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Entry  Fri Mar 12 03:08:23 2021, Koji, Summary, SUS, Coil Rs & Ls for PRM/BS/SRM P_20210311_224651.jpgP_20210311_225359.jpg
    Reply  Fri Mar 12 12:32:54 2021, gautam, Summary, SUS, Coil Rs & Ls for PRM/BS/SRM BS_actuator.pdfPRMact.pdf
       Reply  Fri Mar 12 13:01:43 2021, rana, Summary, SUS, Coil Rs & Ls for PRM/BS/SRM 
          Reply  Fri Mar 12 13:48:53 2021, gautam, Summary, SUS, Coil Rs & Ls for PRM/BS/SRM 
    Reply  Thu Mar 25 16:02:15 2021, gautam, Summary, SUS, Repeated measurement of coil Rs & Ls for PRM/BS 
Message ID: 15907     Entry time: Fri Mar 12 03:08:23 2021     Reply to this: 15913   15966
Author: Koji 
Type: Summary 
Category: SUS 
Subject: Coil Rs & Ls for PRM/BS/SRM 

Summary

Per Gautam's request, I've checked the coil resistances and inductances.

  • PRM/BS/SRM coils were tested.
  • All the PRM coils look well-matched in terms of the inductance. Also, I didn't find a significant difference from BS coils.
  • Pin 1 of the feedthru connectors is shorted to the vacuum chamber.
  • A discovery was that: The SRM DSUB pinouts are mirrored compared to the other suspensions.

Method

A DSUB25 breakout was directly connected to the flange (Attachment 1).
The impedance meter was nulled every time the measurement range and type (R or L) were changed.

Result

Feedthru connector: PRM1
Pin1 - flange: R = 0.8Ω
Pin11-23 / R = 1.79Ω / L=3.21mH
Pin 7-19 / R = 1.82Ω / L=3.22mH
Pin 3-15 / R = 1.71Ω / L=3.20mH

Feedthru connector: BS1
Pin1 - flange: R = 0.5Ω
Pin11-23 / R = 1.78Ω / L=3.26mH
Pin 7-19 / R = 1.63Ω / L=3.30mH
Pin 3-15 / R = 1.61Ω / L=3.29mH

Feedthru connector: SRM1
Pin1 - flange: R = 0.5Ω

Pin11-24 / R = 18.1Ω / L=3.22mH
Pin 7-20 / R = 18.8Ω / L=3.25mH
Pin 3-16 / R = 20.3Ω / L=3.25mH

Feedthru connector: PRM2
Pin1 - flange: R = 0.6Ω
Pin11-23 / R = 1.82Ω / L=3.20mH
Pin 7-19 / R = 1.53Ω / L=3.20mH
Pin 3-15 / R = N/A

Feedthru connector: BS2
Pin1 - flange: R = 0.6Ω
Pin11-23 / R = 1.46Ω / L=3.27mH
Pin 7-19 / R = 1.54Ω / L=3.24mH
Pin 3-15 / R = N/A

Feedthru connector: SRM2
Pin1 - flange: R = 0.7Ω
Pin11-24 / R = N/A

Pin 7-20 / R = 18.5Ω / L=3.21mH
Pin 3-16 / R = 19.1Ω / L=3.25mH

Observation

The SRM pinouts seem mirrored compared to the others. In fact, these two connectors are equipped with mirror cables (although they are unshielded ribbons) (Attachment 2).

The SRM sus is located on the ITMY table. There is a long in vacuum DSUB25 cable between the ITMY and BS tables. I suspect that the cable mirrors the pinout and this needs to be corrected by the in-air mirror cables.

I went around the lab and did not find any other suspensions which have the mirror cable.

WIth the BHD configuration, we will move the feedthru for the SRM to the one on the ITMY chamber. So I believe the situation is going to be improved.

 

Attachment 1: P_20210311_224651.jpg  1.869 MB  Uploaded Fri Mar 12 04:41:03 2021  | Hide | Hide all
P_20210311_224651.jpg
Attachment 2: P_20210311_225359.jpg  1.229 MB  Uploaded Fri Mar 12 04:41:03 2021  | Hide | Hide all
P_20210311_225359.jpg
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