Baumuller b maXX 1000 - Page 129

Parameter
Parameter manual b maXX
®
1000
Document no. 5.07004.03
129
of 208
4
From the table, we see that the PWM carrier frequency has a significant influence on the
electromagnetic noise, b maXX
®
1000 heat dissipation, and motor acoustic noise.
The PWM carrier frequency will be decreased automatically by heat sink temperature and
output current of the b maXX
®
1000. It is used as a necessary precaution to prevent the
b maXX
®
1000 from overheating and thus extends IGBT's life. Example for 460V models:
Assume the carrier frequency to be 15 kHz, the ambient temperature is 50 °C with a sin-
gle b maXX
®
1000 (mounting method A). If the output current exceeds 80% * rated cur-
rent, the b maXX
®
1000 will decrease the carrier frequency automatically according to the
following chart. If output current is 100 % * rated current, the carrier frequency will de-
crease from 15 kHz to 12 kHz.
Figure 59: PWM carrier frequency