Realize the fan variable speed have installed frequency converter or use DC brushless motor, the difference between the two

Fan loads are best used with inverters, DC motors are not only large and bulky, and maintenance costs are high, the failure rate is also high, the biggest drawback is that it is more expensive than inverters to go. But the DC motor also has its own unique advantages is the low-speed torque is very large, but the fan class load is not need so big low-speed torque. Moreover, now the inverter technology has progressed very quickly, low frequency torque can achieve the effect of DC motor low-speed torque.