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5
PRECAUTIONS FOR USE OF THE INVERTER
The FR-D700 SC 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.
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Use crimping terminals with insulation sleeve to wire the power supply and motor.
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Application of power to the output terminals (U, V, W) of the inverter will damage the inverter. Never perform such wiring.
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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 a control
box etc., take care not to allow chips and other foreign matter to enter the inverter.
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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
for the recommended cable size.
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The overall wiring length should be within the prescribed length.
Especially for long distance wiring, the fast-response current limit function may be reduced or the equipment connected to the
inverter output 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
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Electromagnetic Compatibility
Operation of the frequency inverter can cause electromagnetic interference in the input and output that can be propagated by
cable (via the power input lines), by wireless radiation to nearby equipment (e.g. AM radios) or via data and signal lines. Install
an optional filter if present to reduce air propagated interference on the input side of the inverter. Use AC or DC reactors to
reduce line propagated noise (harmonics). Use shielded motor power lines to reduce output noise.
For EMC correct installation refer to the Manual for Frequency Inverters and EMC.
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Do not install a power factor correction capacitor, varistor or arrester on the inverter output side. This will cause the inverter to
trip or the capacitor, varistor, or arrester to be damaged. If any of the above devices is installed, immediately remove it.
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Before starting wiring or other work after the inverter is operated, wait for at least 10 minutes after the power supply has been
switched off, and check that there are no residual voltage using a tester or the like. The capacitor is charged with high voltage
for some time after power off and it is dangerous.
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A short circuit or earth 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 fault caused by wiring inadequacy or reduced motor insulation resistance may damage the
inverter modules.
– Fully check the to-earth insulation and inter-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.
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Do not use the inverter input side magnetic contactor to start/stop the inverter.
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.
Always use the start signal (ON/OFF of STF and STR signals) to start/stop the inverter.
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Across P/+ and PR terminals, connect only an external regenerative brake discharge resistor. Do not connect a mechanical brake.
The brake resistor can not be connected to the FR-D720S-008SC and 014SC. Leave terminals P/+ and PR open.
Also, never short between P/+ and PR.
Summary of Contents for FR-D720S-008SC
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