Operation; Precautions For Use Of The Inverter - Mitsubishi Electric FR-E700 Instruction Manual

Operation

4 Operation
4.1

Precautions for use of the inverter

The FR-E700SC 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.
● Use crimping terminals with insulation sleeve to wire the power supply and motor.
● Application of power to the output terminals (U, V, W) of the inverter will damage the inverter.
Never perform such wiring.
● 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.
● 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
3-10 for the recommended cable sizes.)
● 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 page 3-13.)
● 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 a line noise filter to minimize interference.
● 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 (e. g. high carrier frequencies).
– Decrease the carrier frequency.
– Consider the use of a sine wave output filter.
● Do not install a power factor correction capacitor, surge suppressor or radio noise filter on the
inverter output side.
This will cause the inverter to trip or the capacitor and surge suppressor to be damaged.
● 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 30 V DC using a tester.
FR-E700 SC EC/ENE
Precautions for use of the inverter
4 - 1