Alcator C-Mod Run 1001004 Information

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Miniproposals
Miniproposal:
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Session Leader:Steve Wolfe (shots 1-1)

Operators
Session leader(s):Steve Wolfe
Physics operator(s):Steve Wolfe
Engineering operator(s):Bill Parkin,Bill Byford

Engineering Operator Run Comment
Eng. Test, mp268, mp282a, mp248; Sl: Wukitch, PO Wolfe, EO: Byford/parki

Session Leader Plans

Physics Operators Plans

Session Leader Summaries

Physics Operator Summaries

Session Leader Comments
Oct 5 2000 11:18:50:780AM1001004001Steve WolfeMoved the engineering test shots #2574-2586 described in my notes
to the cmod$saved_shots:[engineering] directory using
@sys$manager:move_test engineering

seems to have worked.

Physics Operator Comments
Oct 4 2000 02:37:08:590PM1001004001Steve WolfeCommon mode test of bus instrumentation.
All bus voltage leads shorted and raised to 2KV.
No problem, DC Common mode rejection looks excellent.

GF current traces have been moved to BUSLV:TR16_1, which was
not set up properly on this shot, so traces are missing.
Oct 4 2000 02:39:03:077PM1001004001Steve WolfeTest shot 2574:
switching voltage on/off at ~1Hz, 100V, as yesterday, to look at
Pearson response. Resistor voltage had been moved from EF1L to EF1_U:bus_volt,
and as a result the response had an extra minus sign.
Oct 4 2000 02:41:02:183PM1001004001Steve WolfeTest shot 2575:
switching voltage on/off at ~1Hz, 100V, as yesterday, to look at
Pearson response. Resistor voltage moved back to EF1L.
Signals now look like yesterday's test shot 1001003011,
+80V gives ~+0.4a on pearson
Oct 4 2000 03:01:16:043PM1001004001Steve WolfeTest shot #2576
Use the "ringer" to put a 500V short pulse on the oh2l ground resistor.
The ringer is a 1.5uF cap, which is being discharged through the 150 Ohm
resistor, which is shorter than we really want, but we'll see what happened.

see 400V pulse on the resistor signal, 0.8a on pearson, correct polarity.
No crosstalk or common mode anywhere.
Oct 4 2000 03:18:17:187PM1001004001Steve WolfeTest shot #2577

Go to 1000V on ringer

See 800V on resistor, 4A on oh2l gf pearson.
Also see a small 10V voltage blip on tf bus voltage at at least one of the
pulse times, -.346.

Correction: there is crosstalk from the third spike, at 3.777sec, on
tf and ef2U bus voltage, at the several hundred volt level, when the
oh2 resistor trace shows 500V.
Oct 4 2000 03:36:26:857PM1001004001Steve WolfeTest shot #2578

Get a bigger ringer, try 2000V.
This pulse is shorter and we'll only get one, so it may miss.

Didn't get it, try again
#2579: Got it at 1.664, noise spikes everywhere!
pearsom signal is -8A for a -600V on resistor signal;
note that the rc in the dividers are ~1ms and this looked like a 200usec
pulse on the scope, so we are probably loading it some, and we're only
sampled at 3kHz so it may miss the peak.

Nevertheless, the point is that the spike propagates to all the other
traces.
Oct 4 2000 04:40:34:780PM1001004001Steve WolfeNext shot: #2581
Hook up the resistor to a new divider and A12 channel, putting
the EF1L bus voltage signal back where it belongs. If this fixes
the problem, it will be a miracle, but it's worth a try. The oh2l ground
resistor voltage is now on bushv:a12_2:input_6. Appropriate gain is 1000V/V

OK got it at .968 and no crosstalk, but the pulse shape is much wider than the
before. The crosstalk Gary noted on 2579 was also wide. I think this iso-amp has a filter
in it. It also has a 150V dc offset.


Oct 4 2000 04:56:41:280PM1001004001Steve WolfeNext shot: #2582
Wrong channel had been de-filtered.
This time we are re-doing the slow chop test
Got the pearson signal, no voltage trace.
Oct 4 2000 05:45:23:937PM1001004001Steve WolfeNext shot: #2583
connector problem.
This time, digitize a wavegen signal to verify it's connected

ok, see a saturated slow square wave.
Oct 4 2000 05:51:34:170PM1001004001Steve WolfeNext shot: #2584
Now the 80V off/on test.
See signals ok, but noisy and polarity is backward.
Oct 4 2000 05:55:00:873PM1001004001Steve WolfeNext shot: #2585
Repeat the 80V off/on test with leads reversed

ok, looks reasonable.
next shot: back to the hi-voltage ringer
Oct 4 2000 06:03:31:340PM1001004001Steve Wolfe#2586
back to the hi-voltage ringer

got it, at ..1896, no cross talk on other signals.
GF current reads only 2Amps, but has the correct polarity,relative to
the voltage.

It works!

Engineering Operator Comments
ShotTimeTypeStatusComment
112:59:20:107PMTestOk2KV on bus voltage taps