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Precautions for use of the inverter
3.5 Precautions for use of the inverter
The FR-D700 series is a highly reliable product, but incorrect peripheral circuit making or operation/handling method may
shorten the product life or damage the product.
Before starting operation, always recheck the following items.
(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 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 size to make a voltage drop 2% maximum.
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 17 for the recommended wire sizes.
(5) The overall wiring length should be 500m (1640.42feet) maximum.
Especially for long distance wiring, the fast-response current limit function may decrease or the equipment connected to
the secondary side may malfunction or become faulty under the influence of a charging current due to the stray capacity
of the wiring. Therefore, note the overall wiring length. (Refer to page 19)
(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 the FR-BIF optional capacitor
type filter (for use in the input side only) or FR-BSF01 or FR-BLF common mode filter to minimize interference.
(7) 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 supply
specification, make sure of secure insulation of T/L3-phase, and connect to the input side of the inverter.)
(8) 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 not more than 30VDC using a tester, etc.
The capacitor is charged with high voltage for some time after power off and it is dangerous.
(9) A short circuit or earth (ground) fault on the inverter output side may damage the inverter modules.
Fully check the insulation resistance of the circuit prior to inverter operation since repeated short circuits caused by
peripheral circuit inadequacy or an earth (ground) fault caused by wiring inadequacy or reduced motor insulation
resistance may damage the inverter modules.
Fully check the to-earth (ground) insulation and phase to phase insulation of the inverter output side before power-on.
Especially for an old motor or use in hostile atmosphere, securely check the motor insulation resistance etc.
(10) Do not use the inverter input side magnetic contactor to start/stop the inverter.
Always use the start signal (turn on/off STF and STR signals) to start/stop the inverter. (Refer to page 44)
(11) Across P/+ and PR terminals, connect only an external regenerative brake discharging resistor.
Do not connect a mechanical brake.
The brake resistor can not be connected to the FR-D720-008 and 014 and FR-D720S-008 and 014. Never short
between terminals P/+ and PR.