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General Vintage Technology Discussions For general discussions about vintage radio and other vintage electronics etc. |
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25th Jan 2021, 9:10 pm | #21 |
Heptode
Join Date: Jul 2016
Location: Portland, Dorset, UK.
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Re: Standardisation of Mains Voltages
Going by what I've read on rail forums there were many different ways the bulbs would be wired too depending on where the power was derived from and I believe unpowered coaching stock, EMU's and DMU's all used different voltages. Also some bulbs were 3 lug BC to dissuade theft though I hate to think what would happen with an 80V bulb on 240V!, I would guess very bright for a second.
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25th Jan 2021, 9:37 pm | #22 |
Dekatron
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Location: Leominster, Herefordshire, UK.
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Re: Standardisation of Mains Voltages
Not quite as exciting as a 24V BA22D on 240V
Bulbs in our house were sometimes "liberated" from various sources
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25th Jan 2021, 9:57 pm | #23 |
Dekatron
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Re: Standardisation of Mains Voltages
My understanding is that, before improved manufacturing techniques allowed filaments to be manufactured with closely-controlled resistances, bulbs were tested after manufacture and sorted according to the voltages they were suitable for.
My Victorian GEC catalogue includes an illustration of a bulb marked for 105V. I believe that early electric companies may have provided different voltages in cooperation with the bulb manufacturers to allow most of bulb production to be used. Before the invention of Dumet, part of the reason for the high cost of bulbs was that the only metal capable of wetting to glass to provide a hermetic seal and having a matched coefficient of thermal expansion was platinum. Things were different by the Edwardian era: by 1905 the manufacture of GEC's "Robertson" lamps included a semi-automated step of an operative immersing the mounted filament in bath of liquid benzene and applying current to make the immersed filament glow. As well as removing any localised thinner hot spots by depositing carbon, it allowed the manufacture of filaments with precisely-controlled resistances, current being automatically switched off when the required resistance had been reached. So there was then less need for lots of slightly different mains voltages to make use of bulb manufacturing spreads. Last edited by emeritus; 25th Jan 2021 at 10:04 pm. Reason: Typos |
25th Jan 2021, 10:08 pm | #24 |
Moderator
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Location: Oxford, UK
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Re: Standardisation of Mains Voltages
Of course, before the 1920s most domestic premises used gas or oil lighting, and electric light was a prestige thing for specialist applications. A few areas of central Oxford still used gas street lighting until the 1990s, and there are lots of other examples.
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25th Jan 2021, 10:17 pm | #25 |
Dekatron
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Location: West Cumbria (CA13), UK
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Re: Standardisation of Mains Voltages
I certainly remember gas street lamps in the area of Headington (a suburb of Oxford) where I lived in the 1950s and 1960s. I don't recall when they were eventually replaced with electric ones as I moved away (to areas with no street lighting) at the start of the 1970s and only passed through thereafter.
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25th Jan 2021, 10:32 pm | #26 |
Dekatron
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Location: Warnham, West Sussex. 10 miles south of DORKING.
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Re: Standardisation of Mains Voltages
I have a copy of 'The Practical Electrician's Pocket Book 1925 edition.
It lists Weymouth. Generating station owned by Corporation. Resident Engineers name, G. Nicholson. Voltage of supply, 230 & 460 DC. Cost. Lighting, 7d. Heating and cooking, 2d. Power 2d and electric vehicle charging, 2d. [Old money 240d = £1] It lists all the generating stations in England, Scotland, Wales and Ireland. An incredible mixture of voltages frequencies and DC from 100v-250v with one entry for mining pumps at £6500v! It must have been very difficult for radio dealers and in fact anyone dealing with electrical appliances as some streets had differing supplies in the same terrace of houses! John. |
25th Jan 2021, 10:53 pm | #27 | |
Nonode
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Location: Cambridge, Cambs. UK.
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Re: Standardisation of Mains Voltages
Quote:
Martin
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27th Jan 2021, 12:49 pm | #28 | |
Octode
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Re: Standardisation of Mains Voltages
Quote:
I have vague memory of an electrician from SWEB visiting and changing some appliances belonging to the landlord like the elements in the cooker and providing some spare bulbs dad changed the TV and radio back to 240V and we carried on, some older stuff like a free standing water heater were just left presumable to have a shortened life. Most of the changes were around 1965. There was a previous post on this theme here https://www.vintage-radio.net/forum/...ad.php?t=41380
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27th Jan 2021, 1:09 pm | #29 |
Heptode
Join Date: Jul 2008
Location: Hereford, UK.
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Re: Standardisation of Mains Voltages
#24, Still gas street lamps in parts of Malvern
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27th Jan 2021, 5:07 pm | #30 |
Dekatron
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Re: Standardisation of Mains Voltages
1,500 gas lamps remain in London apparently.
https://www.ppsi.org.uk/ppsi_new/Exp...s%20Lights.pdf
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27th Jan 2021, 5:24 pm | #31 | |
Octode
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Re: Standardisation of Mains Voltages
Quote:
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27th Jan 2021, 5:37 pm | #32 | ||
Nonode
Join Date: Jan 2010
Location: North Somerset, UK.
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Re: Standardisation of Mains Voltages
Quote:
Sockets on 200 volts to 250 volt DC circuits should preferably have been 3 pin with an earth, but not all were. On 100 volt to 125 volt circuits earthing was a lower priority and 2 pun outlets were common. 13 amp fused plugs and sockets were not meant to be used on DC circuits. A radio set should work equaly well on either polarity, most householders probably did not know or care if their supply was positive or negative. A correctly functioning set, or one with a valve rectifier would suffer no harm if connected with the wrong polarity. A defective metal rectifier could blow up the smoothing cap and the rectifier. DC supplies were generaly relatively smooth with little interference. |
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27th Jan 2021, 5:52 pm | #33 |
Nonode
Join Date: Jan 2010
Location: North Somerset, UK.
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Re: Standardisation of Mains Voltages
Domestic supplies of less than 200 volts generally "went out with war" though a handful remained.
Radio and TV sets usualy had a tapped mains dropper resistance with several settings to cater for voltages between 200 and 250 volts. Heaters and cookers were usually supplied in two versions, one for 200 volt to 220 volt circuits and another version for 230 volt to 250 volt circuits. Light fitting were suitable for any reasonable voltage (unless fluorescent, still rare) Lamps had to be the correct voltage and the local electrical shop would stock a range. Trains used various odd voltage lamps. Trams used 110 volt lamps in series groups of 5 from the 550 volt supply. Trolley buses used 34 volts from an on board converter. |
27th Jan 2021, 6:27 pm | #34 |
Dekatron
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Re: Standardisation of Mains Voltages
Lynmouth had one of the last public sub-200V public supplies: 100VAC at 100Hz from a local generating station which was destroyed in the 1952 flood. It was mentioned in a thread here some years ago that Lynmouth was due to have been connected to the national grid the following year, so the flood brought it forward.
Last edited by emeritus; 27th Jan 2021 at 6:31 pm. Reason: Typos |
27th Jan 2021, 6:38 pm | #35 | |
Dekatron
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Re: Standardisation of Mains Voltages
Quote:
Such switches - whether on sockets or light-switches or big metal-clad fuse-boxes - always changed-over with a distinct and satisfying clunk/clang/click. Modern "AC Only" switches just use a cam-and-rocker mechanism which lack the quick-contact-separation mechanism with its reassuring audio-feedback. |
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27th Jan 2021, 6:48 pm | #36 | |
Nonode
Join Date: Jun 2016
Location: Bognor Regis, West Sussex, UK.
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Re: Standardisation of Mains Voltages
Quote:
My father, who was born in 1923, used to recall that as a child his house in Littlehampton was fed from DC, he recalled the lights pulsing slightly from the slow revving generator. The generator was situated in Duke Street, the site now houses an electricity sub station. Peter |
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27th Jan 2021, 7:17 pm | #37 |
Nonode
Join Date: Jan 2010
Location: North Somerset, UK.
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Re: Standardisation of Mains Voltages
Indeed, generators driven by low speed reciprocating engines tend to produce a pulsating output, which is most displeasing on lamps.
If several such engines are interconnected, excessive circulating currents may result. |
27th Jan 2021, 8:04 pm | #38 |
Dekatron
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Location: Warnham, West Sussex. 10 miles south of DORKING.
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Re: Standardisation of Mains Voltages
My Nan lived in Havelock Road Wimbledon and was connected to the old 110v AC loop line.
It consisted of what appeared to be a 6mm lead covered cable that ran neatly along the back of the houses with the input to each house looped through the brick wall high up on the back kitchen wall. [My dad always wondered how the whole lot didn't go up in flames] The box used to receive a clout from a broom to stop it cycling! It terminated into a solenoid and a single fuse. The solenoid was wired in series with the house lighting supply that was limited to about 150w. If you exceeded this load the solenoid would come into operation and the lights would flash on and off until you switched a light off lightening the load. Nan's Philco 444 was run from an auto transformer that stood open behind the radio on a small oak table in the corner of the back sitting room fed from a 2amp socket, the only one in the house. The supply of course was only intended to be a lighting circuit. The generating station was owned by Wimbledon Corporation based in Durnsford Road. You could use as much power as you liked providing it was no more than 150W at any one time with a flat weekly charge of 2/6d [Twelve and a half pence] My dad lived long enough to see the old 110v power station chimney felled in 1962. He died the following year. I believe the old system fed terraced houses around the Wimbledon area including Raynes Park. One of my customers in South Road Merton had a transformer in a sort of rabbit hutch feeding the then dead system in his front garden. It was discontinued in 1961 and I believe it was installed around 1885. I have never been able to trace any reference to it on the Internet. There are still lengths of wire and the solenoid boxes in front porches of houses in Haydons Road that were wired along the front rather than the back. I was absolutely fascinated by the system when I was a kid. John. |
28th Jan 2021, 12:15 am | #39 |
Dekatron
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Location: Greater Manchester, UK.
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Re: Standardisation of Mains Voltages
That made fascinating reading John,
Real social history, especially the bit about banging the box with a broomstick to stop the lights flashing. I hate to think what that would have done to a fridge compressor, but I guess those that wanted a fridge got one from the gas showroom.
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28th Jan 2021, 10:10 am | #40 |
Nonode
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Location: Stafford, Staffs. UK.
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Re: Standardisation of Mains Voltages
I know that Nuneaton went through two changes. I was told this when we visited the local cinema projection room.
The original projectors were still in use, in the late seventies or early eighties. The cinema was built in the thirties. The projectors used arc as the light source, and were installed when the supply was DC. Later the town changed to DC, so a mercury arc rectifier was installed, along with a bank of resistors in 'the resistor room'. Later the AC voltage changed again and became the national standard, so a transformer was added. All of this was still in use. I bought a house there which had 'interesting' wiring, again still in use. It was for lighting only. There were two ceramic fuse wire holders one for L and one for N. The isolator switch was two pole, by way of two single pole switches and a bit of wood joining the two toggles. I assume this was a carry over from being installed back in the DC era. I also think this had all been put in after the house was built since I also found the pipes for the gas lights. |