Thermal Measurement Choices for Correctors

C. Drennan, February 23, 2009

● The corrector is cooled using an upper cooling line and a lower cooling line

● An RTD and a Klixon were originally placed on only the upper portion of the correctors.

End Potted Style BMA

● The End-Potted BMA's have a slightly different placement.

● Thermal test showed that thermal sensors should be added to the lower portion of the BMA's

● The additional Klixon will work well being in series with the first and will provide thermal protection of the BMA.

● How should the second RTD be instrumented?– Should we double the number of RTD transmitters and

MADC channels to read all the RTD's individually?– Should we read out the two RTD's per BMA in series

getting the average of the upper and lower temperature and saving space, equipment and DAQ channels?

● Reading Every RTD– Pro: This is the only way to know the actual

performance of the lower and upper cooling channels separate from one another, with out accessing the Booster tunnel.

– Con: This approach adds an additional 48 channels of RTD Transmitters ($$$ see following) and MADC channels for a total of 96 channels of RTD data.

– Con: Additional rack space or reconfiguration of existing installations is required.

● What is the monetary cost of additional RTD channels.– The cost of the additional RTD transmitters is 12

each 4 input units at $383 each or $4,596.– The cost of the additional cable from the power

supply racks to the magnets is 8,340 Feet x $0.20 / Foot, $1,668.

– Sub-total = $6,264

* Let's assume the labor to install the additional transmitters is the same doing the recalibration necessary for other options.

● Reading the Upper and Lower RTD's in series to obtain and average temperature for the BMA.– Pro: This saves money, data acquisition resources

and data points that must be data logged.– Con: We may not be able to distinguish whether an

increase in a BMA's operating temperature is due to reduced flow in the lower or upper cooling paths.

– Con: One RTD will have an effect on the operational trip point of the other RTD.

– Con: The current stock of RTD Transmitters will not measure two RTD in series without internal or external modification.

● Considering the First Con– I will show that by measuring the average temperature

in place of individual upper and lower temperatures we can still observe trends where the cooling for the magnet as a whole is degrading and can still set rational trip points where action is to be considered.

– Is the action to be taken when the cooling is failing different if we know which cooling path has the problem?

● Considering the Second Con

● Considering the Third Con– The first option to overcome this issue is to buy RTD

transmitters that will measure the RTD when they are in series. This would result in a cost of $3,202. See Doris' estimates in the last slide.

– Rescale the nominal 200 ohm input of the series RTD by wiring a fixed value resistor in parallel with the input. This has pro's and con's to be considered.

– Solder new resistors into the RTD transmitters we have to change the scaling in accordance with the Burr Brown datasheet for the amplifier employed by the transmitter.

● Re-calibration of the RTD Transmitters– The RTD transmitters will need to be spanned and

zeroed.– AD/Instrumentation is reported to have an RTD

Simulator.– Transmitter sensitivity is approximately 0.2 Ohms per

degree F. We could build a calibration fixture ourselves that would provide a sufficient calibration.

Summary● Instrumenting both upper and lower RTD

individually would cost $6,264 and consume 48 more MADC channels in the Booster gallery.

● Knowing the upper and lower temperatures is not necessary for equipment safety or operational efficiency.

● Using the upper and lower RTD's in series can provide the required operation information at less than $50 and not use any more MADC channels.

● The issues with rescaling the transmitters can be addressed.

Data Compiled By Doris Dick

I see the options as:

1. Buy an additional 10 more modules I/Q 510-4B07 at $383 each= $3,830

Allows for readings (0-300 degrees F) Top and Bottom half of each Corrector.

Currently we have 16 modules, need 24 total to read 96 RTD's. 2 Modules would be spares.

Would require extra MADC's or IRM channels.

2. Purchase 14 new modules I/Q 510-4B10 at $383 each= $5,362

This would read out 48 RTD's, while 2 are wired in series per each corrector.

Gives the average temperature of the Top Half and the Bottom Half of Corrector.

Allows for the higher range (0-1000 degrees F) 2 Modules would be spares.

Also return 8 Modules I/Q 510-4B07 and receive credit of $2,160= net expense $3,202

3. Add an input resistor (@210 ohms) to each channel. Recalibrate scaling or

accept a new curve that lacks accuracy of the RTD's.

4. Modify all 16 Modules internally by changing surface mount gain resistors and recalibrating process.

Requires R&D time.