A Universal Motor is a type of electric motor that can operate on both direct current (DC) and alternating current (AC) power sources. It is known as "universal" because it is versatile and can be used in a wide range of applications due to its unique design and characteristics.
Functioning of a Universal Motor:
The Universal Motor operates on the principle of electromagnetic induction. It consists of a wound armature and a set of field coils. The armature is a coil of wire wound around a soft iron core, and the field coils are also wound coils that produce a magnetic field when a current passes through them. The motor has a commutator and brushes.
When electric power is applied to the motor, the current flows through both the armature and the field coils. As a result, a magnetic field is generated in the armature core, and the interaction between this magnetic field and the magnetic field produced by the field coils causes the armature to rotate. The direction of the magnetic field in the armature is constantly changing due to the commutator and brushes, which allows the motor to run on both AC and DC power.
Advantages of Universal Motors in Various Applications:
High speed and power-to-weight ratio: Universal Motors have a high power-to-weight ratio, making them suitable for applications where compact and lightweight motors are required. They can achieve high rotational speeds, making them ideal for appliances that need high RPM, such as vacuum cleaners, drills, and grinders.
Versatility: As mentioned earlier, Universal Motors can run on both AC and DC power sources. This characteristic makes them highly versatile, and they can be used in a wide range of applications where the power source may vary.
Controllable speed: Universal Motors can be easily controlled for variable speed operation, which is valuable in applications where speed adjustment is required, like in handheld power tools or blenders.
Simple design and low cost: The construction of Universal Motors is relatively simple, leading to cost-effective production. This makes them more accessible and widely used in various consumer products.
High starting torque: Universal Motors can provide high starting torque, which is beneficial for applications requiring a motor to start under load, such as in mixers and blenders.
However, there are some limitations to Universal Motors. They are generally less efficient than specialized motors designed solely for AC or DC power sources, and they tend to have a shorter lifespan. Additionally, they may produce more noise and vibration compared to other motor types. Nevertheless, the advantages they offer in terms of speed, power, and versatility make them a popular choice for many portable and household appliances.