Mitsubishi Electric FR-E700 Instruction Manual page 95

Operation
● Inverter input side magnetic contactor (MC)
On the inverter input side, connect a MC for the following purposes.
To release the inverter from the power supply when a fault occurs or when the drive is not
functioning (e.g. emergency stop operation). For example, MC avoids overheat or burnout of
the brake resistor when heat capacity of the resistor is insufficient or brake regenerative
transistor is damaged with short while connecting an optional brake resistor.
To prevent any accident due to an automatic restart at restoration of power after an inverter
stop made by a power failure.
To separate the inverter from the power supply to ensure safe maintenance and inspection
work. If using an MC for emergency stop during operation, select an MC regarding the inverter
input side current as JEM1038-AC-3 class rated current.
● Handling of inverter output side magnetic contactor
Switch the magnetic contactor between the inverter and motor only when both the inverter and
motor are at a stop. When the magnetic contactor is turned ON while the inverter is operating,
overcurrent protection of the inverter and such will activate. When MC is provided for switching
to the commercial power supply, for example, switch it ON/OFF after the inverter and motor have
stopped.
● Countermeasures against inverter-generated EMI
When the motor speed is unstable, due to change in the frequency setting signal caused by
electromagnetic noises from the inverter, take the following measures when applying the motor
speed by the analog signal.
– Do not run the signal cables and power cables (inverter I/O cables) in parallel with each other
and do not bundle them.
– Run signal cables as far away as possible from power cables (inverter I/O cables).
– Use shield cables as signal cables.
– Install a ferrite core on the signal cable (Example: ZCAT3035-1330 TDK).
● Instructions for overload operation
When performing operation of frequent start/stop of the inverter, rise/fall in the temperature of
the transistor element of the inverter will repeat due to a repeated flow of large current, shortening
the life from thermal fatigue. Since thermal fatigue is related to the amount of current, the life can
be increased by reducing current at locked condition, starting current, etc. Decreasing current
may increase the life. However, decreasing current will result in insufficient torque and the inverter
may not start. Therefore, choose the inverter which has enough allowance for current (up to 2
rank larger in capacity).
● Make sure that the specifications and rating match the system requirements.
FR-E700 SC EC/ENE
Precautions for use of the inverter
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