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3
PRECAUTIONS FOR USE OF THE DRIVE UNIT
Precautions for use of the drive unit
3.4 Precautions for use of the drive unit
The FR-E700EX 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 crimping terminals with insulation sleeve to wire the power supply and motor.
(2) Application of power to the output terminals (U, V, W) of the drive unit will damage the drive unit. Never perform
such wiring.
(3) After wiring, wire offcuts must not be left in the drive unit.
Wire offcuts can cause an alarm, failure or malfunction. Always keep the drive unit clean.
When drilling mounting holes in an enclosure etc., take care not to allow chips and other foreign matter to enter the drive
unit.
(4) Use cables of the appropriate size to make a voltage drop of 2% or less.
If the wiring distance is long between the drive unit and motor, a main circuit cable voltage drop will cause the motor
torque to decrease especially at the output of a low speed.
Refer to page 16 for the recommended wire sizes.
(5) The wiring length should be 30m or less.
(6) Electromagnetic wave interference
The input/output (main circuit) of the drive unit includes high frequency components, which may interfere with the
communication devices (such as AM radios) used near the drive unit. In this case, install options among the capacitor
type noise filter FR-BIF (for use in the input side only), the ferrite core type noise filter FR-BSF01/FR-BLF, Filterpack, and
noise filter to minimize the interference.
(7) Do not install a power factor correction capacitor, surge suppressor or capacitor type filter on the drive unit
output side.
This will cause the drive unit to trip or the capacitor and surge suppressor to be damaged. If any of the above devices are
connected, immediately remove them.
(8) For some short time after the power is switched OFF, a high voltage remains in the smoothing capacitor.
When accessing the drive unit 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 drive unit is no more than
30VDC using a tester, etc.
(9) Do not perform wiring or inspection while the 24 V external power is supplied.
When FR-E7DS is installed, if "EV" is displayed on the operation panel, turn OFF the 24 V external power supply before
wiring and inspection. (Refer to page 316)
(10) A short circuit or earth (ground) fault on the drive unit output side may damage the inverter module.
Fully check the insulation resistance of the circuit prior to drive unit operation since repeated short circuits may
damage the inverter modules. These short circuits may be caused by peripheral circuit inadequacy, an earth (ground)
fault caused by wiring inadequacy, or reduced motor insulation resistance.
Fully check the to-earth (ground) insulation and phase to phase insulation of the drive unit output side before power-ON.
Especially for an old motor or use in a hostile atmosphere, securely check the motor insulation resistance etc.
(11) Do not use the magnetic contactor at the drive unit input side to start/stop the drive unit.
Since repeated inrush currents at power ON will shorten the life of the converter circuit (switching life is about 1,000,000
times), frequent starts and stops of the MC must be avoided. Turn ON/OFF the drive unit start controlling terminals (STF,
STR) to run/stop the drive unit. (Refer to page 42)