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Discussion in 'Question of the Day' started by derekleffew, Feb 18, 2008.
What purpose do these two pictured adapters serve and what are their proper names?
NEMA L22-30R to a 5 pin XLR connector on a 22 AWG DMX Cable with 120ohm impedance.
As for why, I have no clue.
Some funny power supply maybe?
Pickle to DMX adaptor? That, or a special cable used on old light boards to, um, remove them from service.
Either way, kinda sketchy.
Kinda what I was thinking...either a chainmotor control adapter of some sort (or, of course, a console decommissioner)
Pickle to data... hmm... that sounds interesting. I can't quite differentiate if that is MIDI or 5-Pin, presumably for DMX. If it's the latter, I'll stand to the side of whatever that chain motor is lifting!
Presuming it is a pickle adaptor, what is the operating voltage of said pickle? I'm thinking perhaps you have a lot of spare 5-Pin data cable (intended for data distribution to hundreds of movers) and the cheapest/easiest/lightest way for you to extend the range of your pickle is to run the low voltage signal through a 5pin data line?
The one on the right, you could actually connect it to a cable from a PD, and then any splitters or controllers or opto-isos to protect said controllers would be fried.
Soundlight, is that more dangerous to people? (Not trying to nitpick, I honestly don't know the answer, but you seem to be referring to gear, where as Ship refers to health and safety.)
Would you like to be operating a console or connecting a cable to a splitter when that kinda power hits it through the DMX connection?
I don't know!
pickle connector, or at least not one I have dealt with, no need for five pins. Why you would need to adapt 30 amps of 3 phase to and from 5 pin XLR is a question I am not sure I want the answer to.
The only thing I can thing of is some long single run where they wanted heavier gauge cable for some reason instead of using an opto or a repeater but that would make sence as it is not twisted. whatever the reason it better be good as it would cost about 60 bucks in parts to make.
adaptor, such that one can test one's 5 pin power cable with a dmx cable tester...
The cable is too thin for any sort of power and to use power cable for any sort of data would be asking for trouble...
NEMA L21-30R because if you look at the female side it looks like the smallest pin is opposite the "bent" one male side is indistinguishable.
as for charc's question about load. the NEMA L21-30R connector is rated at:
30 Amps, and 3 phase power with 120V on each leg.
I did find a note about it being specifically made for unbalanced loads on the legs.
If the cable is indeed 22 AWG DMX Cable, which I see no reason to question the ratings were actually a bit hard to find but the most constant comes from AMDJ and they rater there 5 pin DMX at 2.1 Amps per conductor @ 25 degrees C.
Obviously if for some reason you did use this thats is your weak point.
The one on the left is more dangerous to people, because they could touch the pins while it is live.
And i have no clue what they're for. I've see power adapters for powered speakers similar to this, but those wouldn't be 3-phase.
That's interesting to point out Bret, and gave me an excuse to stare at connectors I've never seen in person. (It happens a lot.)
From my quick research it looks like L20-30R and L21-30R are nearly identical. The biggest difference is that L20-30R is 4 conductor (no ground?) while it appears that L21-30R is 5 conductor, adding a ground pin in the center. Based on that, and looking back at Derek's pics it appears to be L21-30R
Visually they similar but if you look up the L20-30R you'll see it's for 347-600 VOLT 30 AMP 3 phase power. So you're looking at a TON more voltage going through the line, also if I had to venture a guess I'd say with the increased voltage and the lack of a ground pin I'd say you need loads on the legs that are a lot closer to being balanced. Someone will probably call me out on that but that's what my logical brain tells me is the case.
Please justify your statement of live pins being accessible with the adaptor on the left...
I would seriously hope that the only connectors one would see for power, be it for a powered speaker or whatever if not a normal wall sort of connector would be powercon, IEC or Cannon LNE.
Yep, I'm going to call you out on that one. Under normal circumstances, there should be no load on an Earth / ground pin. Now what most people tend to assume is that a 4 pin three phase connector has no Earth. Now at least down here, WRONG. It has no neutral, but definitely has an Earth connection. This "L20-30R" appears to be something which may be suitable for Australian three phase supply, because there are 415V RMS between phases...
Oh and load balancing has bugger all to do with voltage, in fact a higher voltage will lead to less current on all conductors assuming stuff was designed for that higher voltage... I = V/R.
4 pin three phase exists for a] large heating / cooking appliances - where the load will always be even on all three phases b] three phase motors and appliances with these incorporated into them, large cooling devices, bowling green mowers, etc. Bar automation and air con, it has, in my opinion, no place in our industry.
Do the states not use 6 pin Wieland for motor cable?
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