Testing DC/DC Converters

N

Nick Naylor

Guest
Greetings All,

I'm looking for a way to repeatedly test DC/DC Converters. The
largest consideration is wear. I currently use little gold terminals
that the pin slides into. It actually has a little spring in it.
These are high current pins, but once they wear out, the connection
gets very weak and I lose a good amount of voltage because of it. My
goal is to have a repeatable test setup that will not wear. One
requirement is high current, the other is high voltage. Does anyone
work with this sort of thing? Any suggestions?
 
Nick Naylor <naylor_nick@yahoo.com> wrote:
Greetings All,

I'm looking for a way to repeatedly test DC/DC Converters. The
largest consideration is wear. I currently use little gold terminals
that the pin slides into. It actually has a little spring in it.
These are high current pins, but once they wear out, the connection
gets very weak and I lose a good amount of voltage because of it. My
goal is to have a repeatable test setup that will not wear. One
requirement is high current, the other is high voltage. Does anyone
work with this sort of thing? Any suggestions?
Click to expand...
Google ZIF
 
"Nick Naylor" <naylor_nick@yahoo.com> wrote in message
news:f0a720cc.0411111128.648224f0@posting.google.com...
Greetings All,

I'm looking for a way to repeatedly test DC/DC Converters. The
largest consideration is wear. I currently use little gold terminals
that the pin slides into.
Click to expand...
Assuming it is the 'test-side' that is the concern:

Make the test connectors easily replacable ;-)

Most connectors are only guaranteed to be usable for a very small number of
cycles. About 400 is the highest I ever saw promised - and that was for
those round "wire-cage" thingies which-i-cannot-remember-the-name-of in an
Aerospace application I.E: $$$$.
 
In article <cn1uu1$ofh$1@newstree.wise.edt.ericsson.se>,
Frithiof Andreas Jensen

................. - and that was for those round "wire-cage"
thingies which-i-cannot-remember-the-name-of in an Aerospace
application I.E: $$$$.
Click to expand...
"Hypertac", a French patented connector afair.

We used to use them in moderate quantities and, as you
say, big bucks.... even for minor piece parts, such
as the indexing socket-nuts.

Their big deficiency was that they were not neccessarily
self-aligning, so you had to be very careful to ensure
that all pins were centred in their sockets before winding
up the jacking screws..... otherwise bent pins.

A stock of spare contacts and a contact extraction tool
(more big bucks) was an absolute neccessity for anyone
using Hypertacs.

--
Tony Williams.
 
On Fri, 12 Nov 2004 10:33:34 +0000, Tony Williams wrote:

In article <cn1uu1$ofh$1@newstree.wise.edt.ericsson.se>,
Frithiof Andreas Jensen

................. - and that was for those round "wire-cage"
thingies which-i-cannot-remember-the-name-of in an Aerospace
application I.E: $$$$.

"Hypertac", a French patented connector afair.

We used to use them in moderate quantities and, as you
say, big bucks.... even for minor piece parts, such
as the indexing socket-nuts.

Their big deficiency was that they were not neccessarily
self-aligning, so you had to be very careful to ensure
that all pins were centred in their sockets before winding
up the jacking screws..... otherwise bent pins.

A stock of spare contacts and a contact extraction tool
(more big bucks) was an absolute neccessity for anyone
using Hypertacs.
Click to expand...
I've seen military connectors that were designed, or at least
specified, to accommodate multiple insertions, and are self-
aligning, as a unit. The socket side is attached to the airplane
chassis, and a piece of avionics slides into the slot and the
plug on its back panel mates with the socket on the airframe.

This was military, and so no doubt prohibitively expensive.
Then again, I never saw any insertion/extraction life cycle
figures, so for all I know, 400 might be optimistic.

So what then springs to mind is something very similar to
a standard "zero insertion force" IC socket, which has a
lever that has to be moved to the other position to open
or close the contacts. Each contact on the socket side is
like a miniature clamp, and the lever actuates them all
simultaneously. The test piece can literally be dropped
into the socket. For a big high-current, it's almost a
natural to extend this to a kind of "socket" that's, say,
a small array of "lower jaws," around a spot to drop the
DUT, which has tabs that lie on the lower jaws, and when
you mmove the lever, the "upper jaws" of all of these
contacts close around them. With a little compliance
built into the contacts, some wiping action could be
achieved without scraping all the gold off the contacts
within your first few dozen test parts.

Hope This Helps!
Rich
 
In article <pan.2004.11.12.11.35.48.738748@example.net>,
Rich Grise <rich@example.net> wrote:

So what then springs to mind is something very similar to
a standard "zero insertion force" IC socket, which has a
lever that has to be moved to the other position to open
or close the contacts. Each contact on the socket side is
like a miniature clamp, and the lever actuates them all
simultaneously.
[snip]
Click to expand...

That is more or less a description of the Cannon ZIF connector,
used widely in avionics test rigs. Very expensive, (about
GBP250 for a complete 156-way plug/socket pair), but it is
reliable over 100's of plug/unplug cycles.

--
Tony Williams.
 
Frithiof Andreas Jensen wrote:

Most connectors are only guaranteed to be usable for a very small number of
cycles. About 400 is the highest I ever saw promised - and that was for
those round "wire-cage" thingies which-i-cannot-remember-the-name-of in an
Aerospace application I.E: $$$$.
Click to expand...
On the contrary, ODU-Springtac connectors are good for over a million
connect-disconnect cycles.

See [ http://www.odu-usa.com/detail.taf?rowid=169 ].

--
Guy Macon <http://www.guymacon.com>
 
naylor_nick@yahoo.com (Nick Naylor) wrote:

Greetings All,

I'm looking for a way to repeatedly test DC/DC Converters. The
largest consideration is wear. I currently use little gold terminals
that the pin slides into. It actually has a little spring in it.
These are high current pins, but once they wear out, the connection
gets very weak and I lose a good amount of voltage because of it. My
goal is to have a repeatable test setup that will not wear. One
requirement is high current, the other is high voltage. Does anyone
work with this sort of thing? Any suggestions?
Click to expand...
You can use a pin-saver on the test fixture. This is usually a male
and female connector connected back to back.

--
Reply to nico@nctdevpuntnl (punt=.)
Bedrijven en winkels vindt U op www.adresboekje.nl
 
Nick Naylor wrote:

Greetings All,

I'm looking for a way to repeatedly test DC/DC Converters. The
largest consideration is wear. I currently use little gold terminals
that the pin slides into. It actually has a little spring in it.
These are high current pins, but once they wear out, the connection
gets very weak and I lose a good amount of voltage because of it. My
goal is to have a repeatable test setup that will not wear. One
requirement is high current, the other is high voltage. Does anyone
work with this sort of thing? Any suggestions?
Click to expand...
I do not work with this, but the concept of ZIF sockets as used in IC
testers and programmers springs to mind. I've only seen them for IC
packages -- I have no idea of whether other sizes of these are available
on the open market or if you'd have to make your own. At least with the
pin sizes and spacings of the average DC-DC brick you're talking about
something bigger than the usual chip.

There's another thread on this group that mentions fretting corrosion
when you mix gold and tin contacts. I imagine that your converter pins
are tin plated; you may be having similar problems with your contacts.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com
 
Nico Coesel wrote:

You can use a pin-saver on the test fixture. This is usually a male
and female connector connected back to back.
Click to expand...
I worked on an aerospace project where the spec called for replacing
the connector after the third disconnect. two connector savers went
on the male and female connectors and were removed right before final
boltdown of the access hatch and final system test.
 
On 11 Nov 2004 11:28:06 -0800, naylor_nick@yahoo.com (Nick Naylor) wrote:

Greetings All,

I'm looking for a way to repeatedly test DC/DC Converters. The
largest consideration is wear. I currently use little gold terminals
that the pin slides into. It actually has a little spring in it.
These are high current pins, but once they wear out, the connection
gets very weak and I lose a good amount of voltage because of it. My
goal is to have a repeatable test setup that will not wear. One
requirement is high current, the other is high voltage. Does anyone
work with this sort of thing? Any suggestions?
Click to expand...
You need these

http://www.hypertronics.com/



Regards,

Boris Mohar

Got Knock? - see:
Viatrack Printed Circuit Designs http://www3.sympatico.ca/borism/
 
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