Giffen Marr wrote:
Paul
Am I to understand that the TC Drive is to be driven by a shaft from
the
Turbo compressor? If so, aren't shaft rotational speeds of 60k to 80k
going
to present a problem?
Giff Marr
LIV-P/20B 45%
What problems did you have in mind? This is what I tink I am going
to use in the 1/2 inch size.
Paul, you are joking right?
Mark W.
No Not joking. What problems do you see?
--
Paul Lamar ...No rotor no motor.
Lack of balance, lack of strength, a horrible failure mode with an easier
released projectile.
At 80K RPM, any imbalance will be be exciting it with 480KHz (two per
rev).
At this frequency, you will at least wear out the metal to metal contact
points in the universal (although as Reeves says, you will be very
unlikely
to get up to this RPM.). Turbines normally use some sort of splined
coupling, a rigid coupling with a floating oil damped bearing, or driving
lubs these days.
Be really careful testing this Paul.
Mark
Thanks Mark. I think I will test both the bellows type as Reeve
suggested and this type if the off the shelf versions are
reasonable well made with tight tolerances. The drawback to
the bellows type is a somewhat larger OD for a given torque rating.
The second web site Reeve mentioned offer balanced bellows
type.
http://www.rw-america.com/PDF-couplings-line-shafts/MK_miniature-bellows-couplings.pdf
BTW what are "lubs" ?
Alignment is near perfect when the engine is cool.
I am concerned with slight mis-alignment due to temp difference
in the various parts as the engine and turbo charger
warm up.
Paul Lamar ...No rotor no motor.
Sorry, typo, that should have been driving lugs. The early gas turbines used
bolted rotors, but had fatigue issues at bolt holes. Most used driving lugs
forged into the discs which slot into the slots on the shafts. Not really
practical at the size you are making.
Keeping the casings straight and the bearings aligned is the devil in the
details for GE, PW and Rolls as well.
Mark
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