Single phase motor VS AC motor

Single-phase motor and AC motor are two common types of motors, and there are many differences in their working principles, composition, characteristics and application scenarios. They are broken down from these perspectives below. 

How it works

Single phase motor

A single-phase series motor is a general-purpose motor in which the stator and rotor windings are connected in series to form a current loop. Since the direction of the current in the stator and rotor windings is the same, the resulting magnetic fields interact with each other, resulting in electromagnetic torque that drives the rotor to rotate. This motor is capable of operating on both alternating current (AC) and direct current (DC) power supplies, but in most cases it is used in equipment with single-phase AC power.

• Detailed principle:

When the current flows through the stator windings, the stator generates a magnetic field, and at the same time the current also flows through the rotor windings, which is forced by the force in the magnetic field of the stator and begins to rotate.

The rotational speed of the rotor is inversely proportional to the load, and as the load increases, the rotational speed decreases, making the single-phase series motor suitable for high speed, low torque applications. 

AC motor

AC motor is a type of motor that uses the change of alternating current to generate rotational force. Its basic working principle is to generate a rotating magnetic field through the stator coil, and the rotor is driven to rotate by inducing a current under the action of the magnetic field.

• Detailed principle:

1、Induction motor (asynchronous motor): The rotating magnetic field is generated by the stator, and the rotor generates an electric current due to electromagnetic induction, and the interaction force between the current and the rotating magnetic field makes the rotor rotate. The speed of the rotor is always lower than the speed of the rotating magnetic field, and this speed difference is called "slip".

2、Synchronous motor: The stator also generates a rotating magnetic field, but the rotor directly generates the magnetic field through an external power source such as an excitation winding, and the rotor rotates at the same speed as the stator magnetic field, so it is called "synchronous". 

Structure composition：

• Single-phase series motor structure composition

  1、Stator: made of silicon steel sheet, containing windings, used to generate the main magnetic field.

  2、Rotor: Generally composed of armature core and winding, the rotor is connected in series with the stator through electric brushes.

  3、Brush and commutator: Through the relative sliding of the brush and the commutator, the continuity of the current is ensured, and the direction of the current is commutated at the same time, so that the rotor can rotate continuously.

  4、Bearing: support the rotation of the rotor and ensure the smooth operation of the motor.

  5、Cooling system: Some high-load motors are equipped with fans or other cooling devices to prevent the motor from overheating. 

• AC motor structure composition

  1、Stator: It is composed of coil windings and iron core, which is connected to AC power supply and generates a rotating magnetic field.

  2、Rotor: Constructed of conductors (such as cast aluminum or copper strips), an electric current is generated by electromagnetic induction in a rotating magnetic field, and rotated by force.

  3、Bearing: Supports the rotor so that it can rotate smoothly.

  4、End cover: protect the internal components of the motor, fix the rotor and stator.

  5、Fan (optional): Some AC motors are equipped with fans to cool the motors and prevent overheating. 

Features：

• Single-phase series motor features

  1、High speed: The biggest advantage of a single-phase series motor is that it can provide extremely high speed, which is suitable for equipment that needs to run at high speeds.

  2、Strong starting ability: The motor has a large starting torque, which can start quickly under heavy load.

  3、Simple structure: The motor structure is relatively simple, the cost is low, and the maintenance is convenient.

  4、Small size: Compared with other similar motors, single-phase series motors have a smaller volume, which is ideal for equipment with limited space.

• AC motor features

  1、Efficient and stable: AC motors are especially suitable for scenarios that require long-term continuous operation, with high and stable operation efficiency.

  2、Robust structure: The motor structure is relatively simple and sturdy, able to withstand large mechanical loads, and has a long service life.

  3、Simple maintenance: Compared to other types of motors, AC motors are simpler to maintain, especially induction motors, because they do not have brushes and commutators, which reduces friction and wear.

  4、Various starting methods: The induction motor can be started in a variety of ways such as direct start, star delta start or soft starter to adapt to different load requirements. 

Usage scenario：

• Single-phase series motor use scenario

       Due to its high speed, high starting torque and compact structure, single-phase series motor has a wide range of applications in various household and industrial equipment, mainly including:

   1. Household appliances: such as vacuum cleaners, power tools (such as electric drills, angle grinders), mixers, etc. This type of equipment requires a motor with high speed and high power output to meet the needs of the equipment for fast rotation and power.

   2. Small industrial equipment: such as sewing machines, woodworking equipment, food processing machines, etc., these equipment require motors to provide higher speed and better load adaptability.

   3. Other high-speed equipment: such as fans, hair dryers, etc., the high speed characteristics of single-phase series motors make them very efficient in these applications. 

• AC motor usage scenario

     AC motors are widely used, mainly including the following types of scenarios:

    1. Industrial automation equipment: Conveyor belts, processing machine tools, lifting equipment, etc. in industrial production usually use AC motors because they need to operate stably for a long time and can cope with different mechanical loads.

    2. Household appliances: Many household appliances, such as air conditioners, refrigerators, washing machines, etc., use AC motors. These appliances require long-lasting power and reliability, and the efficient performance of AC motors meets these needs.

    3. Fan and pump equipment: AC motors are widely used in fans and pumps, such as ventilation equipment, water pumps, oil pumps, etc. These devices require a constant rotational force to ensure the flow of air or liquid.

    4. HVAC systems: Heating, ventilation, and air conditioning (HVAC) systems also rely on AC motors to drive compressors, fans, and pumps to provide comfortable environmental control for buildings.

    5. Elevators and lifting equipment: In elevators, escalators and other vertical transportation equipment, AC motors are widely used due to their high efficiency, safety and easy control.

AC's future development potential

With the rapid development of industrial automation and the demand for energy conservation and environmental protection, AC motors are developing in the direction of high efficiency and intelligence. Future AC motors will be more energy-efficient and may integrate variable frequency control technology (VFD) to adjust the motor speed according to the load situation and improve power utilization. In addition, with the advancement of intelligent manufacturing technology, the combination of AC motor and Internet of Things (IoT) will realize remote monitoring and intelligent maintenance, greatly enhancing its application potential. 

Summary

Due to its high speed and high starting torque, single-phase series motors are widely used in various equipment that requires high-speed operation. Its simple structure, small size, and low price make it ideal for everyday home appliances and industrial equipment. However, due to their high noise and wear at high speeds, some applications are transitioning to quieter and more durable technologies such as brushless motors. BG Motor can provide a variety of specifications of single-phase series motor customization services according to customer needs to meet the needs of specific application scenarios.

As a mature and widely used motor type, AC motors are widely used in industrial and household equipment because of their high efficiency, stability, and robustness. Whether it's industrial equipment that requires continuous operation, or a power system in a home appliance, AC motors provide reliable performance. With the advancement of intelligent technology in the future, the application of AC motors will be more extensive, and continue to promote the automation and efficiency improvement of various industries. BG Motor can provide customers with high-efficiency AC motors and provide professional customized services to meet customers' special needs.