Azuma Power Sockets - no power through neutral sections

[samuelmorris]

I'm not sure of how the Azuma's are wired electrically but my understanding is the Mark 4's have a battery that supplies power for the door circuits, PA and lighting and I always assumed that it was this battery that the inverters for the 230V AC supply are connected to that supply the sockets. There will be a battery in each coach and when the ETS drops out at a neutral section the inverter continues to operate. Presumably there's some sort of load shedding capability to save power for the emergency lighting and PA should the ETS be off for too long?

Maybe the Azuma's have a battery that supplies multiple coaches and so this arrangement wouldn't be practical?



I think I have read somewhere that some coaches (Mark 3 Loco Hauled?) have a catering low load switch that reduces the catering electrical demand. Do the Mark 4's have something similar or does all catering, even the buffet, have to stop?

Perhaps there are multiple inverters - you can hear the ones in Mk IVs very clearly and they power down in neutral sections.

 

[James James]

Perhaps there are multiple inverters - you can hear the ones in Mk IVs very clearly and they power down in neutral sections.

Inverters outside of the railway industry generally aren't noisy, are these different? (On many trains I can certainly hear the AC going on/off in neutral sections, I seem to remember that on my one and only Mk4 trip too.)

 

[ryan125hst]

You can hear the static converter on each Mark 4 coach from both the inside and the outside. These convert the Electric Train Supply feed (1000V AC or DC) to 400V AC three phase for the air conditioning, and 230V single phase for single phase loads, plus battery charging (110V?). There was a brochure about loco hauled Mark 3 coaches online a few years back that had this information and Mark 4's are similar as far as I know.

My understanding of the sockets is that they use an inverter connected to the coach battery that produces 230V AC. If the 230V supply from the static converters were used it would go off every neutral section which it doesn't on Mark 4's.

As Azuma's are EMU's, i'd imagine a static converter supplies more than one coach. There's probably one battery supplying more than one coach as well so that's why i'm assuming the above.

I'd love to know the actual configuration if anyone can provide it.

 

[hwl]

You can hear the static converter on each Mark 4 coach from both the inside and the outside. These convert the Electric Train Supply feed (1000V AC or DC) to 400V AC three phase for the air conditioning, and 230V single phase for single phase loads, plus battery charging (110V?). There was a brochure about loco hauled Mark 3 coaches online a few years back that had this information and Mark 4's are similar as far as I know.

My understanding of the sockets is that they use an inverter connected to the coach battery that produces 230V AC. If the 230V supply from the static converters were used it would go off every neutral section which it doesn't on Mark 4's.

As Azuma's are EMU's, i'd imagine a static converter supplies more than one coach. There's probably one battery supplying more than one coach as well so that's why i'm assuming the above.

I'd love to know the actual configuration if anyone can provide it.

You can hear the fans...

Correct -ish. Current EMUs (aventra desiro city etc) and IET/Azuma are wired very differently. The current way of doing things is that static converter is co-located with all the traction inverters in a big box so 3 boxes for 5car IET or 5 for 9 car feeding a buses for 3phase 415V (which can provide 3x single phase 230V between each live and neutral) as well as the separate lower voltage DC bus for the battery charging and control systems (110V)

 

[AM9]

Inverters outside of the railway industry generally aren't noisy, are these different? (On many trains I can certainly hear the AC going on/off in neutral sections, I seem to remember that on my one and only Mk4 trip too.)

The inverters used on all transport vehicles are designed to be of minimum weight/space with the necessary cooling, (normally air). If you think that inverters on trains are noisy, you should compare that with those on aircraft. Aircraft power systems usually run from a 400Hz source, (it mans that power inductors can be smaller with much less iron content). Input circuits buzz at 800Hz or higher with a 400Hz supply. Fans are of small diameter and are thus required to rotate at high speed to achieve the airflow mass.
Given the normal background noise of rail vehicles, inverters are designed to operate at sound levels compatible with that environment. Take even an early design of DC-DC converter, the class 319s which have a 300Hz'ish hum when under load. Considering that their load can be up to 1MW, they are pretty quiet, (converters have the same thermal/accoustic design issues as inverters).

 

[ryan125hst]

You can hear the fans...

That is a good point, I guess it must be because a static converter is..well...static so has no moving parts. They do have a very distinctive sound on Mark 4 coaches though.

Correct -ish. Current EMUs (aventra desiro city etc) and IET/Azuma are wired very differently. The current way of doing things is that static converter is co-located with all the traction inverters in a big box so 3 boxes for 5car IET or 5 for 9 car feeding a buses for 3phase 415V (which can provide 3x single phase 230V between each live and neutral) as well as the separate lower voltage DC bus for the battery charging and control systems (110V)

It seems sensible to locate the static converter in the same box as the traction converters. On a 5 car IET/Azuma at least, the transformer is located in the driving trailers which would cut down space for the static converter anyway. There can't be much under the two unpowered trailers in the centre of the formation though?

as well as the separate lower voltage DC bus for the battery charging and control systems (110V)

Do you know how many batteries each set has and which coaches they are in?

If you think that inverters on trains are noisy, you should compare that with those on aircraft. Aircraft power systems usually run from a 400Hz source, (it mans that power inductors can be smaller with much less iron content). Input circuits buzz at 800Hz or higher with a 400Hz supply. Fans are of small diameter and are thus required to rotate at high speed to achieve the airflow mass.

There's always a very distinctive noise when you board an aircraft, presumably due to the 400 Hz AC power in comparison to the 50 Hz AC we are used to (or 60 Hz in the States).

 

[hwl]

It seems sensible to locate the static converter in the same box as the traction converters. On a 5 car IET/Azuma at least, the transformer is located in the driving trailers which would cut down space for the static converter anyway. There can't be much under the two unpowered trailers in the centre of the formation though?

Which unpowered cars in the middle of a 5car? The end vehicle are unpowered with the middle 3 cars with traction motors...

5-car: DPTS-MS-MS-MC-DPTF
9-car: DPTS-MS-MS-TS-MS-TS-MC-MF-DPTF

 

[ryan125hst]

Which unpowered cars in the middle of a 5car? The end vehicle are unpowered with the middle 3 cars with traction motors...

5-car: DPTS-MS-MS-MC-DPTF
9-car: DPTS-MS-MS-TS-MS-TS-MC-MF-DPTF

Sorry, I meant the unpowered vehicles in the 9-car set in that sentence but failed to mention 9-car in it

 

[rebmcr]

Quite apart from screen brightness (which is a setting easily changed), it is objectively bad for a Lithium battery's health to undergo repeated interruptions in its charging cycle. One or two blips would be understandable, but nineteen cutouts on a London-Edinburgh journey is likely to cause early failures for regular travellers' devices.

I think that, in combination with oft-reported touchscreen problems, warrants conversion to a system that isn't so directly attached to the traction supply. It needn't even be battery-based, an axle-linked alternator can cover for the neutral sections while on the move (if stopped in a neutral section, sockets can turn off), and both systems feed a convertor/rectifier/similar which has its own 'ground' reference.

 

[superjohn]

(if stopped in a neutral section, sockets can turn off)

Hopefully a rare occurrence!

 

[edwin_m]

Hopefully a rare occurrence!

But if it does happen, you'll probably be there for quite a while...

 

[Domh245]

But if it does happen, you'll probably be there for quite a while...

Hopefully not if it's an Azuma, and whatever made you stop in the neutral section isn't a job stopper - even the 801s have got a single genset onboard that should give them enough power to limp out of the neutral section!

 

[AM9]

Quite apart from screen brightness (which is a setting easily changed), it is objectively bad for a Lithium battery's health to undergo repeated interruptions in its charging cycle. One or two blips would be understandable, but nineteen cutouts on a London-Edinburgh journey is likely to cause early failures for regular travellers' devices. ...

The power available to passengers on some trains is fully compliant with electricity regulations. Short term disconnections from a charging current do not affect the life of a Lithium Ion battery. Any compliant charger will be able to establish the correct charging current no matter how many times it is reconnected to a prime power supply. I can't say what might happen to devices that have inadequate chargers, or indeed sub-standard batteries, but that is the responsibility of the device's owner.
Nobody is obliged to take up the offer of power for charging suitable devices.

 

[rebmcr]

Nobody is obliged to take up the offer of power for charging suitable devices.

This isn't very fair when the visually-standard socket is presented without notice of its difference from every other actually-standard socket in trains and in buildings.

 

[AM9]

This isn't very fair when the visually-standard socket is presented without notice of its difference from every other actually-standard socket in trains and in buildings.

Sockets anywhere can be subject to interruptions in power unless they are stated to be high priority. Passengers can use those sockets but if their personal electrical devices aren't of suitable quality, that's their problem. The ticket entitles passengers to travel safely. If a continuous supply is so important, then as @Bletchleyite and others have posted here so many times, carry you own portable charger.

 

[rebmcr]

Sockets anywhere can be subject to interruptions in power unless they are stated to be high priority. The ticket entitles passengers to travel safely. If a continuous supply is so important, then as @Bletchleyite and others have posted here so many times, carry you own portable charger.

People should indeed carry such a charger for continuous, guaranteed uninterrupted power — but at the same time, no rational person who is OK with interruption would expect nineteen of them.

Passengers can use those sockets but if their personal electrical devices aren't of suitable quality, that's their problem.

First, that's a very nasty disregard for others. Second, if we're applying "you should have thought of that" to rail facilities, we might as well be running flat wagons with "bring your own roof" instead of well-equipped intercity stock.

When I board a service and see what looks like seating, I don't think "maybe it will fold underneath me every now and then, I'd better just use this camping chair I brought with me". The same is true of a visually-standard BS1363 socket. You might just have a point that I'd disagree with if they were labelled, but otherwise you're not even giving a fair chance for 'let the buyer beware'.

 

[James James]

People should indeed carry such a charger for continuous, guaranteed uninterrupted power — but at the same time, no rational person who is OK with interruption would expect nineteen of them.

As AM9 said, these interruptions are NOT a problem for devices. You're trying to paint a problem where there is none. The sockets supply power most of the time, and when they don't it's not a problem, hence they're not defective.

You'll see the exact same thing in lots of other locations: aircraft power sockets (longer journeys) can turn off at random, in fact many aircraft power sockets can't even handle higher power laptop chargers. Oh, and did I mention those sockets often don't even work when on the ground? Trains all around the world, not just in the UK, will have interruptions in neutral sections.

A camping chair that folds under you could hurt you. A power socket that turns off during neutral sections has no side effects UNLESS the software on your device is configured to respond to changes in power supply. Your comparison is in no way warranted.

 

[AM9]

People should indeed carry such a charger for continuous, guaranteed uninterrupted power — but at the same time, no rational person who is OK with interruption would expect nineteen of them.



First, that's a very nasty disregard for others. Second, if we're applying "you should have thought of that" to rail facilities, we might as well be running flat wagons with "bring your own roof" instead of well-equipped intercity stock.

When I board a service and see what looks like seating, I don't think "maybe it will fold underneath me every now and then, I'd better just use this camping chair I brought with me". The same is true of a visually-standard BS1363 socket. You might just have a point that I'd disagree with if they were labelled, but otherwise you're not even giving a fair chance for 'let the buyer beware'.

Where in any marketing or ticket conditions does it say that you will have uninterrupted power at your seat, (in fact, where does it guarantee a seat in standard class)? All issues that affect your safety on a train are covered by legislation that the TOC must observe.
You buy a ticket to travel on the basis of those publically accessible conditions. Optional services may be provided which may or may not match your lifestyle expectations. If they don't, the very technology that you seem so dependent on offers you solutions, i.e. in this case a portable charger. Essentially the same applies to wi-fi, - nice to have but if your need is greater than the TOC's ability to provide it, the solution is in your own hands.

 

[samuelmorris]

People should indeed carry such a charger for continuous, guaranteed uninterrupted power — but at the same time, no rational person who is OK with interruption would expect nineteen of them.



First, that's a very nasty disregard for others. Second, if we're applying "you should have thought of that" to rail facilities, we might as well be running flat wagons with "bring your own roof" instead of well-equipped intercity stock.

When I board a service and see what looks like seating, I don't think "maybe it will fold underneath me every now and then, I'd better just use this camping chair I brought with me". The same is true of a visually-standard BS1363 socket. You might just have a point that I'd disagree with if they were labelled, but otherwise you're not even giving a fair chance for 'let the buyer beware'.

I get where you're coming from with this, I do somewhat agree about there being parts of the way the railway operate that are less customer-focused than I would like, but realistically, this isn't one of them. Most people's devices aren't affected unduly by the power going off in neutral sections, it's a bit annoying that perhaps your screen brightness will change but if you have a computer unduly affected by mains power being disconnected, either fix that or don't rely on it when you travel. The real issue with power sockets on trains is how often they simply don't work at all. Even then, it's not a god-given right. I think an unnecessarily big deal is being made out of this.

 

[edwin_m]

Not sure about Azumas but most of these sockets have a sticker saying they are for phones and laptops only. Since all phones and laptops have a battery then I'd say the sockets were fit for their stated purpose even with the occasional interruption of power. There was someone complaining on here a few weeks ago that they couldn't use their laptop which had a defective battery circuit and would only run on mains, but to me that's a bit like expecting the operator to lend you a keyboard if your own is faulty.