Drive rating selection - Solutions - Huaqiang Electronic Network

The rating of a frequency converter is typically indicated on its nameplate, with separate specifications for both the input and output sides. Understanding these ratings is essential for proper selection and application of the inverter.

1. Input Side Rating

The input side rating primarily includes the voltage and phase configuration. For small to medium-sized inverters, common input voltages are as follows (all are line-to-line voltages):

• 1380V / 50Hz, three-phase – widely used in most industrial equipment.
• 220V / 50Hz or 60Hz, three-phase – commonly found in imported equipment.
• 230V / 50Hz, single-phase – mainly used in small devices and household appliances.

2. Output Side Rating

The output side ratings are equally important and include the following key parameters:

1. Rated Output Voltage (UN)

This refers to the maximum voltage that the inverter can supply. It is usually the same as the input voltage when the output frequency matches the motor's rated frequency. This ensures compatibility with standard motors.

2. Rated Output Current (IN)

The rated output current represents the effective value of the continuous AC current that the inverter can deliver. This is a critical factor for users when selecting an appropriate inverter model.

3. Output Capacity (SN) in kVA

The output capacity is calculated based on the product of the rated output voltage and current, using the formula: SN = √3 × UN × IN. This gives the apparent power the inverter can deliver under normal operating conditions.

4. Applicable Motor Power (PN) in kW

This indicates the maximum motor power that the inverter can drive under its rated current. It is typically specified for a 4-pole standard motor, which is the most common type used in industrial applications.

5. Overload Capability

The overload capability defines how much current the inverter can handle beyond its rated value and for how long. Most inverters are designed to handle up to 150% of IN for 60 seconds or 180% of IN for 0.5 seconds. Specialized inverters for fan and pump applications may have slightly different specifications, such as 120% of IN for 60 seconds.

Understanding these ratings helps ensure that the inverter is properly matched to the application, improving efficiency, reliability, and longevity of the system.