This paper deals with cryogen, which is used as solid nitrogen (SN2) to keep the operating temperature of high temperature superconducting (HTS) synchronous rotating machine. To solidify liquid nitrogen, liquid helium (LHe) passed into the heat exchanger and cools its own temperature. Two types of heat exchangers were designed and fabricated for making the SN2, and the temperature characteristics of both case was compared. The rotor of HTS synchronous rotating machine was cooled by latent heat of SN2 and it was kept under 40 K for 2 h and 30 min without the additional supplement of LHe.
- HTS rotating machine
- Solid nitrogen