8-1
Description
Contents
Display
Over current
protection
A currrent due to the alternating current CT between the power module
and output terminal {U(T1), V(T2), W(T3)} is detected.
When the motor is restricted or decelerated suddenly, a large current
flows through the inverter and causes a fault. Therefore, when an
abnormal current is detected by the alternating current CT and it exceeds
a specified value, the output is cut off. (An abnormal current is also
detected in the power module. Refer to , , , and .)
Constant
speed
Dec.
Acc.
Overload
protection
(NOTE 1)
When a motor overload is detected by the electronic thermal function, the output
of the inverter is cut off.
Braking
resistor overload
When the braking time exceeds the satting by braking duty factor, an
overvoltage the output of the inverter is cut off.
Overvoltage
protection
When the converter voltage exceeds a certain level due to regenerative energy from
the motor, this protection function engages, and the output of inverter is cut off.
EEPROM error
(NOTE 2)
When the memory built in has problems due to noise or excessive temperature rise,
this protective function engages, and the output of inverter is cut off.
Undervoltage
protection
A decrease of the input voltage of an inverter results in improper function of the
control circuit. It also generates motor heat and causes low torque. Output is cut off
when the input voltage goes down to less than 150-160V/300-320V(200/400Vclass).
CT error
Abnormality on built-in CT and the output of the inverter is cut off.
CPU error
Malfunction or abnormality on built-in CPU and the output of the inverter is cut
off.
External trip
An abnormality signal from external equipment cuts off the output of the inverter.
(When external trip function is selected)
USP error
It indicates an error when power is turned on while the inverter is being run.
(When USP function is selected)
Input overvoltage
When the input voltage is higher than the specified value, it is detected 100 seconds
after power is turned on and the output is cut off. However, when a voltage higher
than approx. 250 to 270 V (200V class),
500 to 530 V (400 V class) is inputted, it is higher than the rated value of the part
in use, so that the part may not be protected and damaged.
Ground fault
protection
The inverter is protected by detection of ground faults between the inverter output
and the motor upon power on. There may be the possibility of power module failure.
Instantaneous
power failure
(NOTE 4)
When an instantaneous power failure for more than 15 ms occurs, the output is cut
off. When the instantaneous power failure time is long, the fault signal is released.
Note that when restart is selected, the equipment restarts when the running
command remains.
8. PROTECTION FUNCTIONS
The J300 series inverters are equipped with protection functions against overcurrent,
overvoltage, and undervoltage which protect the inverter. If the protection functions are
engaged, the output is shut down, motor runs free and holds that condition until it is reset.
