DC Motor: The Physics Of A DC Motor

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An armature rotates inside a magnetic field[3] in a DC motor[1].Based on the fact of the fundamental operating principle of a DC motor that whenever a current carrying conductor is placed inside a magnetic field, the conductor experienced mechanical force. All kinds of DC motors work on the same principle. Hence for developing a DC motor, it is important to establish a magnetic field. The magnetic field is established by means of a magnet[2].The magnet can be any sorts for instance it might be electromagnet or can be permanent magnet.
At the point when permanent magnet is utilized to create magnetic field in a DC motor, the motor is known as permanent magnet DC motor or PMDC motor. The motor can be easily to build. These motors are usually …show more content…

PMDC motor has some advantages over other types of dc motors. They are does not need of field excitation arrangement. No input power in consumed for excitation which it improve efficiency of DC motor. No field coil hence space for field coil is saved which reduces the overall size of the motor. It’s cheaper and economical for fractional kW rated applications.
In this case, the armature reaction of DC motor cannot be compensated hence the magnetic strength of the field may get weak due to demagnetizing effect armature reaction. During starting, reversal and overloading condition of the motor, there is a chance of getting the poles permanently demagnetized or partially due to excessive armature current. Another major disadvantage of PMDC motor is the field in the air gap is settled and constrained, so it cannot be controlled externally. Because of that, an efficient speed control of DC motor for this type of motor is hard to be made.
PMDC motor is widely used where small DC motors are needed and very effective control is unnecessary, such as in automobiles starter, toys, wipers, washers, hot blowers, air conditioners, computer disc drives and in many

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