Extending the range of an electric bike...

[The Luggage]

On 10 Apr, 17:27, "Clive George" <[email protected]> wrote:
> "naked_draughtsman" <[email protected]> wrote in message
>
> news:[email protected]...
>
> > Not a turbine as other have mentioned, but I think quite a few diesel
> > trains have electric transmission.
> > I guess among other things it makes it very easy to make diesel and
> > electric versions of the same type of train.
>
> I think the main reason is that it means you don't need a mechanical gearbox
> + clutch, so controlling the drive is much much easier.

All diesel freight engines have electric transmission because the
forces required to start a 2,000 tonne train cannot be accomodated by
a mechanical system. Many regional passenger trains have a diesel
engine and torque converter / gearbox system. I'm not aware of any
designs that have been made in both diesel & electric versions, though
I'm sure someone will be along in a minute to correct me...

TL

 

[Pyromancer]

On Apr 8, 3:15 pm, Tony Raven <[email protected]> wrote:
> Pyromancer wrote on 08/04/2007 14:48 +0100:

> > Obviously horrendously inefficient compared to a motorbike, but would it
> > get round all the legal requirements for tax, mot, etc? Not that I'm
> > planning to build one (original idea dates from my mid teen years when
> > electric vehicles were legal but fuel-driven ones were not), just
> > curious.

> Not inefficient at all and been done for cars. The engine can be
> optimised to run very efficiently at one speed only and combined with
> the electrical efficiency it can work out to be much more efficient than
> a petrol engine designed to cover the full range of speeds and torques.

Efficient if done as full on petrol- or diesel-electric, but I was
thinking more of the "generator charges one battery while you ride
using the other" done as a way round the "no-one under 16 can drive/
ride a motor vehicle" rule, which must surely be hauling huge amounts
of weight about unnecessarily. I used to dream of such contraptions
as a 13/14 y/o struggling up big hills. Was always worth it for the
feeling of flying coming back down though!

 

[Tony Raven]

The Luggage wrote on 11/04/2007 16:13 +0100:
>
> All diesel freight engines have electric transmission because the
> forces required to start a 2,000 tonne train cannot be accomodated by
> a mechanical system.

Good job no-one told the steam locomotive designers that ;-)

--
Tony

"The most savage controversies are those about matters as to which there
is no good evidence either way."
- Bertrand Russell

 

[David Damerell]

Quoting The Luggage <[email protected]>:
>All diesel freight engines have electric transmission because the
>forces required to start a 2,000 tonne train cannot be accomodated by
>a mechanical system.

That would come as news to the operators of some of the largest steam
locomotives; later Big Boys were rated at circa 4.5 thousand tons.
--
David Damerell <[email protected]> Kill the tomato!
Today is Monday, April.

 

[Ziggy]

On 11 Apr 2007 18:19:08 +0100 (BST), David Damerell
<[email protected]> wrote:

>Quoting The Luggage <[email protected]>:
>>All diesel freight engines have electric transmission because the
>>forces required to start a 2,000 tonne train cannot be accomodated by
>>a mechanical system.
>
>That would come as news to the operators of some of the largest steam
>locomotives; later Big Boys were rated at circa 4.5 thousand tons.

He's obviously talking about the transmission from a diesel engine to the
driving wheels.

But of course you knew that and just had a quick look on google after seeing T.
Ravens post abouut steam engines - no?.

It wasn't that many hours ago that you knew so little about train
engine/transmission systems that you thought HST's included a turbine in the
transmission!

 

[Rob Morley]

In article <[email protected]>, Tony Raven
[email protected]lid says...
> The Luggage wrote on 11/04/2007 16:13 +0100:
> >
> > All diesel freight engines have electric transmission because the
> > forces required to start a 2,000 tonne train cannot be accomodated by
> > a mechanical system.
>
> Good job no-one told the steam locomotive designers that ;-)
>
I'm no expert in trainspotting matters, but it seem to me that steam
locos aren't really diesels.

 

[Alan Braggins]

In article <[email protected]>, Tony Raven wrote:
>The Luggage wrote on 11/04/2007 16:13 +0100:
>>
>> All diesel freight engines have electric transmission because the
>> forces required to start a 2,000 tonne train cannot be accomodated by
>> a mechanical system.
>
>Good job no-one told the steam locomotive designers that ;-)

Possibly the steam locomotive designers spotted that a cylinder
filled with high pressure steam can exert a steady[1] pressure on
even a stationary piston, so a steam engine doesn't need a clutch
to avoid stalling below a minimum engine speed, and the Luggage was
eliding off topic details.

[1] I know, not completely, see "eliding off topic details".

 

[Tony Raven]

Rob Morley wrote on 11/04/2007 18:59 +0100:
> In article <[email protected]>, Tony Raven
> [email protected]lid says...
>> The Luggage wrote on 11/04/2007 16:13 +0100:
>>> All diesel freight engines have electric transmission because the
>>> forces required to start a 2,000 tonne train cannot be accomodated by
>>> a mechanical system.
>> Good job no-one told the steam locomotive designers that ;-)
>>
> I'm no expert in trainspotting matters, but it seem to me that steam
> locos aren't really diesels.

They are mechanical systems though which are allegedly unable to
accommodate "the forces required to start a 2,000 tonne train"

--
Tony

"The most savage controversies are those about matters as to which there
is no good evidence either way."
- Bertrand Russell

 

[Ziggy]

On Wed, 11 Apr 2007 19:14:32 +0100, Tony Raven <[email protected]>
wrote:

>Rob Morley wrote on 11/04/2007 18:59 +0100:
>> In article <[email protected]>, Tony Raven
>> [email protected]lid says...
>>> The Luggage wrote on 11/04/2007 16:13 +0100:
>>>> All diesel freight engines have electric transmission because the
>>>> forces required to start a 2,000 tonne train cannot be accomodated by
>>>> a mechanical system.
>>> Good job no-one told the steam locomotive designers that ;-)
>>>
>> I'm no expert in trainspotting matters, but it seem to me that steam
>> locos aren't really diesels.
>
>They are mechanical systems though which are allegedly unable to
>accommodate "the forces required to start a 2,000 tonne train"

No Tony.

What he means is that there are no mechanical systems that will provide the
variable transmission required to allow a diesel engine which has to rotate at a
certain minimum speed to transfer power to a train that has to start from rest.

In a steam engine it is not really a mechanical system, that is doing that, it
is a property of team engines that they can develop power at rest and thus do
not *need* a mechanical system interposed between the engine and the driving
wheels to adapt the speeds. It is the steam pressure that handles the adaption
and that isn't really a 'mechanical system' in the normal parlance.

Hope that helps.

 

[M-gineering]

Ziggy wrote:

> What he means is that there are no mechanical systems that will provide the
> variable transmission required to allow a diesel engine which has to rotate at a
> certain minimum speed to transfer power to a train that has to start from rest.
>

No problem making a mechanical system, but from a certain powerlevel
electric drive is probably more economical
--
---
Marten Gerritsen

INFOapestaartjeM-GINEERINGpuntNL
www.m-gineering.nl

 

[Rob Morley]

In article <[email protected]>, Tony Raven
[email protected]lid says...
> Rob Morley wrote on 11/04/2007 18:59 +0100:
> > In article <[email protected]>, Tony Raven
> > [email protected]lid says...
> >> The Luggage wrote on 11/04/2007 16:13 +0100:
> >>> All diesel freight engines have electric transmission because the
> >>> forces required to start a 2,000 tonne train cannot be accomodated by
> >>> a mechanical system.
> >> Good job no-one told the steam locomotive designers that ;-)
> >>
> > I'm no expert in trainspotting matters, but it seem to me that steam
> > locos aren't really diesels.
>
> They are mechanical systems though which are allegedly unable to
> accommodate "the forces required to start a 2,000 tonne train"
>
He was talking about a practical mechanical system attached to a diesel
engine. Diesels and steam engines have very different torque
characteristics.
Actually you could use a purely mechanical transmission for large diesel
trains, but the generator/motors setup is simpler and more reliable than
a clutch driving lots of gear ratios and distribution shafts.

 

[Rob Morley]

In article <[email protected]>, Ziggy
[email protected] says...
<snip>.
>
> In a steam engine it is not really a mechanical system, that is doing that, it
> is a property of team engines that they can develop power at rest

Nothing can develop power at rest, because power is work done per unit
time and work is force exerted over a distance - if there's no movement
there's no distance so there's no work and no power.

 

[Ziggy]

On Wed, 11 Apr 2007 20:09:47 +0100, Rob Morley <[email protected]> wrote:

>In article <[email protected]>, Ziggy
>[email protected] says...
><snip>.
>>
>> In a steam engine it is not really a mechanical system, that is doing that, it
>> is a property of team engines that they can develop power at rest
>
>Nothing can develop power at rest, because power is work done per unit
>time and work is force exerted over a distance - if there's no movement
>there's no distance so there's no work and no power.

Yeah, yeah, hoist by my own pedantic petard

I meant, of course, 'from rest'.

Plus, I burned my dinner as I hurridly (but not hurridly enough) typed that in.

 

[Ziggy]

On Wed, 11 Apr 2007 20:59:17 +0200, M-gineering <[email protected]>
wrote:

>Ziggy wrote:
>
>> What he means is that there are no mechanical systems that will provide the
>> variable transmission required to allow a diesel engine which has to rotate at a
>> certain minimum speed to transfer power to a train that has to start from rest.
>>
>
>No problem making a mechanical system, but from a certain powerlevel
>electric drive is probably more economical

Indeed, but remember that the person who said it was a problem was talking about
a transmission system that would have to occupy a space inside a railway
locomotive. Since we are obviously talking about a rather powerful engine spare
space would be limited.

AFAIK it has never been attempted with a large diesel in the UK. The only large
diesel transmision used other than electric was hydraulic and that was phased
out in the mid seventies.

 

[Tony Raven]

M-gineering wrote on 11/04/2007 19:59 +0100:
>
> No problem making a mechanical system, but from a certain powerlevel
> electric drive is probably more economical

Indeed and it would appear they are not unknown and more efficient:
http://en.wikipedia.org/wiki/Diesel_locomotive#Diesel-mechanical

--
Tony

"The most savage controversies are those about matters as to which there
is no good evidence either way."
- Bertrand Russell

 

[Niall Wallace]

"Ziggy" <[email protected]> wrote in message
news:[email protected]...
> On 11 Apr 2007 18:19:08 +0100 (BST), David Damerell
> <[email protected]> wrote:
>
>>Quoting The Luggage <[email protected]>:
>>>All diesel freight engines have electric transmission because the
>>>forces required to start a 2,000 tonne train cannot be accomodated by
>>>a mechanical system.
>>
>>That would come as news to the operators of some of the largest steam
>>locomotives; later Big Boys were rated at circa 4.5 thousand tons.
>
> He's obviously talking about the transmission from a diesel engine to the
> driving wheels.
>
> But of course you knew that and just had a quick look on google after
> seeing T.
> Ravens post abouut steam engines - no?.
>
> It wasn't that many hours ago that you knew so little about train
> engine/transmission systems that you thought HST's included a turbine in
> the
> transmission!

There are turbines in the HST, as part of the exhaust/induction system in
the form of Turbochargers.

Niall

 

[Ziggy]

On Wed, 11 Apr 2007 21:25:34 +0100, Tony Raven <[email protected]>
wrote:

>M-gineering wrote on 11/04/2007 19:59 +0100:
>>
>> No problem making a mechanical system, but from a certain powerlevel
>> electric drive is probably more economical
>
>Indeed and it would appear they are not unknown and more efficient:
>http://en.wikipedia.org/wiki/Diesel_locomotive#Diesel-mechanical

Yes, we have already established that they are used in lower powered diesels.
Obviously they are more efficient otherwise buses and cars would use electric or
some other conversion transmision.

But, again as already stated, they are not practical for the higher powered
railway locomotives.

You seem to be leading us back around in a circle

 

[Ziggy]

On Wed, 11 Apr 2007 21:59:32 +0100, "Niall Wallace"
<[email protected]> wrote:

>"Ziggy" <[email protected]> wrote in message
>news:[email protected]...
>> On 11 Apr 2007 18:19:08 +0100 (BST), David Damerell
>> <[email protected]> wrote:
>>
>>>Quoting The Luggage <[email protected]>:
>>>>All diesel freight engines have electric transmission because the
>>>>forces required to start a 2,000 tonne train cannot be accomodated by
>>>>a mechanical system.
>>>
>>>That would come as news to the operators of some of the largest steam
>>>locomotives; later Big Boys were rated at circa 4.5 thousand tons.
>>
>> He's obviously talking about the transmission from a diesel engine to the
>> driving wheels.
>>
>> But of course you knew that and just had a quick look on google after
>> seeing T.
>> Ravens post abouut steam engines - no?.
>>
>> It wasn't that many hours ago that you knew so little about train
>> engine/transmission systems that you thought HST's included a turbine in
>> the
>> transmission!
>
>There are turbines in the HST, as part of the exhaust/induction system in
>the form of Turbochargers.

But as you well know that is not what he was refering to when he wrote "The HST
125s are diesel-electric turbines".

The turbines are part of the diesel system whereas he is using 'diesel-electric'
as an adjective to qualify 'turbines'. Complete nonsense!

 

[Stuart Millington]

On 6 Apr 2007 16:45:30 -0700, [email protected] wrote:

>(36v 12 amp lead acid battery)
....
>A 12v to 36 dc to dc convertor - £70

As other(s) have said, a DC-DC converter is /extremely/ inefficient.
You would get a far better electrical performance out of 3 smaller
12VDC batteries with the same Ah rating in series than trying to use a
converter under high-load conditions.

>ie 12v at 110amps,

You've got major losses in the converter, plus running a lead-acid
battery at high (near limit) amperages is going to seriously reduce
its effective capacity too. IMO don't even think about DC-DC voltage
conversion in this sort of application.

 

[Stuart Millington]

On Sun, 8 Apr 2007 03:06:13 +0100, "Paul Murphy"
<[email protected]> wrote:

>It's actually neither an electrically assisted bike nor a moped and it's a
>grey area where trading standards haven't acted to stop such bikes being
>sold here. In other parts of Europe electric bikes must be assisted and not
>capable of being fully self powered at any speed. For whatever reason the UK
>authorities seem to have a more relaxed view to "these things".

Indeed. The /big/ gray area seems to be: "would the Police prosecute
you for using one"?

>See the Legal Things section at the bottom of this AtoB page for further
>info http://www.atob.org.uk/questionselectric.htm .

And that does not answer it - that's probably deliberate though ;-)