
500m 500m 500m
200m 300m 500m
100m 100m 100m
75m 100m 100m
100m 100m 100m
50m 75m 100m
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