Power Cabling and Cooling Update Details

IU iTOP cables/power/cooling update 12/19/2014 also see other slides on cooling G. Visser Power supplies selection/evaluation Wiener PO issued, expect module early January Andreas Ruben will travel to IU to setup, and discuss requirements etc. Keysight i.e. HP Matt shipped 2nd unit here; examined but not powered yet Excelsys Cost is such as to merit serious consideration Will sketch out what I think would be a good design around these, and cost it Matt has sent 2 Xg3 power modules (the ones we d use) and 6-slot mainframe (not exactly the one we d use but close enough for evaluation). The setup (Too) Heavy cables found for basic preliminary evaluation of supplies with 0.5V drop restriction Bought 12AWG cable for test (Belden #5000FE, 2C 12AWG + foil shield) Sense cable found I think (have to get permission to borrow) 200VAC power source found, 100VAC also possible (both 60Hz though but should be ok); will start with 208VAC for simplicity

SCROD cables Have some super-limp flexible wire (1.8m, 16AWG & 20AWG) samples from Jaguar Industries. Also some decent (tougher but less limp) wire from Polar Wire Inc. Breaking news just received from Jaguar 1000ft 16AWG white, ordered on Wednesday (see next slide) Patch connectors See following slides External power cables Urgently need info on cross-section constraints Length info is also needed for proper evaluation of the power supplies, almost as critical Meanwhile have started process for custom combined power & sense cable Request for design & quote initiated with Alpha Wire That was the vendor for several very similar cables I did for STAR Cooling issues Did get some communication back from EPEC technical contact (Will discuss). I need to get back to him for more info, but I am not hopeful on a reasonable price. Ordered 4x4 2mil indium foil, in stock, maybe have it monday.

For module 01, use colored heatshrink for wire id. Need to order some 20AWG or 18AWG if that must be the plan (tbd ) instead of all 16AWG.

Power wire termination at SCROD Soldering: adequate wetting of all strands of a large wire like 16AWG is difficult to achieve. Particularly with a fine stranding and in a small space on a high-value PCB assembly. Use of a large amount of flux is not desirable (would need to be cleaned, and that is difficult). The result can be disconnected strands, unequal stresses when flexing and then broken strands, a hot connection and ultimate failure. Matt s soldering of the two regular stranded smaller wires on this board (for cal circuit power) also does not achieve adequate wetting through the whole hole/wire. The better way is to crimp the wire to a pin and then solder the pin to the board. (Or, consider a connector but the latter is probably out of the question.) Of course, have to identify a pin of the right size and shape, since this is too small a job for custom pins. Fortunately, I think that is done next slide. Most of the difficult termination work can be done in advance, soldering to the board is a relatively simple final step. Wire strain relief to the pin is easily achieved with glue-loaded heatshrink unlike strain relief for direct connection to a PCB hole, I don t know a good simple plan there apart from making a bracket to tie the wire down someplace else on the board.

I believe some changes are necessary in the hole size, solder pad size, and locations of the power wires on SCROD production rev. Understood the details will need to be defined soon. The existing SCROD boards will not be compatible with production power (at least) pigtail. But I m sure we can hack it somehow to enable module 01.

These are the best contacts I know of (and the contacts are the most crucial feature of course) Used (equivalent D connector) in STAR, excellent results Is 11mm height too much? Plastic dummy in fab now at IU

Thinnest option I know of But rather wide A=34mm 6 contacts Mouser has some stock (2 ordered) Not clear if 16AWG crimp is available, but we do not want solder connection I think. Needs investigation. Equivalent to Nicomatic 220 series

candidates for power cable connector for SCROD pigtail (and would be nice if possible on SCROD itself, but let's not think of that as a plan or requirement ) MFR P/N or series Contact rating, A Envelope height, mm Envelope width, mm # pos fixing notes similar to (or intermateable even to) Nicomatic? Harwin M80-4000000F1-06-325- 10A or 15A, not clear 5.55 34 6screw this is 2.7mm contacts (16AWG crimp) Nicomatic 221EF21-0006-3310 10 5.6 34 6jackscrew this is 2.7mm contact (14AWG crimp as required (officially) for 15A rating) Nicomatic 221EF21-0006-3315 15 5.6 34 6jackscrew this is 1.85mm contacts (16AWG crimp) Nicomatic 341EH01-0006-3310 10 7.8 21 6jackscrew 1.58mm contacts (Posi- band?) Positronic DF07 20 11 23 7side latch

A backup plan not preferred 10A 23.5mm