[Takahashi, Ikeda, Hirata]
We investigated the small horizontal actuation problem in the BF damper. Particularly, the efficiency of the H1 actuator was too small (2um/1000count). We checked the following points.
- Resistance and inductance of the primary and secondary coils: They were normal.
- Cabling around the H1 coils: There was a small change in the LVDT signal by touching the connection points.
- Coil driver and LVDT combiner: The efficiency of the H1 coil was still small by swapping the channels of H1 and H2.
Finally, we found that a cable at the Dsub connector on the BF side plate was touching the bracket for the secondary coils of the H1 LVDT. The cable was treated to keep a gap from the bracket. When the cable was released from touching, the BF rotated much in yaw. We offloaded the BF with the F0 yaw FR.
