Variable frequency motor no-load test run - Solutions - Huaqiang Electronic Network

PESD1CAN electrostatic protection SOT23-3 24V two-way

Photocoupler

When operating an inverter motor under no-load conditions, it's essential to set the power rating and the number of poles for the variable frequency motor. The inverter's operating current should be taken into account comprehensively to ensure safe and efficient performance. It's also important to configure the maximum output frequency, base frequency, and torque characteristics of the inverter. Most general-purpose inverters come with multiple V/f curves, allowing users to choose the most suitable one based on the type of load. For fan and pump applications, it's recommended to set the inverter's torque control to variable torque mode with reduced torque characteristics. To enhance the low-speed performance during startup, the motor’s torque output should meet the load requirements, so adjusting the starting torque is crucial. In asynchronous motor variable frequency drive systems, torque control can be more complex. At low frequencies, the impact of resistance and leakage reactance becomes significant. If the V/f ratio remains constant, the magnetic flux decreases, leading to a reduction in motor output torque. To counter this, voltage compensation is typically applied at lower frequencies to improve torque output. This compensation is often manually adjusted by the user. Additionally, the inverter should be set to keyboard operation mode, where pressing the start and stop buttons allows you to check if the motor starts and stops correctly. Understanding the inverter's fault protection codes is also vital. Monitoring the factory settings of the thermal relay and the overload protection threshold is necessary, and adjustments should be made if needed. Users can configure the inverter’s electronic thermal relay function according to the manufacturer’s instructions. If the inverter’s output current exceeds its allowable limit, the overcurrent protection mechanism will automatically shut down the output. Therefore, the maximum setting for the electronic thermal relay must not exceed the inverter’s maximum allowable output current to prevent damage.