Funicular railway power question

Why would they be? If the rails were earthed...

a three phase supply doesnt have to have each limb symmetrical with respect to earth.

Consider a star or delta transformer with one phase earthed.

Feeding overvoltage back into a low impedance supply.

I just spent ten minutes trying to check you out - and failed. I can't find anything saying that in either English or French.

One of the few other such systems is the Jungfraubahn, which I went on a couple of years ago. I'm damn sure there isn't a live rail - I walked across the track - so your guess must be correct.

Or you have a source I couldn't find!

Andy

You should be able to have anything earthed if you use a transformer for the supply with a separate secondary. Brian

If you have ever played with slot racing cars the breaking when you bring up the plunger is done by shorting out the track. Brian

It was done on large three phase motors on radars which tended to have to be tested with covers off, and it was most certainly earthed on one rail. Brian

Tim+ expressed precisely :

It could have been single phase and neutral on the wires, or two phases and an earth via the earthed rail.

The motor would likely be synchronous, driving a worm gear. The drive would only allow the car to decend limited by the motor's speed.

I think you mean a rack Railway using cogs on a toothed Rail between the running rails.

Funiculars are rope hauled and purists reckon there must be an up and down cabin/carwith one counter balancing the other either by using water filled at the top or a motor to overcome any weight difference, even so the term as spread to other types but they all have a rope permanently attached to the vehicle which differentiates them from cable trams like in San Francisco where they can be released by a grip mechanism.

As for the 3 phase electrification there are not many examples left of this style which was a way of using AC at the beginning of the 20th century when motor technology was in its in infancy and speed control crudely done by pole changing, it also allowed for easy regeneration by using the motors as generators and feeding back into the supply. Frequencies were low as again motor technology was not advanced enough at the time for higher. The biggest user of the system was Italy where the 3600volt 16.7 Hz system remained in use on a good proportion of the network till the mid 1970?s. Junctions were very complicated as the two overhead wires had to have long insulated sections over pointwork and to cope with that the locomotives had a strange look due to the collector arms reaching out or extremities to cope with crossing the neutral sections.

At one time the system was almost adopted by the Metropolitan Railway in London to replace the original steam traction as electrical expertise for such things existed in Eastern Europe with the Ganz company of Budapest and not here at that time and their tender had been accepted. Only the arrival of American finance on other parts of what would become the London Underground network and the board of trade arbitrating in favour of the others whose American financier prefered the DC live rail system he knew from Chicago stopped the contract.

GH

There's a link you must have missed.

???

It is three phase and the rail is one phase and is earthed.

Phases are only phased with respect to each other, they dont care about their relationship with 'earth'.

Voltage is not absolute, It is relative, as any bird sitting on a 132KV line can tell you

He does, you can see the rack very clearly in the pictures on wonkypedia.

Had me confused as funiculars are passive not electrically powered. Two cars llinked via a rope going round a wheel at the top. Make the one at the top heavier than the one at the bottom (commonly done by adding water to a tank in the top car and letting the water out of the lower) and gravity does the rest.

There are rope hauled "inclined elevators / lifts" that are powered but at a stationary winch not in the car.

With pure 3 phase (ie only the three phases no "neutral") the voltage between the phases is relative to each phase. Bonding one (only one!) to earth doesn't affect these relative voltages.

The Natural Philosopher has brought this to us :

I see how that would work now. I had in mind star, with the centre point grounded - a delta output transformer with one point to ground would do it.

Marland formulated the question :

Thanks, I have always wondered how they worked!

Probably more than you really wanted to know at

GH

You really have to admire the ingenuity of people who managed to make these work so well! It's (sort of) a logical successor to Brunel's atmospheric railway.

Oh well,I?m glad someone does. ;-) Our physics classes never progressed to three phase power when I was at school and I?ve never had a need to understand it in any depth (or at all really) since then.

Tim

Blimey.

I sort of thought that anyone in a DIY group would have basic electrical knowledge

The only one I have ever actually worked on was at my mate's small business. Unless you have three phase at home for a lathe I'd have thought even fairly experienced DIY people wouldn't come across them.

You call it ?basic? but it?s knowledge needed by 0.01% of the population I would hazard. I guess the education system I went though didn?t see it as important.

Of course I could spend time reading up on it but without any need to understand it it any depth at all, I prefer to do other things with my time.

Hands up every DIYer here who dabbles with three phase power?

Tim