Power Supply Connectors

[jackinnj]

I have been using 0.200 inch (5.08mm) power connections in which connection to the power cables is secured via screw-down clamping action -- these should be good for 10 or more amps.

i wonder, however, whether to make the switch to the male spade connectors on PCB mount -- might these be preferable and easier to use? i would guess that there is quite a bit of stress on the PCB when the mate is pushed on...thoughts, ideas appreciated. if you have no thoughts or ideas send scotch whiskey.

[lndm]

For what it's worth, it never ceases to amaze me how much stress and distortion a PC motherboard will accept when plugging things into it. Such fine tracks, mulitlayers and all, and they just seem to take it.

[poobah]

Actually, the spades can be a real pain to align while soldering. And, you will put considerable stress on the board the FIRST time you mate it... after that they loosen up... best used for a one-shot assembly, non servicable type of thing.

The rising cage clamps are nice because they only put twist on board... no real bending force to speak of.

[davidlzimmer]

Not EXACTlLY sure of what you are asking but, as an electronics installer for many years, I can tell you that a spade lug only offers another chance for an error or resistance. If the connections are permanent, screwed down copper is best. I think the advantage of a spade lug is that it allows mass connections to be made without any stray conductors. I DIYer as you are will certainly take the time to make each connection perfectly.

It's the poor guy out there whos boss is constanly pushing him to get it done faster that needs the spade lug.

JMHO

[poobah]

I've had trouble finding the kind of spades that you can use twice... at least least the female half. You know... the kind made with real spring grade copper... beryllium copper... phosphor bronze.

Spades are great for rapid assy... and they stay there well enough... but they are pretty weanie the second time round.

[davidlzimmer]

Yeah, that's what I ment to say! ''

[wine&dine]

I'm quite fond of Mate-N-Lok II connectors for that purpose. Standard contacts are rated 19A, 31A also available. I use e.g. 2x3 connector cases and parallel 2 each for +/0/-. Can't be put in backwards.

[alitaido]

I use MOLEX brand spades connectors at work and, in my experience, this brand continues to make a reliable connection time and time again without getting loose. On the other hand, for PCBs I wouldn't use them because of the stress factor. It's not the traces you have to worry about, its the solder joints that can start to go bad.

[Shredly]

My tendency is to agree with others about spring connectors working great the first time and not so good after that- but I assume as others have you're talking about the kind that hold together with spring action, which technically aren't spade connectors at all.

Real spade connectors are the kind with two prongs that you mount captive under a screw, with a star washer to bite into the metal if you're anal-retentive. That kind handle many, many amperes at most voltages you'll ever use, and don't put any stress on the board at all- all the stress is on the screw, its mounting, and the connector, and if the mounting is well-designed, it's not a problem. If you're talking about that kind, they are the best from both an assembly and a repair point of view, and there's very little to argue about in terms of their current handling capability either; and if you're worried, use bigger ones. However, IMHO, ring lugs go one better for current-handling, although they're harder to deal with (you can just slip the spade on without removing the screw, whereas you have to take the screw out to get a ring lug off).

The real problem with any connector is securing it to the cable. Cheap crimpers are the bane of the homebrewer, and the good ones are hard to find. A good crimp isn't just mechanically sound, it crushes the connector and the wire in such a way that oxygen is excluded from the inside of the crimp. The seam down the center of the top should be folded into the wire. Cheap crimpers can't do that.

[alitaido]

Sargent Tools makes a great and affordable crimper (ratchet action with mech advantage design) and I believe you can get it from McMaster-Carr. The best part is that you can buy different die sets for a wide range of crimp sizes.