Output Current Detection Characteristics - Hitachi SJ100 SERIES Service Manual

5-2. Output Current Detection Characteristics

Frequency inverter has several detection characteristics for output current to protect IGBT from break
down, or to protect motor from over heat.
[1] Over current
Frequency inverter shuts off the output instantaneously when output current exceeds to 220%(190)
of its rated current. (OC level is no link with Electronic thermal level)
e.g. Over current protection level of SJ100-015NFE (7.1 Amps of rated current) is
7.1 [Arms] * 200% = 14.2 [Arms] = 20.1 [A peak]
[2] Over load (Electronic thermal protection)
Frequency inverter shuts off the output when integration value of output current and time exceeds
specific value.
time
180s
120s
60s
0
This Electronic thermal level can be changed from 50% to 120%. (Initial setting is 100%.)
time
180s
120s
60s
0
No over load trip with
115% load
100%
% output current of the rated current of the frequency inverter
E-Thermal Level = [50]
50% 100%
% output current of the rated current of the frequency inverter
E-Thermal Level = [100]
150%, 60s
150%
150%, 60s
150%
5-3
Over Current trip
220%(-> 4kW)
190%(5.5kW ->)
180%, 10s
220%(190%)
180%, 10s
220%(190%)