Selection of inverter ratings

The rated values ​​of the inverter are mostly marked on its nameplate, including the rated values ​​on the input side and the rated values ​​on the output side.

(1) Rated value on the input side.

The rated values ​​of the input side are mainly voltage and number of phases. The rated values ​​of the input voltage of small and medium capacity inverters are as follows (all are line voltages):

①380V/50Hz, three-phase, used in most devices.

②200~230V/50Hz or 60Hz, three-phase, mainly used in some imported equipment.

③200～230V/50Hz, single phase, mainly used for small capacity equipment and household appliances (2) Rated value on the output side.

①Rated output voltage UN.

The rated output voltage refers to the maximum value of the inverter output voltage.

In most cases, it is the output voltage value when the output frequency is equal to the rated frequency of the motor. Usually, the rated output voltage is always equal to the rated value of the input voltage.

②Rated output current IN.

The rated output current refers to the effective value of the maximum AC current that the inverter can continuously output, and is the main basis for users to select inverters.

③Output capacity SN (kVA).

The inverter output capacity is determined by the three-phase apparent output power of the rated output current and rated output voltage. The relationship between SN, UN and IN is:

SN=&raDIC;3UNIN

④ Applicable motor power PN (kW). Applicable motor power refers to the motor power that can be driven within the rated output current for a 4-pole standard motor.

⑤Overload capacity.

Overload capacity refers to the allowable range and time of the output current exceeding the rated current. Most frequency converters are specified as 150% IN, 60s or 180% IN, 0.5s. Frequency converters specifically used for speed regulation of fans and pumps are specified as 120% IN, 60s.