What is the difference between a variable frequency motor and a regular motor

Hengli Motor Business Xiaoju often encounters customers who don't know which motor to choose, which occasions to use ordinary motors, and which occasions to use variable frequency motors. Today, let me briefly introduce the differences between ordinary motors and variable frequency motors

There are essential differences between variable frequency motors and ordinary motors:

1. The cooling system is different; The cooling fan in a regular fan and the fan core use the same wire, while in a variable frequency motor, these two are separate. So when the frequency conversion of a regular fan is too low, it may burn out due to overheating.

2. Due to the need to withstand high-frequency magnetic fields, the insulation level of variable frequency motors is higher than that of ordinary motors. Variable frequency motors enhance slot insulation by strengthening the insulation material and increasing the thickness of slot insulation to improve their ability to withstand high-frequency voltages.

3. Increased electromagnetic load. The working point of ordinary motors is basically at the magnetic saturation inflection point. If used as a variable frequency motor, it is prone to saturation and generates high excitation current. However, variable frequency motors increase the electromagnetic load during design, making the magnetic circuit less prone to saturation. In addition, variable frequency motors are generally divided into constant torque specialized motors, specialized motors with feedback vector control and speed measurement devices, and intermediate frequency motors.

The requirements of frequency modulation technology for motors mainly include three aspects: first, insulation level; Secondly, forced cooling; Thirdly, the rotor bearings. If the speed is adjusted upwards beyond the fundamental frequency, the mechanical strength of the motor structure should also be considered. Variable frequency motors can be adjusted freely within their speed range without damage to the motor. Generally, most domestic ordinary motors can only operate under AC380V/50HZ conditions. Ordinary motors can be used for frequency reduction or increase, but the range cannot be too large, otherwise the motor will heat up or even burn out. In principle, ordinary motors cannot be driven by frequency converters.

What are the differences between variable frequency motors and ordinary motors in practical applications?

1. Hengli motor variable frequency motor can be adjusted freely within its speed range without damage to the motor. Generally, most domestic ordinary motors can only operate under AC380V/50HZ conditions. Ordinary motors can be used for frequency reduction or increase, but the range cannot be too large, otherwise the motor will heat up or even burn out.

Under variable frequency drive, the efficiency and temperature rise of the motor will be increased by about 10%, while the temperature rise will be reduced by about 20%, especially in the low-frequency range of vector control or direct torque control.

The cooling fan in a regular fan and the fan core use the same line, while in a variable frequency fan, these two are separate. So when the frequency conversion of a regular fan is too low, it may burn out due to overheating. Ordinary motors are designed based on the frequency and corresponding power of the mains, and can only operate stably under rated conditions. Variable frequency motors are different. Variable frequency motors need to overcome overheating and vibration at low frequencies, so their design should have better performance than ordinary motors.

Compared to ordinary motors, variable frequency motors are not much more expensive, but their advantages are very obvious. The variable frequency motor adopts the AC speed regulation method of "dedicated variable frequency induction motor+frequency converter", which greatly improves the degree of mechanical automation and production efficiency, and increases equipment miniaturization and comfort.

1. Equipped with soft start function

2. Adopting electromagnetic design reduces the resistance of the stator and rotor

3. Adapt to frequent shifting under different working conditions

4. To some extent, it saves energy