Ideas for E-DMU possibilities?

[apk55]

I would see a Bi mode unit as an EMU with a diesel generator set(s) added. An alternator bolted directly onto the diesel engine crankshaft is a nice simple arangment and would weigh less than a mechanical transmision. If three phase drive is used then the EMU equipment would require minimal modification, posibly some changeover contacts and software modifications.

Diesel electric transmision is in effect a contiously varible transmision system enabling the diesel engine to run a optimum speed for either efficiency or power output. Diesel mechanical systems often mean the engine runs at a none optimum speed and torque converters are not very efficient. They are often quite complicated mechanicaly with several gear chains and carden shafts

 

[The Ham]

I would see a Bi mode unit as an EMU with a diesel generator set(s) added. An alternator bolted directly onto the diesel engine crankshaft is a nice simple arangment and would weigh less than a mechanical transmision. If three phase drive is used then the EMU equipment would require minimal modification, posibly some changeover contacts and software modifications.

The problem is (as I understand it) that it would require a new build EMU to be able to couple up to a generator set, as the wiring for our current EMU's isn't designed to have all the power coming from the end of the train as would be required with a generator set.

 

[apk55]

The problem is (as I understand it) that it would require a new build EMU to be able to couple up to a generator set, as the wiring for our current EMU's isn't designed to have all the power coming from the end of the train as would be required with a generator set.

The major problem would be mounting the the diesel engine on a coach, with consideration for fuel tanks, exhaust etc. Running a pair of power conductors along a coach would be trivial in comparison. When running on diesel I would expect the unit to be lower powered, so existing conductors may be ok.

 

[Kali]

Traction power busses aren't unknown already, although the example I can think of ( 313 ) only sends 750v. Still, it is not really a problem designing a coupler especially for intermediate vehicles - I am assuming we're talking about an EMU with a trailer with underfloor generators. If you're going to couple a generator unit up to a current EMU then put motors in it & call it a locomotive .

New build EMUs really *should* have the capability to take power from couplers - that way you could mix AC & DC units easily too, not just attach generator units.

 

[brianthegiant]

New build EMUs really *should* have the capability to take power from couplers - that way you could mix AC & DC units easily too, not just attach generator units.

I'm not sure that's electrically/mechanically feasible? at 750VDC, any connections need to be quite solid (no gap) to prevent arcing across contacts which would cause overheating. At 25kV AC connections need to be well sealed to prevent arcing to other metallic components which could cause shocks.

Either way I think it might be difficult to achieve with a coupling & why traction power connections between electric carriages are usually 'hard wired'.

 

[RichmondCommu]

I'd say you'd be better off with New Build rather then converting existing.

Wonder why Bombardier don't look over channel at their French Factory's AGC - A Bi Mode Bi Voltage regional unit. (Diesel, 1500V DC, 25kV AC)

By all accounts these units are very heavy; indeed they weigh more than a Class 185!

 

[DDB]

It should be easy to have semi permanent cables of suitable thickness and robustness between carriages within one multiple unit. I can see that having connections between separate emus carrying the power to transport an entire train would be very difficult.

I would see a Bi mode unit as an EMU with a diesel generator set(s) added.

That is how I see it as well. Apparently there isn't space in the UK loading gauge to fit the generators beneath the floor of a carriage. It would therefore have to be in the cabin of one of the carriages.

The ROSOCs appear to be very reluctant to fund any new DMU due to the rise in electrification so I would design it to be convertible to a pure EMU at a later date. I.e. if the generator set needs a 1/3 of a carriage put it in a normal body shell with 1/3 2/3 doors, with the end with the generator blocked off ensuring that the separation from the passenger cabin is not structural and can be cut out later. As far as possible arrange the air intakes so they occupy the same space in the side walls as the windows in the rest of the carriages.

Therefore as the amount of electrification increases the engines can be removed to leave a pure EMU.

DDB

 

[Kali]

I'm not sure that's electrically/mechanically feasible? at 750VDC, any connections need to be quite solid (no gap) to prevent arcing across contacts which would cause overheating. At 25kV AC connections need to be well sealed to prevent arcing to other metallic components which could cause shocks.

Either way I think it might be difficult to achieve with a coupling & why traction power connections between electric carriages are usually 'hard wired'.

I'm assuming you convert down to some intermediate voltage - you'd have to convert up to 25kV if you were drawing from third rail so it would make more sense to pick something intermediate. There are high-power jumpers around already - the ETS sockets on 92s are rated for 1500v/800a ( for Nightstar - that's well over half what you'd need to supply a 76 with ) and don't have any sort of power locking/closing/tightening which you could incorporate in an autocoupler.

Irrespective of that it should not be beyond the bounds of human ingenuity to create something simple like a reliable 25kV coupler anyway