Thread: 32 Volta

I think that was the common phrase used but was in fact 36V but to allow for voltage loss and drop in the wiring, it was commonly called 32V.
In the beginning most systems were done by what they called 'Accumulators' or even 'Capacitors' and could be recharged with a motor generator set.
I have seen different versions of an 'Accumulator' from a single cell glass jar connected to to others to what we use today.
The word 'Capacitor' seems to have meant it had the 'Capacity' to store electricity as a battery does rather than todays use in electronics.
Lighting would not have been the prime use of these systems for most as they either used candles or 'Oil' (Kerosene) for lighting but a Radio needed power.
I read the practice in rural areas was to take your battery to a local garage for a charge and then with judicious use it would run the Radio for an hour or 2 after Tea.
It wasnt until the 50's that many areas finally got connected to the Grid we have today.
After all 3 X 12V batteries in series = 36V on a good day but with loss due to connections etc, 32V may be more accurate overall.

One day at work I was talking to a relieving Railway Signal Electrician and he couldnt work out why at one location just on 2 miles away all the relays and other equipment was built for a specific DC voltage that wasnt used any where else.
When I told him that some years before there had been a bank of large Tractor sized Lead Acid batteries installed under the Signal Box at some past time.
This was now around 1970 and the batteries had long gone and had been replaced by a 33KV AC mains when the Western Electrification was planned but never completed.
He went away and with pencil and paper, finger and toes worked out that to supply the DC voltage from these batteries to that location 2 miles away there would be a specific voltage drop and so everything there was made in the workshops to suit the supply available.
When they made the AC Mains available to the location, they left all the old equipment in use and just adjusted the input voltage to match as it was cheaper than removing and replacing it.
This was still functioning as late as 1994 and may well be still in use now, 60 years later.

Just curious why the actual 32 volts. I understand the 3 x 12 volts in series, but why not 24 volt or 48 volts? 24 Volts you could hook up the truck to run things in a pinch. There must have been a good reason for 32 (or 36) volts.
I think there is still an old (kerosene ??) generator for the system still up on the farm, from memory had an unusual mechanical speed regulator that caused issues a lot, probaly hasn't been started up since the 70's.

It is weird isnt it but why do they set the DC limit of an arc welder at 28 Volts ?
I wouldnt be surprised if the '32V Lighting Plant' did run on kerosene as it was cheap and readily available and lots of tractors did back then.
One old tractor I saw used petrol to start then you switched over to Kerosene and boy did it stink.
Over the years there were different Tax rates for fuels depending on if it was for use in a standing plant, farming or on road going to market so naturally to keep costs down, you bought engines and fuels and hoped they didnt alter the Tax rates too soon.
Even today we still call a Car battery 12V when in fact at full charge its closer to 15 Volt but for convenience we stick to the old 2v per cell measurement.

Originally Posted by gordon_s1942

I wouldnt be surprised if the '32V Lighting Plant' did run on kerosene as it was cheap and readily available and lots of tractors did back then.
One old tractor I saw used petrol to start then you switched over to Kerosene and boy did it stink.

That brings back some memories.

Growing up in South Australia in the 1950's, a family friend was an electrician. In the late 1950's, SWER lines were being installed, and farms were being converted from 32 volt dc systems to 240 volts ac, and I was permitted to accompany him as he did this. It probably garnered my interest in things electric & electronic, as it turned out. Most of the time, I think I was just a gofer for tools & stuff, the rest of the time I just free ranged wherever we were until it was time to go.

A lot of the places we went to had kero fridges, chip heaters for the bath, & wood stoves/slow combustion heaters with or without hot water attachments. There were even 32 volt washing machines & 32 volt vibrator wireless sets as I remember.

The power sources were usually Dunlite wind generators, augmented by a variety of stationary gensets, connected to garden varieties of batteries, & then the load, by fencing wire, or its equivalent. Distilled water & a hydrometer were essential.

Some of the gensets, as well as tractors, used to run on power kero (which my dad used as weedkiller), and were the petrol start/kero run type that were switched over when engine running temperature was high enough.

The power kero could be purchased from the local BP/COR servo down the road from where I lived. It was in one of the dispensers where the fuel was pumped up into a glass bowl above head height, with gradations on the side to show volume, & then gravity fed into either a fuel tank or container. My thrill was to be allowed to pump the lever to get the fuel up into the bowl. I've no idea what the fuel cost was per gallon (4.54 litres), but a couple of bob (20¢) comes to mind!

2/- a gallon pumped up in the same sort of 'Bowser' in Katoomba between 1954 and 63.
We had the good old Fireside heater and my grandmother had a Valor brand and that thing stunk when lit unlike the Firesides.
It was around the early 60's I believe they added the blue dye to household kerosene to distinguish it from either Power Kero or Petrol as most fuels were just clear liquid and there had been a few cases of the wrong fuel being sold.
I also have a feeling that Power kerosene which was intended for use in tractors etc had a lower tax attached and was cheaper.
The fantastic 'Silent Knight' kerosene refrigerator served both city and country as it worked well and was very cheap to operate as I remember my great Aunt had one at Pennant Hills, then a rural suburb of Sydney and when she moved to Ashfield, she took the Silent Knight with her.
People forget that many Towns didnt get electricity until the 1920's and it only covered the immediate area so if you were more than a mile from the Town center it most likely it didnt reach the area until after WW2 and the mid 50's and even then it was generated locally as the Grid system of today only began in the late 50's.

Thanks all, I guessed it was likey regulations rather than a technical reason. I'll have to have a look at some of the old kit next time I am up at the farm, maybe rescue some of it for old time sake.

Note gordonwh40 mentions '2 Volt cells' were used hence the total voltage of 36v but those cells most likely put out slightly higher, like 2.3 to 2.7V but no doubt those forming the rules wouldnt have considered that a problem because that only occurs when a battery is fully charged and it drops back to a nominal 2V shortly after, plus the resistance in the wires pulls it down too.
As if the 4 volt difference would cause harm to a person is very unlikely.
Higher voltages would make bigger sparks if a problem occurs so as 32V is quite sufficient for most needs its not economical to go higher.
Lots of those analog Volt meters wernt too precise like a 7 digit meter is today when measuring voltage.

You can still buy those 12v to 32V plugs and sockets with one pin offset at 90 degrees to maintain the correct polarity for when connecting to batteries or appliances, light globes dont care what the polarity is in most cases.
Many small generators available today use the same design on their 12v outlets.