Articles

Is There an Optimum Price-Performance Metric for Permanent Magnet Materials?

John Ormerod, Principal and Founder, JOC LLC

Attend any magnetics conference or seminar and I can guarantee a slide will appear in someone’s presentation showing something along the lines of the year of introduction of a permanent magnet material versus the corresponding (BH)max. Continue reading

Low Weight – High Torque Motors for Commercial Drones

Lowell Christensen,  Consultant • Lowell Christensen LLC

We have heard of the desire to make home deliveries using commercial drones. There are several logistic issues with drone deliveries. These issues will soon be overcome and commercial delivery drones will be a fast growing application. This will require changes in motor design to meet the requirement for high torque in a low weight motor. Continue reading

Extending the Limits of the Sm2Co17 System

By Steve Constantinides  | Arnold Magnetic Technologies

The 2010-2011 rare earth crisis appears over. Prices are low and adequate raw material is available. Many of the efforts initiated to find a better non-rare earth permanent magnet have ended in disappointment. Programs such as Fe-nitride, core-shell exchange coupled magnets and enhanced alnico are continuing but with limited success to-date and significant hurdles remaining. It is in this framework that revisiting one of the more significant magnet materials seems a reasonable proposition. What material, you ask? Well, the strongest permanent magnet material at and above 150°C, the one with excellent corrosion resistance and superior temperature stability – Sm2Co17. Continue reading

The Design of a Permanent Magnet Motor for a Direct Drive Fan Application

By Lowell Christensen, Consultant | Lowell Christensen LLC

In this case study we will compare two types of permanent magnet brushless motors for a medium size overhead fan used in agricultural types of applications. The comparison will be done on the magnetic circuit portion of the motors only so the only volumes and weights compared will be the magnetic circuit parts including the magnet, back iron, lamination and copper wire. Continue reading

Some Design Considerations Using Permanent Magnets

By Jinfang Liu, Chief Operating Officer | Electron Energy Corp.

Permanent magnets are critical components for many applications including motors, generators, computers, instrumentation, automation, oil exploration, aerospace and defense systems. Continue reading

Permanent Magnets in a Changing World Market

By Steve Constantinides | Arnold Magnetic Technologies

There are several commercially available permanent magnets. In sequence of invention they are: alnico, ferrite, SmCo (samarium cobalt), NdFeB (neodymium iron boron, Neo), and SmFeN (samarium iron nitride). The last three types are considered “rare earth” magnets because they contain one or more rare earth elements. In terms of total quantity produced each year the permanent magnet market is dominated by the ferrite and rare earth types. Approximately 70 weight percent of ferrite and rare earth permanent magnets are utilized in motors. Permanent magnet motors have several advantages over induction (non-magnet) types, the most notable being efficiency. This coupled with the pervasive use of motors means that permanent magnets are a key enabling material in modern economies. Continue reading

Insulated Iron Powders, SMC, Current State and Future Possibilities

By Dr. Kalathur Narasimhan | P2P Technologies

Insulated Iron or iron-silicon for soft magnetic powder composites (SMC) are a niche unique to powder metallurgy.  This method uses pure iron powder with a highly insulating coating to provide a soft magnetic ferrous material that is suitable for a variety of electromagnetic applications. Continue reading