# Tesla turbie question!

1. Jan 25, 2014

### roineust

Hello!

Here is a small Tesla turbine:

http://www.epicphysics.com/model-engine-kits/tesla-turbine-kit/

First of all, for some reason, he doesn't say how many PSI he puts in, to reach that 80-100K RPM goal.

Does anyone have a crude estimation of the PSI? Would it be in the area of 1-10 PSI or 10-20 PSI ? I saw other DIY style Tesla turbines on the web, that claim they use 20-40 PSI, so i guess that would be the range in this case as well, although somewhat a smaller turbine here?

Secondly, just from looking at the design and understanding the underlying principles of the Tesla turbine, does anyone know if it's possible to connect a small CD DC motor to the shaft and create the reverse operation? e.g. make the turbine act as a compressor?

If this is what will happen, when attaching a motor to the turbine, as is, with no changes at all, it will become a compressor, then my question is this:

Say the motor attached is as mentioned, a 50K RPM CD DC small motor. If he needed, say, 15 PSI, to create 50K RPM, does it mean that when i connect the 50K RPM motor, i will get back somewhere close to 15 PSI or much less?

Thanks a lot!

Last edited: Jan 26, 2014
2. Jan 26, 2014

### CWatters

As I understand it the main advantage of a Tesla Turbine is ease of construction. Lots of info here. Looks like code to simulate one as well..

http://www.stanford.edu/~hydrobay/lookat/tt.html

I believe they can be used as a pump but how efficient they are I don't know. The fact that they are rarely used suggest they probably don't have advantages over other types of pump.

3. Jan 26, 2014

### sophiecentaur

I couldn't find any quantitative figures on efficiency - just numbers of 'breaths' needed to get it and keep it going. I wonder if this would have the 'legs' if the name Tesla weren't attached to its name.
A fun project, possibly, but the fact that they don't appear to be used in practice anywhere, rather makes the point that they are not very practicable. Unless the ant- Tesla conspiracy theory is invoked to explain the lack of popularity, I suppose.

4. Jan 26, 2014

### roineust

Yeah, i guess you guys are right...
Indeed, since that was the first time i saw this kind of turbine, i was probably hyped by the name Tesla.

Anyway, the whole thing is for a practical use and not for some kind of urban myth science history thesis...

Thanks...

5. Jan 26, 2014

### sophiecentaur

After such a gracious reply. I have to declare a bit of an interest (anti-Tesla) and to say I tend to get a bit more grumpy than necessary at the mention of that guy's name.
There are dozens of things that are still attributed to him, despite the fact that he often did little more than make a vague proposal for something. He is taken seriously in the same way as Nostradamus and Old Moore. (Not very charitable, perhaps).

It's a great shame that Arthur C Clarke, for example, doesn't get the same level of adulation. He made a lot of accurate predictions about the future of Space engineering.

BTW What is the proposed "practical use"? I'm sure we can deluge you with a load of alternative solutions. lol

6. Jan 26, 2014

### Enigman

http://en.wikipedia.org/wiki/Tesla_turbine

An article on the turbine:
Tesla Turbomachinery

7. Jan 26, 2014

### mrspeedybob

It seems to me like the main operating principal is the use of friction between the air and the discs to transfer energy from the air to the turbine. Friction results in heat which is waste energy in most cases is something you try to minimize.

If you have a case where you want to simultaneously power a mechanical load and heat a space using the same piece of equipment it could be cost effective. Perhaps a generator for your cabin in Alaska.

8. Jan 26, 2014

### roineust

My application is a miniature handheld multi purposed compressor, that can output somewhere between 10-20 PSI.
I can easily find on Ebay and other such places, compressors that output 10 PSI, but they weigh around 200-300 grams, wheres, i am trying to find a way to achieve such pressure, at no more than 10% of that weight.

9. Jan 26, 2014

### sophiecentaur

Worth a try, I suppose but will you be able to save weight on the motor? It's hard to do without a certain amount of iron and magnets. What sort of volume per minute would you be going for? It would be for boats and air beds?

10. Jan 26, 2014

### roineust

No, for smaller stuff such as basketballs, footballs and for keyboard and electronics cleaning.

11. Jan 26, 2014

### sophiecentaur

I see. I suppose a small, paddle-less rotor could take up less room and be stronger for the same weight. That would be in its favour. What about machining tolerances? That could put the price up a bit as it could demand special materials. I think 30g is a bit hopeful but you could get quite a bit lower than 300g, I'm sure. Small motors are in the order of 30g (??)
It could be something that we'd see on the shelves of sports shops etc. before long.

12. Jan 26, 2014

### roineust

Thanks.
I found some interesting leads in LEGO compressors.