balanced time relay? - Page 1
Forum section: electronics / projects

author: coppercone2
author_rank: Super Contributor
timestamp: September 15, 2024, 01:58:33 am
content: You can actuate more then one thing with a single magnetic field.A relay arm can have as many circuits on it as you want.It seems that its a question of mechanical design to control the phase shift between the two signals.I understand that timing the "when" of the whole arm is difficult, but how about different contacts on the same arm?is it that devilishly hard to get two contacts to make at the same time? How good can they get?I had a design fail on me because of a race condition on a multi switch, about 30 % of the time it was wrong enough to make the machine lock up the power supply because of timing errors. I figured with the switch it would be damn close. I always wondered if I used a dual relay, would it have fixed the problem.

author: PCB.Wiz
author_rank: Super Contributor
timestamp: September 15, 2024, 03:34:23 am
content: Quote from: coppercone2 on September 15, 2024, 01:58:33 amIt's not just first contact time, but also bounce time.The latter will vary, even if you strive to make first contact as close in time as you can.If your design really does need similar contact times, (seems a very rare need, most want a dead time) you would be better off using SSR.For modest loads you can buy pairs of SSR in single packages, and you could use adjusted LED drive to tune their turn-on times, if you really, really needed matching sub 1msQuote from: coppercone2 on September 15, 2024, 01:58:33 amThere are break before make and make before break variants of switches, to help designs where this matters.

author: coppercone2
author_rank: Super Contributor
timestamp: September 15, 2024, 04:10:10 am
content: nah that project is long gone and not my problem but its what made me think about it.I am not trying to solve any problem I just wanna know if there is like some 10th generation "matched" relays research going on. (apparantly by the 80's we were on gen-4 relays)The thought was, if you built a relay with a expensive/heavy design, how good could it get?I imagined shooting a heavy lead "T" shape down a channel at some forks

author: Kim Christensen
author_rank: Super Contributor
timestamp: September 15, 2024, 04:55:45 am
content: Mercury wetted relays have virtually no bounce, but you won't see many of those anymore.

author: PCB.Wiz
author_rank: Super Contributor
timestamp: September 15, 2024, 05:10:12 am
content: I found a good statistical spread plot for relay activate and bounce times.That shows the operate time variations of ~ 200us are swamped by bounce time variations of ~ 1ms

author: coppercone2
author_rank: Super Contributor
timestamp: September 15, 2024, 05:35:23 am
content: I wonder if you can get those numbers waaaaaaaaaaaaaaayyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy dowwwwwwwwnnnnnnnnnnlike so the scale is us or ns.How about just dropping a heavy bar of lead or very anneled copper into a set of hardened forks in a pool of liquid metal, with gauge block level surfaces and alignmentI have been looking to do something meaningful with my gallistan. If you clean it and have it under inert gas it should work like mercury.But I think with mercury, you get god damn surface tension problems, meaning your "level" is gonna be random based on fludics. if its dry you can align everything nearly perfectly if you spend enough timeI was reading about the history of relay developments and I feel like we have not even scratched the surface of what is possible.....There must be some quantum limit that you would reach for timing a matched pair with sufficient precision based on tunneling and distance.... at least at firstthat is eventually when your mechanics are precise enough, your main source of error would be the quantum tunneling that occurs when they are REALLY close together, I think that is inherently random. So that is like a 'fuzzy region' that we don't know how to compensate for yet. anyone wanna do a number crunch real quick?

author: inse
author_rank: Super Contributor
timestamp: September 15, 2024, 06:16:25 am
content: N/R

author: coppercone2
author_rank: Super Contributor
timestamp: September 15, 2024, 06:32:22 am
content: is that a quantum formula?

author: gcewing
author_rank: Regular Contributor
timestamp: September 15, 2024, 01:18:50 pm
content: If your circuit depends critically on contacts closing at exactly the same time, it's badly designed. The solution is to redesign the circuit, not try to build a super-accurate relay.

author: Haenk
author_rank: Super Contributor
timestamp: September 15, 2024, 02:36:59 pm
content: Quote from: coppercone2 on September 15, 2024, 05:35:23 amYeah, sounds like a mercury switchI'd say you will not find a mechanically actuated contact without some bouncing. And the higher the rated voltage/current, the heavier the contacts, the more bounce you will have