|
|
Post by ajw373 on Dec 18, 2021 7:29:08 GMT
I mean, theoretically you could have a 6-rail system to deliver three phase AC to the train, but I suspect it would rather fail the cost/benefit analysis compared to having switch mode supplies on board the train! The Italians and Swiss managed it, but the knitting was more complicated... en.wikipedia.org/wiki/Three-phase_AC_railway_electrificationWow. Didn’t know that! But niche use of course. |
|
|
|
Post by 35b on Dec 18, 2021 8:06:18 GMT
The real ''father'' [if you like that term] of all this is Nikolai Tesla [1856-1943]. Alas often overlooked by rail traction 'historians'. In simple terms he laid out all the steps to have allow asynchronous motors to have worked in trains, at concept level, without specifically including trains, his general principles applied. Reading about all he invented and got up to is a fascinating subject in itself, a big digression here though. If ever there were a person I rank as important as the likes of Brunel or Gooch or Churchward or Stephenson or Raworth or Diesel anyone else to propose naming a traction vehicle after, I would nominate Tesla. End of rant. Just on that digression, I suspect that name has now been fully appropriated elsewhere |
|
|
|
Post by dm1 on Dec 18, 2021 14:05:56 GMT
A key point in all this is that ever since man devised rotating electrical machines, as far as traction is concerned, the asynchrnous AC motor has always been the holy grail, right back to Victorian times. The difficulty of controlling the adaption neccessary from the transmitted supply to the motor always held it back. A slight correction, in that increasingly synchronous AC motors are making a comeback in a big way, especially for trains. In particular Permanent Magnet Synchronous Machines (PMSMs) are proving popular, due to their higher torque density compared to asynchronous or DC motors. To very briefly try to explain how they work - a syncrhonous motor is effectively a DC motor, where the rotor and stator swap places. So instead of supplying a DC voltage to the stator and and an AC voltage to the rotor (created by the brushes), in a synchronous motor you supply an AC voltage to the stator and a DC voltage to the rotor. But supplying a DC voltage to the rotor is cumbersome mechanically, so it is possible to replace it with permanent magnets instead (to continue the analogy with the DC motor, it's the same idea as when you build a simple DC motor from a a horseshoe magnet and a coil of wire, but in reverse). There are certain differences between the speed-torque curves of synchronous and asyncrhonous motors that can be advantageous in certain situations, but I won't go into that here. I can't find a source at the moment, but I seem to recall reading somewhere that the new Siemens Tube stock will be using PMSMs. There are various trains around the world that use them - the main argument against them is that the extremely powerful but small magnets needed are very expensive, compared to the coils of wire you need for an asyncrhonous motor. The power electronics and control circuitry is also fairly challenging. |
|
|
|
Post by 100andthirty on Dec 19, 2021 9:06:24 GMT
Building on dm1's comment, although one VVVF inverter may feed several asynchronous motors - four per inverter on LU - it is usual for each permanent magnet synchronous motor to have its own inverter.
|
|
|
|
Post by t697 on Dec 19, 2021 9:30:20 GMT
Building on dm1's comment, although one VVVF inverter may feed several asynchronous motors - four per inverter on LU - it is usual for each permanent magnet synchronous motor to have its own inverter. I understood the new Picc trains do have an inverter per motor. It will be interesting to see whether that reduces the rate at which rail corrugation develops compared to lines with four AC motors per inverter.
Oops, this stuff about permanent magnet motors should be in the Picc or Rolling Stock thread really.
|
|
|
|
Post by coldplayfan18 on Dec 19, 2021 19:50:18 GMT
Any more news on the train that’s currently being refurbished?
|
|
Tom
Administrator
Signalfel?
Posts: 4,196 
|
Post by Tom on Dec 19, 2021 21:28:57 GMT
I would envisage that the work is currently slowing down, considering we are approaching the end of the year. I'm sure that when someone is able to provide an update, they will do.
|
|
|
|
Post by noddymac on Dec 20, 2021 0:15:29 GMT
The last I saw recently was a “prototype” CLIP train being tested on LU metals! It appears as though good progress is being made but it’ll be a while yet before we see the first one in passenger service.
|
|
|
|
Post by coldplayfan18 on Dec 21, 2021 11:47:35 GMT
Okay, so is all the refurb work on this train completed? And now it’s just a testing phase?
|
|
|
|
Post by Dstock7080 on Dec 21, 2021 15:10:38 GMT
Okay, so is all the refurb work on this train completed? And now it’s just a testing phase? Which train? the one that successfully completed the recent test run on the Central Line? As mentioned above, it contains most of the enhancements except the AC motors, which are under the 8-car train returned to Ruislip from Asfordby Test track in November. |
|
|
|
Post by coldplayfan18 on Jan 15, 2022 20:17:44 GMT
It’s late but happy new year guysss. Hope you had a good Christmas. Any updates for 2022?
|
|
|
|
Post by Dstock7080 on Jan 15, 2022 20:58:43 GMT
It’s late but happy new year guysss. Hope you had a good Christmas. Any updates for 2022? Weekend overnight testing of an empty 8-car AC motor fitted train, will commence next week on the Central Line. |
|
|
|
Post by coldplayfan18 on Jan 16, 2022 10:56:16 GMT
It’s late but happy new year guysss. Hope you had a good Christmas. Any updates for 2022? Weekend overnight testing of an empty 8-car AC motor fitted train, will commence next week on the Central Line. Okay, so there is this train with just the AC motors? And is there another train in Acton Works as well undergoing the inter and refurb work? |
|
|
|
Post by Dstock7080 on Jan 16, 2022 11:36:46 GMT
Okay, so there is this train with just the AC motors? And is there another train in Acton Works as well undergoing the inter and refurb work? This 8-car train is the one sent to Bombardier (Derby) and Asfordby test track last year for AC motor fitment. There are three other trains at Acton undergoing refurbishment. |
|
|
|
Post by coldplayfan18 on Jan 16, 2022 12:34:59 GMT
Okay, so there is this train with just the AC motors? And is there another train in Acton Works as well undergoing the inter and refurb work? This 8-car train is the one sent to Bombardier (Derby) and Asfordby test track last year for AC motor fitment. There are three other trains at Acton undergoing refurbishment. Okay thanks for the info. Did you have a good Christmas and New Year? |
|
Tom
Administrator
Signalfel?
Posts: 4,196
|
Post by Tom on Jan 16, 2022 12:45:40 GMT
Did you have a good Christmas and New Year? |
|
|
|
Post by d7666 on Jan 18, 2022 1:14:52 GMT
Weekend overnight testing of an empty 8-car AC motor fitted train, will commence next week on the Central Line. Okay, so there is this train with just the AC motors? And is there another train in Acton Works as well undergoing the inter and refurb work? Perhaps I have missed a post somewhere, and can't find the answer in a search, so bringing things down the the lowest common denominator of trainspotting  , What Are The Car Numbers of this set please ? Assuming someone knows that is ! |
|
|
|
Post by Dstock7080 on Jan 18, 2022 4:38:21 GMT
Perhaps I have missed a post somewhere, and can't find the answer in a search, so bringing things down the the lowest common denominator of trainspotting , What Are The Car Numbers of this set please ? Assuming someone knows that is ! 91263-92263+93446-92446+93222-92222+92111-91111 |
|
|
|
Post by d7666 on Jan 18, 2022 5:24:29 GMT
Perhaps I have missed a post somewhere, and can't find the answer in a search, so bringing things down the the lowest common denominator of trainspotting , What Are The Car Numbers of this set please ? Assuming someone knows that is ! 91263-92263+93446-92446+93222-92222+92111-91111 thanks ! was it buried in another thread here and I missed it, just as a matter of interest ? |
|
|
|
Post by Dstock7080 on Jan 18, 2022 7:21:18 GMT
thanks ! was it buried in another thread here and I missed it, just as a matter of interest ? This post lists some of the numbers; other posts give the other units: districtdavesforum.co.uk/post/501834/threadA little bit of progress, cars 91111 92111 92446 93446 have returned to Ruislip from Derby by road today. They will now undertake testing on LU after the dynamic testing at Derby, including running mixed trains of 1xAC/2xDC 2xAC/1xDC etc |
|
|
|
Post by d7666 on Jan 18, 2022 21:48:49 GMT
thanks ! was it buried in another thread here and I missed it, just as a matter of interest ? This post lists some of the numbers; other posts give the other units: districtdavesforum.co.uk/post/501834/threadA little bit of progress, cars 91111 92111 92446 93446 have returned to Ruislip from Derby by road today. They will now undertake testing on LU after the dynamic testing at Derby, including running mixed trains of 1xAC/2xDC 2xAC/1xDC etc Thanks for this, my bad, had obviouisly been skimming this thread upthread too lightly  But I still have a question that I can't see the answer. This 8car set : 91263-92263+93446-92446 + 93222-92222+92111-91111, Is this ALL AC motor equipped, or is it a mixed AC/DC motor set, seeing as mixed testing is referred to ? |
|
|
|
Post by Dstock7080 on Jan 19, 2022 4:50:48 GMT
But I still have a question that I can't see the answer. This 8car set : 91263-92263+93446-92446 + 93222-92222+92111-91111, Is this ALL AC motor equipped, or is it a mixed AC/DC motor set, seeing as mixed testing is referred to ? Mixed testing was referred to in April 2021. The post from January 2022: districtdavesforum.co.uk/post/509020/threadIs quite clear, “an 8-car AC motor fitted train”, “mixed” was deliberately not used. |
|
|
|
Post by coldplayfan18 on Feb 19, 2022 22:08:35 GMT
A month since the last post. Was going to ask if the units are still being tested?
|
|
|
|
Post by noddymac on Feb 21, 2022 19:25:17 GMT
A month since the last post. Was going to ask if the units are still being tested? Yes, the first CLIP train is being tested during Night Tube hours between Debden and Epping. |
|
|
|
Post by coldplayfan18 on Feb 22, 2022 7:57:20 GMT
A month since the last post. Was going to ask if the units are still being tested? Yes, the first CLIP train is being tested during Night Tube hours between Debden and Epping. Niceeeee! Any idea when it will come into service? |
|
|
|
Post by Dstock7080 on Feb 22, 2022 11:02:16 GMT
Yes, the first CLIP train is being tested during Night Tube hours between Debden and Epping. Niceeeee! Any idea when it will come into service? Remember this is only the AC motor fitted train, without the other improvements - mentioned on 15 January. |
|
|
|
Post by coldplayfan18 on Feb 22, 2022 12:02:52 GMT
Oh yeah I keep forgetting there’s that one, and there’s another that does have the interior refurb work.
|
|
|
|
Post by jimbo on Feb 22, 2022 19:52:28 GMT
"Central Line Improvement Programme The first train was expected to be in service in March 2022, but the forecast shows this will be 160 days late. The programme continues to be delayed by a lack of resource and an inability to recruit. The team is reviewing the plan to identify delivery dates based on the current available resources and validate the impact to delivery. Although there is a plan to try to recover some of this time, the current forecast shows the first train will be later than planned." (Programmes and Investment Committee papers for 2 March 2022)
|
|
|
|
Post by coldplayfan18 on Feb 23, 2022 10:03:04 GMT
"Central Line Improvement Programme The first train was expected to be in service in March 2022, but the forecast shows this will be 160 days late. The programme continues to be delayed by a lack of resource and an inability to recruit. The team is reviewing the plan to identify delivery dates based on the current available resources and validate the impact to delivery. Although there is a plan to try to recover some of this time, the current forecast shows the first train will be later than planned." (Programmes and Investment Committee papers for 2 March 2022) Ooh so that means September at the latest… Hopefully if they can recover some of the time then it could come over summer. |
|
|
|
Post by Dstock7080 on Feb 26, 2022 10:11:28 GMT
|
|
, What Are The Car Numbers of this set please ? Assuming someone knows that is !
