How do I derate the drive output current when operating at high altitude or high temperature?

For installations above 1000 meters above mean sea level, derate the output current (In) by 5% per 1000 m and do not exceed 4000 m. For operation above 40°C, derate In by 2.5% per degree Celsius above 40°C and do not exceed 55°C. Additionally, increasing the carrier frequency via parameter P166 also requires current derating — for example, on NEMA 1 models, setting P166 to 8 kHz requires derating to 92% of the drive rating. (Page 10)