Variable-period permanent magnet undulators

Pushing the Limits of Short Period Permanent Magnet Undulators

Short period undulators to be used as FEL radiators permit lower electron energies and, thus, reduced linac and undulator lengths. The first X-ray FEL facility based on in-vacuum permanent magnet undulators has gone into operation, already (SACLA). Another in-vacuum undulator based X-FEL is planned (SWISS-FEL). The in-vacuum undulators have period lengths of 18mm (SACLA) and 15mm (SWISS-FEL), r...

Measurement of radiation-induced demagnetization of NdFeB permanent magnet material for ERL undulators

The note describes measurement of NdFeB permanent magnet (PM) material demagnetization induced by high-energy electron radiation. In experiments we compared N40 and N40SH grades from Stanford Magnets Company, which have different intrinsic coercive forces. Dimensions of the tested PM blocks were close to those that will be used for ERL undulator construction. It was found that depending on dire...

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