Reason for uniform spacing of molex 4-pin h/d power connectors?

  • Thread starter Thread starter Doc
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Doc

I notice that the distance between the molex 4-pin hd power connectors
on a given line from the PSU seems to be uniform, and seems to be very
similar even on different PSU's from different manuf's from different
eras. Is there a specific reason for this?
 
Doc said:
I notice that the distance between the molex 4-pin hd power connectors
on a given line from the PSU seems to be uniform, and seems to be very
similar even on different PSU's from different manuf's from different
eras. Is there a specific reason for this?
Click to expand...

Industry standard, maybe? They're all color-coded the same and keyed alike,
so it lessens the chance of blowing something up.
 
Industry standard, maybe? They're all color-coded the same and keyed alike,
so it lessens the chance of blowing something up.
Click to expand...


There's no electronics-related reason that you're aware of?
 
Doc said:
There's no electronics-related reason that you're aware of?
Click to expand...

Molex power cables, don't have a signal reflection issue.
You could stack the connectors right next to each other if
you wanted.

The dimensions are influenced by:

1) Sufficient spacing between connectors, so they can be
fitted without abusing the wire too much.

2) Not too much wire, as wire costs money.

3) Some ATX supplies, the cables are only long enough for
top-mounted ATX supply installation. Supplies with a longer
loom provided, can be installed in bottom-mounted cases.

4) A cheap supply, can use a wire gauge which is one AWG number too
thin. Probably not an issue, until you draw the rated current
from the supply. The companies that make $20 supplies, they
depend on you not drawing the rated current from them. (I.e.
The "500W" supply which is a "350W" supply in disguise.)

BTW - this is my favorite (unintentially) funny power supply advertisement.
Because everybody likes a power supply that looks like it's on fire :-)

http://images10.newegg.com/NeweggImage/productimage/17-163-018-06.JPG

Paul
 
JEEZUS how I hate those Molex connectors. Was so glad when SATA came in.
Once I worked on exploration crew in the desert. They had two-way radios with
those Molex connectors. Very unreliable in a 4WD bouncing over dirt tracks.
 
JEEZUS how I hate those Molex connectors. Was so glad when SATA came in.
Once I worked on exploration crew in the desert. They had two-way radios with
those Molex connectors. Very unreliable in a 4WD bouncing over dirt tracks.
Click to expand...

I don't know how much better SATA connectors are, the one on my other
computer is incredibly flakey, and requires very specific routing if I
intend to boot it. At least with the Molex four pin barrel connectors
you could close down the female end so that they worked better.

Jon
 
Jon said:
I don't know how much better SATA connectors are, the one on my other
computer is incredibly flakey, and requires very specific routing if I
intend to boot it. At least with the Molex four pin barrel connectors
you could close down the female end so that they worked better.

Jon
Click to expand...

Any time there's a danger of a connector working loose, the connector
can have a positive retention feature. On the motherboard connectors,
that takes the form of a latch.

http://www.playtool.com/pages/psuconnectors/main20pin.jpg

Connectors work loose for two reasons. The obvious reason is
shock and vibration. But it's not the only reason. "Thermal walkout"
can be a pretty severe effect too (and that's why your motherboard
has the latch on its connector - its not there to stop vibrations).

On my Sony Trinitron CRT monitor, none of the connectors inside
the thing had positive retention features, and one of the connectors
worked itself loose. And that wasn't due to vibration. Just thermal cycling
was enough to work the connector loose.

If you look at the power connectors used in your car, they
tend to have pretty good retention features. To get the tail light
assembly off my old car, you have to press pretty hard on the release
tab of the power connector.

Paul
 
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