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RE: (ET) Re: new electrics
I am so sorry to have to agree with the less optimistic posters on this
thread.
>From the Baker Electric to electric versions of the HMV Freeway to the
>EV1 to the Corbin Sparrow (poor Sparrow!) to the TH!NK... well, the side
>of the road is littered... (I pray for the Gizmo NEV all the time.)
Take the GEM, for instance. All-electric NEV. Still available ready to
roll for <$4k.
AND YET!....
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&category=6737&item=2459708782&sspagename=STRK%3AMEBWA%3AIT
If you missed it, it was converted to ICE-power.
"We am a idjit."
Long may we, and other similarly aware consumers, make occasionally good
choices. And long live the ET.
-Maxo
--
http://www.maxmatic.com/
> William, if I told you what we pay for a battery or power electronics,
> you would
> be floored. What I mean by cheap is tens of dollars for the whole
> battery pack.
> The cost of materials won't let that happen for a flooded lead-acid
> battery.
> Any efficiency improvement of AC to what GE did is marginal. GE did a
> good job,
> at a low price, and did better than break even. The problem is
> pencil-pushers
> always compare profit to what the same money would do as simple
> investment, and
> simple investment won. It still would today.
>
> Larry Elie
>
>
>
> -----Original Message-----
> From: William Korthof [mailto:wkorthof earthlink net]
> Sent: Friday, February 20, 2004 11:46 AM
> To: Elec-Trak
> Subject: RE: (ET) Re: new electrics
>
>
> The cheap batteries have been around for quite a while...
> golf cars have created this market: a pack of six US2200
> or T105 batteries cost just a few hundred dollars (~$300).
>
> I think the improved power electronics and motor choices
> (in volume, a 3-phase inverter is cheap enough to allow
> use of 3-phase AC motor). An AC motor driven by normal
> vector drive inverter obviates the need for multiple gears.
> Regenerative braking is also easy with AC drive. All the
> above would result in significantly improved efficiency vs
> GE Electrak-era hardware.
>
> Any necessary 12vdc accessories can be operated
> directly from a DC-DC converter. Lighting and markers
> could use LEDs and compact fluorescent lamps.
>
> Todays power electronics also make it easy to have a
> powerful automatic charger that is "plug and play" to a
> standard outlet and provides most of a charge within
> 2-3 hours. Faster, smarter charging, improved efficiency,
> and more completely balanced battery discharging
> (vs electrak taps) would lower the AC power use, extend
> run time, and lengthen battery performance and pack life.
>
> In addition, todays inverters could easily provide a nice
> supply of 120 VAC for portable power tools.
>
> I do think that a modern electric tractor is an unexplored
> product with a significant un-served market.
>
>
> /wk
>
>
> At 09:46 AM 2/20/04 -0500, Elie, Larry (L.D.) wrote:
> >Hydrostatic is 65 to less than 80%, depending on many factors including
> >temperature. It's used on gas tractors for connivence, nothing
> >more. Hydrodynamic (car automatic) can go much higher, but isn't
> >really
> >variable speed at all; just shift-on go.
> >
> >It's always funny when our 30 year hindsight realizes that people 30
> >years
> >ago weren't dumb. If electric tractors rise again, it will be because
> >someone has a cheap battery or ultra-cap... or perhaps uses a cheap
> >fuel
> >cell. This market is already poisoned, and no large marketing guy will
> >touch it. Once business people 'know' that no one will buy something,
> >they stop trying. Another example: Diesels have 50% market
> >penetration
> >in Europe at higher fuel price. In the US it's 5%, because GM failed
> >marketing it in 1980, and now everyone 'knows' that no one will buy
> >them. Service is part of that. They tried, but not well. People paid
> >a
> >large premium to buy the early ones, and then averaged over $1,000/year
> >for repairs. I'm afraid Honda or Toyota may poison the electric market
> >for the next 25 years too. If they start passing on real their costs,
> >they will indeed kill the market. I'm glad GM pulled out before they
> >poisoned the electric market. No one will take large los!
> > ses for long before they pass them on or pull out, and pulling out to
> > give others a chance is the BETTER choice for everyone else.
> >
> >Larry Elie
> >
> >
> >-----Original Message-----
> >From: Ralph & Elaine Vogan [mailto:ralphgv centurytel net]
> >Sent: Friday, February 20, 2004 3:33 AM
> >To: Elec-Trak
> >Subject: Re: (ET) Re: new electrics
> >
> >
> >Does anyone know the efficiency of a hydrostatic drive? Use a single
> >speed
> >motor and the drive for forward, reverse, and speed changes. I have an
> >old
> >White ice tractor with a very small hydrostatic drive unit bolted to the
> >differential. It has plenty of power. Or a hydrolic pump & motor to
> >drive
> >the blades?
> >
> >Ralph V
> >
> >
> > > With all this talk about new ETs and better or cheaper ways to make
> > > them
> > > please remember that due to the limited energy storage on board our
> >tractors
> > > efficiency must be paramount.
> > >
> > > V belt drives tend to be only 90-95% efficient when everything is in
> > > good
> > > condition and clean.
> > >
> > > Friction drives are 80-90% efficient.
> > >
> > > Chains, again in good condition, are 98 % efficient, but high
> > > maintenance
> >to
> > > keep them in good shape in a tractor application. Notice that they
> > > are
> >not
> > > used except in high torque attachments like the snowblower. A worn,
> > > dry,
> > > and/or rusty chain can have efficiencies as low as 60-70%. The
> > > wasted
> > > energy turns to heat and destruction of what is left of the chain and
> > > sprockets.
> > >
> > > Direct drive, like the mower decks, are 100% efficient.
> > >
> > > GE used VX series V belts for the traction motor because the VX
> > > series V
> > > belts are more efficient than the old A/B/C/D series V belts. If
> > > the new
> > > Poly V belts, which are like the serpentine belts on modern cars,
> > > had been
> > > available when the Elec Traks were designed they would have been used
> > > preferentially over VX belts.
> > >
> > > What GE did was make a whole series of design choices to keep
> > > efficiency
> > > high. Where they lost efficiency was in the motor controls, and
> > > that was
> > > mainly a limitation of affordable DC drive technology of that time.
> > > If
> >you
> > > were, in your new tractor, to use a friction drive for the traction
> > > motor
> > > and belts in the mower deck, and then allowed for lack of
> > > maintenance,
> >you'd
> > > find extra losses of 10-25% after 1 or 2 years of service. I mean
> > > 10-25%
> > > higher losses than in a tractor with direct drive to the blades, and
> > > a
> >high
> > > efficiency belt somewhere in the traction drive.
> > >
> > > With respect to protecting the mower motor with a circuit breaker:
> > > This
> > > will not work well with a permanent magnet motor. In permanent
> > > magnet
> > > motors there is some critical armature current above which you will
> > > demagnetize the magnets. The friction washers, while crude, act as a
> >torque
> > > limiting clutch. By limiting torque, you effectively cap the
> > > armature
> > > current. If you use a circuit breaker alone the current can, and
> > > most
> > > likely will, pass well above that critical current before the breaker
> >trips.
> > >
> > > Steve Naugler
> > > snaugler earthlink net
> > >
> > >
> > >
> > > _______________________________________________
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> > > Elec-trak cosmos phy tufts edu
> > > https://cosmos.phy.tufts.edu/mailman/listinfo/elec-trak
> > >
> >
> >
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