Re: serial cable current capabilities

Hi,

I looked up the specs for subminiature D connectors from half a dozen
mfgs. The maximum rated current per contact is 5A for machined
contacts and 3A for stamped contacts.

My experience has been phosphor-bronze sockets will anneal at higher
currents, resulting in poor contact pressure. This will increase
contact resistance, resulting in even more heating until the
connector fails (melts). Do not exceed the rated maximum current
specs.

I would also recommend using the screws to keep the connector mated.
This way the plug cannot be inadvertently pulled from the socket
while it is carrying current.

Finally use the socket part of the connector on the drive side and
the plug part towards the motor. Otherwise Murphy will again
demonstrate a practical application of his Law by having something
short across the pins while the power is on and the connector is
unmated.

Mariss

--- In CAD_CAM_EDM_DRO@y..., Scot Rogers <scotr@b...> wrote:
> shoutout to all,
>
> I'm finishing up my first controller/powersupply and I had some
questions.
> I'm running gecko's to motors that can pull 3.3 amps. I have a
bunch of
> open spaces on my control enclosure that are made for a standard 9
pin
> serial connection coupler. My question is this. Could I use
standard
> serial connections and ribbon cable to match to connect the geckos
to the
> motors? Or would the current burn up the wire? And If I used a
larger
> gauge wire to carry the current, would the connectors be able to
handle the
> amperage?
>
> The reason that I want to use the 9 pin connection is so I can have
some
> versitility of which kinds of motors that I can run. Concievably I
could
> run any 4 6 or 8 lead motors if I limit the current correctly
right? Then
> all I would have to do is get the pinout straight on the serial
cables for
> each motor connector. I could even put a current selector switch
on the box
> with the right limitors and just switch motors and current when I
switch the
> machines right?
>
> Scot