The "All American Five", & more dangers!! - Page 1
Forum section: electronics / general

author: GlennSprigg
author_rank: Super Contributor
timestamp: April 27, 2020, 01:16:40 pm
content: (Please don't move this. It's mainly about 'general' topics)..The "All American Five" refers to the mass produced valve radios, by very many manufacturers, from the 1930's. Apart from the standard 5 tubes & their functionality, their emphasis was on 'cheapness' of manufacture. There is/wasNOpower transformer, and relied on the American line voltage of 110/120-v to directly feed Plates (partly via resistors), and series connected tube 'heaters' of higher Filament Voltages etc., so thatnomains transformer is/was needed. OK, I get it, but half the time, one ended up with a 'Live' Chassis for the uninitiated!?So many times, I've seen ccts where a 'power' switch, if any, actually switches the Neutral! The VAST majority of power plugs I've seen in America have only 2 pins, and no 'Earth' pin. Now I know that most 'modern' plugs/sockets there now are 'polarized' by way of a slightly wider pin, but still with no Earth?? I understand too that this is 'just' 110v, not 240v like in Australia, but I don't understand the attitude. I see numerous Youtube videos where people in the U.S. plug equipment into un-switched outlets on their bench. Ok, YOU might have wired it correctly.In Australia, we MUST have an Earth too, unless the device/machine is 'Double-Insulated', like a certain hair dryer etc. It just seems that America is more blase' about Neutrals & Earthing ?? (And yes, I understand about isolation transformers & isolated Variacs etc.)

author: joeqsmith
author_rank: Super Contributor
timestamp: April 27, 2020, 01:44:11 pm
content: This old Crosley 718 belonged to my wife's grandparents. A couple more tubes and it uses a transformer.https://www.eevblog.com/forum/repair/old-console-radio-repair/msg1455644/#msg1455644I posted once a section from the ARRL handbook on safety. They talk about the dangers of 110, mainly because people feel working with it is low risk and get comfortable around it.

author: Tom45
author_rank: Frequent Contributor
timestamp: April 27, 2020, 02:05:45 pm
content: Yes, everything you described is accurate. In addition,nooutlets back then had grounds nor were they polarized.The All American Five radios were designed to be extremely low cost. The enclosures and knobs were plastic so in normal use there was no chance that a user would be exposed to a possibly hot chassis.You are getting alarmed over practices from well over a half century ago.Automobile seat belts and child car seats didn't exist either. I was born in 1945 and nobody thought twice about having their children free to roam around in the back seat while driving. Today parents would be in big trouble if they did that.Somehow most of us managed to survive radios with hot chassis and cars with no seat belts or child seats.Were people tougher back then? Are people a bunch of wimps now? I'll leave that to others to decide.

author: 16bitanalogue
author_rank: Regular Contributor
timestamp: April 27, 2020, 02:42:08 pm
content: Quote from: Tom45 on April 27, 2020, 02:05:45 pmNeither. It has more to do with safety, policy, and the squeaky wheel. "Unsafe At Any Speed" is what sparked the safety revolution in the automobile industry in the US.Are manufacturers responsible to ensure that their products can be used safely (seat belt) even though the individual may not use that mechanism (seat belt). Let's have some real talk. People will be stupid and cause accidents, so additional safety mechanisms are, I would argue, value added.When do they become intrusive and/or political is the question IMO. See mandatory back up camera because Mom ran over her daughter while backing up. Tragic. Truly. But a necessity?

author: rstofer
author_rank: Super Contributor
timestamp: April 27, 2020, 02:45:25 pm
content: Quote from: GlennSprigg on April 27, 2020, 01:16:40 pmYou must have been living in some pretty old housing because U-ground receptacles have been required since 1951 for the laundry and eventually covered the entire house by 1962. Polarized receptacles have been available since the 1880s but not mandatory until 1962 when the NEC required receptacles to be both polarized and grounding but they were in common use much earlier.I use power outlet strips on my bench and most have switches. I have never used the switching feature but it does exist. There are a number of GFCI device configurations and I suppose a receptacle style could be used on a bench.Today we have a requirement for arc-fault breakers serving certain areas of the residence and GFCI protected outlets in many others.Lowe's still carries 2 wire unpolarized plugs. I saw some on the shelf the other day when I was looking a 2 wire polarized plug which they didn't have. There are a lot of two-wire applications including table lamps, toasters, hair dryers and carving knives. Mostly, it works out fine.

author: rrinker
author_rank: Super Contributor
timestamp: April 27, 2020, 06:25:51 pm
content: Our house was built in the early 50's. There were no grounded outlets in the entire place. We had to add them when needed for newer appliances. Grounds WERE run to the boxes, but all of the outlets were basic 2 prong type.Paul Carlson isn't joking when he says those All-American 5's can be dangerous - and when you're literally a young player and your life flashed before your eyes, it doesn't take long. A neighbor down the street who was moving knew I had an interest in electronics, so he gave me a huge box full of stuff - components, built up devices which I had no idea, and a couple of old tube radios, one AM only (in retrospect, an AA5 design) and an AM/FM one. The AM/FM was in working condition and I actually used it for a while. The AM one had the large plastic tuning 'knob' (it was a huge wheel) snapped off. I wanted to see if it was otherwise working, so i was using an insulated handle screwdriver to reach down in and turn the tuning capacitor. All went well until my hand slipped down to the shaft of the screwdriver. Standing on the cement floor of the basement, the high voltage froze me in place. Through the windows, I could see my Mom and some others out on the patio, but I couldn't call out. Eventually I started shaking enough that the screwdriver came away from the tuning cap. It seemed like I had been frozen there for 15 minutes, but it was probably more like 15 seconds. I was damn lucky, and I developed a healthy respect for high voltage circuits after that.As for "Unsafe At Any Speed", don't get me started on Ralph Nader. There was nothing inherently wrong with the Corvair, that same swing arm suspension had been is use for decades in VW Beetles and Porsches, among others.

author: chris_leyson
author_rank: Super Contributor
timestamp: April 27, 2020, 07:54:24 pm
content: I have a Bush DAC90A which I believe was manufactured up until about 1957. AC/DC 5 valves and has a double pole single through mains switch so safe when switched off. I really like the loop antenna mounted on the side, you can turn the radio around and null out the worst of the local QRN. I'm still considering retro fitting an isolation transformer but finding one that fits and gets rid of the hot dropper resistor is going to take a bit of work.

author: james_s
author_rank: Super Contributor
timestamp: April 27, 2020, 08:08:47 pm
content: There are vast numbers of houses in the US built in the period shortly after WWII that do not have grounded receptacles, both of my grandparents lived in such homes. Many of those receptacles are polarized but most plugs of the era were not.As someone else said, these radios were from a different era that had different attitudes about safety. They were born from the Great Depression, designed to be as cheap as possible so as to be affordable by ordinary people, the classic AA5 was the VW Beetle of radios. They were designed to not have any exposed metal parts that could be live but this safety margin could be lost if the radio was damaged. People were occasionally killed by them, especially from trying to use one while in the bath or shower if it had a missing knob or back cover which allowed exposed metal to be live.Things were just different back then though, people didn't have the same expectation of someone else looking out for their safety that they have today. I suppose compared to glass oil lamps, gas, and exposed flames used for a majority of lighting just a few short decades earlier these radios did not seem all that dangerous.For what it's worth, I have a couple of vintage AA5 radios and I use them, they don't worry me. I'm aware of the hazards and I make sure the back cover is intact and the knobs are in place, I don't leave them plugged in all the time and I don't have kids. Personally I quite like the design, it's very elegant, extremely simple and yet it performs remarkably well in most cases. This thread really seems like mountains out of mole hills, the world is dangerous, there are countless things all over trying to kill you if you're not careful, enter at your own risk.

author: james_s
author_rank: Super Contributor
timestamp: April 27, 2020, 08:13:35 pm
content: Quote from: rrinker on April 27, 2020, 06:25:51 pmThe Corvair was a fascinating car, and extremely innovative for GM when compared to everything else that was coming out of Deteroit at the time. They were really thinking outside of the box with that one, it had some unusual handling characteristics compared to the American land yachts of the time but I'd argue that they were no less safe than countless other small and inexpensive cars of the era.

author: GlennSprigg
author_rank: Super Contributor
timestamp: April 29, 2020, 01:59:03 pm
content: Quote from: james_s on April 27, 2020, 08:08:47 pmThank you for your (and others!) reply. I understand that 'standards/safety' was different back then. And here in Australia too, our original vehicles had no seat-belts etc. And we had people back in the 40's/50's unplugging a light-socket overhead, to plug in an electric Iron.Now though, all light sockets must have an Earth wire present, whether used or not!, in case it is ever changed to say a metal bodied Fluoro fitting. And I see/review countless relatively 'modern' videos on Youtube etc, where they are still using/connecting 2-pronged plugs/cables to countless pieces of equipment. Correct me if I'm wrong, please, but it seems that 110-v is just considered 'bitey' there, as opposed to our 240-v, even today?? I know it's not, but even today they don't SEEM to adhere to the same Earthing standards we do???

author: TimFox
author_rank: Super Contributor
timestamp: April 29, 2020, 04:03:42 pm
content: When the AA5 sets were first designed before the War (typically 12SA7, 12SK7, 12SQ7, 50L6, and 35Z5), there was still domestic power distribution of 110 VDCin certain parts of the US, especially in the northeast. Consolidated Edison in New York finally ceased DC distribution totally in 2007. With the transformer-less “AC-DC” circuits, the radio could work with either supply.I have a classic E H Scott merchant-marine receiver that has a more complex AC-DC circuit, since DC was common on such vessels during WW II. The DC within the box was (almost) isolated from the metal chassis, and hermetic “bathtub” capacitors bypassed the cathodes, screens, grid returns, etc. to the chassis.

author: james_s
author_rank: Super Contributor
timestamp: April 29, 2020, 04:38:22 pm
content: Quote from: GlennSprigg on April 29, 2020, 01:59:03 pmYes 2 prong (non-grounded) cords are still common here, I don't recall ever seeing a lamp with a grounded cord. 120V can and does occasionally kill people but it's pretty rare. I've been bit by it numerous times and I'm still here, but it certainly can be dangerous. I'm actually not sure why lamps aren't grounded, even those with exposed metal parts. Years ago I had one of those halogen torchier lamps in my office and a wire had chafed where it passed through a metal nipple making the entire lamp live. I thought I'd felt a tingle from it on occasion but then one day I was moving a PC and the end of the VGA cable bumped the post of the lamp and BANG. After that I disassembled the lamp and realized what had happened.

author: 16bitanalogue
author_rank: Regular Contributor
timestamp: April 29, 2020, 05:10:51 pm
content: Quote from: james_s on April 27, 2020, 08:13:35 pmThis goes beyond the Corvair itself. Nader's book sparked the safety revolution in the automotive industry. No one could reasonably argue that what has happened since was for naught.Per Peter Kohler (retired GM engineer from the video):"If you know what you are doing you can drive a Corvair." That right there is a red flag that such a car should not be a daily driver. Not only should I have a license, but like Hagerty I should be a race car driver to "know what I am doing." Peter goes on to state that other cars share the same type of suspension and implies that it is not that big of a deal. Sorry, but they are different cars that will have different handling capabilities. Per his own comparison of Corvair vs Porche. This sounds like a bitter, old man yelling at a cloud. These statements are immediately followed from Jim Musser, Head of GM Engineering at the time, "The problem was too much weight transfer to the rear axle...causing oversteering and eventually go out of control."Hell, at the end of Hagerty's video he states:"I think of the Corvair as a sacrificial lamb that motivated Nader to write a book that got the industry to make some initially painful changes that ultimately proved necessary."Oof. Personally, I would not die on this hill.

author: bob91343
author_rank: Super Contributor
timestamp: April 29, 2020, 05:44:20 pm
content: I agree with much of the above. I recall being irritated on the freeway by a jerk driving a Corvair. He was tailgating me at one point and I slammed on the brakes. He reacted quickly but due to the piece of garbage he was driving, immediately lost control. His vehicle started to spin out and, while he didn't hit anyone, I suspect his adrenaline level took a big jump.The hot chassis of the AA5 presented some safety issues but I have never heard of a case where someone was electrocuted by 120 Volts. My first radio was a one-tube regenerative broadcast radio with a resistor line cord that kept me warm on many a winter night.I have been around the block a few times and have many stories to tell, although very few are interested. The number of times I have been zapped by 120V and more, rf burns, and other stuff is so many that I lost count long ago. Inhaling solder fumes and paint spray, grabbing the wrong part of the soldering iron, I could go on. I have made it to nearly 88 years and am still healthy and active and still have all my fingers and both eyes.

author: themadhippy
author_rank: Super Contributor
timestamp: April 29, 2020, 05:55:36 pm
content: A bigger risk than the lack of earthing in lighting circuits is the existence of the ES lamp base

author: amyk
author_rank: Super Contributor
timestamp: April 30, 2020, 12:44:38 am
content: A lot of appliances today are not that much different; plenty of them use capacitive droppers to power control electronics, so no isolation, but the outer housing and user-facing parts are nonconductive. With TVs, I believe "hot chassis" continued into the 70s and later.

author: Electro Detective
author_rank: Super Contributor
timestamp: April 30, 2020, 01:53:46 am
content: Quote from: themadhippy on April 29, 2020, 05:55:36 pmNo contestand the aussie bayonet push and twist socket isn't any better, but easier than screwing aroundI'll bet a lot of dim bulb testers come poor mans current limiters out there, have the active line wired to the bulb socket and or bypass switch,their tinkering owners just begging to be zapped real good one day,or unattended kids messing about in the workshop sticking their finger in the socket, or curious cat, dog, or lizard sticking in the tongueFWIW and I may not be the first with the idea..but my dim bulb tester/s are wired with the confirmed Neutral, to the ES and or bayonet base, not the Active.It works the same in use afaict and little to no chance for a zap with no lamp attached, assuming that's the only item handled or touched by accidenti.e. you would be touching an exposed earthed Neutral socket whilst you are earth/grounded yourself, be it on concrete, tiled floor or grounded bench/devices etcso in theory and practice, assuming everything in the mix is correctly wired, nothing should happen, not even a tingleand it's what two multimeters agreed on..Add to that, for switching in the DUT in or out, that switch MUST be a double pole type, so OFF really means OFFIf you play with fire and really need a no brainer OFF OFF OFF, consider an addon three pole switch to kill all three wires, placed wherever you see fitNow HONESTLY:how many members here have their dim bulb testers wired with the Active 120 or 240 volt line to the socket base ?If I'm wrong about all this, please correctbut 'Neutral to socket base' works for me and no dramas yet with zaps, RCD breaker trips,or current limiting performance as I've done A-B tests with flipped polarity to confirm identical performance,and no earth/neutral leakage issues passed on upstream or downstreamYMMV + EMMV appliesand everyones favDisclaimer'DO NOT try this at home, and if stupid enough to attempt it, you do so at YOUR OWN RISK'

author: Miti
author_rank: Super Contributor
timestamp: April 30, 2020, 02:02:11 am
content: Quote from: Tom45 on April 27, 2020, 02:05:45 pmYes.

author: Electro Detective
author_rank: Super Contributor
timestamp: April 30, 2020, 02:17:45 am
content: Quote from: Tom45 on April 27, 2020, 02:05:45 pmThey're wimps because the only weights they lift are smartphones,and brained to believe with all the information available at their fingertips, as well as watered down/dumbed down diplomas and qualifications,that they have more intelligence, resourcefulness and smarts than previous generations,generations who could survive and entertain themselves with bare essentials,no electricity, no batteries, no 'internet'.. zip nada etcTalk about these wimps being easy pickings for suckers and ripe for mass deceptionLOL, I forgot, they are already there now and clueless to it,they better ask their mate google to suss it all out for them and contribute some clever comeback replies here

author: themadhippy
author_rank: Super Contributor
timestamp: April 30, 2020, 02:29:27 am
content: QuoteAt least with newer, better quality BC holder's you have to physically push the pins down before you get to feel the power

author: schmitt trigger
author_rank: Super Contributor
timestamp: April 30, 2020, 03:29:21 am
content: Back in the vacuum tube days, if one repaired electronic equipment, one acquired experience by getting burned, shocked or cut.Those were the good old days.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: April 30, 2020, 04:25:59 am
content: It all depends on what your definition of terribly unsafe is. Over the last few decades the decimal point has moved several places. I now watch national news items wringing their hands about something that has "doubled the death rate". From 2.4 per million to 4.2 per million. Personally, I have trouble worrying about anything that is measured in per million, but that doesn't seem to be the general attitude these days. Arguments about whether this is a good thing or a bad thing are best done in a pleasant setting with an adequate supply of beer.

author: james_s
author_rank: Super Contributor
timestamp: April 30, 2020, 04:41:44 am
content: Quote from: 16bitanalogue on April 29, 2020, 05:10:51 pmBullshit.All cars have handling characteristics that vary from other types of cars, a significant part of driving is knowing what you're doing. A high performance RWD sports car has a tendency to oversteer, FWD cars have torque steer, big older American cars understeer, trucks and SUVs have a high center of gravity making them prone to rollovers, a pickup truck with no load is very light in the back end which adds its own unique handling quirks, I could go on and on. As a driver it is 100% YOUR responsibility to learn the handling capabilities of the car you are driving and stay within the limit. You don't have to be a race car driver to safely drive a Corvair, you just have to be modestly competent and have a basic understanding of physics, something you should have to drive ANY car. The similarly configured VW Beetle he mentioned was safely driven by millions of people for decades. It was nowhere near as safe as modern cars but people somehow managed. The AA5 radios that started this thread, the VW Beetle, the Corvair, the Pinto, these were all designs that were made to satisfy a goal of low cost, (and high fuel efficiency in the case of the cars) making them affordable to as many people as possible. Designs that required compromises to attain these goals within the technology available at the time. Maybe kids these days are just completely out of touch with how things were just a few decades ago before the influx of incredibly cheap technology and toys that we have today.Yes Nader's book did help kickstart some important changes, but calling the Corvair "unsafe at any speed" is pure hyperbole. Sensationalism to sell books.

author: Tom45
author_rank: Frequent Contributor
timestamp: April 30, 2020, 04:46:18 am
content: Quote from: TimFox on April 29, 2020, 04:03:42 pmTo be fair to Con Ed, I think they carried on with DC service for such a long time because there were a few elevators in NYC that used DC motors. Substituting AC motors and controls was apparently deemed to be a bigger problem than just continuing DC service to the few ancient DC installations.A search brought this article:https://cityroom.blogs.nytimes.com/2007/11/14/off-goes-the-power-current-started-by-thomas-edison/Apparently the hold outs haven't converted to AC. They just installed AC to DC converters on site.

author: james_s
author_rank: Super Contributor
timestamp: April 30, 2020, 04:50:14 am
content: Quote from: Tom45 on April 30, 2020, 04:46:18 amMakes sense. I could see it costing many millions to retrofit the elevators in an old building with a modern system. Assuming the old equipment is still serviceable then installing a rectifier to supply DC sounds like a pretty reasonable option. It's not like you can just swap out the motor, a conversion in a historic building would be opening a big can of worms.

author: Mp3
author_rank: Frequent Contributor
timestamp: April 30, 2020, 05:18:23 am
content: It's a tradeoff. You guys get to power a jackhammer off the outlet in your kitchen because of 220/240v, we get to be more careless with mains due to the lower voltage.In regards to the earthing aspect.....Japan does this as well and is actually worse because the earth in Japan is the screw on your outlet. Likewise, an American came up with the lightning rod method of groundingSo does it come as much surprise that our design philosophy is to do as much work with as few parts as possible?I mean, does it really matter on 100-120v mains? My whole life i've plugged things in either way around and they work. If the plug isn't polarized so it can only be put in one way. And even then, the majority of American households made before the later-mid 1900's out here have awful nightmarish electrical wiring.Half the outlets in my apartment built in the late 1800s - ancient as far as USA buildings go - are wired backwards. The worst that happens is a spark when you plug something in. (I know, some of you in other countries probably can't fathom that, but it's one of the joys of low mains voltage)Anyway, if you look at trends in American design philosophies, we have an affinity for having a minimal amount of components do a large amount of work. A lot of designs that came out of the USA that compete with European/Australian/Asian designed boards are way more overbuilt, way more simplistic, and expected to be treated MUCH worse IMO. (We are really rough with our belongings compared to other nations, I think)

author: vk6zgo
author_rank: Super Contributor
timestamp: April 30, 2020, 08:52:05 am
content: Quote from: GlennSprigg on April 27, 2020, 01:16:40 pmQuote from: GlennSprigg on April 27, 2020, 01:16:40 pmThe AA5s were more a thing of the 1940s on.If you look at most published 1930s US radio designs, they used power transformers, with secondaries of from 285 to 385 volts "a side".Factory made Radios were fairly expensive back then, & a lot of circuits were designed for a fair bit of output power for use with the fairly inefficient "Electrodynamic".speakers in common use.After WW2, the USA manufacturers wanted to produce cheap radios.For some reason, power transformers were expensive, & "series string" tubes fairly inexpensive.This, along with the fairly low (then) 110v Mains supply, lent itself to the "AA5" design.Other developments, like more efficient "Permag" speakers, & improvements in tube efficiency also contributed.In Australia, the economics went another way:-Tube factories had massively increased their production during the War, but virtually all the tubes they produced were in the heater voltage values of 1.5v, 2.0v, 3.0v, 6.3v (the vast majority) & 12v.There were also, in the early days, many hundreds of surplus tubes on the market, mostly 6.3 volt heater typesHigher voltage heaters suitable for "series strings" were not normally made, & usually had to come from the USA, the UK, or Europe.The higher Mains voltage in Australia also made the case for transformerless designs much less compelling .Transformers for domestic radios were neither excessively large or heavy, nor, in the Australian context, expensive.The upshot was what became fairly standard in this country----- a 5 "valve" "mantel" radio using a power transformer, a tube rectifier, a mixer, one stage of IF gain, then a detector/audio driver stage (a "double diode, hi mu triode") & an audio power tube(usually a beam tetrode of the 6V6/ 6AQ5/6M5 ilk.There were a few "transfomerless" radios around----some custom made. for the few remaining DC Mains Supplies.Of these, some were 110v DC, & the relatively simple "AA5"type circuit could be used.Others were 240v DC, & the radios were messy things with series resistors, "barrettors", etc.Transformerlesss designs were dubbed "death radios" & loathed by radio servicemen.

author: nfmax
author_rank: Super Contributor
timestamp: April 30, 2020, 08:55:55 am
content: Transformerless TV sets - known and marketed as AC/DC designs - were very common in the UK. More valves makes series heater strings feasible with 240V mains.Surelythe AC/DC TV set must have been a thing in Australia, of all places?

author: vk6zgo
author_rank: Super Contributor
timestamp: April 30, 2020, 12:21:24 pm
content: Quote from: nfmax on April 30, 2020, 08:55:55 amNope!When TV arrived in Oz, the valve type TVs followed the same pattern as the radios, using a transformer, with a 300-350v "a side" at 300mA secondary.The early ones used things like 5V4s for the rectifier.They soon moved to silicon diodes, for a while retaing the centre tapped HT winding, then later, 200-odd volts non tapped windings with a voltage doubler.By 1956/57, DC Mains supplies were reasonably rare in Australia, so the advantages of being compatible with AC & DC were not very compelling.The only AC-DC TV I remember being sold here was an early Admiral "portable" .It was hardly that, as it needed to be plugged into the Mains.It didn't sell all that well, & was discontinued after a few years.A lot of people worry about the weight of power transformers, but. you can hold a "mantel set" transformer in the palm of your hand, & carry it around,Similarly, you can pick up & hold a BW TV power transformer in the same way although your hand would get a bit tired after a while.After having become used to carrying Australian BW TVs, I picked one up in England, expecting it to be lighter, but, too my surprise, it felt about the same.I think much iof the weight of such a TV is the tube, chassis material, & the extra safety stuff which is not needed on the transformer equipped version, leaving the relative weights pretty much the dame.When colour TV came to our shores, we went straight to standard SMPS in the locally made TVs.The imported (mainly Japanese) TVs did the same.Both sides of thei Mains were isolated from the chassis, with the only connection to it being on the secondary of the high frequency transformer in the switchmode.We never had the SMPS built around the Horizontal output circuit that was evidently common in UK & EU..

author: 16bitanalogue
author_rank: Regular Contributor
timestamp: April 30, 2020, 01:18:23 pm
content: Quote from: james_s on April 30, 2020, 04:41:44 amI'll quickly summarize your position:"It is owner's responsibility to understand our cheap, flawed, mass market design."Be honest, did you even watch the video you posted?

author: TimFox
author_rank: Super Contributor
timestamp: April 30, 2020, 01:24:41 pm
content: Quote from: Tom45 on April 30, 2020, 04:46:18 amYes, the very late dropping of DC service in New York was related to elevators. However, before the War, there was a lot of DC distribution in New York and Boston, a big problem for transformer-operated equipment and the origin of AC-DC jokes (another topic).Around 1965, I visited the roundhouse of the Duluth, Missabe, and Iron Range Railroad in Proctor, MN, which still had one or two Yellowstone 2-8-8-4 simple articulated steam locomotives (the most powerful ever built, slightly more tractive effort than the more famous Big Boys of the Union Pacific). The big electric motors ran on 25 Hz power for historical reasons, which they could still obtain from Minnesota Power and Light Co., although the rest of us enjoyed modern 60 Hz power.

author: andy2000
author_rank: Frequent Contributor
timestamp: April 30, 2020, 03:03:17 pm
content: Quote from: nfmax on April 30, 2020, 08:55:55 amTransformerless TVs were common in the US well into the 90's. They did have a polarized plug in the later years, but the chassis was hot regardless of which way the plug was inserted (the negative side of a full wave rectifier was tied to the chassis). They used an isolation capacitor on the antenna inputs, and made sure there were no exposed metal parts. Higher end sets with A/V inputs often used optoisolators, or transformers to isolate the inputs. Occasionally, they installed an isolation transformer, or even added a SMPS to higher end models rather than redesigning the whole set.It wasn't an issue other than having to remember to use an isolation transformer while servicing them.

author: james_s
author_rank: Super Contributor
timestamp: April 30, 2020, 04:57:29 pm
content: Quote from: 16bitanalogue on April 30, 2020, 01:18:23 pmAbsolutely it is, and yes of course I did. I've been a car enthusiast all my life, I've not yet had an opportunity to drive a Corvair but I'd love to do that. I've driven lots of other interesting and unusual cars, vintage stuff is a lot cooler than anything you can buy today, it's a whole different experience.Everything is flawed, it's called compromise, can optimize for a number of factors, you can't have it all. You must be very young, cars are a lot different today than they were even 20-30 years ago. Also you seem to have fixated on the Corvair, what about the SUVs that are prone to rolling due to the high center of gravity? Is it not the owner's responsibility to understand this "flawed" design and not drive a big tall truck the same way they'd drive a low slung sports car?My point is not that the Corvair was a particularly good car, but it was nowhere near as bad as the hype you have bought into. Like the enormously popular VW Beetle it was engineered to be cheap and fuel efficient, and with that came some compromises. I'm going to assume you've never driven a Corvair, or even Beetle or any other cars of that era, you're simply parroting what you've heard without any experience to back it up.

author: Sal Ammoniac
author_rank: Super Contributor
timestamp: April 30, 2020, 05:27:43 pm
content: Quote from: GlennSprigg on April 27, 2020, 01:16:40 pmWe have 330 million people here in 'Murica, so we have a lot more spares than you do in Australia in case someone gets fried.

author: 16bitanalogue
author_rank: Regular Contributor
timestamp: April 30, 2020, 05:37:42 pm
content: Quote from: james_s on April 30, 2020, 04:57:29 pm...and that the manufacture also has responsibility to make sure their product is safe. Which leads one to...QuoteThis. Duh.QuoteThere is as fundamental difference between "flaws" which appear when the vehicle is pushed to its limit and real flaws that arise from everyday driving. ESC and other electronic nannies, side skirt air bags, crumple zones certainly have made SUVs safer. That's is the fundamental point that automobile safety was an issue even before Nader's book, although hyperbole for some, highlighted the indifference of car manufactures toward safety during that time.QuoteExactly.QuoteNope. Per the conclusion in thevideo that you posted, it was not as bad as it was made out to be, but it did have its problems that lead to loss of control - directly from head GM engineer at the time.QuoteDifferent cars with the same suspension, yet not the same problem.Per the video that you posted, from the head GM engineer stated the excess weight (due to the rear engine) also played a role.I never argued that the Corvair was a horrendous death trap. In fact, I stated that it certainly has its flaws (you finally admit to that), the video you posted concluded with that, and that Nader's book (among other articles and studies) highlighted automobile safety concerns. The Corvair was an (exaggerated) example used, but certainly flawed as, again,admitted by you and the video you posted, to propel the industry toward safety.Please do not continue to dig into this hill you are hell bent on dying on, because now I am just arguing with a stone wall.Cheers.

author: rsjsouza
author_rank: Super Contributor
timestamp: April 30, 2020, 10:22:55 pm
content: I told this story somewhere else in this forum, but I grew up with non-polarized and non-grounded round and flat plugs all my life in Brasil. The standard until the mid 2000s was to try to be friends with the US and some of Europe's standards and we got away with the ground plug in most types.With the explosion of the PC era in the 1990s, the three prong grounded US plug started to become quite common and, with the existing non-grounded and non-polarized outlets, the obvious solution was to rip apart the third pin - not without that tingling sensation when one touched the metal housing. Worse, a lot of people started warning about cutting the third pin and therefore a market of "electricians" was created, retrofitting the existing outlets by simply replacing the outlet but not wiring the ground. Most houses and buildings were only two-wire circuits unitl 1994, where the new constructions required the ground wire but everything else was grandfathered.Fast forward to mid 2000s, the stupid swiss standard was approved, which was pretty much incompatible with everything else in existence in the country and in the world and from night to day it obsoleted hundreds of millions of appliances, equipment and parts. Someone made wads of cash then.The newer standard is safer? You bet. The older standard was useable? Of course! Did people get shocked? Yes, but it was considered a growing pain, really. Given that electric appliances and gadgets were not as ubiquitous as today, people gave it the proper respect it requires and used it in a much more responsible way.I see the case with the safe/unsafe cars the same: in my experience, the individuals had much more respect for the act of driving due to the mechanical limitations of a car and knew they could really die if pushed above certain limits - the safe car propaganda tends to infuse a sense of indestructibility, where people become so confident they even consider (and several actually do) deviate their eyes from the traffic to interact with their smartphones. And no, I am not saying that we should roll back the incredible progress done with the safety aspects, but we should equally stress the dire consequences even with all this techno-nanny gizmos.As others have said, you can't make the world "safe at all costs". A part of the responsability has to come from the individual.

author: Electro Detective
author_rank: Super Contributor
timestamp: April 30, 2020, 11:50:23 pm
content: @ rsjsouza: great commentbut someone has to say it..that's an awesome collection of wrist bands in that pictureIron Man would be green with envy

author: rsjsouza
author_rank: Super Contributor
timestamp: May 01, 2020, 01:27:46 am
content: Quote from: Electro Detective on April 30, 2020, 11:50:23 pmI have never saw them from this angle... you are right.

author: GlennSprigg
author_rank: Super Contributor
timestamp: May 01, 2020, 12:33:34 pm
content: Quote from: TimFox on April 30, 2020, 01:24:41 pmWasn't the U.S. still using DC for some TRAMS for quite a while??Also, until recently seeing a "Mr. Carlsons Lab" radio restoration video, where it had an extra large transformer, designed to work down to 25-hz supply frequency, had I ever HEARD of the use of 25-hz !!Also, torsjsouza, regarding Earthing. I don't know how 'Earths' are set up in the U.S., but here in Australia, it goes like this... The 'Earth' is not supplied to the property. An Earthing stake is driven into the ground close to the Switchboard/Meterboard. All the earth wires within the property (outlets/lights) go back to a dedicated earth-termination bar in the main switchboard. The Earth-stake in the ground is also connected to this bar. However, 'we' ALSO have a hefty cable link in the switchboard, linking that Earth-Bar to the Neutral-Bar, under what we call 'M.E.N.', meaning a 'Mains-Earth-Neutral' system. So that the Neutral is always referenced to Earth also! Often, old un-earthed circuits simply need the addition of a separate earth wire, (if not included in the cables), to bring it up to spec. And we 'virtually' have no power outlets without a built in switch, which obviously switches the Active. And our outlets are automatically 'polarized' due to the diagonal layout of the prongs.

author: rsjsouza
author_rank: Super Contributor
timestamp: May 01, 2020, 03:02:18 pm
content: Quote from: GlennSprigg on May 01, 2020, 12:33:34 pmGlenn, the standard here varies a lot around the country - since I don't work in the professional electrician field, I wouldn't risk throwing my inaccurate hints.In my house I have a ground wire being fed to the panel, but I didn't pay attention if there is a connection to a bar near my meter - it could be done that way or perhaps there is a larger ground bar in the neighbourhood. Overall it seems the ground connection is alright as no tingling sensation happens with grounded chassis and no equipment was ever damaged due to lightning (and there is a LOT of lightining where I live).

author: TimFox
author_rank: Super Contributor
timestamp: May 01, 2020, 04:40:57 pm
content: Quote from: GlennSprigg on May 01, 2020, 12:33:34 pmThird-rail subway, elevated, and suburban trains in US are usually DC (about 600 to 750 V) and originally ran with DC brushed motors for speed control. Modern cars use inverters driving induction motors at variable frequency for speed control. Overhead wires are often higher voltage DC; the Illinois Central suburban line in Chicago uses 1500 V DC. For mainline service, the Pennsylvania RR electrified at 12 kV, 25 Hz, as a compromise between weight of control transformers in locomotives and DC motors driven by AC. (Similarly, the Swiss railways used 16-2/3 Hz, a subharmonic of 50 Hz.)

author: james_s
author_rank: Super Contributor
timestamp: May 01, 2020, 05:59:53 pm
content: Quote from: TimFox on May 01, 2020, 04:40:57 pmWasn't the low frequency AC used so they could run large rotary converters back before mercury arc and later solid state rectifiers capable of handling high power levels were developed?

author: jogri
author_rank: Frequent Contributor
timestamp: May 01, 2020, 06:23:16 pm
content: Quote from: TimFox on May 01, 2020, 04:40:57 pmActually, germany, denmark and austria also use this system... It's a relict from the early 20th century, but it still works (some german powerplants even have dedicated 16 2/3Hz generators for that purpose). Btw, we even have a 400V three-phase suspension railway over here, i'd like to know which engineer envisioned this monstrosity (he was probably bored and decided he needed a new challenge).

author: CatalinaWOW
author_rank: Super Contributor
timestamp: May 01, 2020, 09:51:51 pm
content: Whether totally factual or not, we were taught at university that all of the early power operating frequency decisions were actually fact based. The analysis was presented and variations given in homework problems and tests. They had a specific set of materials available at the time which set core losses in the transformers and also saturation levels. Each system had an expected distribution architecture which set line losses through capacitance. Set up the equations, take the derivative, find the zero point and you have the optimum frequency. And with the data available to us at the time it appeared that the calculations were done correctly. The difference between the European and North American solution is well with what would be expected from slightly different material costs and distribution arrangements. And you would expect the distribution arrangement to be very different in a dedicated rail power system, so the frequency is significantly different (as is the frequency chosen for airborn and ship power systems).Once a few were built the benefits of standardization outweighed the benefits of optimization and folk settled on just a few options.

author: Electro Detective
author_rank: Super Contributor
timestamp: May 01, 2020, 11:44:32 pm
content: Quote from: GlennSprigg on May 01, 2020, 12:33:34 pmafaik the incoming 'Neutral' is also earthed via the power pole transformer box to an earth ground in the soil belowso the Neutral comes into the mains switchboard sort of 'pre-earthed'the premises 'earthing stake/copper plated rod' is wired to its own earthing buss barwhich in turn is then linked via a thick wire/link to the Neutral buss barIf you lose the neutral, or any neutral, things still work via the earth return paths, but not safeOpen for correction on this,stubborn humming coffee machine undergoing diagnosis, dis-assembly and blockage purge/clean

author: vk6zgo
author_rank: Super Contributor
timestamp: May 02, 2020, 02:17:41 am
content: Quote from: GlennSprigg on May 01, 2020, 12:33:34 pmThe Melbourne trams (streetcars) use DC, as did the long extinct Sydney & Perth ones.For many years, Perth had a sustantial network of trolleybuses, which also used DC.In the Sydney CBD, several old buildings were an "island" of DC into the 1950s, one strangely, being the headquarters of Australia's then premium Electronics magazine "Radio & Hobbies", (later "Radio,Television & Hobbies", then "Electronics Australia").To provide ac for their design lab, & for anything else that needed it, there were "rotary converters" in the basement.Unfortunately, there were power outlets of both "species" of electricity in the lab, so they occasionally let large quantities of "magic smoke" out of something.The main reason for retaining DC was for the "Lifts"(elevators)Later, the setup was reversed, with AC to the building, but rectifiers in the basement for the lifts.Later, still, it was becoming obvious that the old lifts couldn't meet modern safety standards, & parts were virtually unobtainable, so building management "bit the bullet" & replaced them with modern ones.

author: schmitt trigger
author_rank: Super Contributor
timestamp: May 02, 2020, 04:29:12 pm
content: I know that New York’s subway, Paris metro and others still use DC. But how about London’s tube?

author: TimFox
author_rank: Super Contributor
timestamp: May 02, 2020, 06:04:08 pm
content: I have not seen a reference to this, but I believe train cars with sliding power contacts to DC feed (third rail or overhead wire) use capacitors on the vehicle to mitigate rough connection.

author: Gyro
author_rank: Super Contributor
timestamp: May 02, 2020, 06:20:08 pm
content: Quote from: schmitt trigger on May 02, 2020, 04:29:12 pmYes, 600V DC irrc. The London tube actually has a fourth (centre) rail. It returns current through this insulated rail, rather than the running rails, to prevent corrosion of surrounding metal structures, pipes, etc.UK suburban 3rd rail systems are also 600V DC. They used to use mercury arc rectifiers, I don't know about these days.In days gone past, the London underground had its own coal fired power station near the Thames, the coal was stored under water to prevent spontaneous combustion (funny how you remember little facts like that), but these days the supply is derived from the grid, with a gas turbine powered backup station.P.S. There used to be nothing better than watching the 3rd rail slippers on a train sparking violently on a really cold, frosty morning (school day memories!). I suppose it's all VFDs these days, but back then, it was brushed DC motors and stepped resistor current controllers.

author: TimFox
author_rank: Super Contributor
timestamp: May 02, 2020, 07:10:20 pm
content: The Chicago Transit Authority retired the last 6000 series ‘L’ cars in 1992, after 42 years of service. IIRC, there were three forward settings on the speed lever: resistor, series, and parallel (fastest). Until VF drives, DC motors were the practical choice for variable speed.

author: Gyro
author_rank: Super Contributor
timestamp: May 02, 2020, 07:43:31 pm
content: It used to be interesting to look at the dates on the brass door sills in the tube trains, the older lines like the Northern. Many of them were early 1920s and still going strong (this was back in the '80s mind you). The bodies were original but of course there was regular replacement and renovation of all of the running gear.A lot of these underground / suburban DC systems were specifically designed for fast acceleration and deceleration.

author: vk6zgo
author_rank: Super Contributor
timestamp: May 03, 2020, 01:36:16 am
content: Quote from: Gyro on May 02, 2020, 07:43:31 pmI used to love the "pentagon? shaped" lift in one of the tube stations.It had an ancient recorded warning system that said "mind the doors" or something like that, in a rather "non human" voice.(that was before the advent of speech synthesisers, so I don't know why!)I think it is closed now.The Paris Metro back in 1974 had some really ancient carriages which looked like something out of a Wild West movie.Those were otherwise normal, running on standard rails, but they also some mid/late 1950s "high tech" ones which had rubber tyres, with the rails basically just acting as guides & power feeds.The suburban trains in Oz are 25kV ac for Brisbane, Adelaide & Perth, as they were later adopters of electric traction.Sydney & Melbourne are stuck with 600 or 750v DC (can't remember which).Back in 1971, Melbourne was still running the antique "Tait" cars, which shared the "Wild West" vibe with the Paris Metro cars mentioned previously.

author: Homer J Simpson
author_rank: Super Contributor
timestamp: May 03, 2020, 01:50:52 am
content: Hidden Killers of the Post-War Home

author: Gromitt
author_rank: Regular Contributor
timestamp: May 03, 2020, 09:49:25 am
content: Quote from: jogri on May 01, 2020, 06:23:16 pmNot Denmark. They use 25kV 50 Hz. Sweden and Norway uses 15kV 16 2/3 Hz.

author: richard.cs
author_rank: Super Contributor
timestamp: May 03, 2020, 02:40:37 pm
content: Quote from: Gyro on May 02, 2020, 06:20:08 pmIn some areas (the south east basically) full sized trains on national rail are 700 V d.c. third rail, in most of the other electrified areas it's overhead 25 kV 50 Hz. Then there are lots of areas that only run diesel trains. It's a bit of a mess.

author: Tepe
author_rank: Frequent Contributor
timestamp: May 03, 2020, 03:23:49 pm
content: Quote from: Gromitt on May 03, 2020, 09:49:25 amAnd Copenhagen S-trains use 1500V DC

author: vk6zgo
author_rank: Super Contributor
timestamp: May 03, 2020, 11:35:20 pm
content: Quote from: richard.cs on May 03, 2020, 02:40:37 pmYeah, I remember when I lived in Southampton for nearly a year, back in 1971.Some of the level crossings had an attendant full time, who closed a full gate, completely blocking acesss to the crossing when the rails were "hot", not just a boom,like I was used to from Oz.Other trains into SOTON were diesels.When I travelled further afield, I discovered a different mix, this time diesels & overhead cable pantograph types.Years later, back home, when Perth WA was first being electrified, the bus I took to work used to cross the line near the city station.When the lights went green we waited for a moment till a truck with a big excavator from the work site crossed.They got their heights wrong, & hit the already activated overhead cables, causing a blinding flash, & eveything shut down.We were still running diesels, so loss of 25kV didn't automatically shut them down, but it made all the lights red for that section.Needless to say, I was late for work!

author: richard.cs
author_rank: Super Contributor
timestamp: May 04, 2020, 08:48:27 am
content: Quote from: vk6zgo on May 03, 2020, 11:35:20 pmI'm from Southampton. The manned level crossings are gone, the current approach is automated gates, basically booms with a hanging fence below it, and having the third rail stop a few metres short of the road from each direction. Quite likely some of the crossings have been replaced with bridges too.

author: vk6zgo
author_rank: Super Contributor
timestamp: May 05, 2020, 02:51:42 am
content: Quote from: richard.cs on May 04, 2020, 08:48:27 amI tried looking at SOTON with Google Earth a while back, & couldn't recognise a lot from the old days.I finally found the railway station & the Bargate, but the latter looks insignificant compared to how it used to be------------ somehow "pushed off into a corner" & ignored.My memories of places in the UK are, of course, suspended in time from the early '70s, & I was only there for a short time.I can understand how people who lived their whole lives in that country, then migrated to another are shocked when they return for a visit after many years.Of course, there have been huge changes here in Perth, WA over the same time period, but being here as they happened, I have become used to them.All the suburban trains here were diesel railcars back then-------- we went electric in the mid/late 1980s.As an old fart, it is hard to realise there are now adults in this city who have never known anything but electric trains.

author: G7PSK
author_rank: Super Contributor
timestamp: May 06, 2020, 01:45:12 pm
content: I grew up in Cambridge UK during the 60's and there was still areas that were 240 volt DC. They were switching over gradually, the house e were in was changed over just a few days after we moved in from London, a tutor I had just ten minuets walk away house got changed over in 62, I went there in the early afternoon and there was no power and men all over her house changing things like parts on the cooker and sockets etc.

author: 25 CPS
author_rank: Frequent Contributor
timestamp: May 07, 2020, 12:31:31 am
content: Quote from: Gyro on May 02, 2020, 07:43:31 pmAgreed. It was always interesting to look down and see who built the train and when. To my mind, the British always made the best builder's plates. It was educational doing that in the various places I grew up in back when a lot of cities still had old junks running on their public transportation systems. I always loved the worst, oldest, most beat up stuff running because it was always the most interesting.Quote from: TimFox on May 02, 2020, 06:04:08 pmNo. No need, the inertia of the whole mechanical system that is a subway train is far better a filter than a bank of capacitors would be. The exception is for equipment that has chopper controls and there's a smoothing filter on the output side of the chopper which is to clean up the square waveform output of the chopper, not filter current collector bounce.Quote from: TimFox on May 02, 2020, 07:10:20 pmYes, normally those three power positions would be switching, series, and parallel as you mentioned but the CTA 6000 series cars and the 1-50 series cars which were single units with a cab at each end instead of a married pair were exceptions to the rule. Those were basically repackaged PCC streetcars and those were permanently wired in parallel. Westinghouse supplied the stuff on those cars and what the controller positions did was change the value of traction motor current being demanded by the limit relay and rheostatic controller, to control acceleration rate. Eventually, or not so eventually depending on what position you stick the handle in on one of those, you get full speed no matter what vs. a traditional switching/series/parallel traction package does.

author: Electro Detective
author_rank: Super Contributor
timestamp: May 12, 2020, 10:41:05 pm
content: Butting in with a quickie query:Were the techs of yesteryear using AVOmeters and Simpsons etc for checking and confirming railway voltages 600v and beyond?or were there specific tools for that?Were there any high zappage risks even for cautious operators with the right gear and PPE?and Danger Money rates that made it sort of worth it?

author: jeffheath
author_rank: Regular Contributor
timestamp: May 13, 2020, 01:29:42 am
content: Say what you will about corvairs, but like AA5 radios were, they're cheap! They're the cheapest classic car there is other than all those bland moredoors.

author: 25 CPS
author_rank: Frequent Contributor
timestamp: May 13, 2020, 05:29:56 pm
content: Quote from: Electro Detective on May 12, 2020, 10:41:05 pmFor checking the presence of 600 V in a is it there/is it not there way the quick, easy, and cheap way was with a 600 volt test light be it a string of 5 120 V bulbs in series or a dropper resistor feeding one or two bulbs. This was less expensive than giving everyone meters, but yes, techs troubleshooting more complicated faults would use Simpsons, AVOs, Tripplets, that sort of thing when a test light wasn't suitable.As far as the safety aspect goes, under normal circumstances, it's neither here nor there compared to a modern Fluke meter. You still need to be careful of live electricity and if you slip up and touch something that's live by mistake, it doesn't really matter what kind of meter's hooked up to your probes, there's always the risk of getting zapped when you're working on live power equipment of any kind if you mess up. I can't really speak to danger pay since I've only worked on streetcars at a handful of railway museums whenever they've asked for help with difficult electrical problems so that's strictly volunteer basis, but I have used my own Simpson 260s and Agilent U1641A insulation tester multimeter and an Agilent U1213A clamp meter when doing so and a couple of other people have Fluke DMMs.

author: rsjsouza
author_rank: Super Contributor
timestamp: May 13, 2020, 08:37:03 pm
content: Quote from: Electro Detective on May 12, 2020, 10:41:05 pm600V?!? Pffft! ATriplett 630-NAwas rated to 6kV! Pizz o' cake!

author: CatalinaWOW
author_rank: Super Contributor
timestamp: May 13, 2020, 08:53:36 pm
content: And remember attitudes toward HV weren't so fearful then. Every radio had from 150V to 450V inside. TVs had 15-35kV on the CRT. A huge number of stores had 15-35kV transformers to power their neon signs. Familiarity bred a certain contempt.

author: TimFox
author_rank: Super Contributor
timestamp: May 13, 2020, 09:19:41 pm
content: Note that the Triplett meter had an extra input connection (unshrouded banana) for the 6000 V input. I wonder if it used an external probe?

author: rsjsouza
author_rank: Super Contributor
timestamp: May 13, 2020, 10:26:55 pm
content: Not according to its manual straight from "the source" (CIA)https://www.cia.gov/library/readingroom/docs/CIA-RDP70B00584R000100220001-9.pdf(the only mention of high voltage probes is coverinh 12kV and higher)

author: calzap
author_rank: Frequent Contributor
timestamp: May 13, 2020, 11:53:01 pm
content: I owned and drove a Corvair for a few years. My mom gave me the money to buy it from my dad, and he was selling it cheaply. I really enjoyed it and the way it handled. It was a medium sized car (for the time) with a relatively heavy opposed-six, air-cooled engine in the rear. Main difference between it and other cars of the time was that you needed to be a little slower going into a corner, but could accelerate midway through it. Start a corner too fast, and that heavy rear could swing around, wheels could lose their grip, and a spin would ensue. Once you got the hang of it, it could be fun to go into a curve and let the momentum of the rear finish the steering. I drove it on gravel roads, snow and ice without a problem. It had great traction because the engine weight was over the driving wheels, which was unusual at the time. I think accidents occurred because its handling was so different, and some folks couldn't adapt.Biggest problem for me and caused me to get rid of it wasn't the location of the engine but another design feature. It was a split block engine with the two halves bolted together with a gasket in between. Eventually, the gasket started to deteriorate, which had two consequences. First was oil leakage. Second was more serious. Recall that it was an air-cooled engine. So to heat the cabin, air was circulated through a chamber attached to the engine. When the main gasket started to fail, crankcase/exhaust gases started entering the heater chamber. Not comfortable to drive in winter with the windows open to avoid asphyxiation. Replacing the gasket was very expensive because the engine had to be pulled to do it. So, I traded it to help buy a pickup.Mike in California

author: 25 CPS
author_rank: Frequent Contributor
timestamp: May 14, 2020, 04:06:44 pm
content: Quote from: CatalinaWOW on May 13, 2020, 08:53:36 pmTo a degree; those high voltages were familiar but the lack of current delivery with those sources could definitely lead to contempt for sure because the output of those were measured in mA vs. thousands, potentially many thousands, of amps from a traction power substation that's available on the supply side buss bars inside a propulsion package in a streetcar or subway car. A better comparison would be large industrial electrical distribution like 600 v three phase which is common in Canada or 480 v three phase common elsewhere with a similarly large current capability.Quote from: rsjsouza on May 13, 2020, 08:37:03 pmI've got a nice army surplus Bach-Simpson 635 that takes care of my 6 KV needs. No problem there!