[GreenKeys] 120vdc connectors - opinions?

Mon Jun 25 01:01:09 EDT 2018

First, out of the D-Subminiature connector family, a DB has 25 contacts, period.  The 9-contact variant is a DE.  Of the rest, 15 is DA, 37 is DC and 50 is DD.  So DB9 doesn't exist.  However, I know that from long usage (or mis-usage), DB9 is commonly used, and so long as you aren't trying to buy some, there's no danger of picking up the wrong plug.

With the fine thread circular connectors commonly thought of as military, about 30% of people call them Amphenol Connectors, another 30% call them Cannon Connectors, and most of the remainder call them Bendix Connectors, all because that's who made the ones that those people first became familiar with.  A fourth manufacturer was Pyle-National and I can't recall the 5th, although it might have been Aero.  But I never heard the connector family referred to as any but the first three.  In any case, in most of the manuals, they are referred to generically as AN-Connectors (1940's and early 1950's), MS connectors (late 1950's through about 1980's), and since then MIL-C-5015 Connectors.

To finally answer your question, the smallest pin used in any of the inserts is the #20, rated at 10A.  The most common is the #16, rated at 22A.  above that, there are #12, 41A, #8, 73A, #4, 135A and #0, 245A.  If the connector insert face has "INST" molded in along with contact letters and mfg name or symbol, the voltage rating is 250DC and 200AC rms.  Otherwise, the minimum voltage rating for about 95% of the inserts is 700DC and 500AC.  Some have higher ratings up to 4200DC and some have different ratings for some of the pins.  Number of contacts runs from 1 to a max of 52.  I have never counted them but there are around 200 different inserts.  One thing that confuses most people is that the insert number rarely equals the number of contacts.  The insert number was assigned sequentially, so insert #36-1 has 22 contacts because it was the first #36 insert assigned.

Robert Downs

-----Original Message-----
From: greenkeys-bounces at mailman.qth.net [mailto:greenkeys-bounces at mailman.qth.net] On Behalf Of acti at provide.net
Sent: Sunday, June 24, 2018 21:32
To: Greenkeys at mailman.qth.net
Subject: Re: [GreenKeys] 120vdc connectors - opinions?

Hey Nick...
What are the max # of connections/shell, and max current/pin specs?

Voltage ratings are rarely a problem in full sized connectors.
It's all about the current...

You'll need to choose a connector set with:
A) Enough pins that are each heavy enough for the current(s),
B) Sufficient pin-pin and shell voltage isolation for the job,
C) Reasonable cost & availability,
D) Whether or not you desire secure locking connections
(ie round mil connectors with a locking ring or something
like a Molex connector with a lock tab)
vs one that slips in and out easily, like wall plugs.
and
E) won't be confused with another connector tech in the same project
(ie using an audio connector for power in an audio device is foolish).

FYI... Searching "connector" on Digikey yields over 2.5M hits.
... https://www.digikey.com

Bear in mind that if you are only doing this for yourself,
and nothing will be exposed outside the chassis, you can easily
repurpose old generic connectors of the right specs,
that will never be seen in that context.

For example, years ago I USED to use DIN audio connectors
for other purposes, as well as left over D-Sub solder
style DB-9 & DB-25 RS-232 serial connectors as non-computer
project internal power connections. The DBs were darn
cheap, available locally back then at Radio Shack,
had decent voltage isolation between pins, and easily handled
several amps per pin.  Nothing else around here could do that.

I hope this helps!
- Keith Mc.
---
Geeky Full Deck-isms: "He was a few pins short of a DB-9 connector..."

On 2018-06-24 15:12, Nick England wrote:
> I have a number of devices to run off 120vdc - relays, motors, etc.
> thanks to Jerry I now have a nifty supply but I am trying to decide how 
> I
> want to hook things up.
> I could just use a terminal strip but I was thinking about plugs and
> sockets instead.
> Is it still possible to find the connectors that Teletype used for 
> 120vdc
> in early equipment.
> 
> I thought about using an odd AC connector like the 120vac 20a with one
> blade sideways, but I can�t find a duplex receptacle with only the 
> sideways
> slot. They all have a T slot to take either 15a or 20a plugs.
> 
> Or should I just say the heck with it and use Cinch-Jones 3-pin plugs 
> with
> chassis mounted receptacles.
> Or just live with terminal strips?
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