Bitte wählen Sie ihr Lieferland und ihre Kundengruppe
The set of tests which have been performed during about 500 h at 4.2 K, proofs that the cryoalternator works satisfactorily both during permanent and transient regimes. The magnetizing effect of the hypersynchronous shield and the gain obtained on the cryogenic losses (3) gives advantage to the g = O solution. During transients, no difference appeared between the two solutions although some calculations (4) suggest a better comportment as fas as low frequency oscillations are concerned. Nevertheless thermal losses are developped in the rotating shield (g = 0) and the mechanical arrangement (two parts are rotating at different speeds) is more complicated. When the size of the machine increases by a factor n, electrical power is as n3 and the losses in the shield vary as gP (1/n2)n3 = n. On the other hand, cryogenic losses depends on the maximal torque on the superconducting rotor, and vary also as n; in the g= 0 solution, the thermal pieces supporting the dipole see only a very small torque (identically zero between the hot end and the thermal shield (4)) and have only to support the inertial forces. Unfortunately this advantage is destroyed because some mechanical restrictions (stiffness, critical speed, vibrations...) limit the thickness of the piecs.