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- Newsgroups: sci.electronics
- Path: sparky!uunet!cs.utexas.edu!swrinde!sdd.hp.com!ux1.cso.uiuc.edu!cs.uiuc.edu!morrison
- From: morrison@cs.uiuc.edu (Vance Morrison)
- Subject: Re: Flywheel batteries as EV power source
- Message-ID: <BzD4As.Cup@cs.uiuc.edu>
- Organization: University of Illinois, Dept. of Comp. Sci., Urbana, IL
- References: <Bz6nuM.LCo@acsu.buffalo.edu> <1992Dec13.114534.961@cmkrnl.com> <BzB2Iq.Jqn@wang.com> <Ligon-161292082905@3.1.100.11>
- Date: Wed, 16 Dec 1992 17:23:13 GMT
- Lines: 41
-
- Ligon@macgw1.ge.com (Woody Ligon) writes:
-
- >If such effects are significant they could be, I suppose, an additional
- >selling point both in terms of ride quality and safety.
-
- >I am assuming of course that the flywheel axle is vertical and the plane of
- >rotation is horizontal.
-
- >Also wouldn't it seem that the gyroscopic effects would put terrific
- >strains on the flywheel bearing systems whenever the car hit a bump in the
- >road? And how do you make a bearing strong enough to take that beating and
- >still be extremely low friction?
-
- Actually, the rotational inertia is not really the big problem with flywheels.
- First of all, if you do it right, the inertia can help, not hurt (mounting
- the flywheel horizontally will keep the car from tipping left to right
- or up and down, which is desirable (just the wheels move up and down)).
-
- If you REALLY don't want the angular inertia, you can get rid of it one
- of two ways. First, you could mount the flywheel in a gyroscope. Thus
- the flywheel simply moves without effecting the car. This also removes
- flywheel axial loads. The other possibilty is to have to counter-rotating
- flywheels. In this case the angular inertia cancels out (there is high
- axial load between the two flywheels, however).
-
- The REAL problem with flywheels is safety and weight. Remember that a
- flywheel has the energy equivalent of gallons of gasoline. If you were
- in a accident, this energy could all be release suddenly. Thus there
- MUST be some sort of containment system to insure that even in the worst
- case the flywheel does not turn into a very large hand grenade. This
- can be done, but the containment system adds even more to the cost and
- weight of the system. Since flywheels are not the greatest in terms of
- energy density to begin with, this is not good.
-
- It seems to me that flywheels DO have good potential in small, stationary
- applications (for example storing PV solar electricity during the day
- for use at night, here weight is not a problem, and the flywheel's
- VERY long life is a major advantage).
-
- Vance
-
-