EV Digest 4140
Topics covered in this issue include:
1) Re: more about Nagashima's EVs
by Michael Shipway <[EMAIL PROTECTED]>
2) Re: NEDRA rule changes
by Ryan Stotts <[EMAIL PROTECTED]>
3) Re: Dave Cloud's Rules ideas.
by "Roderick Wilde" <[EMAIL PROTECTED]>
4) Re: Question: 3 phase alternator- SiC diode
by Rod Hower <[EMAIL PROTECTED]>
5) Re: 3 phase PM
by Lee Hart <[EMAIL PROTECTED]>
6) RE: 3 phase alternator-why not an induction machine?
by "Claudio Natoli" <[EMAIL PROTECTED]>
7) Re: Dave Cloud's Rules ideas.
by Lee Hart <[EMAIL PROTECTED]>
8) Re: 3 phase alternator-why not an induction machine?
by Lee Hart <[EMAIL PROTECTED]>
9) Re: AC vs. DC / 100 mph club with AC?
by Lee Hart <[EMAIL PROTECTED]>
10) Re: Dave Cloud's Rules ideas.
by Victor Tikhonov <[EMAIL PROTECTED]>
11) Re: AC vs. DC / 100 mph club with AC?
by Victor Tikhonov <[EMAIL PROTECTED]>
12) Re: Dave Cloud's Rules ideas.- Homopolar motors
by Rod Hower <[EMAIL PROTECTED]>
13) RE: 3 phase alternator-why not an induction machine?
by "djsharpe" <[EMAIL PROTECTED]>
14) RE: 3 phase alternator-why not an induction machine?
by "djsharpe" <[EMAIL PROTECTED]>
15) Re: 3 phase alternator-why not an induction machine?
by Seth Allen <[EMAIL PROTECTED]>
16) Re: Question: 3 phase alternator- SiC diode
by Seth Allen <[EMAIL PROTECTED]>
17) Re: Dave Cloud's Rules ideas.
by "Roderick Wilde" <[EMAIL PROTECTED]>
18) Re: 3 phase alternator-why not an induction machine?
by "Dave" <[EMAIL PROTECTED]>
19) Hybrid battery pack question
by Jeff Shanab <[EMAIL PROTECTED]>
20) Re: 3 phase alternator-why not an induction machine?
by Lee Hart <[EMAIL PROTECTED]>
21) Re: 3 phase PM
by "David Chapman" <[EMAIL PROTECTED]>
22) Re: Dave Cloud's Rules ideas.
by Lee Hart <[EMAIL PROTECTED]>
23) Re: Dave Cloud's Rules ideas.
by Lee Hart <[EMAIL PROTECTED]>
--- Begin Message ---
ProEV wrote:
Look at this EV(behind the bondage babe).
http://www.carview.co.jp/tas/2005/car/html/zero_sports/super_elexceed/01.asp
Website here.
http://www.zero-ev.com/index.asp
I don't see any specs in English.
Also for his mini car, but I hope they don't mean the top speed is 45
MPH.
http://www.caranddriver.com/article.asp?intAsvPageCurrent=3§ion_id=31&article_id=9123
Cliff
www.ProEV.com
Babel Fish did a pretty good job of translating the spec page.
http://babelfish.altavista.com/
Here is the specification table for the "Super Elexceed" as Babel Fish
rendered it.
------------------------------------------
The corporation zero sport which is the automaker, concentrated the
electric automobile technology which is cultivated so far in "Tokyo
automatic salon 2005 with NAPAC", announced the concept car "??????????"
which aims for the establishment of worldwide full speed record of the
electric automobile. "??????????", in order to expand the possibility of
the electric automobile which is the ultimate echo car which does not
put out the exhaust altogether largely, with the combination, advanced
lithium ion electric battery and the direct current motor, challenging
to speed record in purpose, in the future has planned development.
In order to expand the possibility of the electric automobile which is
the ultimate echo car which does not put out the exhaust altogether in
21st century which is called century of environment, largely, future of
the echo car is cut and zero sports start continuing further research
and development as an electromotive it keeps developing air automaker
young. Expectation future in zero sports.
* "Tokyo automatic salon 2005 with NAPAC"
It is automobile industry biggest festival model of one time in the year
when the automaker and the after part manufacturer mind in all, it is a
match to "Tokyo motor show" of automaker subject, it is the event whose
domestic degree of attention is very high.
*?????????? Leading particular
*
------------------------------------------------------------------------
Size Weight
Total length Mm
4450
------------------------------------------------------------------------
Full-width Mm
1920
------------------------------------------------------------------------
Total height Mm
1100
------------------------------------------------------------------------
Empty car weight Kg
850
------------------------------------------------------------------------
Crew-member fixed capacity person
4
------------------------------------------------------------------------
Motor
Type
Direct current series
------------------------------------------------------------------------
On-board quantity
2
------------------------------------------------------------------------
Installed capacity Kw
158
------------------------------------------------------------------------
Control method
MOS-FET chopper PWM System
------------------------------------------------------------------------
Main battery
Type Type
Lithium ion Electric battery
------------------------------------------------------------------------
Capacity Voltage (1 module)
24V-15Ah
------------------------------------------------------------------------
On-board quantity
32 (2 Parallel �8 Series ) �2 Parallel
------------------------------------------------------------------------
Entire voltage
192
------------------------------------------------------------------------
Tire
Nosewheel
235/35ZR19
------------------------------------------------------------------------
Rear wheel
255/40ZR19
----------------------------------
End of translated stuff
Looks like it's got 11.5 kwh worth of Lithium Ions in 4 strings of 192
Volts.
Mike-
--- End Message ---
--- Begin Message ---
Raymond Knight wrote:
>a 7second daily driver, at under 96volts.
Are you talking about 0 - 60 mph in 7 seconds or doing a 1/4 mile in 7 seconds?
--- End Message ---
--- Begin Message ---
Yes Peter, you hit the nail on the head with the I2R loses. The other thing
Dave is missing the point on is having a motor that pulls hard through the
entire RPM range which is needed to be competitive. Sure he can run 6 or 12
volt motors but as far as I know there are no production motors in low
voltages that are designed to take very high amperages efficiently when
overvoltaged. Even the big ADCs aren't efficient at the amp levels we
utilize. It's a real uphill battle. For someone who is doing the talk of low
budget it seems to me he is biting off a big budget. Dave is famous for
using homemade contactors for motor control. He has melted them and blown
the tips off and welded them. This is not a safe way to go. I have video
from years ago from hooking up 240 volts of high amp output Interstate
Megatron Pluses direct through a big forklift contactor to a 9 inch ADC
motor when testing the "Maniac Mazda" in the street. This was pre Zilla
days. It launched very hard. In the video you can see the flames shoot out
of the motor and contactor. It blew molten holes through the end bell
housing of the motor. I am so glad we have Zillas now. I can just imagine
the added weight of all those 4/0 cables.
Roderick Wilde
"Suck Amps EV Racing"
www.suckamps.com
----- Original Message -----
From: "Peter VanDerWal" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Tuesday, March 01, 2005 2:52 PM
Subject: Re: Dave Cloud's Rules ideas.
Horsepower is still watts and watts is volts times amps. Let's see, to
make
a 600,000 watt car you divide by 72. That is over 8000 amps. Show me the
batteries. Drag racing is still horsepower per pound. You can only build
a
car so light before you are pushing safety limits. Rich, please pass on
to
Dave.
Hold on here, watts is still watts too. If you have a pack that can
deliver 600kW it can do it whether or not you wire it up in series for
360V or in parallel for 72V.
Of course your I2R losses go up at the higher amp level, but you can fix
that with bigger conductors. Then again, bigger conductors weigh more and
weight is always a concern on drag racers.
--
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--- End Message ---
--- Begin Message ---
I checked out their web site.
Their '20A' diode has forward drop ratings
at 10 Amp, 1.2 to 1.4V at 25C junction and
1.4 to 1.8V at 175C junction.
Kind of interesting, this diode has a positive
voltage drop with increased temperature.
Check this out,
http://www.irf.com/product-info/datasheets/data/30eph03.pdf
This has the following in a TO-247
Vf = 1.25 at 30A and Tj=25C
and Vf = 1.0V at 30A and Tj=125C
I think I'll use the IR part!
Rod
--- Seth Allen <[EMAIL PROTECTED]> wrote:
> Add a zero to that sixty volts, Rich. Cree makes
> 600V Schottky SiC
> diodes. A spinoff of making all those blue LEDs...
>
> How about that in a motor controller. Forward
> voltage drop still isn't
> great, but they burn less power switching off.
>
> Caveat Emptor on these, as I haven't used them (much
> at least), but
> they are available in Otmar's favorite package, the
> TO-247.
>
> Seth
>
>
> On Mar 1, 2005, at 3:25 PM, Rich Rudman wrote:
>
> > OK Lee...
> > Schottkys can only be gotten up to about 60
> volts, The voltage spikes
> > ring
> > higher than that while boosting.
> >
> > Good fets usually have good body diodes or are
> co-packed with better
> > diodes..
> >
> > Yup... unless you can't use Schottkys then fets
> are your only choice.
> >
> > I predicted a full Fet bridge was going to be
> better. Switching the top
> > allows you to reduce rectification losses. A ON
> fet is a LOT lower
> > than
> > even a Schottky.
> >
> > They staid with diodes on the top side. ...I
> think. We had long
> > arguments
> > about what was doable and what was right and cost
> effective. Yea to do
> > topside sync rect they needed encoders,
> > Not cheap and easy. Doing this with BEMF sensing
> and a DSP... Would...
> > allow for cheap commutation control.
> > Then again they didn't want to use a expensive
> Micro, they used a
> > MicroChip
> > of some sort.
> >
> > So... there are ways to suck Trons from small
> sources... elegantly...
> >
> >
> >
> >
> > ----- Original Message -----
> > From: "Lee Hart" <[EMAIL PROTECTED]>
> > To: <[email protected]>
> > Sent: Tuesday, March 01, 2005 10:43 AM
> > Subject: Re: Question: Max efficiency charging
> with 3 phase alternator
> >
> >
> >> Rich Rudman wrote:
> >>> The best in the Buisness are PM windturbine
> power sections.
> >>> They use FETs and Diodes. The top of the 3 phase
> bridge is Diodes,
> >>> Low voltage, low conduction losses. Ultra fast
> soft recovery.
> >>
> >> Who cares if they are fast or soft recovery?
> We're only dealing with
> >> low
> >> audio frequencies. I would think they would
> choose the diodes based on
> >> forward voltage drop (probably schottkys).
> >>
> >>> The bottoms are FETS that can be PWMed. This
> allows normal
> >>> rectification when there is enough windblowing.
> >>
> >> Presumably by using the MOSFET's body diode? This
> is a high-drop
> >> diode.
> >>
> >>> When there is not sufficient wind for conduction
> into the Batteries,
> >>> but there is voltage, they switch the bottoms
> Fets as a boost
> >>> converter.
> >>
> >> Clever.
> >>
> >>> Fet can be better than a diode, if switched
> properly.
> >>
> >> True, but if they are using ~1v drop body diode
> and non-schottkys,
> >> there
> >> goes efficiency.
> >> --
> >> If you would not be forgotten
> >> When your body's dead and rotten
> >> Then write of great deeds worth the reading
> >> Or do the great deeds worth repeating
> >> -- Ben Franklin, Poor Richard's Almanac
> >> --
> >> Lee A. Hart 814 8th Ave N Sartell MN 56377
> >> leeahart_at_earthlink.net
> >>
> >
>
>
--- End Message ---
--- Begin Message ---
Myles Twete wrote:
> Did I say this is a steam engine? ... An open-frame 2-cylinder
> 2-cylinder 1.5HP Tiny Power arrangement like my friend's gets
> noisy above 5cps (300RPM) and loud at 10cps (600RPM).
Ok; to make power efficiently at low rpm, you want a completely
different kind of generator/alternator. It's going to be larger in
diameter than it is in length, and have a lot of poles.
You could start with a PM "stepper" motor as a generator. They are
typically 200 or more steps per revolution, so they are very happy
running at 300 rpm. Most are two phase, so you need two bridges to
rectify each winding (or at least 6 diodes if the two windings share one
pair of higher-current diodes). But I doubt you'll find one big enough
to convert the entire 1.5hp.
For example, a Superior Electric M093 "Slo-Syn" stepper is rated 2.86
ft.lbs torque at 300 rpm = 120 watts = 1/6 hp, and weighs 7.8 lbs.
--
Ring the bells that you can ring
Forget your perfect offering
There is a crack in everything
That's how the light gets in
-- Leonard Cohen, from "Anthem"
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
Misrepresentations of the laws of thermodynamics aside, and looking at actual
numbers:
Diesel: 0.85kg/L and 45.3MJ/kg -> 38.5 MJ/L.
100 mpg -> 2.35L/100 km => 90.5MJ/100km (diesel) => ~250 Whrs/km (400
Whrs/mile) [in diesel calorific content terms]
Assuming the EV motive/transmission requirements at the design speed are half
this (ie. ~ 125 Whrs/km, 200 Whrs/mile), the design would call for a diesel
engine capable of 50% thermal efficiency at the intended generation RPM,load.
If my math is correct, this is a BSFC of a little over 0.26lbs/HP.hr; which is
about the limit for diesels (although less common in small diesels).
Not certain of a good value to take into account charging / electric motor
efficiencies (80%?), but with this in mind it is clear that 100mpg in a
series-hybrid would require a proportionally lower BSFC (which is a big ask!),
or a lower Whr/distance requirement (either by better aero/drag or more likely
by a lower design speed).
Optimistic? Perhaps, but not outside the realms of possibility (assuming I
haven't goofed on the math :-)
Cheers,
Claudio
--- End Message ---
--- Begin Message ---
Tim Clevenger wrote:
> What about four 72V packs of Orbs and four motors for [EMAIL PROTECTED],
> or even two packs of buddy paired Orbs for [EMAIL PROTECTED] amps into two
> motors? Granted it'd be expensive, but that's part of the problem
> with voltage classes.
If you really have a battery pack that can deliver 8000 amps, then a
commutator based motor is not for you. You may want to look at a
homopolar motor, which is a DC motor with slip rings. Physically, it
would be a big copper disk, with one set of brushes in the center, and
another set at the outside rim. A set of neodymium magnets or just big
series field coils produce a magnetic field that goes thru the copper
disk.
Homopolar motors are *really* good at high currents and low voltages.
There are also lots of problems, but they may not matter for the few
seconds it takes for a drag race.
--
Ring the bells that you can ring
Forget your perfect offering
There is a crack in everything
That's how the light gets in
-- Leonard Cohen, from "Anthem"
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
djsharpe wrote:
> I cannot understand why the Toyota & Honda hybrids are not Diesels.
I think the Japanese automakers are more concerned with pollution than
fuel economy -- so they use gasoline-electric hybrids.
The Europeans are more concerned with fuel economy than pollution -- so
they use diesels. To manage pollution, Europe chose to mandate
low-sulfur diesel fuel.
At some point, the two may well get together and produce diesel-electric
hybrids, to get lower pollutin *and* fuel economy.
--
Ring the bells that you can ring
Forget your perfect offering
There is a crack in everything
That's how the light gets in
-- Leonard Cohen, from "Anthem"
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
>> unless you are also running more than rated current.
Ryan Stotts wrote:
> Is it rated at 2,000 amps? ;)
If a brushed motor is to (successfully) carry 2000 amps, you need
several square inches of brush contact area. That means a big
commutator. That means a big motor. It's not problem to build a 2000 amp
motor if it's also built for 2000 volts; everything is scaled up big
accordingly. You'll have a 5000 hp motor that a couple feet in diameter
and a few feet long, and powerful enough to drive a ship!
But that commutator won't fit in a "mere" 500 hp motor. Or rather, the
commutator would be as big as the armature.
Likewise, if you want a 2000 amp AC controller, it's going to several
square inches of silicon. Silicon transistors cost 100s of times more
per square inch than carbon brushes, so you've gone from a $100 set of
brushes to $10,000 worth of transistors!
DC controllers use about 1/3rd the amount of silicon for a given current
and voltage, so they cost a lot less. It's not that you can't build a
very high performance AC controller; it just costs more.
Another trick with silicon devices is that their cost goes up more
slowly as you raise the voltage than as you raise the current. It's
fairly easy to get 400v MOSFETs and 1200v IGBTs. So, they tend toward
higher voltages and lower currents than you see with brushes.
> As far as batteries, I'm currently fond of the Orbitals. Optima's if
> there was a convincing or convenient reason. Is there anything else?
Sure... there are LOTS of alternatives. Nicads have been discussed as
having good potential. Supercapacitors may also be viable. Even flooded
lead-acid starting batteries are a possibility.
--
Ring the bells that you can ring
Forget your perfect offering
There is a crack in everything
That's how the light gets in
-- Leonard Cohen, from "Anthem"
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
Sure. Pure math. 8 strings and 16,000A then must be
no problem either, right? And, so on...
Victor
To set to the record straight...
8000A... no problem.
4 strings of 72V, 2000A each string.
Of
course that would be with mulitiple high-efficiency motors
Dave Cloud
---------------------------
--- End Message ---
--- Begin Message ---
You can pay me and I will get you Elfa already made. 560A per phase,
(2x280A, 6 phases for 2 motors), 650V max. No need to wait.
~30k item indeed.
Anyone?
Victor
Ryan Stotts wrote:
Rich Rudman wrote:
At a 10sofK$ for AC inverters that can make 600 amps per phase... it's not
cheap or easy to pull it off.
I remember a while back Otmar mentioned on this list making an AC
inverter... What if some people payed in advance for it? Would that
get it into production this year?
I want a Zilla style AC controller. Keep it simple and not a fancy
~$30,000 item. ;)
--- End Message ---
--- Begin Message ---
Perhaps we need to change the 1/4 mile on pavement
to water,
http://www.ga.com/atg/homo.php
I could use a superconducting motor on the TEVan.
:-)
--- Lee Hart <[EMAIL PROTECTED]> wrote:
> Tim Clevenger wrote:
> > What about four 72V packs of Orbs and four motors
> for [EMAIL PROTECTED],
> > or even two packs of buddy paired Orbs for
> [EMAIL PROTECTED] amps into two
> > motors? Granted it'd be expensive, but that's part
> of the problem
> > with voltage classes.
>
> If you really have a battery pack that can deliver
> 8000 amps, then a
> commutator based motor is not for you. You may want
> to look at a
> homopolar motor, which is a DC motor with slip
> rings. Physically, it
> would be a big copper disk, with one set of brushes
> in the center, and
> another set at the outside rim. A set of neodymium
> magnets or just big
> series field coils produce a magnetic field that
> goes thru the copper
> disk.
>
> Homopolar motors are *really* good at high currents
> and low voltages.
> There are also lots of problems, but they may not
> matter for the few
> seconds it takes for a drag race.
> --
> Ring the bells that you can ring
> Forget your perfect offering
> There is a crack in everything
> That's how the light gets in
> -- Leonard Cohen, from "Anthem"
> --
> Lee A. Hart 814 8th Ave N Sartell MN 56377
> leeahart_at_earthlink.net
>
>
--- End Message ---
--- Begin Message ---
The 2003 Shell Eco-Marathon run was once nearly 10000 mpg (Imperial) on
petrol. Vehs were purpose built and average speeds no less than 15mph.
So a light weight vehicle high pressure tyres etc and small displacement
engine and say 80kph max is going to get good results. A Peugeot 406
Diesel 2 litre engine with 3 people on board once had the Guiness Record
and achieved Melbourne to Rockhampton on one tank about 75l, nearly
100mpg (Imp). Veh was manual, av speed about 60kph.
David
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Claudio Natoli
Sent: Wednesday, 2 March 2005 12:46 PM
To: [email protected]
Subject: RE: 3 phase alternator-why not an induction machine?
Misrepresentations of the laws of thermodynamics aside, and looking at
actual numbers:
Diesel: 0.85kg/L and 45.3MJ/kg -> 38.5 MJ/L.
100 mpg -> 2.35L/100 km => 90.5MJ/100km (diesel) => ~250 Whrs/km (400
Whrs/mile) [in diesel calorific content terms]
Assuming the EV motive/transmission requirements at the design speed are
half this (ie. ~ 125 Whrs/km, 200 Whrs/mile), the design would call for
a diesel engine capable of 50% thermal efficiency at the intended
generation RPM,load. If my math is correct, this is a BSFC of a little
over 0.26lbs/HP.hr; which is about the limit for diesels (although less
common in small diesels).
Not certain of a good value to take into account charging / electric
motor efficiencies (80%?), but with this in mind it is clear that 100mpg
in a series-hybrid would require a proportionally lower BSFC (which is a
big ask!), or a lower Whr/distance requirement (either by better
aero/drag or more likely by a lower design speed).
Optimistic? Perhaps, but not outside the realms of possibility (assuming
I haven't goofed on the math :-)
Cheers,
Claudio
--- End Message ---
--- Begin Message ---
The Diesels have carbon particle trap exhausts that burn off the
particles at intervals but are no good for high sulphur fuel. Perhaps
the Japs are worried about Diesels bad public image.
David
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Lee Hart
Sent: Wednesday, 2 March 2005 2:55 PM
To: [email protected]
Subject: Re: 3 phase alternator-why not an induction machine?
djsharpe wrote:
> I cannot understand why the Toyota & Honda hybrids are not Diesels.
I think the Japanese automakers are more concerned with pollution than
fuel economy -- so they use gasoline-electric hybrids.
The Europeans are more concerned with fuel economy than pollution -- so
they use diesels. To manage pollution, Europe chose to mandate
low-sulfur diesel fuel.
At some point, the two may well get together and produce diesel-electric
hybrids, to get lower pollutin *and* fuel economy.
--
Ring the bells that you can ring
Forget your perfect offering
There is a crack in everything
That's how the light gets in
-- Leonard Cohen, from "Anthem"
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
It is wandering off topic, but if you look at a BSFC map of a Diesel
versus gasoline, then it becomes clearer. Having built both series and
parallel with diesel, I can explain the ins & outs, but why don't I do
it offlist or in an appropriate forum if someone can identify it.
Seth
On Mar 1, 2005, at 10:55 PM, Lee Hart wrote:
djsharpe wrote:
I cannot understand why the Toyota & Honda hybrids are not Diesels.
I think the Japanese automakers are more concerned with pollution than
fuel economy -- so they use gasoline-electric hybrids.
The Europeans are more concerned with fuel economy than pollution -- so
they use diesels. To manage pollution, Europe chose to mandate
low-sulfur diesel fuel.
At some point, the two may well get together and produce
diesel-electric
hybrids, to get lower pollutin *and* fuel economy.
--
Ring the bells that you can ring
Forget your perfect offering
There is a crack in everything
That's how the light gets in
-- Leonard Cohen, from "Anthem"
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
Yep, worse than the IR part for DC, but switching is a whole different
ballgame in the tens of kHz and above, there they really start to
shine. There are times in a switchmode converter where you could use
one SiC diode where no ultrafast silicon would work. And you could
parallel them if needed.
This is also a new process. So there is likely going to be more rapid
improvement in characteristics versus silicon diodes. If the Vf gets
better, silicon diodes might go out of fashion.
Seth
On Mar 1, 2005, at 8:33 PM, Rod Hower wrote:
I checked out their web site.
Their '20A' diode has forward drop ratings
at 10 Amp, 1.2 to 1.4V at 25C junction and
1.4 to 1.8V at 175C junction.
Kind of interesting, this diode has a positive
voltage drop with increased temperature.
Check this out,
http://www.irf.com/product-info/datasheets/data/30eph03.pdf
This has the following in a TO-247
Vf = 1.25 at 30A and Tj=25C
and Vf = 1.0V at 30A and Tj=125C
I think I'll use the IR part!
Rod
--- Seth Allen <[EMAIL PROTECTED]> wrote:
Add a zero to that sixty volts, Rich. Cree makes
600V Schottky SiC
diodes. A spinoff of making all those blue LEDs...
How about that in a motor controller. Forward
voltage drop still isn't
great, but they burn less power switching off.
Caveat Emptor on these, as I haven't used them (much
at least), but
they are available in Otmar's favorite package, the
TO-247.
Seth
On Mar 1, 2005, at 3:25 PM, Rich Rudman wrote:
OK Lee...
Schottkys can only be gotten up to about 60
volts, The voltage spikes
ring
higher than that while boosting.
Good fets usually have good body diodes or are
co-packed with better
diodes..
Yup... unless you can't use Schottkys then fets
are your only choice.
I predicted a full Fet bridge was going to be
better. Switching the top
allows you to reduce rectification losses. A ON
fet is a LOT lower
than
even a Schottky.
They staid with diodes on the top side. ...I
think. We had long
arguments
about what was doable and what was right and cost
effective. Yea to do
topside sync rect they needed encoders,
Not cheap and easy. Doing this with BEMF sensing
and a DSP... Would...
allow for cheap commutation control.
Then again they didn't want to use a expensive
Micro, they used a
MicroChip
of some sort.
So... there are ways to suck Trons from small
sources... elegantly...
----- Original Message -----
From: "Lee Hart" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Tuesday, March 01, 2005 10:43 AM
Subject: Re: Question: Max efficiency charging
with 3 phase alternator
Rich Rudman wrote:
The best in the Buisness are PM windturbine
power sections.
They use FETs and Diodes. The top of the 3 phase
bridge is Diodes,
Low voltage, low conduction losses. Ultra fast
soft recovery.
Who cares if they are fast or soft recovery?
We're only dealing with
low
audio frequencies. I would think they would
choose the diodes based on
forward voltage drop (probably schottkys).
The bottoms are FETS that can be PWMed. This
allows normal
rectification when there is enough windblowing.
Presumably by using the MOSFET's body diode? This
is a high-drop
diode.
When there is not sufficient wind for conduction
into the Batteries,
but there is voltage, they switch the bottoms
Fets as a boost
converter.
Clever.
Fet can be better than a diode, if switched
properly.
True, but if they are using ~1v drop body diode
and non-schottkys,
there
goes efficiency.
--
If you would not be forgotten
When your body's dead and rotten
Then write of great deeds worth the reading
Or do the great deeds worth repeating
-- Ben Franklin, Poor Richard's Almanac
--
Lee A. Hart 814 8th Ave N Sartell MN 56377
leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
Lee, You forgot to give us an idea of price for the Homopolar motors. I am
aware of really efficient brushless DC motors that produce 1800 foot pounds
of torque and are fairly light. They are used in the oil drilling industry.
There is only one minor reason I am not currently running them. It is the
$50,000.00 price tag per unit, not counting the controller. When Dave talks
about expensive cars it is all very relative after all. When we see REAL
money get in this sport then you will see the ETs go way down and the MPHs
go way up. We are all hobbyists at this point in history but history has to
start somewhere. We all do the best with the budget we can scrape together.
Roderick Wilde
"Suck Amps EV Racing"
www.suckamps.com
----- Original Message -----
From: "Lee Hart" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Tuesday, March 01, 2005 7:48 PM
Subject: Re: Dave Cloud's Rules ideas.
Tim Clevenger wrote:
What about four 72V packs of Orbs and four motors for [EMAIL PROTECTED],
or even two packs of buddy paired Orbs for [EMAIL PROTECTED] amps into two
motors? Granted it'd be expensive, but that's part of the problem
with voltage classes.
If you really have a battery pack that can deliver 8000 amps, then a
commutator based motor is not for you. You may want to look at a
homopolar motor, which is a DC motor with slip rings. Physically, it
would be a big copper disk, with one set of brushes in the center, and
another set at the outside rim. A set of neodymium magnets or just big
series field coils produce a magnetic field that goes thru the copper
disk.
Homopolar motors are *really* good at high currents and low voltages.
There are also lots of problems, but they may not matter for the few
seconds it takes for a drag race.
--
Ring the bells that you can ring
Forget your perfect offering
There is a crack in everything
That's how the light gets in
-- Leonard Cohen, from "Anthem"
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
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--- Begin Message ---
http://finance.groups.yahoo.com/group/LOCOMOTIVE/ ?
David C. Wilker Jr. USAF (RET)
Children need love, especially when they do not deserve it.
- Harold S.
Hulbert
----- Original Message -----
From: "Seth Allen" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Tuesday, March 01, 2005 7:02 PM
Subject: Re: 3 phase alternator-why not an induction machine?
It is wandering off topic, but if you look at a BSFC map of a Diesel
versus gasoline, then it becomes clearer. Having built both series and
parallel with diesel, I can explain the ins & outs, but why don't I do it
offlist or in an appropriate forum if someone can identify it.
Seth
On Mar 1, 2005, at 10:55 PM, Lee Hart wrote:
djsharpe wrote:
I cannot understand why the Toyota & Honda hybrids are not Diesels.
I think the Japanese automakers are more concerned with pollution than
fuel economy -- so they use gasoline-electric hybrids.
The Europeans are more concerned with fuel economy than pollution -- so
they use diesels. To manage pollution, Europe chose to mandate
low-sulfur diesel fuel.
At some point, the two may well get together and produce diesel-electric
hybrids, to get lower pollutin *and* fuel economy.
--
Ring the bells that you can ring
Forget your perfect offering
There is a crack in everything
That's how the light gets in
-- Leonard Cohen, from "Anthem"
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
In the past we have discussed hybrid battery packs where we have lithium
ion in parrallel with lead acid so that the lead acid takes the brunt of
the amps.
Would it be a good idea to be able to parrallel/series switch the
battery pack?
Parrallel to start, with current limit set to give max lead acid amps
that still limits the lithium ion amps to a safe level.
Then after the mass has gotten moving we switch to series doubling the
voltage to allow the controller to downconvert to higher amps at now
higher rpms
Could we take the motor switching setup on a zilla and wire it to the
hybrid pack and set it to switch at a certain rpm or mph and, more
important, does it let us set differnet current limits for the series
and for the parallel configurations?
say 10 orbitals for 120Volts @ 400lb plus about 33 100ah TS cells for
another 217lbs
120*40*.8 = 3.8 useable KWH
120*100*.5 = 6 useable KWH 10Kwh for a solid 33 mile range with a
617 lb pack ?
oh and 900+6600 = $7500 min
For that matter, would there be a benifit to hooking the parallel/series
setup from the zilla to a lead/lead pack ?
--- End Message ---
--- Begin Message ---
Peter VanDerWal wrote:
> Do you really think the Prius engine is so much more efficient
> at the higher power level that it makes up for double conversion
> losses AND NiMH charge efficiency?
I *have* a Prius, and it *does* work like this.
I'd say that in general, the efficiency curve for every engine will have
operating points that are less than half as efficient as its peak
operating efficiency. By the time you figure the losses of the electric
motors, inverters, and batteries, you probably get back about half the
power you stored. So, as soon as your driving speed is such that you
would be forced to run the motor at half its peak efficiency, then
cycling the engine on/off and using electric power to maintain constant
speed will be more efficient overall.
> Besides, the Prius isn't a series hybrid, it's a series/parallel
> hybrid.
True, but I don't think that's important for this discussion.
> If you went double conversion *always* plus charge efficiency for
> when the motor is off, you'd have to be about three times more
> efficient at the high power level compared to the lower power
> level ICE only setup
I think you are correct that a pure series hybrid will have a harder
time delivering higher fuel economy than if the same engine drives the
wheels via a transmission. But, it is still possible.
Obviously, you need a very efficient motor and generator. With 90%
efficient units, you could have about 81% efficiency from engine to
wheels. If you compare this to a conventional car's 90% efficient
automatic transmission, you're about 10% behind.
However, I can well imagine using a much smaller engine that is
operating at peak efficiency at cruise, and so has more than 10% better
fuel economy. The power for accellerating, hill-climbing, passing, etc.
will come from the batteries.
Efficiency calculations get complicated when you start accellerating and
decelerating. In theory you can do better than the ICE alone, but
details are important. Many people have tried and if the details are
wrong, you wind up worse off.
--
Ring the bells that you can ring
Forget your perfect offering
There is a crack in everything
That's how the light gets in
-- Leonard Cohen, from "Anthem"
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
I looked at the web page for Hornet and am somewhat confused when they talk
about needing high speeds (18,000 rpm) to make the fan cooling effective and
in the same breath talk about how these are effecient at low speeds. I guess
Im confused. How high a speed would be needed to output 240 volts? Would
this be fast enough to make the fan function properly? Just wondering if
these PM alternators could be used as a direct charging method for higher
voltage packs. Rectified of course. And are these alts 3 phase? I have a lot
of 400 cycle transformers, I think I even got in a couple last week that are
3 phase. I would have to determine the specs tho, don't think they are
marked. This indeed might be a solution, gear the thing up 4-6 X. I wonder
how lossey this would be?
David Chapman.
----- Original Message -----
From: "Seth Allen" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Tuesday, March 01, 2005 8:52 AM
Subject: Re: 3 phase PM
The voltage regulator will usually keep this from blowing up things, at
least short term. A PM alternator doesn't have this sort of control
available to it, but the wound rotor alternator does.
If Myles were to speed up that alternator and feed the unrectified output
through an appropriate stepdown transformer (maybe a lightweight 3 phase
400Hz surplus military job would do) to step the voltage down, he should
get a lot more power out of that PM alternator.
Seth
On Mar 1, 2005, at 10:09 AM, Ivo Jara wrote:
Odd, it says:
(You will never be able to see voltages this high because the battery
pulls
all power inputs DOWN to its own voltage level AND that's why you NEVER
pull
off the battery cables when an engine is running because your fuses, dash
board lights and regulator blow up !!!!!!! (Especially if you rev the
engine! ,,,, NO battery---- NO buffer!!)
I have unhooked my batt from the car, even revved up, and nothing
happens,
when I was a kid I used to take it out, just to save weight on the strip,
this just doesn't soud right.
Ivo
-----Mensaje original-----
De: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
nombre
de Peter VanDerWal
Enviado el: martes, 01 de marzo de 2005 12:15
Para: [email protected]
Asunto: RE: 3 phase PM
Jeff asked:
I can't find the link I had to a less expensive unit but here
is a ready made unit. Anyone tried one of these?
http://www.hydrogenappliances.com/powerpmas.html
Yes---sad to say that I have.
-snip-
That, coupled with the rudest and least technically knowledgeable
response
I've ever received from anyone running a high tech manufacturing
business,
Yeah, reading the statements on the website like:
" NOTICE FOR ANY OF YOU A.E. NOVICES OUT THERE:
If these voltages seem high just remember that standard automotive
alternators are usually putting out 40 to 50 volts into the 12 volt
battery in your car. "
Makes it pretty clear the guy doesn't quite understand what he's talking
about.
That and the fact that he uses a short circuit to measure the output
current??!??!!
Why not hook the thing up to a battery bank and post current vs RPM @ X
voltage?
That would be usefull info, the stuff on his website is just about
useless
for the average person, especially since he doesn't post internal
resistance figures.
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Roderick Wilde wrote:
> Lee, You forgot to give us an idea of price for the Homopolar motors.
I don't know of any that are commercially available. You'd have to make
one yourself. However, they are a peculiar motor, and not all that hard
to build. The rotor is basically just a solid slab of copper. A set of
brushes connect power the central axle, and outside rim, so the current
flows radially outward. The magnets are oriented over the surface of the
disk, like a pancake motor, only with all the North poles on one side
and all the South poles on the other. The magnetic structure (which is
just solid unlaminated iron) connects the back sides of the magnets.
The classic lab demo for a homopolar motor is a board with a slot cut in
it. Two uprights hold a horizontal axle, with a sheet copper disk on it.
Place a horseshoe magnet so its field penetrates the disk. The edge of
the disk rides in the slot in the board. One brush is a wire that
touches the center axle. The other brush is a wire in a pool of mercury
in the slot in the board.
It has no trouble running on a single 1.5v battery or just one solar
cell. If your bearings are good, it will even run (slowly) on a few
millivolts from a thermopile.
The classic problem with homopolar motors is that they have just
one-turn "coils", and so are intrinsically low-voltage motors. High
power requires high amps at low voltages.
--
Ring the bells that you can ring
Forget your perfect offering
There is a crack in everything
That's how the light gets in
-- Leonard Cohen, from "Anthem"
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
Victor Tikhonov wrote:
>
> Sure. Pure math. 8 strings and 16,000A then must be
> no problem either, right? And, so on...
I would rather have to deal with high currents than high voltages. In
the extreme, you could make your frame out of two aluminum bussbars,
with the batteries and motors connected between them. Tens of thousands
of amps would still be no problem. :-)
--
Ring the bells that you can ring
Forget your perfect offering
There is a crack in everything
That's how the light gets in
-- Leonard Cohen, from "Anthem"
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
