Power-Off And Magnetic Contactor (Mc) - Mitsubishi Electric FR-A820-00046 Instruction Manual

Precautions for use of the inverter
3.4

Power-OFF and magnetic contactor (MC)

Inverter input side magnetic contactor (MC)
On the inverter input side, it is recommended to provide an MC for the following purposes:
(Refer to page 2-4 for selection.)
● To disconnect the inverter from the power supply at activation of a protective function or at
malfunctioning of the driving system (emergency stop, etc.). For example, an MC prevents
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 power restoration 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.
NOTE 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 magnetic contactor must be
avoided. Turn ON/OFF the inverter start controlling terminals (STF, STR) to run/stop the inverter.
FR-A800
Power-OFF and magnetic contactor (MC)
3 - 17