High Speed generator for automotive applications 1

[Sridhar1806]

Hey guys,

I am looking for a high speed generator for making a turbo-generator for LDT. What kind of generators should I use for 2-5 kw at 30,000 R.P.M.? Is there any place where I can get such generators.

Thanks

 

[GregLocock]

It's called a high speed alternator. You could try Lotus Engineering, it will cost you a lot.

Alternatively you could develop one, I have contacts in the Australian electric motor world if that helps.


Why not just gear down to a conventional alternator?

or these guys

http://www.bowmanpower.com/technology/high-speed-alternators/

Cheers

Greg Locock


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[Sridhar1806]

Thank you greg.
I am running a little tight on budget here. Even if I use a alternator would that not create a resistance to the turbine movement. Is there any way that I could use a permanent magnet motor as a generator. If yes, where can get one?

 

[MikeHalloran]

Acronym Finder says it has 140 definitions for LDT. What's yours?


Capstone Microturbines contain alternators driven at 25k..75k rpm.

http://www.microturbine.com/prodsol/products/

I have no idea if they sell parts, but some of their illustrations and other sales material may be helpful for rolling your own.

I agree with Greg; a regular car alternator, geared down 3:1 or 4:1, would probably do, especially on a limited budget.

Let me amend that; you will go crazy or broke trying to get gears to survive at 30k rpm; you might do better with Poly-V belts, or even flat belts.



Mike Halloran
Pembroke Pines, FL, USA

 

[Sridhar1806]

Thanks mike. LDT stands for Light Duty Truck.

 

[GregLocock]

Yes, of course you could use a permananet magnet motor. I think i see where you are coming from (ducted fan motors for RC aircraft). Only worry there is that the vibration environemnt on an engine is unkind, and the temperatures near turbos likewise.

A conventional alternator will generate plenty of resistance to motion if you adjust it that way.

Cheers

Greg Locock


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[LionelHutz]

Typical car alternators will withstand 16k to 20k rpm. They typically run on a belt drive in the 1:2.5 to 1:3 ratio. I have no idea how long they can withstand such speeds.

FYI, a permanent magnet generator won't provide any load to the turbine either unless it has a load connected to the motor leads. Similar to how a car alternator will only load the shaft if it has a load connected to it's output.

You'd be designing your own generator or consulting with a manufacturer for a custom design if this was a commercial venture and not a hobbyist attempt.

 

[DHambley]

Sridhar,

PMG is the way to go at 30krpm. Capstone makes PMG's which may work for you. You might also want to contact Brij Bhargava at Ashman Technologies, Santa Barbara. He specializes in high-speed motors. He built a perm magnet motor for an 8kW project of mine several yrs ago.

Darrell Hambley
SENTEK Engineering LLC

Darrell Hambley P.E.
SENTEK Engineering, LLC

 

[JayMaechtlen]

ISTR that some motorcycle generators do it a bit differently:
The field is stationary, and so is the stator.
Fingers are rotated between the field and stator - I guess that has the same effect as having a rotating field assembly?
They sweep or pulse the magnetic field across the stator?

Anyway - no brushes. No electric coils spinning at 10000 or 16000 RPM.
Does someone build such a thing for 30,000 rpm? No idea. But that would prob be easier than trying to make a car-style unit live at that RPM.


Jay Maechtlen

http://www.laserpubs.com/techcomm

 

[GregLocock]

Damn that's a good idea. Probably not as efficient but bulletproof.

Cheers

Greg Locock


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[MikeHalloran]

ISTR that 'brushless' truck alternators are made that way.

A Google search was productive.

One mfgr here:

http://www.ceniehoff.com/

Mike Halloran
Pembroke Pines, FL, USA

 

[GregLocock]

good stuff "Typical claw pole alternator efficiency is 50%. Typical CEN alternator efficiency is 70%. "

I was wrong and pleased to hear it.

Cheers

Greg Locock


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