Due to higher rotational speeds and the use of magnetic bearings, Calnetix’s high-speed motors and high-speed generators offer smaller footprints, lighter weight, higher efficiency, higher reliability and lower maintenance than traditional gear box machines. Our electric motors and electric generators range from only a few watts to megawatt power levels with speeds ranging from 4,000 rpm to 450,000 rpm. Calnetix's high-speed motor generators provide the following advantages:
Electric machines can be much smaller and have better efficiency when they can operate at a higher speed than the 3,600 rpm limit imposed by 60 Hz power systems. Solid state inverters remove the speed limit. The power rating of a given machine increases directly with speed until structural, thermal or dynamic stability limits are reached. A good high-speed design is where these limits are approached in harmony.
By trading speed for torque, solid-state inverters with their unique ability to change the frequency has enabled the following benefits:
Ability to greatly reduce the size, complexity and weight of electrical machines
Ability to use more robust motor rotors that don’t need insulated windings, slip rings, and sliding contacts (brushes)
Ability to accommodate frequencies up to 3,000 Hz
Proprietary design processes and material selections are utilized to meet the demands of the customer’s application, including efficiency and temperature requirements. The benefits include:
Reduced losses at the component level through the use of special coatings and manufacturing methods
Ability to operate in harsh ambient environments up to 90⁰C by using thermal management and high-performance encapsulation techniques
For applications where light weight is of utmost importance, such as in aerospace and motorsports, Calnetix’s high-speed motors and generators are designed to provide maximum power density while maintaining high operating efficiency and good thermal performance consistent with design requirements. An example of a power dense machine that we have designed and manufactured is rated at 100 kW and weighs 7.7 kg in a 2.3-liter volume, which is equivalent to a machine power density of 13 kW/kg and 43 kW/liter. Calnetix is able to achieve such high-power density due to the following:
Optimization of electromagnetic design, including magnetization topologies
Optimization of the machine’s L/D (length over diameter) aspect ratio
Optimization of the magnetic circuit
Selection of materials, including the grade of magnets, the stator laminations and their thickness, the magnet retention sleeve and other materials
Calnetix’s high-performance motors and generators can be designed along with magnetic bearings and high efficiency variable speed drives (VSD) completely in-house. This enables us to achieve the most compact, optimized solution for each application without compromising any inherit benefits, such as high-speed, high-efficiency operation and zero maintenance requirements. The special construction features and fabrication of our high-performance stators and rotors provide some unique benefits, including:
Optimized stator configuration due to utilizing in-house tools, such as fill factor, end-turn bundle and neutral termination techniques
High back EMF per magnet volume with high magnetizing efficiency due to the rotor’s ability to magnetically couple to the stator with minimal flux fringing in the axial and transverse directions
Minimal rotor harmonic currents due to surface mounting techniques that keep circulating electrical paths isolated without loss of electromagnetic or structural integrity
Minimal rotor air gap and air gap cooling requirements due to high strength composite sleeve that has near-zero losses from harmonic eddy currents
Advanced electromagnetic efficiency, rotor tip-speeds and industry-leading power densities due to the proprietary technologies in Calnetix’s PM rotors
Calnetix’s high-speed motors and generators provide the best combination of small size, high efficiency and integration flexibility to meet the requirements of special applications and provide unique features and benefits, such as:
Hermetical sealing
Oil-free operation
In-line motor generator configurations
Direct mount bearingless motor configurations
Calnetix’s high-speed motors and generators have been widely used in industrial applications due to their high performance and high efficiency. Calnetix’s permanent magnet motor has proven to be highly desirable, not just for efficiency reasons, but also for reliability, elimination of maintenance costs and ease of implementation. The two standard Calnetix high-speed motor generators are shown and described below.
Magnaforce™
Ultraforce™
Low voltage
Less than 1 MW
Applications such as blood pumps, electrically assisted turbochargers, UXVs, satellites, test stands, food spray dryers, precision lasers, turbo expansion and chiller systems
The continuous desire for increased high-power density, oil-free operations, high efficiency and zero emissions are leading to a growing demand for high-speed permanent magnet motors and generators. A high-speed motor or generator combined with active magnetic bearings is a 360-degree solution for increasing energy efficiency, reliability and compactness. Some of the advantages of switching to permanent magnet motors, include:
Zero excitation power
Efficiency of 95% or higher
Smooth rotor
Large air gap
High resistivity and very low permeability of the rotor
Reduced inverter size and losses
And many more…
To see more information about permanent magnet machine advantages,click here.