[time-nuts] Power connectors continued

Didier Juges shalimr9 at gmail.com
Sat Jun 24 19:54:33 EDT 2017

I have been forced to use micro-D by a customer on a military power supply,
not even space rated, it was well over $100 each in 50 piece quantity (I
think it was a 25 pin).

However, unless they are mistreated (which is easy for the reason you
listed), they seem reliable. I do not believe we have replaced one in over
400 units shipped and a 15 year period (aside from a couple of prototypes
that went through hell). That must be one of our better customers...

The design choice of protecting the pin instead of the socket is baffling.

On Jun 23, 2017 7:03 PM, "jimlux" <jimlux at earthlink.net> wrote:

On 6/22/17 4:22 PM, William H. Fite wrote:

> A good friend of mine, sadly of blessed memory, was a lead engineer for
> Grumman on the comm systems of the lunar lander. He spoke of small
> space-rated multi-pin connectors that cost upward of $500 each.
> The Micro-D is widely used in spaceflight, and is a pox on the connector
world - not only are they expensive, the way the pins and jacks are made is
almost asking for damage - the pin is shrouded in a hole, and the jack is
exposed. $100 for a 9 pin wouldn't surprise me.

Lately, I've been encountering nano-D (Glenair, Omnetics) - they're not as
delicate, they're smaller.

> On Thursday, June 22, 2017, Arnold Tibus <arnold.tibus at gmx.de> wrote:
>> Hello,
>> I can second Magnus and want to throw in some more details.
>> Cannon, Deutsch, Bendix, Souriau, Matrix, Amphenol,  etc. etc. are (big)
>> companies manufacturing all kind of connectors and are  n o t  connector
>> type designations! Important are the type numbers of the manufacturer or
>> higher level specification numbers.
>> We used in the aircraft and spacecraft business naturally the military
>> (MS-) numbers listed in the MIL-QPL (or eg. for Spacelab with GSFC spec.
>> no). Most types of connectors are under these numbers available from
>> different manufacturers, of course with different manufacturer in house
>> part numbers. Attention: the 'same' connectors may be bought w/o the
>> Mil.-spec. sheets with somewhat lesser quality. Important details are
>> the max. mating number, the contact resistance (e.g. 20 mOhm) and the
>> max. continuous current, max. Voltage, vibration resistance and
>> reliability etc.  Of course, this makes good connectors somewhat
>> 'expensive'. Hirel and non-magnetic gold plated D- subminiture type
>> connectors do survive e.g. the rocket launch phase (high vibrations),
>> vacuum and low temperatures and are still used for space projects.

AMP (and others) sell a lower cost version called the "Circular Plastic
Connector" or CPC. A coarser screw thread than the round metal MS

The round connectors (called Bendix connectors by some at JPL, because, of
course, that was the mfr for some batch of them) have a nice mil-std to
define them.  There's a Shell, an Insert, and pins/jacks.  You can get
shells and inserts with different keys and "clocking" to prevent mismates.
There are coax and triax inserts, high voltage inserts, etc.

While they're pricey brand new, there are numerous surplus suppliers (Apex
Electronics in Sun Valley, CA used to have thousands of them).

You can get them hermetic, vacuum tight, waterproof, locking, non-locking,
every kind dielectric imaginable, etc.

>>  The D-sub series of connectors was introduced by Cannon in 1952. They
>> are still available as standard, hirel, and non-magnetic versions. The
>> contacts were machined contacts forcrimping or soldering connection and
>> made of massive copper with gold finish. (more see e.g.
>> https://en.wikipedia.org/wiki/D-subminiature). Example for the standard
>> 9 pin connector designation (crimp): DEMAM-9S and DEMAM-9P. Today are a
>> big number of companies producing equivalent types. Cheap ones are
>> equipped with contacts made of sheetmetal. Nobody should expect then the
>> same spec. values as reliability, mating numbers, contact power rating
>> etc.
>> It is up to the designer of a product to be informed and select the
>> right quality device for his product ...

My problem with D-sub is two fold:
1) making a chassis hole is a pain - although now, with places like Front
Panel Express, it's less so.
2) the shroud around the plug/male gender is easy to bend if it gets
stepped on.  Sure, for flight hardware, carefully handled under the
watchful eye of QA, not an issue, but I have lots of these from my
not-entirely-mis-spent youth that are bent.

They do come with removable pins/jacks, and you can get coax flavors too.
They're fairly compact in a panel.

Other connectors of interest are those made by Lemo and Hirose.  Lemo are
locking, pretty rugged when mated, and small for the number of conductors.
You see them on high end video and medical gear.

There's also something about double banana plugs and mating jacks. I go
back and forth between PP and banana plugs for preference.

BTW, there are panel mounts for PP.

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