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Benefits of Motors with Copper Rotors
Minute Lectures
• Copper has a higher conductivity than aluminum (57 MS/m compared to 37 MS/m) An induction motor with copper rotor can
be more efficient, or for the same efficiency, lighter and smaller
• For a long time, the high melting point of die-casting copper was a major barrier
Copper or Aluminum for Motor Rotor?
Benefits of Motors with Copper Rotors
Minute Lectures
• Over the past years, several breakthroughs in copper die-casting technology have been achieved Leading to industrial production of copper motor rotors
Die casting copper
Benefits of Motors with Copper Rotors
Minute Lectures
• Regular production of copper rotor motors in the range 100W – 100kW
• 250,000 units are in use• Average efficiency improvement compared to
aluminum rotor motors is around 3%• Global electricity savings potential is 108 TWh/year
Equivalent to 60-70 million tonne CO2 emissions
Copper rotor today
Benefits of Motors with Copper Rotors
Minute Lectures
• Two ways to use the higher conductivity of copper: Same design
The motor has a higher efficiency, compensating for its higher purchasing price
Same efficiencyThe motor can be made lighter and
smaller, and therefore cheaper
Main benefits of motors with copper rotor
Benefits of Motors with Copper Rotors
Minute Lectures
Other benefits of copper rotors
1. A lower temperature rise in operation Other parts can heat up more, or less
cooling facilities are required A more compact machine,
fitting better into a system2. A flatter efficiency curve
Smaller efficiency drop whendeviating from the nominal load
Benefits of Motors with Copper Rotors
Minute Lectures
Other benefits of copper rotors
3. Torque-speed characteristic reaches maximum torque at higher speed Useful for combining high speed
with high torque (e.g. centrifugal pumps)
Benefits of Motors with Copper Rotors
Minute Lectures
Other benefits of copper rotors
4. Improved steel properties Due to the higher melting point of copper,
the temperature of the surrounding steel becomes higher during die-casting, which can lead to a more energy-efficient magnetic steel with proper steel specifications
Benefits of Motors with Copper Rotors
Minute Lectures
Environmental performance
Two possibilities: Constant efficiency
= reduced material consumption Improved efficiency
= reduced energy lossesRecycling:
A copper rotor is a composite material= difficult to recycle, but techniques exist to separate copper
Benefits of Motors with Copper Rotors
Minute Lectures
Operation issues
A copper rotor motor has: Lower starting torque
→ can be addressed by a special design of the rotor slot shape
Higher start-up current→ requires use of a soft starter
A higher rotor inertia
Benefits of Motors with Copper Rotors
Minute Lectures
Examples of applications
• Agricultural pumps (efficiency, torque)• Water circulation pumps (efficiency, torque)• Oil well pumps (efficiency, torque)• Airport baggage handling (low volume)• Rolling curtains (low volume, high speed)• Aeronautic applications (low volume, high speed)• Refrigeration compressors (high efficiency)• Ceiling conveyor belt (low weight)
Benefits of Motors with Copper Rotors
Minute Lectures
Round-up
• Industrial production of induction motors with die-cast copper rotor is available today
• Main advantage: better conductivity of copper, leading to improved efficiency, or with the same efficiency, to lower volume, weight and variable cost
• Improved steel in combination with die-cast copper rotors enables Eff1 performance, or better, resulting in reduced environmental impact
Benefits of Motors with Copper Rotors
Minute Lectures
Further information
• Websitewww.copper-motor-rotor.org
• Production of copper rotors www.favi.com
• Motors with Copper Rotors Can Cost Less to Produceview article
