2 Coil Mechanical Latching Relay - Page 1
Forum section: electronics / projects

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: November 24, 2021, 12:54:50 pm
content: I have a 2 coil latching relay that I can't find any data for.I'd like to hook it up as it does the latching mechanically.Has anyone here used such a relay before?One coil is 110 VAC and the other 110 VDC.The relay mechanism appears to latch magnetically to either position on its own if you move the "∧" section by hand.Hillburn has apparently gone away or was bought up in the 70's.

author: mag_therm
author_rank: Frequent Contributor
timestamp: November 24, 2021, 03:27:46 pm
content: I used 4 similar back in ...1973..At that time plcs did not have non volatile (retentive) memory and I needed to storeprocess states in case of a blackout in a power generation station.

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: November 24, 2021, 06:56:41 pm
content: That would make sense.I hope it wasn't TMI.I 'm looking for the answer as to how one would use it in a circuit to emulate a flip-flop for HV.

author: Gregg
author_rank: Super Contributor
timestamp: November 24, 2021, 10:24:17 pm
content: I remember using dual coil latching relays for dual pump lead-lag control where they switched control power to larger motor contactors. They are quite robust and fairly easy to trouble shoot in the field. The ones I used had nylon latching mechanisms. I still have a few around somewhere.It looks like the Hilburn set you have can change the individual relay modules to different configurations as they seem to be individually mounted to the base. It could a problem if the fasteners to the base become loose. As to the reason why one is AC rated and the other DC rated is anyone’s guess.

author: CaptDon
author_rank: Super Contributor
timestamp: November 25, 2021, 03:22:35 am
content: A normal self holding relay circuit found in many industrial machines will drop out during a power failure. That seems like a good thing in case your head is in the machine when the power comes back on. I am referring to the normal 'green start button' and 'red stop button' circuit. Your relays on the other hand will 'remember' their most recent position even in a power failure. So if the machine was in the run mode, it will still be in the run mode when power is restored. If it was off, it will remain off. With a bit of wiring of the contacts and coils you can make these relays perform a divide-by-two operation also, the first push of the button can perform a 'set' function, the second push of the same button can perform a 'reset' function.

author: BrianHG
author_rank: Super Contributor
timestamp: November 25, 2021, 03:30:06 am
content: Quote from: Quarlo Klobrigney on November 24, 2021, 12:54:50 pmI'm not sure if you are dead set on using that particular relay because of stock, but many mechanical latching relays exists today with 2 coils and 1 coil DC iterations at multiple voltages which should be far more sturdier in function than that old one you have where the mounting distance between the 2 relays needs to be kept extremely well to prevent malfunction.If you do not need to switch more than 1amp, telecom latching relays are the cheapest and available in the highest quantity where the device is also hermetically sealed with gold switch contacts offering incredible life time and quantity of toggles.

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: November 25, 2021, 04:28:43 am
content: I would like to use it as it is rugged, cheap, will switch AC line voltage, DC +250 VDC and present a 2x NO, whilst the other is NC contacts and vice-versa. 2x DPDT.The 220VAC can be dropped by a resistor, capacitor or transformer tap for the 110V AC or DC coils.I can, if I spend enough time figure out how to use the other spare contacts to do the logic.I was asking for the industrial folks if they have used this type of relay before and understand how to apply it without the "deep thinking" I would have to do.Keep the comments coming please.

author: BrianHG
author_rank: Super Contributor
timestamp: November 25, 2021, 05:36:26 am
content: You cannot beat the utility of what you have on hand. But you need to ask yourself:What will you build?How many of these relays do I have?What do I do when the relay dies if I have a limited number of them?Using a telecom DPDT relay, with a 240v 2 amp AC rated switch, you just wire the DPDT output to drive 2 off the shelf normal 240v coil relays with 15-30amp rated contacts and run your heavy duty devices off of those industry stock standard relays. If anything breaks, you may get replacements anywhere, even Aliexpress.The telecom relays offer 5v coils for MCU control and go all the way up to 48v coils which you can drive from rectified 240v mains with a resistor dropper. They come with 2 coils for set and reset, or, 1 coil where you drive 1 polarity to set, and reverse the DC polarity for reset.It's up to you, but, what you showed us in your photo does not appear to be future proof.

author: jonpaul
author_rank: Super Contributor
timestamp: November 25, 2021, 06:27:48 am
content: Bonjour, I used one in 1950s as a demo of a one bit "memory" in a science faire.I still have several similar, Magnecraft, Potter-Brumfield and other old line USA relay and transformer from .1960s.Much smaller versions in hermetic cans were common for military and defense use in 1950s..1970s.I doubt if the coils are AC/DC, normally both coils are same rating.For any power switching check if the load is inductive eg motor or transformer as the relay may not have sufficient contact rating.For loads over a few 100 VA, I would augment the relay with a contactor.Bon chanceJon

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: November 26, 2021, 12:32:14 pm
content: Interesting seeing the past applications of this kind of relay.The load will be a transformer at >2A and B+ of 250V to ground via a bleeder resistor.When the transformer is on the bleeder is off, and then the reverse.The bleeder will shunt the audio B+ supply to mute the audio.Why this relay, you have to guess the application.I'm open for guesses.... let's see who canI did find an ad for Hillburn in Electronics magazine dated 1960-05-13.

author: NiHaoMike
author_rank: Super Contributor
timestamp: November 26, 2021, 01:35:00 pm
content: I suspect the original application had some unusual requirement where one mode was set by a circuit switching 120V AC and the other set by a vacuum tube or thyristor circuit.

author: CaptDon
author_rank: Super Contributor
timestamp: November 26, 2021, 02:50:18 pm
content: Why guess the original application?Do you know what it came from? Unless someone owns the exact piece of equipment this came from we would never know the correct answer. May as well guess the liquid liters in the oceans.

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: November 26, 2021, 04:37:25 pm
content: I think some are confused by the question.It's not what itwasused for, but what I'm trying to with it now.Toggle between NO and NC with the opposite state on the other relay.I must stay latched whilst the power is on or off.It will be triggered by a reed switch & magnet to a driver relay as a pulsed .5s relay.The magnet is on a metal rod, which travels in a stroke on, stroke off motion.The rod always returns to the neutral position.Example On= forward and then back, with the same for the Off motion.So it's toggling between 2 states but the same rod strokes.Anyone have a guess what this is going in to? c 1957

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: November 28, 2021, 09:55:08 pm
content: I returned the original relay but found the same thing.What I found was another with both internal coils at 24VAC in an "Ice Cube" package.Evidently the original relay and all the others like it may have been removed from this kind of package.The new one is an 8 pin octal socket which makes mounting easier.It was getting late and I didn't notice it's only a SPDT.A DPDT version to do both the AC line and B+ switching would have been better, but B+ switching can be shifted to the small relay.The small SPDT (12VDC) relay will be for switching the series bleeder to ground from the 250V B+.One set of 2 NPN's will alternately toggle the 2 large relay tails to common ground.It turns out that they are DC coils after all, with a diode in series to each coil from the 24VAC input.I can add a small electrolytic to each coil to slow things down.I made sure the big relay worked this way before leaving the surplus store.Depending on which relay coil tail is momentarily brought to common, the relay latches into that position.There's no need to keep the coil energized as it is now latched.A simple 7414 (or 4093) Schmitt trigger to debounce the reed switch to a 4013 (or 7474) FF to an NPN to toggle and hold the small DC relay with a capacitor, and to the other 2 NPN's to give a kick, 250ms, the big relay coils.Sounds simple.Wait a minute, do I need another relay?There is no simple substitute to this mechanical issue given the constraints of where the switch is mounted and the mechanism rod returning to home after a press.Has nobody tried to guess what this is all for yet?