Where was the mains voltage 140 Volts AC ?

[broadgage]

Originally Posted by emeritus

Thanks for these. Presumably A = AC and C = DC? From a quick scan the closest to 140V are the 150V supplies for Leyton and Leytonstone, but these were apparently DC alternatives to 230VAC.

I am intrigued by the 400, 440 and 450V AC supplies for Foulridge (P118), Lochaber (P121); Norton (P122); Tanfield, Tantobie and Trawden (P125), as the sole supplies for these places.

I would presume that the 400, 440, and 450 volt AC supplies were intended for industrial use, not domestic.
I presume that a householder could take this supply and install a transformer for lighting.
Or more likely, perhaps a much lower voltage DC supply was also available for domestic use.

[Nicklyons2]

Interesting to see 'C' for continuous current was still the preferred usage for what we now call DC this 'late'. Sadly this list doesn't give us the benefit of the plethora of frequencies in what are 'innocently' labelled a.c. Denaby Main for example was hive of 40Hz activity and, though not shown on this list, Barnsley had been DC and was being changed over to a.c. in this era.

To the original 140 Volt question; I have it in the back of my memory that some Italian equipment we had many years ago had 140 volt tappings as well as the 220 one we used. As Italy was a lover of 2-phase mains may I propose it as V-line on a 2-phase 100V system?

[SteveCG]

Thank you all for your info.

I'd love to know the region Grundig had in mind for their TK 35 voltage selections ! Perhaps others with access to Grundig service data might check as to what other models had this 140 Volt option? It could help to pin down the era at any rate if not the exact area.

I remember reading that some UK Railway companies used 25 c/s because the lower frequency was more reliably generated. However the down side was that there was a little flicker to be seen looking at tungsten filament lamps in the stations.

[hannahs radios]

Hi yes indeed Italy did have 140 volt supplies in places in places. I'm not sure where but i think it might have been North Italy as it was their version of the Austrian 150 volt system. Many years ago a friend of mine was working in an old Austrian substation and saw a socket labelled 150 volts AC 50 cycles he measured it and sure enough there was 155V AC coming out.

[broadgage]

Re post #23, lower frequencies were used by railways for two reasons, firstly in the case of electric traction, or indeed other high power uses, then lower frequencies were more suited to early AC electric motors.
IIRC 16.6 cycles is still used in Belgium.

For electricly powered signalling equipment, then a different frequency to both the local AC mains and any electric traction was preffered in order to reduce interference.

Frequencies below 50 cycles are not ideal for lighting due to lamp flicker, lighting was often either DC or gas in such cases, or somtimes 6 volt lamps worked from transformers.

[QQVO6/40]

Originally Posted by Broadgage

16.6 cycles is still used in Belgium.

I was just thinking Broadgage that isn't 16 Hz the magic frequency with lighting to bring on an epileptic fit in a person that suffers from that condition?
Somewhere in my dusty long ago past I remember doing some electrical work on a sheep station in the far West of New South Wales and some of the electrical equipment was 140 volt 50cps. I had not given it any thought until this thread popped up. I am guessing it might have been to suit some particular electrical equipment at the time because a lot of the other appliances around that property were 32volt DC which was common for outback properties around that period.
Just a side note. Some more distant parts of the state run electrical grid in Western Australia had a nominal voltage of 265 volts at 50Hz. I remember it well as over this side of the country it was a nominal 240volts. I used to put in lighting on rural properties over here and when it was towards the end of a line, the voltage would fluctuate quite a bit with the varying loads. Especially at milking times of an evening. Quite often I would use normal incandescent light bulbs intended for Western Australia as they were rated for 265volts and would last for many years in this sort of environment.

Enough of my banter for now. Bye.

Cheers, Robert.

[broadgage]

16 cycles is not really suited to lighting, which is why that and other frequencies below 50 cycles have fallen out of use except for specialist applications.

If such a low frequency must be used for lighting, one way of reducing flicker was 6 volt lamps from transformers. A 6 volt, 60 watt lamp would have a very thick filament and not flicker much.
A 240 volt, 60 watt lamp would flicker very displeasingly at 16.6 cycles and not be viable for normal lighting. (it might be acceptable as secondary or emergency escape lighting in premises where the main lighting was gas, or DC, or higher frequency AC)

Lamp flicker is roughly inversely proportional to lamp current.
It is perceptible even at 50 cycles with high voltage, low wattage lamps such as 240 volt, 15 watt.
Americans visiting the UK in years gone by used to complain that they noticed line frequency lamp flicker.
American lighting was of course 60 cycles, and for a given wattage lamp was also at twice the current which also reduced flicker.

[winston_1]

Originally Posted by QQVO6/40

I spent some time in the early 70's in Port Hedland WA and noticed light bulbs (globes over there) with 260v on them. When I asked about this I was told the voltage was 440/254. I also was told that previously 40c/s had been used.

[emeritus]

I've now managed to dig out my copy of the 4th edition of the ITT Reference Data For Radio Engineers, 4th edition, 1956, which I recalled has a table of the "Principal low-voltage power supplies in foreign countries", derived from a US government publication dating from 1954.

It can be seen from the attached PDF that, while no 140V AC supplies are listed, Italy has 150V (and 127V) given as its predominate (Sic) voltages, along with 160V and voltages as high as 280V. In addition to their respective principal voltages, less common supplies at 150V existed in The Netherlands, Norway, and Rumania, and at 135V in Ceylon and China.

While 50 and 60Hz predominated, 25, 40, 42, 45, and 76 Hz supplies are noted, although frequencies are not associated with voltages where more than one exists for a given country. The existence of 40Hz in Australia is mentioned, but its 265V supply is not. However, the list does not claim to be comprehensive: see the "Caution" note at the end.

[SteveCG]

Emeritus - an interesting list.

I wonder whether my memory is slipping and the Grundig TK35 tapping was 150 V !

[colly0410]

The 150 volts supply I refer to in post # 7 is in Columbia according the ITT ref data in post # 29. I knew it was somewhere in South America. Thanks for info Emeritus..

[timohaveri]

Originally Posted by SteveCG

I wonder whether my memory is slipping and the Grundig TK35 tapping was 150 V !

It says here -> http://www.radiomuseum.org/r/grundig_tk35.html that the Grundig TK35 has a 150 V voltage tapping.

[SteveCG]

Ah, thank you timohaveri. Now I know that my memory is slipping - but will I remember that point??

All this discussion of different mains voltages make me wonder what the TK35 (and other multi-voltage tapped domestic equipment) did for the value of the mains fuse.

[dave walsh]

An interesting thread starting with an apparent 140v supply voltage "anomaly" that has expanded to illustrate the variations over the years and local conditions including voltage and frequency settings to suit demand and expedience. As mentioned in post 1* 140 v is not so far from the 115/120v in America and elsewhere. The comments on supply operating frequency [from 27*] explain a few things. I didn't know that lighting flicker is a problem below 50 Hz but I had heard that UK tram supplies ran at 16 Hz, giving rise to a characteristic [now nostalgic] buzzing sound under rainy conditions. I relate these things to the audio range ie "mains hum" at 50Hz, bottom 'E' on a bass guitar is 33 Hz.
I understand that the resonant frequency of human cells is not so far away ie 8-9Hz and exposure to this is possibly lethal.
Dave

[emeritus]

16 2/3 Hz may have been used in some locations to convey power from the power station to local substations for conversion to DC, but I understand that the trams themselves usually ran on DC. Until the 1960's London Transport's own power stations generated electricity at 11,000V at 33 1/3 Hz for distribution to substations equipped with rotary converters which converted it to the 660VDC used by its trains. I thought that most municipal tramways used 660V DC supplies generated directly at local power stations. This was certainly the case in Cardiff, where one of the factors in scrapping the trolleybus system was the life expiry of the power station that supplied the public DC supply and the lack of other customers (by 1969, the only other remaining one being the power lab of the electrical engineering department of the university).

I wonder if Columbia's old system explains the 150V voltage rating embossed on a bakelite US-type plug I recently bought from Maplin (although the corresponding line socket made from modern plastic is only rated at 125V)?

There are no 150V supplies explicitly mentioned in the corresponding table in the 6th edition (1983). For some countries (not Columbia) the existence of "others" is noted, and only 50Hz and 60Hz frequencies are shown.

[Herald1360]

Wasn't 16 2/3 Hz used by the railways because you got the transmission advantages of AC- transformers etc- but series wound DC traction motors would still work on it (maybe with laminated rather than solid field cores).

Modern variable speed AC drives were a long way in the future and big rectifiers were expensive.

[cmjones01]

Originally Posted by Herald1360

Wasn't 16 2/3 Hz used by the railways because you got the transmission advantages of AC- transformers etc- but series wound DC traction motors would still work on it (maybe with laminated rather than solid field cores).

Modern variable speed AC drives were a long way in the future and big rectifiers were expensive.

That frequency is still used in Germany, Austria, Switzerland and much of Scandinavia, and I believe it's exactly for that reason.

[kalee20]

Originally Posted by broadgage

Re post #23, lower frequencies were used by railways for two reasons, firstly in the case of electric traction, or indeed other high power uses, then lower frequencies were more suited to early AC electric motors.

Isn't it also the case that low frequencies were used to reduce transmission losses?

If the 'return' line is via the rails themselves, then, these being ferrous and magnetic, skin effect will kick in at a very much lower frequency than for copper.

[hannahs radios]

Hi, when i was about 10 years old I can remember going to Paddington train station and noticing that the lamps there had a flicker. My question is did 25 and 16 cycle supplies get used in main stations like that or was this some other effect in play?

[Nicklyons2]

Originally Posted by cmjones01

That frequency is still used in Germany, Austria, Switzerland and much of Scandinavia, and I believe it's exactly for that reason.

There are 2 major systems of mainline overhead electrification used in Europe, broadly speaking as stated above the 'Germanic' countries use 15KV 16Hz and the French, Holland, UK etc use 25KV 50Hz.

As I understand it, the use of low frequency supplies (16 & 25Hz) dates from the very early years of the electrical industry and was an early attempt to practically utilise induction motors for traction. The modern methods of control were unavailable then but there was still a desire to try and use induction motors for they are cheaper to build and, not having brushes & commutators to wear, are lower in maintenance. The early induction motors and controllers apparently worked much better on low frequencies. Remember that traction was an important use in the early days of the electricity industry; almost no domestic usage, but every large town and city had a tram system. I believe success was only limited as evidenced by the fact that many systems of the period ended up using 550-750 VDC. Clearly the Germans persevered a bit longer.

At this point I think I should bow out and leave it to the 'Heavy Current' experts such as Lucien to give the definitive explanation,
Nick