INVT GD300-01A-011G-4, Руководство по эксплуатации

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Goodrive300-01A series VFD for air compressor Appendix E
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action and time gap between them should be set to a value larger than 20ms eg 1s, 0.5s and 0.2s.
It is recommended to use electromagnetic RCD for the electrical circuit of VFD system. Such RCD
carries strong anti-interference capacity to prevent the RCD from being affected by high frequency
leakage current.
Electronic RCD Electromagnetic RCD
Low cost, high sensitivity, small size,
vulnerable to voltage fluctuation of
the grid and ambient temperature,
weak anti-interference capacity
Require the zero sequence current transformer to be quite
sensitive, precise and stable, made from permalloy
material with high permeability, complicated process and
high cost, immune to voltage fluctuation of the grid and
ambient temperature., strong anti-interference capacity
Solution to mal-operation of RCD (on the part of VFD)
a)
Try to disassemble the jumper cap in “EMC/J10” (refer to chapter 3.1.3 and 3.1.4 for the position
of J10)
b) Try to decrease the carrier frequency to 1.5kHz (P00.14=1.5);
c)
Try to change the modulation mode to “3PH modulation and 2PH modulation” (P8.40=00)
Solution to mal-operation of RCD (on the part of system distribution)
a) Check and confirm the power cable is not immersed in water
b) Check and confirm the cable is not broken or switched over;
c) Check and confirm if secondary grounding occurred to the null line;
d) Check and confirm if power cable terminal is in the air switch or the contactor is poorly contacted
(loose screws);
e) Check the single-phase electric equipment and confirm if the ground line is misused as null line;
f) VFD power cable and motor cable should not be shielded ones.
Leakage protection of motor autotuning
During motor autotuning, the measurement on differing motor parameters is conducted step by step,
in which the first two steps is to measure the resistance of motor stator/rotor while the VFD will output
square wave to motor stator winding at 4kHz (default carrier frequency), as leakage current
generated by 4kHz carrier frequency against distributed capacitance between motor rotor and stator
during charging/discharging is quite obvious, which may cause mal-operation of RCD. If such
problem occurred, bypass RCD first and restore after parameter autotuning is completed.
E.5 Problem of charged device shell
The problem mainly lies in that the device shell carries detectable voltage which gives anyone who
touches it a feeling of electrical shock, however, when the VFD is powered up without running, the
shell will be uncharged (or the voltage it carries is far lower than human body safety voltage).
Solution:
a) If there is distribution groundin
g or ground pile on users’ site, ground the shell of VFD cabinet by
power GND or ground pile;
b) If there is no grounding connection on site, it is necessary to electrically connect the motor shell
to grounding terminal PE of the VFD and confirm that the jump
er in “EMC/J10” of the VFD is
short connected (refer to chapter 3.1.3 and 3.1.4 for the position of EMC/J10).