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PMAG

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tim2542(at)sbcglobal.net
Guest

Posted: Wed May 30, 2012 7:03 pm Post subject: PMAG

Hey gang, what grommet or gadget was being discussed to use on the wires ends to the PMAG connector? I ended up using SD male 

D-sub pins with the pin clipped off and just the crimp left over the wire.  Seems ok, but I don't get warm fuzzys from these connectors. Not at all....

Thanks, Tim



[quote] 	  Quote: 	
		  

	




[b]

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fvalarm(at)rapidnet.net
Guest

Posted: Wed May 30, 2012 8:42 pm Post subject: PMAG

I ordered wire ferrules from McMasterCarr for the Pmag  connections.  See

  

 http://www.mcmaster.com/#lug-terminals/=hrnvdt

  

 Bevan



   From:  owner-aeroelectric-list-server(at)matronics.com  [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Tim  Andres

Sent: Wednesday, May 30, 2012 8:03 PM

To:  aeroelectric-list(at)matronics.com

Subject: AeroElectric-List:  PMAG

 

 Hey gang, what grommet or gadget was being discussed to use on the wires  ends to the PMAG connector? I ended up using SD male 

 D-sub pins with the pin clipped off and just the crimp left over the wire.   Seems ok, but I don't get warm fuzzys from these connectors. Not at  all....

Thanks, Tim



 [quote]                   	  Quote: 	
		  

	








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tim2542(at)sbcglobal.net
Guest

Posted: Wed May 30, 2012 8:59 pm Post subject: PMAG

Ok thanks! I'll give them a try.

Tim



Sent from my iPad



On May 30, 2012, at 9:39 PM, "B Tomm" <fvalarm(at)rapidnet.net> wrote:



[quote] I ordered wire ferrules from McMasterCarr for the Pmag connections.  See

  

 http://www.mcmaster.com/#lug-terminals/=hrnvdt

  

 Bevan

 

 From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Tim Andres

 Sent: Wednesday, May 30, 2012 8:03 PM

 To: aeroelectric-list(at)matronics.com

 Subject: PMAG

 

 Hey gang, what grommet or gadget was being discussed to use on the wires ends to the PMAG connector? I ended up using SD male 

 D-sub pins with the pin clipped off and just the crimp left over the wire.  Seems ok, but I don't get warm fuzzys from these connectors. Not at all...

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

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nuckolls.bob(at)aeroelect
Guest

Posted: Thu May 31, 2012 7:41 am Post subject: PMAG

At 11:39 PM 5/30/2012, you wrote:

 I ordered wire ferrules from McMasterCarr for the Pmag connections.  See

  

  http://www.mcmaster.com/#lug-terminals/=hrnvdt

  

 Bevan



  Hmmmm . . .  Not sure these terminals will add anything useful to the  mating of wires to the pmag. The wire grip in Emagair's  control plugs are designed to grab stranded wire. One  might improve on the grip slightly by combing the strands  out so that they don't over-lap each other in the grip  area. Having made the electrical connection secure, legacy  termination techniques call for support of the wire+  insulation immediately adjacent to the electrical  connection. This design goal is addressed in Emagair  instructions with use of M21919 padded clamp  as shown. 



 [img]cid:.0[/img]



  Adding a device like this . . .



  [img]http://images1.mcmaster.com/Contents/gfx/large/8009k26p1l.png?ver=10574016[/img]  



  . . . to the end of the wire decreases effectiveness  of the electrical connection. Closing the wire grips down  on 19 strands of wire offers as many as 38 points of  hi-pressure contact with the stranding layup. Crimping a  'pin' on the strands reduces this to 2 points of contact  (maybe 3 if the 'groove' in the pin is flat against a  contact surface.  Therefore, I suggest that more elegant technique is  to follow Emagair instructions as published.

 

    Bob . . .

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fvalarm(at)rapidnet.net
Guest

Posted: Thu May 31, 2012 8:43 am Post subject: PMAG

Good thoughts Bob,

  

 I have been of the opinion (perhaps wrongly) that these  type of connections (found on Pmags) were designed for use with solid  wire.  If used on finely stranded wire in a high vibration environment,,  wouldn't the sharp pinch force eventually squish/sever some of the small  strands effectively loosening the contact?  Initially. not all the strands  can be in contact with the connector (maybe half at  best). 

  

 Bevan 



   From:  owner-aeroelectric-list-server(at)matronics.com  [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Robert  L. Nuckolls, III

Sent: Thursday, May 31, 2012 8:25 AM

To:  aeroelectric-list(at)matronics.com

Subject: RE: AeroElectric-List:  PMAG

 

At 11:39 PM 5/30/2012, you wrote:

I ordered wire ferrules from  McMasterCarr for the Pmag connections.  See

 

http://www.mcmaster.com/#lug-terminals/=hrnvdt

 

Bevan



    Hmmmm . . .    Not sure these terminals will add anything useful to the    mating of wires to the pmag. The wire grip in Emagair's    control plugs are designed to grab stranded wire. One    might improve on the grip slightly by combing the strands    out so that they don't over-lap each other in the grip    area.    Having made the electrical connection secure, legacy    termination techniques call for support of the wire+    insulation immediately adjacent to the electrical    connection. This design goal is addressed in Emagair    instructions with use of M21919 padded clamp    as shown. 



[img]cid:671353116(at)31052012-18FC[/img]



    Adding a device like this . . .



[img]http://images1.mcmaster.com/Contents/gfx/large/8009k26p1l.png?ver=10574016[/img]  



    . . . to the end of the wire decreases effectiveness    of the electrical connection. Closing the wire grips down    on 19 strands of wire offers as many as 38 points of    hi-pressure contact with the stranding layup. Crimping a    'pin' on the strands reduces this to 2 points of contact    (maybe 3 if the 'groove' in the pin is flat against a    contact surface.    Therefore, I suggest that more elegant technique is    to follow Emagair instructions as published.

   

  Bob . . .

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nuckolls.bob(at)aeroelect
Guest

Posted: Thu May 31, 2012 10:16 am Post subject: PMAG

At 11:39 AM 5/31/2012, you wrote:

  	  Quote: 	
		   Good thoughts Bob,

  

 I have been of the opinion (perhaps wrongly) that these type of connections (found on Pmags) were designed for use with solid wire.  If used on finely stranded wire in a high vibration environment,, wouldn't the sharp pinch force eventually squish/sever some of the small strands effectively loosening the contact?  Initially. not all the strands can be in contact with the connector (maybe half at best). 

  

 Bevan 	


 Had a chat with Brad Dement about an hour ago to

 confirm validity of my earlier post. Perhaps I can

 offer a clarification of the science behind this relatively

 new wire termination technology.



 Clamping solid wires under screw heads and nuts or between

 washers is a legacy technique going back a century or more.

 When stranded wire became the material of choice for ease

 of installation and vibration resistance, getting a good

 clamp under a rotating fastener became problematic. An ol'

 gray beard electrician once advised me to put a counter clockwise

 twist on strands and them wrap the wire around a stud in a

 clockwise direction so that rotational motion of the fasteners

 tended to tighten the twist as opposed to unwinding it. This

 technique recognized the fact that stranded wire was really

 a different animal for achieving enduring connections.



 Then folks like AMP, Molex, T&B came along and figured out

 ways to crimp a terminal onto a stranded wire in a way that

 essentially turned terminal and wire into a single piece

 of metal. 



 But the guys who made a living figuring out ways to connect

 wires came up with a new idea which I've illustrated below.

 The goal is to make a high pressure, tightly constrained joining

 of wire strands (green) with an electrical conductor within

 the assembly (red). Design goals included taking both the

 screw and the mechanical structure around the joint out of

 the current pathway. It would also be nice if the end of

 the screw did scrub against the strands during rotation.

 [img]cid:.0[/img]

 What you see above is a generalization of the elegant solution.

 Stranded wires are captive within the 'box' along with a large

 area conductor driven into intimate contact with the strands

 by screw pressure. The end of the screw never touches the

 strands. Further, the box around the joint and the screw

 are rather robust. Brad tells me that he has put a lot of

 torque to these seemingly small screws without stripping

 the threads or twisting the head off.



 So what appears to be a joining process that favors

 solid wire, the technique actually accommodates stranded

 wires equally well . . . if not better. The magic happens

 by combining high pressure to a constrained bundle of

 strands and keeping the numbers of joints in the power

 path to a minimum. The forces are less than for a crimped

 joint . . . the strands are minimally deformed and certainly

 not gas-tight with the red conductor . . . but it's adequate

 to the task. No value is added by converting the strands

 into a 'solid' conductor.



 Pretty slick.



 That takes care of electrical issues . . . and in the

 stationary environment is probably sufficient. In a high

 vibration environment, the installation is not complete until

 the bundle coming off the terminal strip is firmly constrained

 in a closely co-located clamp.



 

 

   Bob . . .

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tim2542(at)sbcglobal.net
Guest

Posted: Thu May 31, 2012 10:43 am Post subject: PMAG

Thanks for following up on this Bob

Tim

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