[sdiy] External power connectors

[Peter Swarbrick]

As Steve notes, the good old XLR4 rivals the XLR3  for popularity in the
Broadcast and Film world.
There is no standard for using pins 2 +3 : sometimes they are paralleled( ie
1+2= 0v /3+4= +12v ) for heavy current applications and  battery packs and
their chargers will often use one or both of these pins for charging input /
temperature monitoring etc.
FWIW use of the 3-pin XLR for  24 Volt power is  commonplace on 35mm film
camera equipment, further complicated by two opposing "standards" which are
the reverse of each other!! Companies such as mine (Panavision) have battery
packs clearly labelled in order to minimize toasted gear, but it still
happens occaisionally. Another problem arises with interchanging audio leads
and power leads - leading to either hummy one-legged audio or film cameras
that power up but refuse to run when trying to pull some 10A+ starting
current through 3 metres of star quad!

My two-pennorth

Pete
----- Original Message -----
From: "Steve Ridley" <spr at spridley.freeserve.co.uk>
To: <synth-diy at dropmix.xs4all.nl>
Sent: Friday, December 03, 2004 10:35 AM
Subject: Re: Re: [sdiy] External power connectors


> > I recently got a bunch of 4-pin XLR connectors (both male and female)
> > at an unbeatable price. Now, I'd *never* use a 3-pin XLR for power,
> > but what about this odd form? I've never seen 4-pin connectors on
> > any kind of gear. Who uses them, and for what applications?
>
> Standard in the broadcast industry for +12v power distribution
> to cameras, monitors etc.  Pin 1 = 0v, pin 4 = 12v.  I'm not sure
> if there's a standard wiring for the other two pins.
>
>
> Steve
>
>
> --
>
> Whatever you Wanadoo:
> http://www.wanadoo.co.uk/time/
>
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