XX. On permanent magnet circuits

On Permanent Magnet Material Testing

Note describes two experiments made to explore basic properties of permanent magnet (PM) material and to obtain “first hand” experience. In the first experiment, magnetic moments of NdFeB permanent magnets (PM) were fine tuned. The magnetic moment spread among 17 PM magnets was reduced by a factor of 5 from 2.8% to 0.5%. The note describes setup used for magnetization and presents result. The s...

Brushless Permanent Magnet Servomotors

Electrical motors drive a variety of loads in today’s world. Almost every industrial process relies on some kind of electrical motors and generators. There exist billions electric motors used in different applications all over the world. Majority of them are small fractional HP motors use in household appliances. However, they used about 5% of the electricity used by the motors. Three phase mot...

Controlled Permanent Magnet Drives

The considered converter-fed permanent magnet motor could alternatively be operated in two basically different states − the vector control mode or alternatively the brushless dc, also known as electronically commutated mode. Several quality aspects concerning the system performance have been comparatively investigated in practical as well as theoretical manner. Focus is thereby given to the num...

Permanent Magnet Materials

Sensorless Permanent Magnet Drive Design

The development procedure of permanent magnet drives for sensor less operation beginning from standstill under overload conditions has to consider different design aspects coevally. First, the robust rotor position sensing by test signal enforces a design with a strongly different behavior of the spatial dq-oriented differential inductance values. Therefore, the interior rotor magnet array arra...