Precautions For Use Of The Inverter - Mitsubishi Electric FR-E720-0.1K Instruction Manual

3 PRECAUTIONS FOR USE OF THE INVERTER

The FR-E700 series is a highly reliable product, but using incorrect peripheral circuits or incorrect operation/handling methods
may shorten the product life or damage the product.
Before starting operation, always recheck the following points.
(1) Use crimp terminals with insulation sleeve to wire the power supply and motor.
(2) Application of power to the output terminals (U, V, W) of the inverter will damage the inverter. Never perform
such wiring.
(3) After wiring, wire offcuts must not be left in the inverter.
Wire offcuts can cause an alarm, failure or malfunction. Always keep the inverter clean.
When drilling mounting holes in an enclosure etc., take care not to allow chips and other foreign matter to enter the
inverter.
(4) Use cables of the appropriate size to make a voltage drop of 2% or less.
If the wiring distance is long between the inverter and motor, a main circuit cable voltage drop will cause the motor torque
to decrease especially at the output of a low frequency.
Refer to page 13 for the recommended wire sizes.
(5) The total wiring length should be within the prescribed length.
Especially for long distance wiring, the fast-response current limit function may decrease, or the equipment connected to
the output side may malfunction. This is caused by a charging current due to the stray capacity of the wiring. Therefore,
note the overall wiring length. (Refer to page 14)
(6) Electromagnetic wave interference
The input/output (main circuit) of the inverter includes high frequency components, which may interfere with the
communication devices (such as AM radios) used near the inverter. In this case, install options among the capacitor type
EMC filter FR-BIF (for use in the input side only), the ferrite core type EMC filter FR-BSF01/FR-BLF, Filterpack, and EMC
filter to minimize the interference.
(7) Electrical corrosion of the bearing
When a motor is driven by the inverter, axial voltage is generated on the motor shaft, which may cause electrical
corrosion of the bearing in rare cases depending on the wiring, load, operating conditions of the motor or specific inverter
settings (high carrier frequency, use of a capacitive filter).
The following shows examples of countermeasures for the inverter.
Decrease the carrier frequency.

Remove the capacitive filter.

Provide a common mode choke on the output side of the inverter. (This is effective regardless of the use of the

capacitive filter.)

Mitsubishi Electric capacitive filter: FR-BIF, SF[], FR-E5NF-[], FR-S5NFSA[], FR-BFP2-[]

Recommended common mode choke: FT-3KM F series FINEMET
FINEMET is a registered trademark of Hitachi Metals, Ltd.
(8) Do not install a power factor correction capacitor, surge suppressor or capacitor type filter on the inverter
output side.
This will cause the inverter to trip or the capacitor and surge suppressor to be damaged. If any of the above devices are
connected, immediately remove them. (When using capacitor type filter (FR-BIF) for single-phase power input model,
make sure of secure insulation of T-phase, and connect to the input side of the inverter.)
(9) For some short time after the power is switched OFF, a high voltage remains in the smoothing capacitor.
When accessing the inverter for inspection, wait for at least 10 minutes after the power supply has been switched OFF,
and then make sure that the voltage across the main circuit terminals P/+ and N/- of the inverter is no more than 30VDC
using a tester.
PRECAUTIONS FOR USE OF THE INVERTER
®
common mode choke cores manufactured by Hitachi Metals, Ltd.
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