Reports until 12:01, Thursday 30 January 2014
H1 SUS
betsy.weaver@LIGO.ORG - posted 12:01, Thursday 30 January 2014 - last comment - 14:07, Friday 31 January 2014(9658)
Ring Heater in line of fire during welding

We've observed some burn marks on the shielding of the ETMy ring heater cables which occured sometime during the 3 prior weld sessions (May 2012, Dec 2013, Jan 2014).  The burns are on the lowest ring heater cable that laces around the test mass and makes a connection between the test mass and the PUM.  There is a burn on the right segment and the left segment.  I dug up a picture that shows that the burn on the "right" segment (as viewed from the back of the suspension) was there just after the May 2012 weld session, so that one is not new.  However the "left" cable burn is new from the Dec or Jan welding.  We did not see when this actually occured.

Filiberto tested the ring heater cable and found that all pins are operating as per spec, although he thinks pin 1 is shorting.  We are tracking down what this means (did we test it correctly, when was it last tested, is it possible that the burn is contributing to the short, even though it does not look like it is, etc.).

Comments related to this report
betsy.weaver@LIGO.ORG - 12:03, Thursday 30 January 2014 (9659)

This is the picture of the RH "right" cable taken in May 2012.

Images attached to this comment
betsy.weaver@LIGO.ORG - 12:11, Thursday 30 January 2014 (9660)

And here is the "left" RH segment burn which happened in the Dec or Jan weld.

Images attached to this comment
filiberto.clara@LIGO.ORG - 14:07, Friday 31 January 2014 (9723)
For the ring heater cable, the following pins were tested.

Pins 2,3,4, and 5 are tied together.
Pins 14,15,16, and 17 are tied together.
The resistance between these two sets is 47.5 ohms.

Pins 8,9,10, and 11 are tied together.
Pins 20, 21, 22, and 23 are tied together.
The resistance between these two sets is 45.9 ohms.

Pin 1 is tied to shield and shorted to ground.

Filiberto Clara