An electrical motor is a machine that transforms the form of electrical energy to an output of mechanical energy. It is classified into two types depending upon the type of supply given as an input. If the supply given is a DC supply then, it is termed as DC motor and if the input given is an alternating one, then it is termed as AC motor. In this article, we shall discuss what is the difference in the working of AC and DC motor?
It is a machine that changes the form of input alternating electrical energy to an output mechanical energy. It is used in small rating motors and other industrial purposes.
It is a machine that changes the form of input DC electrical energy to mechanical energy. It is commonly used for household purposes like in fans, and blowers.
Difference Between AC and DC Motor
Working of AC Type
It works on the principle of faraday’s law of electromagnetic induction. An alternating motor can be operated in two ways I,e with a stationary armature and rotating field winding and the other way is by arranging field winding stationary and armature winding rotating. A normal AC motor uses rotating armature and stationary field winding. The parts of the machine are shown in the figure below.
The rotating armature type motor consists of an armature slip rings, and brushes. In this type, the coil of armature winding is given an AC supply that allows the current to flow in the winding. As this coil is under the influence of a magnetic field, some force is exerted on it. Due to this force, the coil gets rotated in the magnetic field. The winding structure of the machine is shown in the figure.
The slip rings are used to allow the current to alter between the coil sides so that it can develop uniform unidirectional torque. An AC motor with a stationary armature and rotating field winding is more advantageous compared to a rotating armature type. This type has more efficiency and fewer losses. Here, the Ac supply is given directly to the stator winding. The working of this type of motor is shown in the figure below.
This stator develops a rotating magnetic field in the air gap. This field interacts with the field winding and induces some emf in the winding according to the principle of mutual induction. The emf induced develops some flux in the winding. Both the fluxes tend to develop a force that produces a unidirectional torque that allows the rotor to rotate smoothly.
Working of DC Type
It works on the principle of the Lorentz force equation. The armature winding placed on the rotor is given an input DC supply. When this supply is given, the coil is about to carry current in the windings. Due to this current in the coil, some force is exerted on the coil because of the Lorentz force equation. According to the Lorentz force equation, that a current-carrying coil under the influence of a magnetic field exerts some force upon it. The direction of force is found by using Fleming’s Left-hand rule. The operation of this type of motor is shown in the figure below.
The current in the coil side AB is inwards and outwards in CD. According to the current direction, by fleming’s rule force at the side, ABis upwards and at side CD it is downwards. This force allows the coil to develop to a torque inside the magnetic field. But the exerted when the coil is perpendicular to the magnetic field is not uniform. It produces a non-uniform force such that the coil cannot develop uniform torque. To avoid this, the er of coils are placed together such that a uniform force is developed which in turn develops a unidirectional torque.
Thus, in this article, we had an overview of what is a DC and AC motor. Apart from this, we had also studied the difference in the working of DC and AC motor. Here is a question for the readers, what are the different kinds of AC and DC motors?