| 摘要 |
PROBLEM TO BE SOLVED: To secure the cooling gas wind amount required for cooling a motor without deteriorating economical efficiency in the no-load operation by connecting a joint passage at which branch passages extending from the downstream of an impeller on the rear stage side and an intermediate cooler are connected to each other, and forming a flowing passage in which cooling gas is allowed to flow to a high-speed motor. SOLUTION: An extracting part 14a is provided between an intermediate gas cooler 6a and a second stage compressor 1b, an extracting part 14b is provided on the way of a blow-off passage 18 downstream from a blow-off valve 9, and operating gas of a compressor 1 is extracted from them to cool a motor 2. The extracting parts 14a, 14b are positioned downstream from the gas coolers 6a, 6b, gas to be supplied from them is cooled to the ordinary temperature, and the motor 2 can be cooled by only gas flowing in the motor 2. Extracting passages 22a, 22b branched from the extracting parts 14a, 14b are joined into one passage downstream from check valves 22a, 22b and guided to the motor 2, the guided gas is discharged after cooling the motor 2, and it is guided to a rejoint part 15 between a suction throttle valve 7 and a first stage compressor 1a. |
