Am 02.07.07 19.20 schrieb Spurious Response:
On Sun, 01 Jul 2007 10:49:20 -0700, John Larkin
wrote:

On Sun, 01 Jul 2007 01:16:30 -0500, Wolfi
wrote:

I can't comment on that, since I don't have reliable data, but simply asked,
what about the other plain? And it also is much easier to have a slotted pipe
type receptacle, with a steel tape spring surrounding it to guarantee,
constant, long-term contact pressure for a round, mechanically sound, 5mm pin,
which gives solid, equal contact all around its circumference.

I think it has a good reason that the later added third ground pin for the US
system isn't of flat spade shape anymore, but strangely a round one now with,
who would have thought it, 5mm like in the Schuko system as well ;-)
All three pins on the other end of an IEC power cord are flat blades.

You're talking about this IEC (http://de.wikipedia.org/wiki/IEC_60309) power
connector, rated from 16A up to 250A @690VAC? ;-)
But it also uses round pins, not flat ones.

John

Yes. Thick, flat blades. Leaning toward square even, but not quite so.

Or should you mean that type, which is used for computer monitors and -power
supplies?
If so, then you surely noticed the lousy Ampère rating of mere 10A for it,
which is just 2.3kW, rather than the 3.68kW which you have with a 16A
connector system?

The main reason is that the designers of that chassis end (entry
module) of that chassis connector system wanted large, round nosed
pyramidal points on those strong, flat blades so they could act as good,
repeatable "lead-ins" for the "otherwise only held in by the rubber
squeeze" connector. Also, flat blades do maintain larger swept area of
contact (and therefore safer current carrying capacity) longer than pins
and sleeves after repeated disconnect reconnect cycles. That plug design
was meant for molded on plug assemblies.

Jeez, just think of how huge some strain relieved, metallic, heavy duty
device would be on the back of all our gear over the years.

That's not required at all, but all those connector standards, Schuko, Euro,
IEC 60309, IEC 60906-1 and the forementioned 3-contact socket/plug system used
for computer monitors and SMSP have the removable parts case dive into the
fixed mounted one, taking off mechanical stress from the pins and burden it
onto the housing.
And exactly this point is *not* true for the U.S. style connector system and
this is one of the reasons, why I have quite a low opinion of it.

That was one more benefit of the flat bladed design, was narrower
overall plug size for any given ampacity and voltage compared to what
would have been required for round pins.

Well, it must have some reason that the international standard 230 V household
plug system, specified under IEC 60906-1, uses round pins as well, not flat
ones. http://en.wikipedia.org/wiki/IEC_60906-1