Hitachi SJ700-2 Instruction Manual page 107

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).
Item
Automatic carrier
frequency reduction
- 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.
Carrier frequency reduction start level
(Restoration level)
Less than 60% of rated current
60% (55%) of rated current
72% (67%) of rated current
84% (79%) of rated current
96% (91%) of rated current
Carrier frequency
15.0kHz
12.0kHz
9.0kHz
6.0kHz
3.0kHz
- 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.
Function code
b089
Carrier frequency after
reduction (kHz)
15.0
12.0
9.0
6.0
3.0
0 50
Chapter 4 Explanation of Functions
Range of data
00/01 00: invalid, 01: valid
100
60% 72% 84% 96%
4 - 44
Related code
b089: Automatic carrier frequency
reduction selection
b083: Carrier frequency setting
Description
Output current (%)