An electric motor can be defined as an electrical device which transforms electrical energy to mechanical power by means of an alternating current. All electric motors work on the interaction of electrical current in an electromagnetic coil winding to produce force in a specific shape, in the form of rotational torque applied to the shaft of the electric motor.
The motor consists of a number of coils wound around a magnetic field, which are designed to make use of electromagnetic fields created by a generator or a transformer to produce electrical energy. This can then be transferred to a DC power supply. The size and weight of the electric motor are critical to its efficiency, and therefore it is essential that they are placed carefully to prevent them from weighing more than they have to.
The concept of electric motors is relatively simple to comprehend. Electricity generated by a dynamo is converted into rotary force in the shape of a magnetic motor. As the magnetism in these two forces is in complete opposite polarity the motor produces an alternate action – with an electric motor being similar to a magnetic dipole. The torque produced on the shaft of the motor is produced by the same method.
In most electric motors the power is converted to mechanical power by first converting the electrical energy into magnetic energy, which is then turned into rotary force. When this force is applied to the shaft of the engine the rotational motion of the motor drives the shaft to the end of its rotation and the result is an electric torque.
There is also a third way to convert rotational torque into an electric torque, known as gear reduction. This process is used where the rotation of the shaft is not necessary, but the torque provided by the magnetic force needs to be transformed into electric force. The mechanical force is added to the electrical power to produce a higher amount of torque which in turn causes the speed of rotation of the shaft to decrease. A gear reduction motor has gears at each end of the shaft which reduce the rate at which the shaft is turning, reducing the size and weight of the shaft and reducing the torque produced on it. This is an example of a magnetic motor working.
Motor makers have been making electric motors for decades and many are producing high-powered motors that can provide up to 1000 horsepower. Many manufacturers such as BMW and Honda are producing electric motor racing cars and trucks to race on public roads. This makes these motor racing vehicles suitable for the public and makes the task of purchasing one less daunting than it was before electric motors became common place.