coozer
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| posted on 23/3/10 at 04:38 PM |
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Hybrid Diesel Electric?
Carrying on from the 'sick and tired' thread can we discuss this?
Looking at a 6KVA Alternator in Machine Mart it gives 230v AC
I know that alternators create drag and sap power but how much?
What size engine would power this at 3Krpm and what size motor would it power?
EG: would my 100cc lawnmower engine turn it at a consistent speed to run a motor and keep some battery's charged?
I know trains use it because they could not develop and strong enough transmission for direct drive for the massive 3000hp engines.
So, question is how big an engine based on it running @ 3K to give enough for a decent size leccy motor?
Is it feasable or dead in the water?
 
Rescued attachment 0564.jpg
1972 V8 Jago
1980 Z750
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Liam
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| posted on 23/3/10 at 04:58 PM |
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Simplifying matters slightly, 6kVA is about 8hp, so allowing for efficiency you'd probably want about a 10hp engine to drive it if you want to
get the most out of it, so your 100cc B&S mower engine won't be up to the job. On the output side the 6kVA alternator would drive a motor
something a bit under 6kW allowing for efficiency/pf.
Not sure what the application is - why dont you just get a genny? Maybe I should read that other thread...
Liam
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Mr Whippy
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| posted on 23/3/10 at 04:58 PM |
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Personally I think a diesel generator governed to run at a constant speed for fuel efficiency that then directly drives an electric motor would be the
most cost effective. No gearbox, clutch etc just some heavy amp cable and a switch to change polarity for reverse. As you say Deisel/electric trains
use just this method and I'm surprised no car maker has went this route as it seems the cheapest of all.
Fame is when your old car is plastered all over the internet
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MakeEverything
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| posted on 23/3/10 at 05:03 PM |
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I think youre looking at it the wrong way.
Why do you want a 230V alternator? - Would a 12V alternator and motors not be better? Theres no inverters or rectifiers needed this way.
The load of the motor would increase the strain on the alternator and subsequently the engine.
Look up Diesel Rotary UPS systems, and get some more ideas from there.
Kindest Regards,
Richard.
...You can make it foolProof, but youll never make it Idiot Proof!...
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MakeEverything
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| posted on 23/3/10 at 05:06 PM |
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quote:
Originally posted by MakeEverything
I think youre looking at it the wrong way.
Why do you want a 230V alternator? - Would a 12V alternator and motors not be better? Theres no inverters or rectifiers needed this way.
The load of the motor would increase the strain on the alternator and subsequently the engine.
Look up Diesel Rotary UPS systems, and get some more ideas from there.
This was the engine section of 1 of 24 going onto the roof of a building in London.
Kindest Regards,
Richard.
...You can make it foolProof, but youll never make it Idiot Proof!...
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iDENTITi
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| posted on 23/3/10 at 06:11 PM |
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quote:
Originally posted by MakeEverything
I think youre looking at it the wrong way.
Why do you want a 230V alternator? - Would a 12V alternator and motors not be better? Theres no inverters or rectifiers needed this way.
The load of the motor would increase the strain on the alternator and subsequently the engine.
Look up Diesel Rotary UPS systems, and get some more ideas from there.
More volts, less amps. In theory anyway.
Theyre all higher than 12VDC. For example the tesla roaster runs on 375V AC motors.
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phelpsa
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| posted on 23/3/10 at 06:12 PM |
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Not helpful in the slightest, but Jaguar are doing a similar thing...
http://www.carsuk.net/jaguar-hybrid-confirmed/
They're supposedly using a 1.2 3-cyl engine to power an alternator which charges batteries, and the system can provide quite a bit of power (i
think they said near the 300bhp mark!) for short bursts of a minute or so. Clever stuff!
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smart51
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| posted on 23/3/10 at 07:10 PM |
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6kW is 8.042 BHP. 6kVA is the output. Its efficiency could be anywhere between 80% and 95% depending on its design and the magnets used. So assume
8.5 to 10 BHP needed to turn the motor at the rated speed at full electrical power. Your engine will need to make 10 BHP at the required revs or it
will slow down at full electrical load. Small bike engines will make 10 BHP but at more like 7000 or 10000 RPM, not the 3000 RPM of your motor.
You'd be better off with a small diesel.
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speedyxjs
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| posted on 23/3/10 at 07:17 PM |
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quote:
Originally posted by phelpsa
Not helpful in the slightest, but Jaguar are doing a similar thing...
http://www.carsuk.net/jaguar-hybrid-confirmed/
They're supposedly using a 1.2 3-cyl engine to power an alternator which charges batteries, and the system can provide quite a bit of power (i
think they said near the 300bhp mark!) for short bursts of a minute or so. Clever stuff!
I really like that 
How long can i resist the temptation to drop a V8 in?
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hillbillyracer
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| posted on 23/3/10 at 07:36 PM |
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I think the hard/expensive bit will be the controller for how fast you make the motor go, you could'nt just have it wired to the generator with
just a switch for neutral & direction as you'd get a response like dumping the clutch at full throttle on a conventional engine &
drivetrain.
I dont know how the controller works but I might be going to find out as I work for a dealer for these:
http://www.polarisindustries.com/en-us/ATV-RANGER/2010/Mid-Size-Utility-Vehicles/RANGER-EV/Pages/Overview.aspx
As for the volts, the higher the better from an efficiency point of view, the higher the voltage the lighter the wires & switches etc can be for
the same power, or more power through the same size connections.
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dinosaurjuice
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| posted on 23/3/10 at 07:45 PM |
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a diesel engine driving a CVT would be much simpler and cheaper.
the only reasons trains use the electric system is to have more driven wheels to give better grip, and the issue of transferring 3000hp.....
heres a nice package :
will
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Simon
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| posted on 23/3/10 at 07:48 PM |
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quote:
Originally posted by phelpsa
http://www.carsuk.net/jaguar-hybrid-confirmed/
They're supposedly using a 1.2 3-cyl engine to power an alternator which charges batteries,
I know Jag are interested in stuff more interesting than that, though I can't say anymore
ATB
Simon
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Simon
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| posted on 23/3/10 at 07:57 PM |
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Saying that, it seems to be quite public:
Jets
ATB
Simon
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Kwik
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| posted on 23/3/10 at 08:12 PM |
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think about the efficiancy of the motor too. electric motors are generally quite efficiant, but get less efficiant with heat, so if you putting an
engine next to it, it will just add to heat and therefore resistance...
you could try on a smaller scale like a go-kart... i wouldnt go full scale strait away, just incase it majorly fails 
good luck though, hope it does work
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phelpsa
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| posted on 23/3/10 at 09:15 PM |
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quote:
Originally posted by Simon
quote:
Originally posted by phelpsa
http://www.carsuk.net/jaguar-hybrid-confirmed/
They're supposedly using a 1.2 3-cyl engine to power an alternator which charges batteries,
I know Jag are interested in stuff more interesting than that, though I can't say anymore
ATB
Simon
It hasnt been secretive in quite a while, they came and gave us a lecture on their hybrid technologies a few months ago. They seemed very close to
actually using the piston engined system
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Badger_McLetcher
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| posted on 24/3/10 at 10:18 PM |
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I have to say, top gear was actually nearly spot on with their boxy car a while back when they got a diesel genny. That is to say the genny runs at
constant speed and is so always operating at peak efficiency. Even with electrical losses that should give good efficiency overall.
If disfunction is a function, then I must be some kind of genius.
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