Output Voltage of Frequency Converters:

The output voltage of Frequency Converters can be selected according to the rated voltage of the motor. According to national standards, there are two series: 220V and 400V. For high-voltage motors like 3kV, using a 400V-rated Frequency Converter requires an input transformer on the Frequency Converter's input side and an output transformer on the output side. This step reduces the voltage from 3kV to 400V for the Frequency Converter's use, then boosts it back to 3kV for the motor. Any deviation from normal grid voltage can harm the Frequency Converter. Excessive voltage, like a rise from 380V to 450V, can cause damage. In such cases, transformers are necessary to ensure Frequency Converter safety by adjusting voltage within the specified range outlined in the user manual.

Output Frequency of Frequency Converters:

The highest output frequency of Frequency Converters varies greatly depending on the model, ranging from 50Hz/60Hz to 120Hz, 240Hz, or higher. Typically, 50Hz/60Hz is used for speed control below the rated speed range, especially in large-capacity general-purpose Frequency Converters. Frequency Converters with frequencies exceeding the grid frequency are often small-capacity ones and exhibit constant power characteristics above 50Hz/60Hz. It's essential to note the decrease in torque at higher speeds, although certain machines like lathes can benefit from higher speeds for increased productivity within the constant power range. However, one must ensure not to exceed the maximum allowable speed for the motor and load.

Protection Structure of Frequency Converters:

Frequency Converters generate significant heat internally. For efficient heat dissipation, except for small-capacity Frequency Converters, they typically have an open structure, with larger ones employing forced cooling with fans. In harsh outdoor environments or adverse surroundings, installing Frequency Converters on separate panels with closed structures and cooling devices is advisable. When switching from the grid to the Frequency Converter, the motor must completely stop before restarting on the Frequency Converter side to avoid excessive current and torque, which could trip the power system or damage equipment.

Considerations for Frequency Converter Capacity Selection:

1. Matching Frequency Converter power with motor power is ideal for efficient operation.

2. When Frequency Converter power differs from motor power, it should be slightly higher than the motor's.

3. For motors subjected to frequent starts, stops, heavy loads, or continuous operation, choosing a larger-capacity Frequency Converter ensures long-term and safe operation.

4. If the motor has surplus power, selecting a Frequency Converter with less power is feasible but ensure peak current doesn't trip overcurrent protection.

5. Adjust energy-saving programs accordingly when Frequency Converter and motor powers differ.

6. Frequency Converter rated capacity and parameters are specified for certain altitudes and ambient temperatures. If operating conditions exceed these, consider derating factors before selecting Frequency Converter models.

7. Ensure the Frequency Converter has the required functionality for instant stopping and restarting if needed, to prevent overvoltage or overcurrent faults due to power interruptions.

8. When sensors are used for Frequency Converter speed control, ensure their signal type and magnitude align with the Frequency Converter's speed control signals.