Even in my late 70s and after nearly 50 years as a professional engineer I still find these alien-looking devices quite fascinating.

And this children is why Museums are still an absolute NECESSITY in the digital age.

I love that the cooling fans are actually solid wood propellers

i think photonicinduction just broke the algorithm with his mercury arc rectifier

A work colleague told me he was at a power station which used these devices. I guess possibly to provide excitation for an alternator. One day he had to take a party of school children around the station, all of whom he thought were pretty disinterested. He showed them the steam driven alternator and said this is where we make the electricity and then pointed to the rectifier and said this is where we bottle it. The next day he was taken to task by the station manager...clearly their teacher wasn't happy.

When I was a Post Office apprentice back in the early 1970s these rectifiers were still in use in some telephone exchanges for producing 50 Volts DC to power the exchange, charge the batteries etc. On a dark winter day they produced an eerie, flickering glow on the walls and ceiling near the cage that housed them. This video brought back memories.

Who else got recommended this after seeing Photonicinduction's mercury arc rectifier video?

This video humbles me in how much I still don't know. We stand truly on the shoulders of giants.

When I was a boy there was a man in Bamber Bridge (nr. Preston, Lancs) who manufactured car batteries in a big shed by the railway line. To charge his batteries he had one of these rectifying the mains, and then simply put about 15-20 batteries in series on the output. I remember being fascinated by that shimmering dot of blinding light.

It's great to see such an impressive bit of kit restored by the museum. A very well produced and informative video. Well done.

As a 16 year old industrial plant fitter ( 43 year ago ) , one of my first tasks was to go into the ''rectifier room '' and sweep the black dust of the floor , i was handed a dustpan and brush to do it , a few hours later finished said task but felt strange , kinda burning skin and tight chest . i now know all about U.V. and ozone , safety was truly a joke back yonder . Thanks for posting .

I love how modern solutions are so simple… like solid state vs tubes, fuel injection vs carburation, turbine engines vs reciprocating engines, internal combustion vs external combustion, etc etc.. but engineers had to figure the difficult way that was technologically feasible first before things like materials and processes and tolerances allowed simpler things to be developed.

These were really common on power stations, generating DC for the instrumentation battery backed up DC supply buses. The were a reliable and efficient way of generating large amounts of DC before silicon rectifiers appeared. I worked at Dungeness Magnox power station in the early 2000s. (On a completely separate project but engineers talk). I believe there were a suite of large mercury arc rectifiers supplying power to the instrumentation buses. Apareltly they occasionally blew out, which made for an interesting time I'm sure, (Let them cool down,replace fuses, then restart them and they were good for another few years). The station was scheduled for shut down in 2006 and Magnox were somewhat reluctant to spend millions replacing them with a new silicone rectifier system with so little time left. Obviously there were multiple redundant parallel systems but there were no spares available. Then some identical spare units turned up from the London underground which had never actually been turned on. I'm not sure if they needed to be fitted before the station was decommissioned, that part would have been turned off sometime after the fuel was removed, so probably 2012 ish. The trials and tribulations of keeping 50 year old equipment running :¬)

Electrickery at it's most mesmeric beauty.

Far more impressive than today's rectifiers. I guess this is where ideas for the early sci-fi film sets came from.

And now I feel cheated my car's alternator only has boring diodes. I'd love one of these under the bonnet. Much more exciting.

I've seen one in person, the video can never do them justice for how amazing they look when they load up. it ran a historical tram bus in New Zealand

This equipment was mentioned in a novel I’m reading. I’d never heard of it before, so it was quite cool to see a video of the actual equipment in use. Thanks for posting.

I actually just saw Photonicinduction's new vid the other day powering up a mercy arc rectifier. I had never seen one in action before, though I'd seen several on display before throughout my adult life. Truly fascinating to behold. Works of art, now. These are treasure now. For a time nixie tubes were also in this vintage category until that Czech fellow began producing them again. To be honest, I do think we should interest future generations whatever way we can for fields like these.

Somehow a “!!! FULL BRIDGE RECTIFIER !!!” seems rather puny...

One of my local museums has a set of these supplying power to a heritage street tram system. As the trams accelerate and decelerate, the arc changes. Very cool to see working!

Great to see this old equipment live and working, there's something artistic and magical about the way things were done in the old days.

I was a student apprentice with Hackbridge and Hewittic in 1966 when they still making the MAR.

Such a shame that the mystery, romance and the glow has gone out of electrical devices these days. I am all for efficiency and safety but you gotta love the blue glow

I am always fascinated by the "touch and die" switchboards. Nice restoration.

I saw some in operation when I was a kid on the train line that transported coal from Yallourne Open Cut to the Briquette Factory I Morwell (Victoria, Australia). They were dotted along the track in the power houses to run the DC overhead line for the trains and as the train approached they got brighter then went back to a dull base glow like these as the train got further up the line. We were being shown by a friend of Dads who worked on them - he called them ‘The Purple Octopus’. I worked there when I left School and they had only just replaced them when I started as an Electrician. The units were still in situ but not connected - that was in 1987 so the were in service for quite some time. 👍

I continue to be TOTALLY and COMPLETELY amazed by how people could design electrical items like this during the infancy of electrical power.

HOW CAN YOU ONLY HAVE 2 VIDEOS. THIS IS AMAZING. PLEASE MAKE MORE.

I was an apprentice electrician in a steel works in the mid 70s. The older end of the works employed these MARs. I could never walk past them without being intrigued by their operation and captivated by their beauty. Thank you for posting this video.

I remember seeing one of these things (well, a smaller one) running an elevator somewhere on the Northern line of the London Underground sometime in the late '80s. Apparently the plan was to swap it out when it failed - but it had just carried on working...

Thank you for explaining the basics of mercury rectifiers. I've seen and heard of them before as obscure relics from the past and never really understood the principles of operation. Now I still do not understand it to my satisfaction but I understand a great deal more than I did before watching this video.

As a child I remember going to central London from Kent. There are some big metal doors just outside Embankment tube station. I was fascinated by the glow through the crack from the mercury arc rectified that powered the tube line traction current. I wonder how much UV there is in that glow...

Commenting to feed the youtube algorithm. Excellent informative video, great explanation David Walker.

Great videos operated and did some maintenance on these in the late seventies as a young technician much larger units than shown on this video. DC was still being supplied at 500volts + to - to supply old lifts and escalators in Sydney Australia . The sub converted 11kv three phase to 6 phase low voltage then into the MAR,s then onto a big DC switchboard that looks like something out of Frankensteins Lab. I felt privileged back then to work on such strange and interesting technology , it was shut down completely in the early eighties and customers had to install local rectification in their switchrooms to run their old DC equipment.

the mercury vapor bulbs are about the coolest version of real science being as wild as science fiction. but personally i find all those well maintained, now-antiquated switches and meters to be the most beautiful part of this display.

I worked part time as a projectionist in the 60s and our Gaumont Kalee projectors used these to produce DC for the Arc projection light source. Biggest problem was keeping the arc centre frame!

I used to use these as late as 1998! I was a projectionist at a cinema in Cornwall and these rectifiers were used for our carbon arcs which were the light source for the projectors.

One of my best memories was doing an installation for London Underground around '97 when a chap said "you wanna see this", opened an old decrepit wooden box and one of these was still operational, reminded me of an old Frankenstein film, I was impressed.

And a big thank you to whoever saved this equipment from the scrap heap.

Love the wooden propellers for cooling!

Really good - and really impressive! It’s good to see such a technology conserved and also still working

I remember seeing one of those mercury arc bulbs and had always wondered, what that little electrode bouncing around was doing. Thanks to bring back this technology view.

Nice to see gems of videos unburied I never seen before all due to photonicinduction. Nice job on this one. Cheers.

Excellent presentation. I visited Kempton in November 2017, but the engine wasn't running and we didn't see these rectifiers. But there was a very kind gentleman who gave us a lovely tour of the triple expansion engines and the turbines in the basement. He also told us an interesting story about how a stuck water valve caked up with scale was unstuck. I have to visit again sometime, when the engine will be powered. Thank you for sharing! Matthew

Ahhh. . . There's gotta be a few Photonicinduction fans in the chat eh? Greeting conrades. :)

I watched this, and still have no idea how these things work. but they have to be the single most steampunk devices I have ever seen.

Electrical equipment from the past look all kinds of magical.

I'd love to see some high speed video of the arc jumping from anode to anode. Maybe reach out to the slow mo guys

In America I saw units that were similar in function used in various aluminum smelting plants. The voltages delivered to the pot lines were considerably lower, but the amps were out of sight. Huge magnetic fields made you work differently.

After working in a USA power plant for almost 30 years, I find this fascinating. His explanation was absolute

Very interesting. I once visited the power station supplying the trolleybus system in Tampere, Finland. One could clearly see the difference, when a trolleybus accelerated.

All these people in the comments here are what we need more of! Love to see it. This world is truely fascinating.

More please. David Walker your narration is fantastic. Thanks for making my day😘

looks more like something you would find in a space ship

I saw rectifiers of this type during a school trip to the GPO's Doddinghurst Long Distance Radio Station, near Brentwood, Essex. For a 14 year old, they were fascinating devices to watch as the glowing cyan light danced about in the bottle! The Radio Station is long gone.. part of the site being under a housing estate... ... and I am now 76!

Soo cool people figured these things out back in the day! Looks like it's WAY ahead of it's time! Nowadays, people are more concerned with which color to dye their hair, or which soy latte is the best.

absolutely fascinating. i love seeing how this old technology works

Well that brings back memories of working as an "assistant projectionist" at the Savoy Cinema. The first job when you got to work was to "flash up" the mercury arc rectifier to provide DC power to the carbon arc projectors and slide projector. The rectifier was in a separate room underneath the circle seats, which meant you had to walk through a dark cinema, just with the aid of a torch, to the room and power up the rectifier. The UV glow lit up the whole of the dark cinema, very eerie, bit like the "Quatermass Experiment" film. If it didn't "flash up" when it was powered up the trick was to slam the door to the cabinet and that usually worked, guess it was to get the starter electrode to operate. The cinema is long gone now, I wonder what happened to the rectifier and all that mercury.

I am not much younger than Mr Walker, but i would pay money to apprentice under him. people like David hold the knowledge of the past. Thank you so much for posting this.

Thank you for post that! Almost 20 years ago I discovered an abandoned rectifier station for electric trains in an abandoned site. The station looked perfect with all stuff, including the big transformers and all instruments in the control room, except for the mercury arc rectifier tubes. I think the output voltage was 3,000 V... For some years now all was gone and the station doesn´t exist anymore, except in my memories and in a few pictures I made then.

What a wonderful working museum. Once Covid is consigned to the dustbin of history, I'm going to pay them a visit.

I was waiting for Marty Feldman to make an Appearance when the rectifiers went to 40 Amps.

Fascinating time period. For all these amazing devices, there must be a million near-misses and close calls. I bet the blooper reel from that time period would be terrifying to watch.

First saw M.A.R.s in a PhotonicInduction video! These are *SO COOL*

Fantastic!

photonicinduction just has one of these in some cupboard somewhere in his house

Incredible and scary engineering,.kudos to the ballsy engineers that invented and tested this concept

This was very interesting. Electricity back in the day was visually entertaining.

This is getting recommended after watching Photonicinduction.

You watch one photonicinduction video in 2021 and now yt thinks I want to see mercury arc rectifiers.. well I do, just not on the screen !

I am always amazed at how far we have come with electricity and electronics from those days.

I love these things so much. The blue spectral glow of mercury is so eery.

Very cool devices. Pity mercury is so stupidly toxic; I'd love to have one in my workshop. Every mad scientist needs one of these babies in his lab.

1:50 Actually, 50 Hz current reverses direction 100 times per second. Each reversal is 1/2 cycle.

Thank you for this - very much appreciated! Really good to see these even from a distance and hopefully we can visit and see this museum in person in the coming years!

Shiey recently went into an old WWII bunker that had one of these in it. And it still powered right up. Mad stuff, especially now that I understand how it works.

Great video! No wonder some people thought of electricity as witchcraft.

Some crazy person will hook one of these up in their living room some day...

This is unbelievable to see in action. I know it's not an efficient system compared to modern converters, but I am beyond glad to see the museum rescued and preserved such a wonderful piece of engineering history

Thank you most of all for preserving this, And second for sharing I for one appreciate it.

PhotonicInduction sent me here.

It's great when you can tell something is working just by looking at it. This is like something out of a Hammer Horror film. Solid state just doesn't have any soul to it.

Absolutely fantastic. What a marvelous museum. Thank you so much for your efforts and for sharing.

Wow, never heard of it before! Very well presented, thank you!

Who's here after PhotonicInduction's video?

What voltage drop did the rectifiers have under load?

Thanks for showing this amazing DC system with its mercury arc rectifiers. This is truly art and a treasure to have.

Always been fascinated by these mercury rectifiers. Superb presentation, learned a little too!⭐⭐⭐⭐⭐

rectifiers are nice but those switches are lush too

KZfaq: Sooooo you watched Photonicinduction's video about mercury arc rectifiers. Well anyways, here's another one.

Thank you for restoring these beauties, that blue glow is so heartwarming!

Heard of it, never seen it. Beautiful, thanks for restoring and sharing.

This looks so much retro sci-fi, I still think this is some kind of old science fiction show set X D

Photonic induction brought me here

Wow, thanks for the hard work in making and sharing this! Fascinating to learn to this!!

Probably the coolest thing I've seen in a while!

Nice! Photonicinduction (search here on KZfaq) has one in his living room, powered up. Go have a look. =)

Is the 6 phase from 415V 3 phase but with two of each phase opposite each other?

Came across a couple of these in the powerhouse of a decomissioned railyard, they were still operational and beautiful to look at. Glad to know more about what they do and how they work.

great video, thank you for sharing and demonstrating the increase in load especially