Products > Test Equipment
Wires connected without banana to binding posts (Rigol DP832 power supply)
coppercone2:
I thought for the really high end, like keysight, they should put a light button for the binding terminals to make it easy to thread the wire. They make 500 stupid features like glowing buttons, they could add a connector illuminator
I am sure you know spade lugs come in every size? metric and imperial. From 4-40 to 1/2 inch for all wire gauges. Pick the right ones.
Measure it with a CALIPER to figure out what TYPE of lug you need.
Alligators are also available in a large variety of sizes. I have tons of jumpers made with different sizes
The more modern banana connectors are a bit slimmer and have more contacts. The old one have 4. So alot of modern banana connector are a bit tighter. I prefer them to use with the modern more developed connectors.
Enlarging them should be OK but I would see if you can use a reamer. Then it needs to be well cleaned and greased because the coating is gone, but its easier then replacing the connectors, if you must have them compatible with the old style banana connectors (I recommend you measure your old cable resistance to make sure your not modifying stuff to have it work with defunct test cables with old style contacts that have high R )
Take a good close look at a modern high end banana cable and a old one and you will see why they changed it.
Good binding posts have metal on the bottom of the plastic head. Shit ones have just plastic. The ones that are beefy and have a metal plate are more then 'gently clamping' your connector or wires. I have used the larger ones for 50A no problem no heat with a ring lug or spade.
I made plenty of spade jumpers for dual supplies by clamping and soldering heavy gauge magnet wire to 1/4 inch or so spade connectors. Their pretty good, of course cutting a custom metal bit and plating that would be slightly better.
I consider that binding post hole to be absolutely essential to actually getting lab work done on time without always having to play technician making cables and adapters. Just strip the wire, thread it WITH A LIGHT and you can do a test like that. You can put a ferrule on it too. >:(
I am totally convinced the reason they put safety jacks on things is to make packaging cheaper. They are counter productive to everything besides high voltage portable meters, and I would still like a hand held DMM with binding posts on it (that are firmly attached not an adapter) for safe work instead of having it designed by a nanny. I should rework my 34401a's to have binding posts on them. Alright, MAYBE its a bit of a stretch to have it on a DMM because its possible to short it out connected to a big load. But they don't belong in power supplies unless their really freaking dangerous.
RoGeorge:
Took a close-up picture, with a mirror underneath so to see under the knob, too. It is worst than I thought.
Note how the metal shape and hole finish is different between the + and - metal rods, as if they were manufactured on different machines. It is not just the plastic color that differs, but the shape/size of the metal, too. This explains why the same banana plugs normally into - but get stuck as if it were glued when plugged into a +.
Then, note how the metal ring on the knob has a large space between the nut and the center rod. Strands of wire will fit there and get cut by the screw.
Then look at the metal ring on the rod, at the panel side. The metal ring is "sunk" into plastic, which means a fork lug will sit on the plastic, and will be squeezed against plastic, without touching the metal base from the panel side.
Then look at the edge of the hole in the metal rod. The one on the - was deburred after drilling, while the one of the + was not. This explains the tendency of shearing a wire passed through the hole.
Not to say the the nut is slightly sunk into the plastic knob, too, just like the ring on the other side. This is not very visible in the attached picture, but the plastic knob touches the other side first, before the nut. So all the first contact and pressing force against a wire (or against a spade/fork lug), will come from the soft plastic and not from the metal nut.
I'll have to either go creative when using wires, or replace the binding posts. >:(
watchmaker:
That is one example of crappy machining. It is obvious the holes are drilled before turning to diameter given the material extending into the hole on the positive post. Not even followed up with a chamfering tool. Finish speaks for itself. My guess is threaded, drilled, wire post turned to OD, shoulder, threaded for panel nut and then cutoff. The clearnace between the nut and the wire post (along with the turning marks) looks like the CNC registration for the wirepost changed; swarf caught between bit and work?
Anyway, yeah, solution is to change them all. That shoulder should be proud of the insulator, or you cannot get good contact when using a spade (I use hook) crimp connection or even just wrap the wire around the post.
I like the true 5 way bananas but I also standardized on sheathed banana connectors. SO on PSUs I use a plug to sheathed plug adapter. FOr serious work this would add another connection point to worry about, but I am not in the league.
Wallace Gasiewicz:
I know I am reiterating some of coppercone;s remarks........The hole in the binding post should be even with the base of the post, to avoid cutting the wire that would be inserted.
RoGeorge observation is correct, the base plate (or whatever you call it) should be slightly above the plastic for use with fork connectors.
These are not good connectors.
There is a lot of conversation about good connectors elsewhere on this forum and there are plenty of poor ones. For measuring purposes with good accuracy, metal to metal should be the same without any solder. So the alloy used in the connectors is also an issue. I am not an expert on these connectors but again there are lots of conversations here and some of the "good" binding posts are expensive. As soon as you get into the Banana connector part there are issues with the metal alloys in the banana spring and their effect on measurement, Also issues about how the test lead wire is connected to the banana, solder, pressure, welded, etc. Then there are comments about plating of connectors, gold etc...
For Power Supplies this is not as important and I use spade connectors whenever I can because I think they are more secure. It indeed is a challenge to find the right size horseshoe or spade connector. They probably can also handle more power but this is usually not a consideration for me. Also for PS connections soldering is a good idea for a strong connection. It is impractical to use stranded PS wire without at least tinning the ends.
You theoretically would not use solder connections when measuring microvolts. You would just use clean copper wire to the hole in the 5 way binding post. The hole in the binding post is oriented vertically in my HP gear. I think this is what it should be. It is still hard to get the wire into the hole though.
I have had good luck with old unused binding posts I have picked up at flea markets. I really do not know how they would perform in microvolt measuring but they are built well with good holes and threads and good solder connectors. Even the old plastic appears to be still strong.
PA0PBZ:
Not sure if it makes you happy or sad but I just checked my DP832 and they are as crappy as yours. I never use them apart from plugging in banana plugs.
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version