home *** CD-ROM | disk | FTP | other *** search
- Newsgroups: sci.electronics
- Path: sparky!uunet!zaphod.mps.ohio-state.edu!uwm.edu!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: <BzF6sn.o3@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> <BzD4As.Cup@cs.uiuc.edu> <1992Dec16.160533.981@cmkrnl.com>
- Date: Thu, 17 Dec 1992 20:12:23 GMT
- Lines: 46
-
- jeh@cmkrnl.com writes:
-
- >I think what you mean here is "mount the flywheel in a gimbal mounting". Fine,
- >but now you have to come up with a really creative way of coupling large
- >amounts of mechanical or electrical energy to the part of the car that's
- >outside the gimbal mount. This coupling, plus the gimbal bearings on which the
- >flywheel assembly pivots, needs to be just as frictionless as the ones the
- >flywheel spins on -- any heat produced here is energy drained from the
- >"battery". This ain't gonna be cheap! Nor is it likely to survive long under
- >the "maintenance habits" of the typical American car owner.
-
- I don't see the problem. I mount the flywheel with its axis straight up.
- Turns don't cause a problem, however banking and hill climbing do. The
- resistance to banking may actually be a plus, but lets assume for now that
- it is undesirable. OK so mount it in a gimbal mounting. This allows that
- flywheel to still point straight up as the car banks and goes up and down
- hills. Getting energy out is easy, just hook up the wires. After all
- the steepest banks and hills are under 30 degrees, so the flywheel is NOT
- going to move much in its mounting. This mounting need not be particularly
- frictionless, (conventional bearings are MORE than adaquate, springs are
- probably a possibility), since energy lost is proportional to movment which
- there is simply not very much of. The bearings the flywheel rests on will
- experience NO MORE lateral force than is needed to move the whole flywheel
- in its mounting (which is not very much). By the same token, the car
- can only experience that much undesirable force from the flywheel.
-
- By the way, every flywheel that I have seen that is designed for mass
- energy storage uses magnetic bearings in a vacuum housing. The bearings
- are designed so that permanent magnets hold most of the flywheel up, and
- electromagnets are used to keep the flywheel exactly in place (where it
- touches nothing). In theory such a system could be made to dissipate
- almost no power (in the current state of the art, spin ups can last
- weeks). Conventional bearings also surround the flywheel in case the
- magnetic ones fail and for particularly bad jarring etc.
-
- Anyway, flywheels are definately a possibility. They exist today as
- experimental prototypes (see the Intersociety Conference on Energy
- Conversion Engineering for more information).
-
- Personally I see them only possibly being used in the transportation
- sector in buses (where they can be recharged every 10-20 miles or so)
- That way the flywheels can be smaller, and hence safer and cheaper
- to make. Also buses REALLY need the high power density and long
- life (many charge discharge cycles) that flywheels can give.
-
- Vance
-