Abstract
One of the major problems in helium cooling of field windings of superconducting generators is liquid helium level control in the rotating helium pool. A unique helium flow circuit with positioning the mouth of a liquid helium transfer tube under helium level in the rotating helium pool is proposed for the solution of this problem. This flow circuit is expected that it provides the ability to externally control the liquid helium level in the rotor by adjusting the helium supply pressure. However there has been few papers which have proved clearly that the helium level control device works well and so the feasibility of this device is not clear. Accordingly we constructed a large scale rotating cryostadt which allows to simulate a cryogenic rotor of a superconducting generator and intended to prove stable helium level control by use of this test rig. This paper at first outlines the rotating cryostadt and then describes experimental data. This paper further presents calculation method of liquid helium level and also comparison between calculations and experimental data. We have achieved stable helium level control successfully and proved that calculations agree well with experimental data. These results confirmed that this helium level control device is feasible and applicable to the rotors of large scale superconducting generators in the future.
