Hitachi SJ700-2 instruction manual Automatic carrier frequency reduction

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	b089	00/01	00: invalid, 01: valid
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		Carrier frequency after
(Restoration level)		reduction (kHz)
Less than 60% of rated current	15.0
60% (55%) of rated current	12.0
72% (67%) of rated current	9.0
84% (79%) of rated current	6.0
96% (91%) of rated current	3.0
Carrier frequency
15.0kHz
12.0kHz
9.0kHz
6.0kHz
3.0kHz						Output current (%)
0	50				100
	60%		72%	84%	96%

-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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