2021/July/30, 10:20-10:40
2021/July/30, 14:45-15:00 (we found the source of leak and then stopped it)
The source of the leak is a ventilation fan unit of draft chamber.
The draft chamber can not be used until the ventilation fan is repaired.
[Takase, Miyoki]
Takase-san found a part of the motor of the draft chamber was broken and it stimulated into the motor body. When he removed it, the grounding (electrical leakage) was eliminated.
The reason why this part was broken seems to be because it kept rotating for 4 years!! after setting due to the air absorption power which was generated by a fan in the parking area.
So the lifetime of this part was over, then it has broken into several pieces, and one of them stimulated into the motorhead.
Anyway, the motor will be recovered on 5th August by the technical support of Yamato kagaku.
To avoid such unnecessary rotation, we will put a shutter or a route selector at the output of this draft chamber fan. So we should remeber that this shutter/router should be set at the proper position when you will use the draft chamber.
If you would like to use the draft chamber on 4th August, please contact Miyoki.
The recovery will be delayed more.
So if you want to use this draft chamber, please contact Miyoki. Basically, it can be operational by using a fan at the parking area and some tips.
2021/August/17
As a result of the airflow check, the draft chamber in the center area of KAGRA, which had been prohibited after the electrical leakage, was now ready for use.
Airflow measurement : 0.47m/sec (required value is larger than 0.4m/sec).