Ramblings about Airborne Power supply design and testing

On Sunday, September 29, 2019 at 4:07:09 PM UTC-4, legg wrote:

On Sun, 29 Sep 2019 09:38:15 -0700 (PDT), blocher@columbus.rr.com
wrote:

On Sunday, September 29, 2019 at 10:06:00 AM UTC-4, legg wrote:
On Sat, 28 Sep 2019 15:31:12 -0700 (PDT), blocher@columbus.rr.com
wrote:
snip

Item 17: The link here :

https://www.ebay.com/c/21030870708

shows the picker gradient amplifier
snip

It shows automotive hood springs. Recheck the number.

You might do a pre-qual assurance, but the calibrations and ref
tracing required for most certifications are outside the budget of the
average design/test facility in power conversion field. This requires
deep pockets.

You might be disappointed at the 'expertise' offered at a competative
test facility. Recommend your product guru be there to hold hands to
avoid most issues.

For extraneous specs, in-house hardware capability will always be
useful, but likely with equipment bought surplus or on e-bay, as you
suggest.

RL

That is bizarre. I continue to have the picker gradient amplifiers displayed.

For power input testing I have been able to do "for credit" testing because the only items that need to be in calibration is an o-scope and voltage meters....And a current probe. But for many other tests outside labs are needed.

I am trying to see if I can get my picker to run the AC waveforms and do for credit testing on those items too. ( I am running low power equip and that certainly makes doing it yourself easier)

Perhaps item# 153158735347.

VMEbus?

I had a qual house failing preproduction systems for hipot after
humidity soak. Size and cost of small car.
They'd screwed up connector plugs for the test, even though we'd
provided them with the correct prewired and pretested test harnessing.
Change the test connector - no problem.

RL

Set up issues... I am sure you did not get a refund either

 

On Sun, 29 Sep 2019 08:04:37 -0700, jlarkin@highlandsniptechnology.com
wrote:

On Sat, 28 Sep 2019 12:24:02 -0700 (PDT), blocher@columbus.rr.com
wrote:

On Saturday, September 28, 2019 at 12:05:40 PM UTC-4, bitrex wrote:
On 9/28/19 9:32 AM, blocher@columbus.rr.com wrote:

Item 10. Inrush current. On low power units fight, FIGHT, FIGHT against a hard spec. It will fail. Fight to characterize it. Low power stuff is not going to take down the aircraft power bus and your internal capacitors have to get charged up and yes, your EMI caps theoretically take infinite current for short durations to charge up. When you design around inrush you start to take away internal capacitance that you really want. The aircraft has to tranfer energy into your unit on power up. I think the aircraft manufacturers get that but the designers see a spec as a challenge and try to meet it (at the expense of inadequate internal capacitance or being in the crappy position of telling your management that you failed at test time)...Actually, the customer will probably give you relief on it (not on anything else though)so fight up front to avoid the headaches.

Item 11.....OK I guess I am done for now...Bye

Item 16. Test procedures and reports. I could make a separate post on this....Engineers (young ones rightfully so, I think) hate writing and testing requires a lot (A LOT) of thought to what is going to be tested and how to go about doing it. Younger engineers I think should be allowed to learn the trade and not get bogged down by writing. But, sooner or later, I do not believe you are a good engineer if you cannot write a good test procedure. A good procedure is based upon the right data being taken and the right setups. Engineers are normally not good at writing and unfortunately in many corporations the procedure writer is the "lesser" engineer, but that is a bad wrap ( I have been on both sides ). If you can get past the lesser engineer thing you can learn to use your willingness to write procedures to your (and the programs ) advantage. The thing about procedures, is that nobody wants to look at them until the end of the program, so if you are good, you can write
the
procedures to force things that you know are best for the program. In many respects, writing the tests allows a control over the design the is very powerful and goes unchallenged because a design engineer will design to the test if you can get it through quick enough. I have learned (I am late in my career so I am taking what gets me over the finish line) to embrace writing procedures and reports and to use them to my (and the programs ) advantage


A young adult going to a 4 year college and not coming out of it knowing
how to read & write much better than when they went in is not money
well-spent.

An engineer who is an engineering genius but cannot express him/herself
in a way that other people understand easily...their value drops
considerably. Same for doctor, lawyer, and many other white-collar fields.

"Younger engineers I think should be allowed to learn the trade and not
get bogged down by writing." So a guy comes fresh out of college and he
doesn't know how to engineer and doesn't know how to write, either?
Gosh, what are we paying this fella for, anyway? Way easier to train a
grad with an excellent command of English to be a good test engineer
than vice versa I think...

I don't think most engineers wish to go into testing at the beginning of their career.

My latest hire, we sent directly to the test department for a few
months. Engineers need to design stuff that is easy to test and cal.
And they need to design test sets. He understands that now.

Why? Is your stuff that hard to test/calibrate? ;-)