An electric DC motor is an electric machine that receives AC power, also known as AC, whereas this power can be supplied from a battery or other DC power source. The energy exchange between the stator and the rotor is called switching and can happen by means of or without brushes. In a DC motor, the speed can be controlled quietly only by changing its voltage, unlike an alternating current electric motor, Heavy Duty Retractable Hose Reel which has its speed pointed to by the frequency.
Therefore, AC electric motors need a change in their frequency in case you need to vary their speed, thus involving a much more complicated speed control. However, by changing the speed on an electric DC motor, it will only need to change the voltage level, making it more suitable for 12Vdc-powered equipment, such as cars or even industrial applications that need a fine speed control.