Supplemental cooling system for superconducting electrical machine

A magnetic resonance imaging system, comprising:

• a superconducting electrical machine comprising a superconducting magnet;
• a main cryogenic vessel containing a main cryogen and encompassing the superconducting magnet, containing a cryogen and configured to cool the superconducting magnet;
• a vacuum vessel encompassing the main cryogenic vessel;
• a supplemental cooling system inside the vacuum vessel and comprising:
• a supplemental heat sink
• a gas gap heat switch configured to alternately thermally connect the supplemental heat sink to a component of the superconducting electrical machine and thermally isolate the supplemental heat sink from the component of the superconducting electrical machine;
• wherein the supplemental cooling system is configured to supplement cooling of the component of the superconducting electrical machine by the cryogenic vessel to expedite cooling of the component of the superconducting electrical machine.

A method of controlling a supplemental cooling system for a superconducting electrical system, the method comprising:

• controlling a first gas gap heat switch connected to a component of the superconducting electrical system to thermally connect the component to a supplemental heat sink;
• after a temperature of the component is less than a first threshold temperature, controlling the first gas gap heat switch to thermally isolate the component from the supplemental heat sink;
• and
• slowly dissipating heat from the supplemental heat sink to a main heat sink over a period of time while the first gas gap heat switch is thermally isolating the component from the supplemental heat sink.