The electric fan is a dc motor, or the ac motor is good, why?
This depends on whether your power supply is dc or ac, the general household appliance is communication, because the household voltage is not fixed, usually 220V ~ 250V interval
Dc motors are generally small power, and the general power is communication. First of all, I want to correct a concept, no good questions, dc motor and ac motor is each have their own characteristics and purposes, there is no best motor, only the best manufacturers. That means that there's no better problem with dc motors and ac motors. Dc speed regulation is very convenient, as long as the voltage is changed, and the torque is not affected. Ac speed is more complicated and is known as a frequency changer. It is suggested that ac motor should be used, which is mainly used for ac motor, and dc motor needs a rectifier to work.
Direct current is not changed over time. It is usually divided into pulsed direct current and steady current. Pulsating direct current has ac components, such as the voltage of about 300 volts in the power circuit in the color TV, which is the component of the pulsating direct current that can be removed by capacitance. The steady current is ideal, the magnitude and the direction are constant.
Alternating current (ac). Direct Current, or DC, is a Current that does not make periodic changes in direction and time. AC (alternating current, AC) for short. A current in which the magnitude and direction of a periodic change are made periodically. Alternating current (ac) is to use ac generator, in the process of power generation, more uniform distribution of magnetic pole is according to certain Angle on a circle, make the power generation process, each coil is cutting lines, with much of the poles, each of the lines of magnetic force produced by magnetic pole was cut of voltage and current are change by string pattern, so can continuously produce stable current. Domestic ac frequency is 50 hz, namely change 50 times per second. In some countries, the frequency of the alternating current (ac) is 60 hz, namely changes 60 times per second. Of course there are other frequency. Such as electronic circuit of square wave, triangle, etc., but these waveforms of alternating current (ac) is not a conductor cutting lines, but a capacitor charging and discharging, switch transistor work.
