Turbo compressor and turbo chiller comprising same

A turbo compressor comprising:

• an impeller;
• a shaft portion that rotates the impeller;
• an electric motor that rotationally drives the shaft portion;
• a casing that accommodates the electric motor;
• a magnetic bearing that supports the shaft portion;
• a heat transfer plate of which one surface is attached to an outer surface of the casing;
• a magnetic bearing drive substrate that is in surface contact with another surface of the heat transfer plate opposite to the one surface of the heat transfer plate;
• a cooling section that, by being supplied with a refrigerant from an outside, transfers cold of the supplied refrigerant to the heat transfer plate;
• and
• a box that accommodates the magnetic bearing drive substrate in a state in which an opening faces the outer surface of the casing,
• wherein the heat transfer plate fits into the opening of the box to form a closed space in which an inside of the box is airtightly separated from an outside, and
• air in the closed space is replaced with an inert gas.