Class 350 Cabling between vehicles

[KingDaveRa]

I took a train into Euston yesterday, and was looking at the cabling on the Class 350 Desiros between the vehicles. There's probably about 8, VERY thick cables joining them up. Does anybody know much about them? Obviously they are for traction power, but I'm curious how they are cabled up. Is it DC from the power car to the others? Is there a cable per motor or something? Hopefully somebody who works on Desiros might know more.

 

[swt_passenger]

On a 350, the motors are on the four bogies of the two outer cars, both Driving Motor Standard Open (DMSO), but all the power comes from the pantograph fitted trailer car. The term ‘power car’ isn’t generally used on such a configuration. So the power has to pass from the transformer on the pantograph car (having been rectified to DC) to both end cars. It isn’t going to be as simple as a cable per motor, as the 3 phase motor voltage is derived in the traction converter on the motor cars. I don’t know exactly what each cable does, but I’m pretty sure that using a few smaller cables in parallel for the DC distribution will be more ‘flexible’ than the same cross sectional area in a single heavy cable. There’s also all the auxiliary power and control wiring of course.

 

[37057]

Not sure about each and every cable but there are schematics available for when the time comes to fault find etc.

Each traction converter (two of, one per DMOS) are fed two separate inputs of single phase 460v AC from the main transformer (PTS, so needs inter-car cabling).

Auxiliary converters are on the same car as transformer so no inter-car connections required for input, however 3 phase 400 AC output is distributed across all cars to power the main compressor, HVACs, plug sockets, traction converter cooling pumps and fans etc.

Only one 110v battery pack on a 350, so distribution of DC power is between all cars too.

Control circuits including MVB, TCN network cables also run through them.

Bodyside convection heaters are powered straight from the transformer so the supply cables are distributed between cars.

Also a recent mod is the WiFi cables that run above the gangways.

 

[KingDaveRa]

I assumed it to be DC power, given the thickness of the cables. I assumed the control gear was located on the vehicle with the pantograph, but that seems messy and inflexible as it'd make sense to send a flat current out to all the other cars, and let them do their thing, so it sounds like it's possibly three phase onto each other car? Probably a power bus along the length of the whole unit?

From what I recall seeing, there's other cabling on the other side, so I think the cables I saw were purely for power. They all looked identical, at least.

 

[hwl]

The 350 /1 are dual voltage so there will be a 750V DC bus through the train as well (as per SWT/R 450s)

 

[37057]

3 phase for auxiliary machines. The auxiliary converter is "two in one". One power module powers the car with the compressor and the other module powers the remaining (if I remember correcly, they may power two cars each - I've not got my notes with me). If there's a fault with they can cross feed and load shed the HVACs. That's the only three phase running between cars. The rest is supply to traction converters/bodyside heaters and train control wiring.

That's an AC Desiros anyway. I expect DC and dual voltage to differ. AC units still have some components fitted to allow them to be dual such as shoe gear pipework etc. Some cables may only be "spare".

 

[KingDaveRa]

Thanks, sounds like a fair bit of redundancy in there.