Azuma Power Sockets - no power through neutral sections

ryan125hst · 22 Oct 2019

I travelled to Edinburgh last week on an Azuma in first class and noticed that every time we went through a neutral section, both my laptop, which was plugged in to the 230V socket, and my phone, which was plugged into the USB port, stopped charging until overhead power was restored. This was a little frustrating when trying to work as my screen went black for a second or two when my laptop lost power before doing the same thing again when power was restored.

Curiously, the 225 set I returned home on had no such issues and my laptop didn't stop charging at all as we went through a neutral section.

I was always under the impression that the 225's (and HST's) power their sockets through inverters that are connected to the carriage battery. Therefore, while the battery will stop charging when the Electric Train Supply cuts out as the train goes through a neutral section, the battery will be able to maintain the supply to the sockets.

Do the Azumas not have inverters? Or were the ones on my train incorrectly set to load shed immediately when overhead power is lost?

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hwl · 23 Oct 2019

ryan125hst said:
Do the Azumas not have inverters? Or were the ones on my train incorrectly set to load shed immediately when overhead power is lost?

Or alternatively with no supply they just don't supply any power as the inverters are fed straight from the rectifier (4 quadrant converter in reality) so the sockets + HVAC have no supply when there is no line voltage...
Very little equipment has an alternate feed from batteries these days.

47271 · 23 Oct 2019

I can't think of many trains that keep the power flowing through neutral sections.

It doesn't bother me because the devices I'm charging function regardless on battery - I don't understand why the laptop screen was going blank, unless it had a fault?

jon0844 · 23 Oct 2019

Yes, I've never had a laptop turn the screen off when the charger was unplugged (or in this case, powered down). Does your PC have separate options for on power and on battery? Maybe you've set the battery mode to have the screen brightness turned down too far?

My laptop screen brightness may fall a little but that's it.

ryan125hst · 23 Oct 2019

47271 said:
I can't think of many trains that keep the power flowing through neutral sections.

LNER's 225's definitely do as mentioned above. I'm not sure if any others do though.

47271 said:
It doesn't bother me because the devices I'm charging function regardless on battery - I don't understand why the laptop screen was going blank, unless it had a fault?

jon0844 said:
Yes, I've never had a laptop turn the screen off when the charger was unplugged (or in this case, powered down). Does your PC have separate options for on power and on battery? Maybe you've set the battery mode to have the screen brightness turned down too far?

My laptop screen brightness may fall a little but that's it.

The screen went black for a couple of seconds when it stopped charging and then came back on again fine running on battery. It then went black again for a couple of seconds once power was restored. It does this when ever power is removed or connected to it. It doesn't seem to be unique to my laptop - I was travelling for work and my colleague's laptop did the same.

Agent_Squash · 23 Oct 2019

ryan125hst said:
LNER's 225's definitely do as mentioned above. I'm not sure if any others do though.

The screen went black for a couple of seconds when it stopped charging and then came back on again fine running on battery. It then went black again for a couple of seconds once power was restored. It does this when ever power is removed or connected to it. It doesn't seem to be unique to my laptop - I was travelling for work and my colleague's laptop did the same.

The screen goes totally black? Something’s up. It sounds more like it dims severely.

mightyena · 23 Oct 2019

If the laptop uses Intel graphics, it's likely because by default, it runs the screen at 60Hz when plugged in, but switches to 50Hz on battery. The screen goes blank for a few seconds when it switches over.

It should be possible to change it somewhere in the graphics settings application

ryan125hst · 26 Oct 2019

I've spoken to my IT department who have informed me that it is normal for the laptop screen to do this as it is switching graphics profiles.

Regarding the Azuma though, does anyone know of the technical differences in how the power sockets are wired on the Azuma verses the 225's and why the power goes off during a neutral section on an Azuma but not on a 225?

AM9 · 26 Oct 2019

The 225 uses LHCS which has batteries in each coach. I would imagine that unless the batteries are charged by a generator driven by rotation of the wheels, the feed to the batteries is from the hotel supply, which will drop out when entering a neutral section. On an IET, the feed is from the ac hotel supply which also feeds the air conditioning, so non-essential services are cut when the 25kV is unavailable. This would also apply when the OLE power is missing altogether (typically with a dewirement) preventing wastage of battery power on non-essential use allowing the PA and lighting to operate longer.

AlexNL · 26 Oct 2019

ryan125hst said:
I've spoken to my IT department who have informed me that it is normal for the laptop screen to do this as it is switching graphics profiles.

Perhaps the graphics profiles can be adjusted so that the drivers no longer have to blank the screen while the display reconfigures itself. This will probably come at the cost of slightly shorter battery life - so it's up to you if that's worth it.

I fully understand how annoying it must be to get interrupted like that every 15 miles or so as the train goes through a neutral section.

Harbornite · 26 Oct 2019

Big deal, not all laptops do that when charging stops.

AlexNL · 26 Oct 2019

Harbornite said:
Big deal, not all laptops do that when charging stops.

Mine doesn't either (the screen only dims a little), but @ryan125hst's obviously does.

Bletchleyite · 26 Oct 2019

AlexNL said:
Mine doesn't either (the screen only dims a little), but @ryan125hst's obviously does.

Most Windows laptops allow the brightness to be configured differently for battery vs. mains. As with modern LED backlights it makes half of no difference to battery life, I just set them the same.

route101 · 27 Oct 2019

Was on a HST recently and the phone was on charge but the percentage was not going up . I wonder if that was the cause of my fault i have now where my phone only charges when switched off.

ryan125hst · 31 Oct 2019

AM9 said:
The 225 uses LHCS which has batteries in each coach. I would imagine that unless the batteries are charged by a generator driven by rotation of the wheels, the feed to the batteries is from the hotel supply, which will drop out when entering a neutral section. On an IET, the feed is from the ac hotel supply which also feeds the air conditioning, so non-essential services are cut when the 25kV is unavailable. This would also apply when the OLE power is missing altogether (typically with a dewirement) preventing wastage of battery power on non-essential use allowing the PA and lighting to operate longer.

The Mark 4 coaches have static converters that convert the 1000V Electric Train Supply to 400V three phase for the air conditioning and catering, and they'll also charge the carriage batteries (not seen further details on the Mark 4's other than the presence of a static inverter instead of a motor alternator, but I did read a document once about how this works on loco hauled Mark 3's.) The sockets definitely stayed on during a neutral section and so the 230V must be supplied through an inverter. The question is, clearly the IET has batteries to keep the lights on etc, so given the relatively low power draw of the sockets, why hasn't the power supply to the sockets been designed to stay on during neutral sections. They could have them load shed after, say, 10 minutes which is more than enough time to clear a neutral section, and this would ensure that there was plenty of charge left in the batteries to keep lights on and toilets working in the event of an OLE failure for example.

I'm also not sure whether this is common on the IET's or just a fault with the unit or even carriage I was on.

route101 said:
Was on a HST recently and the phone was on charge but the percentage was not going up . I wonder if that was the cause of my fault i have now where my phone only charges when switched off.

Were you using your phone at the time? If the power required to run the phone equalled or was greater than the power supplied by the charger, then the phone wouldn't be charging. This could easily happen if you were playing a game on your phone for example, especially if you were using a charger that can only supply low currents. My phone can fast charge but I need to use a compatible charger that can supply the higher current to allow this - using a standard charger will result in the phone charging at a slower rate.

GrimShady · 1 Nov 2019

I had nothing but issues charging my phone and laptop on the 800s all the way down the ECML. Long delays before power coming back on, duff charges etc

samuelmorris · 1 Nov 2019

I think battery fed plug sockets are the exception rather than the norm, the sockets on 700s for example also go off during neutral sections. Normally this isn't an issue, but it would be understandably annoying for laptops that don't deal with the switch to/from battery power well.

hwl · 1 Nov 2019

samuelmorris said:
I think battery fed plug sockets are the exception rather than the norm, the sockets on 700s for example also go off during neutral sections. Normally this isn't an issue, but it would be understandably annoying for laptops that don't deal with the switch to/from battery power well.

Agreed.

The OP is just discovering how 98% (and soon much higher) sockets work but is still in denial as to what the norm is.

ryan125hst · 2 Nov 2019

hwl said:
Agreed.

The OP is just discovering how 98% (and soon much higher) sockets work but is still in denial as to what the norm is.

Interesting, I didn't realise that power going off to the sockets when going through a neutral section was the norm. Being based in Retford, it's been HST's and 225's for me mostly - the Pacers on the Lincoln to Sheffield line don't have power sockets (but are diesel anyway so wouldn't be affected by this issue).

I was on a Class 385 to Glasgow afterwards but I didn't plug my laptop in as the battery was fully charged by this point. I'd assume from what you have said that the power to the sockets would have gone off during neutral sections on those as well.

I recall many years ago (I think it was 2008 or 2009) I went to London with my family and my Dad took a rather old portable CD player (this being shortly after smartphones began to appear and he had a basic phone at the time and no MP3 player). He didn't put any batteries in it and powered it from the 230V socket. We were on a 225 and so the power stayed on through neutral sections. If it was other types of train, he would have wondered why the power kept going off! I would have been about 12 or 13 at the time so I'm not certain I'd heard of neutral sections at that point.

On another note, it must make catering tricky if the ovens, hobs, microwaves and toasters keep switching off every time a neutral section is reached. And I wouldn't expect those to be backed up either given their current draw.

AlexNL · 4 Nov 2019

ryan125hst said:
On another note, it must make catering tricky if the ovens, hobs, microwaves and toasters keep switching off every time a neutral section is reached. And I wouldn't expect those to be backed up either given their current draw.

The current draw for kitchen appliances is well-known in advance though, and can be taken into account when the vehicle is designed and built.

GrimShady · 4 Nov 2019

The only time I've noticed power going off on the 225's is the neutral section at Carstairs. It remains on everywhere else....this is not the case on 800s.

samuelmorris · 4 Nov 2019

ryan125hst said:
On another note, it must make catering tricky if the ovens, hobs, microwaves and toasters keep switching off every time a neutral section is reached. And I wouldn't expect those to be backed up either given their current draw.

They go off on neutral sections even on Mk4s.

Mordac · 4 Nov 2019

samuelmorris said:
They go off on neutral sections even on Mk4s.

Indeed, I suspect it's just more noticeable at Carstairs because it's such a tedious crawl, and there's two neutral sections in close succession.

D365 · 17 Nov 2019

Bit of a late reply, but I've also noticed this phenomenon while charging my laptop or iPhone. Sometimes I find that unplugging and replugging the charger seems to bring the power back? Although that could be just a placebo effect.

Good to see you again last week by the way Ryan

ryan125hst · 21 Nov 2019

By the time you've unplugged it and plugged it back in, the power's probably back on anyway tbh.

It was good to see you again as well, sorry I didn't get change to speak to you, too many people to see and not enough time! Hope you enjoyed the day despite the awful weather?

Northhighland · 22 Nov 2019

hwl said:
Agreed.

The OP is just discovering how 98% (and soon much higher) sockets work but is still in denial as to what the norm is.

Think probably the designers have reckoned that with most devices having a battery back up this wouldn’t be an issue. I have a HP laptop and this certainly doesn’t happen so it must be the configuration of the laptop.

hwl · 22 Nov 2019

Northhighland said:
Think probably the designers have reckoned that with most devices having a battery back up this wouldn’t be an issue. I have a HP laptop and this certainly doesn’t happen so it must be the configuration of the laptop.

Agreed. The issues appears to be certain laptops without separate graphic cards but with intel graphics that have battery power saving options and the swap between the 2 modes. I suspect settings could be tweaked.

Marton · 30 Nov 2019

samuelmorris said:
They go off on neutral sections even on Mk4s.

I’m not sure. In a Neutral section yesterday (AirCon off) but my power was still on.
I forget where, but between Edinburgh and Darlington.

Dave44 · 24 Jun 2020

I went North from Kings Cross last week on an Azuma (June2020). Neutral sections seem to occur every 5 minutes at full speed on the train. That's approx 44 neutral sections between KX and the Scottish Border. Too bad if the battery in your equipment isn't working. 44 resets.

Energy · 24 Jun 2020

hwl said:
Agreed. The issues appears to be certain laptops without separate graphic cards but with intel graphics that have battery power saving options and the swap between the 2 modes. I suspect settings could be tweaked.

Its not the graphics card but the screen, many will change to a 50hz when plugged in (50hz is the frequency for mains sockets) but 60hz (what most monitors usually are) when on battery, this is what is causing the black screen for a couple seconds and is to be expected, every screen goes black a couple seconds when changing frequency. Others will stay at 50 or 60hz all the time and may convert the 50hz mains to 60hz although the software will auto dim the screen, it really just depends on how the laptop has been designed but both are normal behaviour and to be expected.

The no power for neutral sections is to be expected, there are quite a few of these threads! The sockets for customers are just not considered important enough for the battery power and are a little unpredictable with how much power they will draw as it depends on the customers, whereas the kitchen/buffet can be easily predicted. Companies don't really care about the sockets not working for a few seconds, to stop it would require considerable expense in extra batteries and they always have a sign up by the socket saying only mobile phones and laptops so it is assumed that your device will have a battery in it and won't mind a couple interruptions in the mains, although these signs are mainly to tell people not to use a high wattage appliance like a toaster on the train as they consume a lot of power.

Azuma Power Sockets - no power through neutral sections

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