User name gilman
Log entry time 00:33:33 on July28,2006
Entry number 175612
keyword=radiator status and problems
On talking with Elaine and Dave Meekins, I was reminded that
we upped the radiator motor voltage to deal with a sticky screw a few years ago, and that if the voltage is too high, the motor does not turn smoothly. I found the motor voltage was still set to 35 V, so I decreased it to the standard 26 V we had used before.
When I went to look at the radiator, is appeared to be near the
in limit position, past the foil 5 position. Since I thought we had taken the Moller measurement with it out, I asked MCC: the controls thought it was out. Somehow we have lost the position information.
When I asked MCC to move it to the out limit, it rotated past the out limit! Perhaps the out limit went bad, or perhaps it got pushed out of the way. This means we can no longer operate the radiator in the
planned mode, having no position feedback.
Steffen and I checked out that the manual control box can still be used to drive the radiator, but to do this we either need to find a square pulse generator or remove the 50:1 gear reducer, so it is only
about 15 steps from one foil to the next. We also then need to get
a camera signal into the counting house to see the position.
Altenatively MCC can continue to control the box, but there is an issue here that if iochla reboots, the radiator is sent to the out limit. Here we still need a camera to check the position conveniently
and reset / rezero the position scale -- it appears that other than reboots it will move reliably between positions.
As a third option, we can stop the experiment, warm up the target, and open up to try to work on replacing the limit. It seems to me that the manual control is a safe and much faster solution. We only need the radiator for ~20 days; replacing the cameras shouldn't cost that much?
Gerfried has an idea about mounting a new limit switch on the
outside of the feed through, to replace the limit inside the
scattering chamber. Assuming the problem is inside the chamber,
this is an easier, more sensible solution than any of those above.