Capstone C30 teardown

[finiteparts]

Hi Patty,

Good to see the interior of a C30 again. First, I am assuming that you do not want to run this engine again. They are tough to get apart and without the factory tools, you will probably destroy it. The tolerances are so tight that they are easily damaged.

That being said, I have never witnessed the center section coming apart, just the engine dismantled to the state that you have it in. If you are trying to look at the air bearings, just look at the ones on the generator shaft. You won't have a thrust bearing, but you can get the basics of the bearing design from the radial air bearings used on the generator.

If you think about the nut holding the turbine onto the shaft, it has to hold the shaft tight while it is providing enough torque to turn the compressor and make an extra 30kW of generator power...so it is going to be tight! I have often thought that the little hex on the shaft can not be enough metal to hold the shaft still while you are removing the 12 point nut, but like I said before, I have never seen it separated. If you don't plan on running it again, then I would heat the shaft while trying to not heat the turbine to hopefully get the shaft to grow while the turbine stays about the same length, thus removing some of the clamp on the turbine tie-bolt.

Good luck!

Chris

[urbansound]

Dry ice the shaft and heat the nut from one side only, stay below 600 degrees.

This oblongs the nut diameter from the shrinking round shaft diameter.

Use an impact wrench.  Static torque likely will not break the tension otherwise.

If it's a dead horse, maybe a cut-off wheel is the answer.  LOL

The kind of heat that turbine has to deal with plus torsional loads at high RPM / balance would require extreme press fit.

It's possible the turbine to shaft was cryo-mounted in the first place.

One would almost expect to find a spline mount to carry the torque demands.

Could that possibly be a solid assembly?  I can't imagine that much stock removal.

[turbotom]

To tell from the considerable length of thread of the tie rod that still projects from the nut, I'ld say Capstone use a hydraulic puller to pre-tension the rod and then, after a predefined force is reached, the nut is just screwed home without any considerable torque. After that, the puller is released, voila. No chance to get that nut loose without the proper tool. On many (half-way) recent small turbines, the rotors are assembled that way. The advantage is that no torsional stress is introduced in the tie rod. See my page on disassembly of a T312, scoll down approx. two thirds: www.turbinemuseum.de/Gasturbines/KHD_T312/khd_t312.html . I had to make such a tool in order to disassemble the rotor. The rod on that engine is tensioned with 50kN! On the Capstone, it probably in the ballpark of 10 to 20kN.

By the way, thanks for the teardown and the photos. I always wanted to have a peek into one of these engines. Interesting to see Capstone utilized rather "conventional" technology, at least turbomachinery-wise... Also quite peculiar that they trimmed back the exducer of the turbine wheel by a considerable amount. Someone must have screwed this up...

[madpatty]

Oct 7, 2018 16:37:26 GMT -5 turbotom said:

To tell from the considerable length of thread of the tie rod that still projects from the nut, I'ld say Capstone use a hydraulic puller to pre-tension the rod and then, after a predefined force is reached, the nut is just screwed home without any considerable torque. After that, the puller is released, voila. No chance to get that nut loose without the proper tool. On many (half-way) recent small turbines, the rotors are assembled that way. The advantage is that no torsional stress is introduced in the tie rod. See my page on disassembly of a T312, scoll down approx. two thirds: www.turbinemuseum.de/Gasturbines/KHD_T312/khd_t312.html . I had to make such a tool in order to disassemble the rotor. The rod on that engine is tensioned with 50kN! On the Capstone, it probably in the ballpark of 10 to 20kN.

It's strange and quite funny, I was just going through your other thread on Williams WR24 engine when you were reading mine.
LOL.

Thanks.

[Chuks]

Is that a 5.6:1 PR in a single stage centrifugal compressor wheel?
Billet wheel..?
Nice website when you want to know more...

[ingeniero]

Are you going to run this unit again? What kind of controls does it have.

[madpatty]

Oct 26, 2018 23:02:00 GMT -5 ingeniero said:

Are you going to run this unit again? What kind of controls does it have.

I don’t think it can run again.

Cheers.

[1000eemonarch]

Why do I fear I'm going down the same road? Just got a Capstone C30 and a C60 to play with, and add to the collection of microturbines with direct-driven alternators......

www.youtube.com/watch?v=0hKs9s_J5Zk

I'm going to try to get the C60 running.... For some reason I have a hankering to make a turbine-electric pickup truck

[turboron]

1000eemonarch, very interested in your Capstone project. Did you buy them at auction?

Thanks, Ron

[1000eemonarch]

Jan 23, 2020 19:59:58 GMT -5 turboron said:

1000eemonarch, very interested in your Capstone project. Did you buy them at auction?

Thanks, Ron

Ebay.... I'll try to take videos how things go. Should be fun to see what's inside, how they run and what I do with them.

I've been thinking about playing with with one of these for a while, but my first hand-on experience.

Thanks,

Alex.