The Inverter - Mitsubishi Electric FR-A700 Installation Manualline

(13) Provide electrical and mechanical interlocks for MC1 and
MC2 which are used for bypass operation.
When the wiring is incorrect and if there is a bypass
operation circuit as shown right, the inverter will be
damaged when the power supply is connected to the
inverter U, V, W terminals, due to arcs generated at the
time of switch-over or chattering caused by a sequence
error.
(Commercial operation can not be performed with the
vector dedicated motor (SF-V5RU, SF-THY).)
(14) If the machine must not be restarted when power is restored after a power failure, provide a magnetic contactor in the
inverter's input side and also make up a sequence which will not switch on the start signal.
If the start signal (start switch) remains on after a power failure, the inverter will automatically restart as soon as the
power is restored.
(15) Instructions for overload operation
When performing an operation of frequent start/stop with the inverter, rise/fall in the temperature of the transistor element
of the inverter will repeat due to a continuous 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).
(16) Make sure that the specifications and rating match the system requirements.
(17) A motor with encoder is necessary for vector control. In addition, connect the encoder directly to the backlash-free motor
shaft. An encoder is not necessary for real sensorless vector control.
(18) When the motor signal is unstable, due to change in the frequency setting signal caused by noises from the inverter, take
the following measures to change 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).
PRECAUTIONS FOR USE OF
Power supply
R/L1
S/L2
T/L3 W
Inverter

THE INVERTER

MC1
Interlock
U
IM
V
MC2
Undesirable current
23