a protection system for electric motors in refrigerated environments , especially those environments cooled to very low temperatures , includes routing a cryogen coolant through the electric motor . a minimum flow of cryogen coolant is maintained through the motor to prevent ingress of moisture in the motor interior . the arrangement is especially useful with cryogenically cooled refrigeration systems , because the same cryogen coolant used to refrigerate the system can also be used to provide a purging flow of cryogen coolant gas through the electric motor .