What is the difference between ventilation motor and ordinary motor?

What is the difference between ventilation motor and ordinary motor?

On December 14, 2021, what is the difference between ventilation motor and ordinary motor?
(1)、 Different design systems:

1. The heat dissipation system is different: the heat dissipation fan in the ordinary fan and the core of the centrifugal fan use the same line, while the two in the ventilation motor are separated. Therefore, when the frequency conversion of ordinary fan is too low, it will be burned due to overtemperature.

2. Electromagnetic design is different: for ordinary motors, the key technical parameters considered in the redesign scheme are overload capacity, operating characteristics, high efficiency and power factors. The ventilation motor, because the critical slip rate is inversely proportional to the power frequency, can be started directly when the critical slip rate reaches 1. Therefore, the load capacity and operating characteristics do not have to be considered too much. The problem to be solved is how to improve the adaptability of the motor to non sine wave power supply.

3. Because the ventilation motor bears high-frequency electromagnetic field, the flame retardant grade is higher than that of ordinary motor. In principle, ordinary motor can not be driven by frequency converter, but in fact, in order to save assets, ordinary motor is used to replace variable-frequency motor in many places where speed change is necessary, but the speed change precision of ordinary motor is not high. In centrifugal fan This is often done in the energy-saving transformation of centrifugal water pump.

4. Expanded electromagnetic load: the output resistance of ordinary motor is based on the inflection point of magnetic saturation. If it is used as frequency conversion, it is easy to be saturated, resulting in high excitation current. While the ventilation motor expands the electromagnetic load in the design scheme, so that the magnetic circuit is not easy to be saturated. Another is that variable frequency motors are usually divided into constant torque special motors, special motors with speed limiting equipment and medium frequency motors with feedback vector control.
(2)、 Differences in measurement:

1. In fact, the output waveform of the frequency converter is sinusoidal wave. In addition to the fundamental wave, it also includes carrier signal. The carrier data signal frequency is much higher than the fundamental wave, and it is a square wave data signal, including many high-order harmonics. For the detection system, higher sampling frequency and network bandwidth are specified.

2. In the environment of frequency converter power supply system, all kinds of high-frequency interference are everywhere, and the interference signal is much stronger than that in power frequency environment, which stipulates that the detection system has stronger professional ability of electromagnetic compatibility.

3. The peak factor of the driving circuit wave is usually high. The provisions are considered in the nature of ordinary instruments. For the frequency conversion detection system, it is required to have higher accurate measurement capability of peak factor.

Post time: Dec-14-2021