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[Sphenix-magnet-l] They're Potentiometers, not LVDT's

From: Kin Yip <kinyip AT bnl.gov>
To: "sphenix-magnet-l AT lists.bnl.gov" <sphenix-magnet-l AT lists.bnl.gov>
Subject: [Sphenix-magnet-l] They're Potentiometers, not LVDT's
Date: Tue, 05 May 2015 16:55:25 -0400

Hi,

We've used the word "LVDT's" for some time.   But from the SLAC list (near the bottom) :

https://collab.external.bnl.gov/sites/sPHENIX-Magnet/Pictures/Potentiometer,%20not%20LVDT/20150424125728261.pdf

you can see that they have used the word "linear potentiometer" (not LVDT's).   Ray Ceruti told me that we have (only)
4 of these though we have 6 slots/covers.    Pasquale told us that these were done by SLAC, not Ansaldo (so that they know
nothing about it).

Paul Giannotti/Thomas Tallerico have taken one such so-called "LVDT" from Ray Ceruti and this afternoon, Dave Gassner
(who is very familiar with LVDT's and helped us with LVDT's for roman-pot position measurement) and I took one unit from
Thomas Tallerico. I took a picture for the entire assembly :

https://collab.external.bnl.gov/sites/sPHENIX-Magnet/Pictures/Potentiometer,%20not%20LVDT/0505151603.jpg

Below is Dave's email after his examination (taking it apart ... he's even got the part no.). It's definitely a "potentiometer",
even though they've been called "LVDT's in various places/occasions --- a misnomer.

Dave's photos on this "potentiometer" (when he opened it up):

https://collab.external.bnl.gov/sites/sPHENIX-Magnet/Pictures/Potentiometer,%20not%20LVDT/IMG_20150505_151533915_HDR.jpg
https://collab.external.bnl.gov/sites/sPHENIX-Magnet/Pictures/Potentiometer,%20not%20LVDT/IMG_20150505_153725358.jpg

Kin

-------- Forwarded Message -------- Subject: Potentiometer Date: Tue, 5 May 2015 15:39:35 -0400 From: Gassner, David M <gassner AT bnl.gov> To: Yip, Kin <kinyip AT bnl.gov> CC: Tallerico, Thomas N <tallerico AT bnl.gov>

Hi Kin,

After some disassembly, it appears clear that the transducer is a resistive potentiometer. It is labeled 0.44 inches (stroke), 5k Ohms. The cage code is 25413-2051410304 (typ made for aircraft), SN is 1008, d/c (date code) is 98-07. The red wire is the wiper, the yellow and green is where we apply the DC voltage reference.

See attached pictures.

Hope this helps,

Dave

[Sphenix-magnet-l] They're Potentiometers, not LVDT's, Kin Yip, 05/05/2015