Hi all.
I want to gear up a 1.1 kW 32,000 rpm rated motor to 120,000 rpm, ie a 4:1 up ratio. Later I will want to gear up a similar 4 kw motor.
It doesn't have to operate continuously, a few minutes at a time will do. It should be reasonably efficient. Most important, it should be easy (and cheap).
Any suggestions as to how/ suppliers/ parts/ sources/ anything else?
Ta
Easy n cheap? I doubt it. However this company may be able help with the bearings, checkout spindle bearings:
Peter can you make sure the motor is pointing North when you run it. This way I'm not liable to see the rotor bouncing thru my garden any time soon..............
If you live to the East or West of Peter be very worried.
-- Regards,
John Stevenson Nottingham, England.
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How very fortunate
Regards, Tony
I hope so, with a bit of luck the rotor shouldn't make it past Watford gap.
Wot's a rotating Art ? I didn't see where he was trying to get a ballerina up to 34,000 rpm ?
-- Regards,
John Stevenson Nottingham, England.
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Three quick replies... may I make it four.
This application needs to be properly engineered, it is potentially very dangerous,... calculate the energy in the rotating arts, and convert the value in kJ to HG's by dividing by 800 ( 1 HG is the energy value of a hand grenade :-) ).
Are you in Surrey ? If so please let me know when you will be testing this machine.
Now tell us, what you need that for!
Gas centrifuge? Dentist's drill with 4kW?
Nick
You'd be into turbo shaft territory at those speeds, so probably plain bearings with pressure feed lubrication would be needed unless you can find ball races that will run at that speed, and they would still probably need full lubrication.
I think you may well end up making something up from shafting and toothed belts, as I cannot see anyone making that as a standard build.
Peter
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Worth considering: The belt will want to form a circle and just the force to keep it oval-shaped might make it kaputt.
Nick
I'm into plain pressure-fed bearings at the moment - the high pressure lubricant supply comes almost free.
Toothed belts? do you think that would be possible? If the small wheel is 10 mm dia the belt would be moving at 60 m/s or 135 mph.
I had in mind a rubber wheel about 24 mm dia rotating a steel shaft of about
12 mm dia. The problem then is power transfer. [btw the largest wheel which will spin at 120,000 rpm is 4 cm diameter, and weighs about 22 g. Tip velocity is 250 m/s. A reasonable guess [1] at the stored energy would be 400J - 1/2,000th of a hand grenade. A bit less than a nine (mm parabellum).This'un ain't particularly scary, although admittedly some of the other things I do might be considered so. It still has a fragmentation shield tho'.
[1] it's a bit hard to calculate exactly as the turbine wheel does not have a constant thickness or density - but say it's the equivalent of half the mass moving at the tip velocity. E = 0.5 x m x v^2= 0.5 x 0.012 kg X (250 m/s)^2 =~ 400kgm^2s^-2 or 400 J.]
Tension is about 20N or 4 lbs.
Ooops - 48 mm
Peter:
How about a multi-ribbed belt as used in automotive service?
Let's see, my RX-7 has a red-line speed of 8500 rpm, an eccentric output shaft pulley dia. of, say, 6".
Belt speed, very roughly: 3 x 6 x 8500 /12 /60 = 212.5 fps
Wolfgang
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