Description

A universal motor is a type of electric motor that can operate on both alternating current (AC) and direct current (DC) power sources. Its design is similar to that of a series-wound DC motor, with modifications to allow efficient operation on AC power. This versatility makes universal motors suitable for various applications, especially where high speed and compact size are desired.

Construction:

• Stator and Rotor: The stator houses the field poles with windings, while the rotor (armature) contains windings connected to a commutator. Both components are laminated to reduce eddy current losses, which is essential for AC operation.
• Commutator and Brushes: The commutator, in conjunction with carbon brushes, facilitates the reversal of current direction in the armature windings, ensuring unidirectional torque.

Working Principle:

When powered, the same current flows through both the field and armature windings, creating magnetic fields that interact to produce torque. On AC supply, both currents reverse simultaneously, maintaining consistent torque direction. On DC supply, the motor operates similarly to a standard DC series motor.

Characteristics:

• High Starting Torque: Universal motors provide substantial torque at startup, making them ideal for applications requiring rapid acceleration.
• Variable Speed: The speed can be easily controlled using methods like variable resistors or electronic controllers.
• Compact and Lightweight: Their design allows for a high power-to-weight ratio, beneficial for portable devices.
• Noisy Operation: Due to the commutator and brush assembly, these motors can be noisier compared to other motor types.

Applications:

Universal motors are commonly found in devices that require high speed and portability, such as:

• Portable drills
• Hairdryers
• Vacuum cleaners
• Blenders
• Sewing machines

Specifications 

• Affordable
• Versatile
• Adjustable speed
• Several powers range

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