Mitsubishi Electric 800 Series, Instruction Manual, Page: 75 / 727

Checklist before starting operation
74
PRECAUTIONS FOR USE OF THE INVERTER
3.6
Checklist before starting operation
The FR-A860 series inverter 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 points.
Checkpoint Countermeasure
Refer
to page
Check
by user
Crimping terminals are insulated.
Use crimping terminals with insulation sleeves to wire the power supply
and the motor.
-
The wiring between the power supply
(R/L1, S/L2, T/L3) and the motor (U, V,
W) is correct.
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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No wire offcuts are left from the time of
wiring.
Wire offcuts can cause an alarm, failure or malfunction. Always keep the
inverter clean.
When drilling mounting holes in an enclosure etc., take caution not to
allow chips and other foreign matter to enter the inverter.
-
The main circuit cable gauge is correctly
selected.
Use an appropriate cable gauge to suppress the voltage drop to 2% or
less.
If the wiring distance is long between the inverter and motor, the voltage
drop in the main circuit will cause the motor torque to decrease
especially during the output of a low frequency.
40
The total wiring length is within the
specified length.
Keep the total wiring length within the specified length.
In long distance wiring, charging currents due to stray capacitance in the
wiring may degrade the fast-response current limit operation or cause
the equipment on the inverter's output side to malfunction. Pay attention
to the total wiring length.
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Countermeasures are taken against
EMI.
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 such case, install a noise filter.
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On the inverter's output side, there is no
power factor correction capacitor, surge
suppressor, or radio noise filter installed. Such installation will cause the inverter to trip or the capacitor and surge
suppressor to be damaged. If any of the above devices is connected,
immediately remove it.
-
When performing an inspection or
rewiring on the product that has been
energized, the operator has waited long
enough after shutting off the power
supply.
For a short time after the power-OFF, a high voltage remains in the
smoothing capacitor, and it is dangerous.
Before performing an inspection or rewiring, wait 10 minutes or longer
after the power supply turns OFF, then confirm that the voltage across
the main circuit terminals P/+ and N/- of the inverter is low enough using
a tester, etc.
-
The inverter's output side has no short
circuit or ground fault occurring.
• A short circuit or ground fault on the inverter's output side may damage
the inverter module.
• Fully check the insulation resistance of the circuit prior to inverter
operation since repeated short circuits caused by peripheral circuit
inadequacy or a ground fault caused by wiring inadequacy or reduced
motor insulation resistance may damage the inverter module.
• Fully check the to-earth (ground) insulation and phase-to-phase
insulation of the inverter's output side before power-ON. Especially for
an old motor or use in hostile atmosphere, make sure to check the
motor insulation resistance, etc.
-
The circuit is not configured to use the
inverter's input-side magnetic contactor
to start/stop the inverter frequently.
Since repeated inrush currents at power ON will shorten the life of the
converter circuit, frequent starts and stops of the magnetic contactor
must be avoided. Turn ON/OFF the inverter's start signals (STF, STR) to
run/stop the inverter.
72
A mechanical brake is not connected
across terminals P3(P/+) and PR.
Across terminals P3(P/+) and PR, connect only a brake resistor. 39 , 65
The voltage applied to the inverter I/O
signal circuits is within the
specifications.
Application of a voltage higher than the permissible voltage to the
inverter I/O signal circuits or opposite polarity may damage the I/O
devices. Especially check the wiring to prevent the speed setting
potentiometer from being connected incorrectly to short circuit the
terminals 10E and 5.
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