B.2.1 Capacity
Choose a VFD based on the rated current and power of the motor. To endure the rated power of the motor, the rated output current of the VFD must be larger or equal to the rated current of the motor. The rated power of the VFD must be higher or equal to that of the motor.
Note:
1. The maximum allowable shaft power of the motor is limited to 1.5 times the rated power of the motor. If the limit is exceeded, the VFD automatically restricts the torque and current of the motor. This function effectively protects the input shaft against overload.
2. The rated capacity is the capacity at the ambient temperature of 40°C.
3. You need to check and ensure that the power flowing through the common DC connection in the common DC system does not exceed the rated power of the motor.
If the ambient temperature on the site where the VFD is installed exceeds 40°C, the altitude exceeds 1000 m, or the switching frequency is changed from 4 kHz to 8, 12, or 15 kHz, the VFD needs to be derated.
B.2.2.1 Temperature derating
When the temperature ranges from +40°C to +50°C, the rated output current is derated by 1% for each increased 1°C. For the actual derating, see the following figure.
When the installation site altitude is lower than 1000 m, the VFD can run at the rated power. If the altitude on the site is higher than 1000 m, and not more than 3000 m, the maximum power is derated by 1% for every increased 100 m. For details about the derating, see the following figure.
When the altitude exceeds 2000m, configure an isolation transformer on the input end of the VFD.
When the altitude exceeds 3000m but is lower than 5000m, contact us for technical consultation. Do not use the VFD at an altitude higher than 5000m.
B.2.2.3 Carrier frequency derating
The power of Goodrive350 series VFDs varies according to carrier frequencies. The rated power of a VFD is defined based on the carrier frequency set in factory. If the carrier frequency exceeds the factory setting, the power of the VFD is derated by 10% for each increased 1 kHz.