1. Energy saving effect
One of the biggest advantages of frequency converters is energy saving, most notably in the fan and pump industry. Since the power consumption of fans and pumps is directly proportional to the cube of their rotational speed, when external air/water demand is low, using a frequency converter to reduce the rotational speed results in significant energy savings. The energy-saving principle in other industries is roughly the same: reducing the motor speed when full-speed operation is not required achieves energy savings.
2. Soft start function
When a motor is directly started at the mains frequency, it will generate 7 to 8 times the motor's rated current. This increased current increases the electrical stress on the motor windings and generates heat, thus reducing the lifespan of the frequency converter. Variable frequency speed control, on the other hand, allows for zero-speed, zero-voltage starting (with the option of appropriately increasing torque).
3. The role of simplifying the control system
Variable frequency speed control can start at zero speed and accelerate evenly according to the user's needs, and its acceleration curve can also be selected (linear acceleration, S-shaped acceleration, or automatic acceleration). The operating speed can be adjusted at any time as needed and can be quickly changed according to the process. Speed changes can also be achieved through remote control PLC or other controllers.
4. Reduces mechanical wear and tear.
Starting at mains frequency generates severe vibrations in the motor or connected mechanical shafts and gears. This vibration further exacerbates mechanical wear and tear, reducing the lifespan of mechanical components and the motor. Variable frequency speed control allows for controlled stopping methods, with different options available (deceleration stop, free stop, deceleration stop + DC braking). This reduces the impact on mechanical components and the motor, making the entire system more reliable, increasing its lifespan, and improving system stability.
5. Adjustable torque limiting function
Variable frequency speed control allows for the setting of appropriate torque limits to protect machinery from damage, thereby ensuring the continuity of the process and the reliability of the product. Current variable frequency technology enables not only adjustable torque limits but also torque control accuracy of approximately 3% to 5%. Under standard operating frequency (SOC) conditions, motors can only be controlled by detecting current values or thermal protection, unlike variable frequency control which allows for setting precise torque values.
