What is the fan current curve?

The stages of fan current curve change can vary depending on the specific fan design, load conditions, and operating characteristics. However, here are general stages that can be observed in the change of fan current curve:

1. Startup Stage: At the initial stage of fan operation, when power is applied, the fan current typically experiences a brief surge or spike due to the inrush current. This surge occurs as the fan motor starts up and overcomes initial inertia to begin rotation.
2. Acceleration Stage: As the fan motor continues to accelerate and the fan blades start spinning, the current gradually decreases from the startup surge to a steady-state level. The rate of acceleration and current decrease depends on the fan design, motor characteristics, and load conditions.
3. Steady-State Stage: In this stage, the fan current reaches a relatively constant level, which is typically the operational current. The current remains stable as long as the fan operates under consistent load and environmental conditions.
4. Load Changes Stage: If there are changes in the load conditions, such as variations in airflow resistance or system demands, the fan current curve will undergo changes accordingly. An increase in load typically leads to a higher fan current, while a decrease in load results in a lower current.
5. Fault or Abnormal Conditions Stage: If there are faults or abnormal conditions in the fan system, such as motor or bearing problems, increased resistance, or blockages in the airflow path, the fan current curve may exhibit irregular or erratic behavior. This can manifest as sudden spikes, fluctuations, or deviations from the normal current curve.