Thanks for that piece of reseach Roy. My career was in the engineering
side of
Pilot devices at G.E. and thus the subject of contacts was very much
my turf.
Anybody can obtain an unused pilot device, pushbutton or what ever and
they can measure the resistance as being in the 100s of ohms area
across the N.C. contacts because of oxide build up even tho under
pressure.
If one was using one of the hand held instruments in a lot of cases it
will show as being open since the battery voltage was less than 28
volts D.C
As far as books are concerned major users such as the auto inductry
required a certain number of operations without failure where in the
past operators would just push the button again until it finally
makes.
This subject came up a few years back when computors came into the
field and the natural reaction was to use gold plated contacts but
these could not meet required criteria because gold plating is porous.
G.E were benefitted with large contracts for contact blocks e.t.c.
using reed switches and the like when the automotives decreed voltages
of less than 28 volts D.C. where other contractors failed to meet
required criteria of the customer. I could go on of course but there
really isn't any need to.
The initial statement that pressure solves things is just not true
even tho in the past when television repairmen had the opportunity of
pressing a button several times to make it operate. In todays world
buyers demand evidence of quality without the option of one or two
second tries
I am surprised that "wipe" was the most common term that you saw in
your brief search where as scrubbing action is more descriptive . Wipe
alone describes distance of button operation after the initial contact
is made which by rolling scraping action creates a side movement to
push the oxides aside. If wipe alone is required without including a
scrubbing action then wipe really only specifies available contact
wear. But on the other hand we can admit that tho English is the
common language there are differences. For your info at San Diego
there is a college for American English no less
I certainly do not advocate the use of acids to clean contacts in the
normal sense but used it as an illustration of how it could remove
oxide created by copper leaching thru the silver plating which
inevitably causes momentary failures especially with older equipment.
The same problem is avoided with reostats where they have a
sliding/scraping motion to ensure accuracy of measurement.
I have said enough since I am 'out of my turf' whereas on my own turf
the grass is growing and it needs to be cut
Regards
Art



crRoy Lewallen wrote in message ...
I just like to give the readers an option. For transmission line terms,
they can choose between HP/Agilent's usages and definitions, or yours.
For terminology regarding contacts, they have their choice between 3M's
and Richard's. And for engineering educational standards, readers can
choose among Ronold King, Terman, and Kraus, or Reg Edwards. I'm sure
each will make the choice that he/she feels most confident with.

Roy Lewallen, W7EL

Reg Edwards wrote:
It's an "abuse of language" shared by many, including manufacturers of
switches and relays of all kinds.


==============================

Yet you still insist on using manufacturers' sales blurbs and specifications
as engineering educational standards.