When it comes to developing new automotive technologies, copper is essential to improving motor efficiency, and standard induction motors require significant improvements in efficiency through more copper in their windings, higher grade steel cores, improved bearings and insulation, and improved cooling fan design.As the quest for greater motor efficiency led to new motor technologies and designs that went beyond induction motors, copper became the focus of these new technologies.
Permanent magnet motor
Permanent magnet synchronous motor (PMSM) has been applied more and more in the drive of industrial motors. Permanent magnet motor technology has replaced the rotor elements with powerful permanent magnets manufactured from rare earth aluminum rods. Permanent magnets are divided into surface mounting and internal mounting.The stator of a permanent magnet motor is very similar to a traditional copper wound motor. The rotor in the motor is unique, with permanent magnets embedded in the rotor sheet or rod surface.A permanent magnet motor uses less copper than a similarly rated AC induction motor, but it still relies on copper for efficiency.
Advantages of PERMANENT magnet motors: excellent torque-speed curve, excellent dynamic response, high efficiency and reliability, low maintenance, longer service life, low noise, high speed capability, high torque/volume ratio or high power density.Cons: High cost, need for variable speed drives, sustainability of rare earth materials.
The number and type of copper wire is important in the design of a switched reluctance motor, where each turn of the coil is nested together to help fill the large stator slots that the switched reluctance motor design allows.Copper is an important part of the coil, and the motor is usually wound with 100% copper, which has much lower resistance than alternative materials such as aluminum.Low winding resistance directly converts to less waste heat, thus improving energy efficiency and advantageous to reduce the operating temperature of the motor.When necessary, switched reluctance motors use a coil made of tether-like copper wire or Litz wire. The coil is made of many smaller copper wires that are twisted into a tether-like rectangle.Using this type of conductor, it is possible to transpose the conductor, thereby reducing the skin effect, which causes the current to migrate to the outside of the conductor, effectively increasing the resistance of the conductor.
Switched Reluctance motor benefits: high efficiency, especially over a wide load range, high torque and high speed, excellent constant power speed range features, high reliability and long life, simple and robust construction, high power density.Disadvantages: Ripple torque, high vibration rating, need for variable speed drive, noise, peak efficiency slightly lower than PERMANENT magnet motors.Copper rotor motor: The innovation of copper rotor motor technology stems from the demand for higher energy efficiency in the low-voltage motor market, which cannot be met by traditional die-cast aluminum rotor design.Using new copper rotor technology to improve efficiency while retaining the same footprint as traditional aluminum rotor designs is important not only for new applications but also for retrofit applications.To develop this new technology, the motor industry redesigned the rotors, particularly the design and development of complex rotor casting processes.The increase in efficiency compared to conventional aluminum rotor designs justifies the large investment in design and development.Using die-cast aluminum technology, die-casting of solid copper rotors yields higher efficiency on motors of the same size compared to traditional energy-saving motors.
Permanent magnet, switched reluctance, and copper rotor induction motors each of these motor technologies in its own unique way relies on copper designs to produce more efficient, more reliable motors.Permanent magnet motors with powerful permanent magnets in their rotors, switched reluctance motors with power electronic switches and their dense copper stators and rotors, and copper rotor motors with cold running rotors with reduced current resistance, all offer options for achieving energy saving goals and improving performance.Through the innovative use of copper, switching technology and permanent magnets, today’s motor designs can choose from many more ways to meet their efficiency and application-specific requirements.