7-4-2 Automatic Carrier Reduction
Use this function to reduce the carrier frequency automatically as the output current and the cooling fin
temperature increase.
To enable this function, set the Automatic Carrier Reduction (b089) to 01 or 02.
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Depending on the ratio of the output current to the rated current and the cooling fin temperature, this
function reduces the carrier frequency to 12, 9, 6, and 3 kHz, as shown below. The normal carrier fre-
quency will be restored when the output current (when dependent on the current) or the fin tempera-
ture (when dependent on the cooling fin temperature) exceeds each carrier reduction start level −5%
or −5°C, respectively.
•
The carrier frequency reduction rate is 2 kHz per second.
•
The upper limit of the carrier frequency changeable with this function is equivalent to the value set in
the Carrier Frequency (b083); the lower limit of the carrier frequency is 3 kHz.
•
When b083 is set to 3 kHz or lower, this function is disabled independently of the b089 setting.
âš«
b089 = 01
Carrier frequency
âš«
b089 = 02
Carrier frequency