I. Selection of Inverter Power
System efficiency equals the product of inverter efficiency and motor efficiency. Only when both operate at high efficiencies will the system efficiency be high. From an efficiency perspective, the following points should be considered when selecting inverter power:
1) It is most suitable when the power value of the frequency converter is comparable to that of the motor, so that the frequency converter can operate at a high efficiency value.
2) When the power rating of the frequency converter is different from that of the motor, the power rating of the frequency converter should be as close as possible to the power rating of the motor, but should be slightly greater than the power rating of the motor.
3) When the motor is frequently started and braked, or is under heavy load and operates frequently, a larger inverter can be selected to ensure long-term and safe operation of the inverter.
4) After testing, the actual power of the motor is indeed sufficient. It is advisable to select a frequency converter with a power less than that of the motor. However, attention should be paid to whether the instantaneous peak current will cause the overcurrent protection to trip.
5) When the power of the frequency converter and the motor are different, the energy-saving program settings must be adjusted accordingly to achieve a higher energy-saving effect.
II. Selection of Inverter Enclosure Structure
The enclosure structure of the frequency converter must be adapted to environmental conditions, meaning factors such as temperature, humidity, dust, acidity/alkalinity, and corrosive gases must be considered. The following are some common structural types available for users to choose from:
1) Open-type IPOO inverters do not have a chassis and are suitable for installation in electrical control boxes or on panels, boards, or racks in electrical rooms. This type is especially suitable when multiple inverters are used together, but it has higher requirements for environmental conditions.
2) The enclosed IP20 type is suitable for general applications and can be used in environments with small amounts of dust or slight temperature and humidity fluctuations;
3) The sealed IP45 type is suitable for harsh industrial environments;
4) The sealed IP65 type is suitable for environments with poor conditions, such as water, dust and certain corrosive gases.
