SJ700-2 Instruction Manual NT204DX - Hitachi America, Ltd.

Chapter 4 Explanation of Functions
4.2.36 Automatic carrier frequency reduction
- The automatic carrier frequency reduction function automatically
reduces the carrier frequency according to the increase in output current.
- To enable this function, specify "01" for automatic carrier frequency
reduction selection (b089).
Related code
b089: Automatic carrier frequency
reduction selection
b083: Carrier frequency setting
Item Function code Range of data Description
Automatic carrier
frequency reduction
b089 00/01 00: invalid, 01: valid
- When the output current increases to 60%, 72%, 84%, or 96% of the rated current, this function reduces
the carrier frequency to 12, 9, 6, or 3 kHz, respectively. This function restores the original carrier frequency
when the output current decreases to 5% lower than each reduction start level.
0.4~55kW
75~132kW
Carrier frequency reduction start level
(Restoration level)
Carrier frequency after
reduction (kHz)
Carrier frequency reduction start level
(Restoration level)
Carrier frequency after
reduction (kHz)
Less than 60% of rated current 15.0 Less than 60% of rated current 10.0
60% (55%) of rated current 12.0 60% (55%) of rated current 8.0
72% (67%) of rated current 9.0 71% (66%) of rated current 6.0
84% (79%) of rated current 6.0 83% (78%) of rated current 4.5
96% (91%) of rated current 3.0 91% (86%) of rated current 3.0
Carrier frequency
15.0kHz
12.0kHz
9.0kHz
6.0kHz
3.0kHz
0 50
100
60% 72% 84% 96%
Output current (%)
- The rate of carrier frequency reduction is 2 kHz per second.
- The maximum limit of carrier frequency change by this function is the value specified for the carrier
frequency setting (b083); the minimum limit is 3 kHz.
Note: If 3 kHz or less frequency has been specified for b083, this function is disabled regardless of the
setting of b089.
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