high curent PCB connector

Nice device, as I understand it what it does is if your cables are too good it randomly makes some of them faulty, and then the user has to figure out which one of them it is. Makes life more interesting!

In the past I have used PCB-mounting screw terminal blocks with wire-protection leaves. I had a whole batch of surplus stock, some were in groups of 4, others in groups of 6 or more. The trick is to put a row of blocks on the edge of the PCB but screw into them the solder pins of another set of blocks. The wires are termnated in the second set of blocks which can then be released from the ones on the board as a single unit. (Lacing the wires to form a solid cable will help keep the blocks together in the right order.)

It doesn't prevent the whole thing from being assembled one step out of line, but that could be prevented by having some solid obstruction at each end of the row. As the machine I built had several different boards, I made sure the pairs of connectors were drilled with a pattern of shallow indentations which were filled with coloured paint to indicate which ones should be mated together.

The idea is to simulate what a cable fault between two boxes would do on an aircraft. This is also called a guillotine box.

Our customer used to make what they call a FITS box to do this, but it wasn't very reliable and has got hard to make. So we did a version. It has polyfuses to help protect the relays. We added voltage and current measurement and BIST, built-in self test.

It can be used to snoop voltages and currents in a cable too.

The board is HEAVY.

Phoenix do make 20 pin version (as two rows of ten) with 10 amp per pin on

Do they actually make them m, as in somebody has them for sale, or are they just listed in a catalogue?

Connector catalogs are full of things that they would love to make for you if you want to order 100,000 pieces and can wait six months.

Cheers

Phil Hobbs

I was fond of the DIN 41612 mixed signal connectors. The basic connector has three rows of pins for a total of 96, but the mixed signal variant had circular holes that knocked out 9 pins and let you put in coax plugs and sockets or 20A heavy duty high current plugs and sockets.

I've got the Phoenix people working on it.

We need a mate that has screws to clamp the wires (not those push spring things) and extraction cams. Even the 5 pin version is about impossible to unmate without the cams.

What's weird about the Phoenix and Weidmuller connectors is that they have no pin numbering convention or markings. You just make up whatever you want, and have to explain it to the customers.

But JL's customers are aerospace so will be used to exotic, hard to find connectors - would they respect him for using an easily buyable connector :)

piglet

The nice thing about the Phoenix connectors is that you don't need a soldring iron or pins and crimp tools to terminate wires, just a small screwdriver.

My customers like the Phoenix's. We sell ground test gear, not stuff that flies, so we don't have to use those crazy MIL type circular connectors.

Somebody does want to fly some P940s, but only in a flying test bed, so commercial parts are still OK. Some of the boards are heavy and flexy, so we are adding some vibration damping in the chassis.

(A flying test bed is an old 747 that they swap one engine out, or strap one more on the side, to test a new engine at altitude. They fill it with test gear and engineers and witnesses.)

That's not nice. It's just cheap. At Cambridge Instruments the argument for going over to crimp connectors was that you found a lot less duff connections when you were putting product through final test.

The parts and tools were more expensive, but fault-finding and fault correction were expensive enough to tip the balance.

Was the cost of repair throughout the equipment's lifetime taken into account? Faulty crimps, especially if the wires are a bit short, can take ages to put right.

Probably not. The crystal ball that tells you how often a crimp will fail over the lifetime of a particular bit of equipment hadn't been been invented back then and I haven't been offered one recently.

The parts I had in mind were coax connectors, and you can check them very quickly with a time domain reflectorometer (and we had a couple of them).

Crimps can also be dud, and they can be difficult to find.

Decades ago, we had a Data Products line printer which occasionally went beserk with paper feed, throwing half a box of chain forms at speed through the printer. The paper feed was a DC servo built by the book, with acceleration and deceleration controls done with suitable integrators. After a long hunt, it was seen that the occasional insanity came from a missing tachogenerator signal. The culprit was one of the tacho signal wires crimped partially on top of the insulation.

I rode a LASH ship from San Francisco to San Pedro, a lovely cruise, to try to find out why it would go berzerk now and then. Turns out it was an intermittent connection from the speed feedback tach.

I had designed the control system some years before, and I limited the influence range of the RPM feedback, so the runaways weren't the full

Nowadays we do most control systems in uP or FPGA code, so we can have lots of protections.

I had one of those problems in the 1970s when I lived in Baltimore, but it was the pickup wires from the electromagnetic phono cartridge on a Dual turntable that caused trouble. Took me a year to figure out.

The phono pickup wires were very small and flexible, and they were attached to the cartridge by a pair of spring clips crimped to the wires. What they meant by crimped was that they stripped the soft PVC insulation off for 1/8", folded the wire strands back over the insulation, and crimped to that. Almost worked.

But after a few years in the industrial atmosphere of Baltimore (we still had a real steel mill!), a little bit of corrosion formed, and the wire to ferrule contact became unreliable, and one channel or the other would go silent, probably due to mechanical motion as one played a record.

How does one fix this? Replacement parts will all have the same problem, and it's too small and delicate to do much, and soldering would yield fatigue breaks.

Welding is the answer! Took the cartridge off so all that's left on the turntable is wire and mechanism, and no fragile electronics. Connected each wire from clip to phono connector in series with a

Joe Gwinn

Fun!

Cheers

Phil Hobbs

I've used Positronic connectors with success.

phoenix (and a bunch of other manufacturers) do connectors with tighter pitch (eg 3.81mm or 3.5mm) and multiple rows of contacts. apparently good for 8A per pin.