Difference Between DC and AC Motors

Electric motors convert electric energy into mechanical energy, which is used to drive numerous objects into motion. You won’t see a single electric machine which doesn’t work on this phenomenon. Electric current caused the magnetic flux within the motor to change and create mechanical movement. However, there are two main types of electric motors available in the market, DC (Direct Current) motors and AC (Alternating Current) motors. Both of these motors produce mechanical energy but the difference lies in the current supply. DC motors are driven by continuous electric current which flows only in one direction, whilst AC motors work upon a current which changes its direction repeatedly after every cycle.

DC motors basically consist of a metal wire coil suspended in a magnetic field and free to rotate. This coil is connected to two brushes, which are in contact with a split ring, and current is provided to the coil via these brushes. The magnetic field is very steady in DC motors and the split rings ensure that the coil keeps rotating in one direct.

AC motors also consist of a metal coil placed in a magnetic field but without any split ring being connected to the brushes. Alternating current flows through the coil and causes it to rotate to in one direction. By the time the coil turns 180 degrees, the AC current and the magnetic field causes the coil to rotate back to its position. This alternating movement continues repeatedly and mechanical energy is produced from the motor.


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    DC Motor

    DC motors consist of a pair of permanent magnets within them and a split ring (also called a commutator). These are the two key features of DC motors which distinguish them from the AC motors. With complex design and more technicalities involved in the production, DC motors are more expensive to make. The speed of a DC motors depends upon the current supplied to them and hence, these motors are best to use when you require a variable speed motor.

    Image Courtesy: pbaindustrial.com

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    AC Motors

    AC motors use electromagnets, which are not permanent magnets and only create a magnetic field when electric current passes through them. These types of motors have simpler design and fewer parts and hence, are cheaper to make. AC motors don’t use any split rings or brushes and are more reliable than DC motors. These motors run on a fixed speed, regardless of the current being supplied to them.

    Image Courtesy: btpart.com

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