Electric motors are devices that generate mechanical energy from electric energy. They operate through an interaction of the winding currents and the magnetic field to create a force within the motor, which is responsible for the rotational effect achieved by the motor. Motors have a range of applications and you will come across them in many of the appliances in your home. These devices include air conditioning fans, water pumps and cooling mechanisms for devices like refrigerators. Ideally, a clear understanding of motor construction will help you to comprehend the role played by each part and any potential defaults whenever they arise. The following discussion unwraps the basic construction elements of an electric motor to better your insight:
Electric motors come with windings in the form of wires laid down in coils. The wires wrap around a laminated magnetic core made from soft iron. This creates two magnetic poles (north and south poles) whenever an electric current flows through the coil of wires. In most cases, electric machines have non-salient or salient poles with respect to the magnetic field. Machines with non-salient poles have pole face slots to accommodate the windings while machines with salient poles produce magnetic fields through the winding with no face slots. Essentially, the purpose of the winding is to generate the rotational effect of the motor. Therefore, a running motor that does not generate rotational effect indicates a problem with the magnetic fields. This is a very common problem in air conditioners and pumps where the motor may be running without generating any rotation.
All electric motors have a stator. This is a stationary part consisting of permanent magnets, windings and laminations in the form of thin metal sheets. One of the main purposes of the stator is to keep the motor from losing the electrical and mechanical energy it generates. Therefore, a motor that takes up too much power with very little mechanical output indicates a problem with the stator.
Initially, one of the important aspects mentioned about a motor is that it converts electrical energy into rotational mechanical energy. To do this, a motor relies on the rotor that turns a shaft to deliver the desired mechanical power. The rotor comes has electrical conductors for transmitting electric current to interact with the magnetic field and shift the position of the shaft. In short, rotation cannot be achieved without the rotor.
There is a small gap between the stator and the rotor referred to as the air gap. Its function is to optimise the magnetic effect of the current flowing through the conductors. The air gap has to be small so that it doesn't impart any negative effects on the magnetic force generated.