As a motor that adjusts its speed by changing the power frequency, the current magnitude of a variable frequency motor involves multiple key factors. During operation, the frequency converter converts fixed frequency AC power into variable frequency AC power to supply power to the motor. In this process, the change in current magnitude is influenced by a combination of multiple factors. Let's explore in detail below.
·Frequency change: When the output frequency of the frequency converter changes, the motor speed will correspondingly change. According to the characteristics of the motor, in the low-frequency starting stage, in order to generate sufficient torque to overcome load inertia, the motor current is usually larger. As the frequency gradually increases and the motor speed accelerates, the current will gradually decrease and tend to stabilize. For example, in application scenarios such as fans and pumps, when starting, the motor needs to drive the stationary impeller, and the low-frequency current may reach several times the rated current; After stable operation, the current will return to the normal range.
·Load variation: The size of the load directly affects the motor current. When the load increases, such as when the resistance of mechanical transmission components increases, the motor needs to output greater torque to maintain operation, and the current will increase. On the contrary, as the load is reduced, the motor output torque demand decreases, and the current also decreases accordingly. For example, when lifting heavy objects with a crane, the heavier the object, the greater the motor load, and the higher the current; When heavy objects are lowered, the load becomes lighter and the current decreases.
·Motor characteristics: Different models and specifications of variable frequency motors also have different current variation characteristics. Efficient and energy-saving variable frequency motors have relatively small current fluctuations during operation, which can more efficiently convert electrical energy into mechanical energy. Under the same load, the current may be lower than that of ordinary variable frequency motors. In addition, factors such as the number of turns in the motor winding and the material of the iron core can also affect the magnitude of the current.
Hengda Electric has always been dedicated to the research and development, production, and service of variable frequency motors. With advanced technology and equipment, lean manufacturing processes, reliable product quality, and satisfactory after-sales service, the company provides customers with the most suitable motor professional solutions and creates greater social value.
