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High-speed motors have the advantages of high efficiency, large specific power, high power factor, high reliability and easy maintenance. In advanced industrial countries, high-speed motors have been widely used in aviation, aerospace and mold industries. China’s high-speed motor industry began in the 1990s. Products have continued to develop from low-end to high-end, and the market size has also continued to expand.
Definition of High-speed Motors
High-speed motors are distinguished by their impressive rotational speeds and advanced engineering, setting them apart from standard motors. These motors are designed to operate at exceptionally high rotational speeds, making them suitable for a variety of specialized applications. The precise definition of a high-speed motor can vary, but certain criteria are commonly used to identify them.
Criteria for High-speed Motors
Rotational Speed:
The primary criterion for classifying a motor as high-speed is its rotational speed. High-speed motors are generally defined as those that exceed 10,000 revolutions per minute (r/min). This threshold is significantly higher than that of typical industrial motors, which usually operate at speeds below 3,600 r/min. The ability to reach and maintain such high speeds requires meticulous design and manufacturing processes to ensure stability, durability, and performance.
Linear Speed of Rotor Rotation:
In addition to rotational speed, high-speed motors are also characterized by the linear speed of the rotor rotation. Linear speed refers to the velocity at which a point on the rotor moves through space. For high-speed motors, the linear speed is typically greater than 50 meters per second (m/s). This parameter is crucial because it impacts the motor’s overall performance and the stresses experienced by the rotor.
Relation between Centrifugal Stress and Linear Speed:
A fundamental aspect of high-speed motor design is the relationship between centrifugal stress and linear speed. Centrifugal stress is the force exerted outward on the rotor as it spins. This stress is proportional to the square of the linear speed, meaning that as the linear speed increases, the centrifugal stress increases exponentially. For instance, if the linear speed doubles, the centrifugal stress quadruples. This relationship highlights the engineering challenges involved in designing high-speed motors, as materials and structural integrity must withstand these elevated stresses without compromising performance or safety.
To manage these stresses, high-speed motors often employ advanced materials and construction techniques. For example, rotors might be made from high-strength alloys or composite materials that can endure the intense forces generated at high speeds. Additionally, precision balancing and alignment are critical to minimize vibrations and reduce the risk of mechanical failure.
Design and Material Considerations:
The materials used in high-speed motors are selected for their strength, durability, and resistance to deformation under high centrifugal forces. High-strength steel, titanium alloys, and carbon fiber composites are common choices. These materials provide the necessary strength while minimizing weight, which is crucial for maintaining high rotational speeds.
The design of high-speed motors also involves advanced cooling mechanisms to dissipate the heat generated by friction and electrical losses at high speeds. Cooling methods may include forced air cooling, liquid cooling, or even the use of special cooling jackets around critical components.
Applications and Implications:
High-speed motors are utilized in various applications where their unique characteristics offer significant advantages. In the aerospace industry, they are used in systems that require high power density and reliability. In the medical field, high-speed motors drive precise surgical tools and imaging devices. Industrial applications include high-speed machining and precision manufacturing, where the efficiency and accuracy of these motors enhance productivity.
Overall, the definition and criteria of high-speed motors revolve around their exceptional rotational and linear speeds, the resulting centrifugal stresses, and the sophisticated engineering required to manage these factors. By exceeding 10,000 r/min and achieving linear speeds greater than 50 m/s, high-speed motors push the boundaries of what is possible in various advanced applications, underscoring the importance of innovative design and material science in their development.
Applications of high-speed motors
The applications of high-speed motors are expanding in an explosive manner. In order of high speed, there are the following applications.
1. Power tools
The electric tool uses a coreless PCB winding process and integrates the control chip. It is very compact. This kind of electric converter can also be used in medical equipment such as dentistry.
2. Molecular pump
Molecular pump is a common physical device for obtaining high vacuum. It can also be used to separate air and obtain high clean air. The motor speed for this application can reach 32 kr/min, 500 W. It can be designed using an induction motor or a concentrated winding permanent magnet motor. It can be designed using an induction motor or a concentrated winding permanent magnet motor.
3. Separate energy storage flywheel
There are many subdivisions of energy storage, including flywheel energy storage used in aircraft and flywheel energy storage used in power stations. The following example is a flywheel energy storage product for vehicle driving. Its concept is equivalent to the battery energy storage of hybrid vehicles. Or supercapacitor energy storage. When the car needs a burst of power, the flywheel energy storage motor can serve as a generator to supply electricity. The energy storage motor below has a power of 30 kW and a rotation speed of 50 kr/min. It adopts an induction motor scheme and the rotor is a solid iron block.
4. Turbocharging
Electronic turbocharging is a new technology that has emerged in recent years. Its function is to supercharge the automobile engine at low speeds to slow down the vortex lag and increase the explosive torque. A 10 kW, 100 kr/min product developed by BorgWarner uses a 2-pole, 24-slot permanent magnet motor structure. Due to the high working environment temperature, in addition to high speed, the design of this type of motor also requires control of the magnetic field. Steel loss and temperature rise.
5. Micro gas turbine
The micro gas turbine is definitely a legendary product. A machine about the length of a pencil can burst out 50 kW of power. It is said that its application in automobiles can reduce the size of the engine by 95%. In addition to automobiles, many devices require such small engines.
6. High speed air compressor
High-speed air compressor is currently the most common type of high-power high-speed motor, with a rotation speed of tens of thousands of rpm and a power between 100-700 kW. It generally uses magnetic bearings and drives turbines or blades through the motor to pressurize the air. The high-speed direct drive motor replaces the original low-speed motor + speed increaser system, which has the advantages of compact structure and high reliability. Two types of motors commonly used are surface-mounted permanent magnet synchronous motors and induction motors.
7. Vehicle drive motor
Vehicle drive motors are still the hottest field at present. The mainstream speed of passenger cars is within 16,000 r/min, and higher speed motors are already being developed.
In order to increase the power density, Integral Powertrain developed a 20,000 r/min, 450 kW permanent magnet motor system with a maximum torque of 900 N·m and a weight of only 28 kg. It uses advanced winding oil injection cooling and a radial stator. Cooling, rotor axial cooling and a series of technologies.
8. Drive motor for aircraft
As the pace of aircraft electrification and semi-electricity accelerates, the demand for high-power and high-speed motors is also rising. Higher-power aviation motors are used in hybrid aircraft. As the core of similar extended-range hybrid architectures, these motors generally use forced air-cooling structures to take advantage of high-speed airflow. In order to improve efficiency, more permanent magnet motors are used than induction motors.
ENNENG specializes in the research and development of various types of high-speed motors. These motors are designed to provide efficient and reliable performance in high-speed applications.
ENNENG‘s high-speed motors are widely used in industries such as power stations, metallurgy, chemicals, water treatment, coal mining, textiles, rubber, petroleum, medicine, paper, cooling towers, and food processing. These motors help companies reduce emissions, save energy, reduce consumption, and minimize noise, promoting green production practices.
The high-speed motors offered by ENNENG are known for their high efficiency and energy-saving capabilities. With power factors over 98% and efficiencies over 95%, these motors contribute to reducing the capacity of power receiving equipment and lowering energy consumption. They are designed to be easily replaceable, with the same installation size as asynchronous motors, making the transition seamless.
ENNENG’s high-speed motors also feature PG vector control, allowing for precise speed control based on specific application requirements. This makes them suitable for various equipment such as printers and punch compactors.
In summary, ENNENG’s high-speed motors are designed to provide efficient and reliable performance in high-speed applications. With their energy-saving capabilities, easy replacement, and precise speed control, these motors are a valuable choice for industries seeking optimal performance and reduced energy consumption.
