Patent ID: 7466045

Claim:
A cryogenic cooler for a dynamoelectric machine that has a superconducting rotor mounted on a dynamoelectric machine shaft and uses a working fluid to cool the rotor, comprising: a cold side heat exchanger mounted proximate the rotor that receives the working fluid and transfers heat Q L from the rotor to the working fluid and discharges the working fluid at a low pressure P L into a cold side heat exchanger output path that extends within the dynamoelectric machine shaft; a regenerator mounted within the dynamoelectric machine shaft that receives the low pressure working fluid from the cold side heat exchanger output path and warms the low pressure working fluid with warm working fluid that it receives from a warm side heat exchanger output path that extends within the dynamoelectric machine shaft and discharges the warmed low-pressure working fluid into a low-pressure regenerator output path that extends within the dynamoelectric machine shaft; a compressor mounted within the dynamoelectric machine shaft that receives the warmed low-pressure working fluid from the low-pressure regenerator output path and compresses the working fluid to a high pressure P L at an elevated temperature and discharges the high-pressure working fluid at an elevated temperature into a compressor output path that extends within the dynamoelectric machine shaft; a warm side heat exchanger mounted within the dynamoelectric machine shaft that receives the high-pressure working fluid at an elevated temperature from the compressor output path and transfers heat Q H from the working fluid to a warm side heat sink proximate the warm side heat exchanger and discharges the high-pressure cooled working fluid into the warm side heat exchanger output path, wherein the regenerator cools the high-pressure working fluid with the low-pressure working fluid that it receives from the cold side heat exchanger output path and discharges the cooler high pressure working fluid into a high-pressure regenerator output path that extends within the dynamoelectric machine shaft; a turbine mounted within the dynamoelectric machine shaft that receives the cooler high pressure working fluid from the high-pressure regenerator output path to drive the compressor by way of a drive shaft that extends within the dynamoelectric machine shaft and to expand the working fluid to a lowest temperature at the low-pressure P L and discharges the lowest temperature low-pressure working fluid into a turbine discharge path that extends within the dynamoelectric machine shaft and supplies the cold side heat exchanger with working fluid; and a supplemental motor coupled to the drive shaft that also drives the compressor.