EV Digest 6812
Topics covered in this issue include:
1) Re: New EV - Thorr roadster
by "Peter Gabrielsson" <[EMAIL PROTECTED]>
2) Re: Ni-Cad Final Taper
by "David Roden (Akron OH USA)" <[EMAIL PROTECTED]>
3) Re: New EV - Thorr roadster
by MIKE WILLMON <[EMAIL PROTECTED]>
4) Re:Go kart drag race safety vs mini-bike
by Michael Haseltine <[EMAIL PROTECTED]>
5) RE: Electric motor for air conditioning or power steering
by Rod Hower <[EMAIL PROTECTED]>
6) Re: AGNS misses 168 record
by Chip Gribben <[EMAIL PROTECTED]>
7) RE: New EV - Thorr roadster
by "Alan Brinkman" <[EMAIL PROTECTED]>
8) Re: New EV - Thorr roadster
by "Peter Gabrielsson" <[EMAIL PROTECTED]>
9) Burnt out PM Motor?
by Mark Hastings <[EMAIL PROTECTED]>
10) Power of DC raffle motor pics up
by Jim Husted <[EMAIL PROTECTED]>
11) Re: Burnt out PM Motor?
by Rod Hower <[EMAIL PROTECTED]>
12) Re: Solectra/Azure - A123 response + A Great Idea!!
by "joe" <[EMAIL PROTECTED]>
13) Re: Victor How regen works
by Victor Tikhonov <[EMAIL PROTECTED]>
14) RE: How regen works
by "Peter VanDerWal" <[EMAIL PROTECTED]>
15) Re: New EV - Thorr roadster
by Victor Tikhonov <[EMAIL PROTECTED]>
16) Re: New EV - Thorr roadster
by Victor Tikhonov <[EMAIL PROTECTED]>
17) Award winner!!
by <[EMAIL PROTECTED]>
18) Re: Fast and Eff!!! Re: White Zombie gets to 'test' drive Lithium!
by Jim Husted <[EMAIL PROTECTED]>
19) Re: AGNS misses 168 record
by [EMAIL PROTECTED]
20) HTML (was Solectra/Azure - A123 response ...)
by "David Roden (Akron OH USA)" <[EMAIL PROTECTED]>
21) Re: To Charge or not to charge
by [EMAIL PROTECTED]
22) RE: How regen works
by "Dale Ulan" <[EMAIL PROTECTED]>
23) U.S. Secretary of State Condoleezza Rice takes a ride in a Tesla
by Bill & Nancy <[EMAIL PROTECTED]>
24) Re: Reality check, Re: Permanent magnet motor question
by "Mark Karatovic" <[EMAIL PROTECTED]>
25) Re: plain text
by Tehben Dean <[EMAIL PROTECTED]>
26) Re: Reality check, Re: Permanent magnet motor question
by Victor Tikhonov <[EMAIL PROTECTED]>
27) RE: plain text
by Mike Willmon <[EMAIL PROTECTED]>
28) Re: Triangle wave generator
by tt2tjw <[EMAIL PROTECTED]>
29) Lancia Scorpion EV site finally up
by Tony Furr <[EMAIL PROTECTED]>
30) Re: How regen works
by "(-Phil-)" <[EMAIL PROTECTED]>
--- Begin Message ---
It's Norwegian.
The article is sparse on details, range 300 km, 190 miles. 180km/h top
speed, recharges in 3 hours. 0-100km/h in 6 seconds, 272hp, cost
990.000 kr = $160.000
"- Damer liker smarte menn. Og smarte menn kjører jo elbil,
understreker han." -Ladies like smart men and smart men drive electric
cars.
On 5/24/07, Victor Tikhonov <[EMAIL PROTECTED]> wrote:
All,
Here is short introductory video of Thorr - roadster EV
which will be marketed (with sufficient demand in USA too) by
EVISOL - Metric Mind's European partner:
http://pub.tv2.no/nettavisen/bil/article1062524.ece
Sorry, interviews are only in North Germanic (or is it Danish?)
The vehicle has been successfully introduced in Norway already.
On this video Thorr has lead acid test pack. Production version
of course is lithium. Granted, AC drive; this version on the
video is standard 100 kW system.
I had privilege to drive Thorr while in Netherlands. Terrific and
fun vehicle, based on Lotus chassy.
I have to coordinate with EVISOL any additional info I can release.
Will keep EVDL posted.
Victor
--
'91 ACRX - something different
--
www.electric-lemon.com
--- End Message ---
--- Begin Message ---
> The manual says to final taper current at 7.5A but
> I think that's a bit much, I'm at C/40 4.5A and they gas
> quite a bit.
That's their nature - they like to burp and belch and bubble. You don't taper-
charge Saft nicads, it's constant current all the way, at least if you follow
Saft's instructions.
They tell you to start a timer and charge them 0.2C (36 amps) constant
current to threshold voltage (8.0 v/block). When that happens you reduce the
current to 1/5 the previous value (7.2 amps) and reverse the timer. When the
timer counts down to zero you have your 20% overcharge and you shut off.
There are periodic equalization cycles, commissioning charges, and a
watering cycle, but the above is all it takes for daily cyclic use. Dead easy.
IIRC, Rod Hower developed a somewhat different algorithm for the STMs in
the TEVan, and he might chime in here.
If you don't have the manual for your STM5-180s, snag it here :
http://evdl.org/docs/STM5-180tech.pdf
--- End Message ---
--- Begin Message ---
I'm a little rusty on my Norwegian, but in the video it looks like the Subaru
won the test race.
Was there something in the interview that stated this was a lead acid pack and
that the lithium pack would kick the Subaru's butt?
Mike,
Anchorage, Ak.
--- End Message ---
--- Begin Message ---
I understand completely, now. And can see that long narrow drag rails
are advantageous for more reasons than traction and aerodynamics.
It's too bad, because that cart was really hot.
Michael
The safety issues of go karts on the drag strip are not obvious, but
quite serious.
It is all about traction, polar moment, and wheelbase. Karts spin
and flip easily on the drag strip.
The traction on the drag strip is three times what it is on the
street or a go kart track. When one rear tire loses traction, (hits
a greasy spot) the other pushes the kart into a spin. The polar
moment of a kart is tiny, and the sticky track gives huge force to
the wheel with traction, so the spin is almost instantaneous. There
is no time for the driver to react, lift the throttle, and steer the
kart straight.
The kart is wide and short, so the rear wheel that has
traction has too much leverage on the CG and can easily overpower
the steering traction of the front wheels. Even if you steer quickly
enough, the rear tire with traction has enough force to make the
front tires skid sideways, so steering has no effect.
On the kart track, if the kart gets sideways, it just slides
sideways. On the drag strip, the traction is so good that the tires
dig in and the kart flips instead of sliding.
Thus, a small greasy section on the track is all it takes to
spin and flip the kart because it happens so fast. A car with more
polar moment, longer wheelbase, and narrower track might just weave
a bit over the same greasy spot.
With a motorcycle, there is only one back tire. If it loses
traction briefly, the bike still goes straight down the track.
Losing traction briefly does not cause a bike to instantly spin and
flip, like it will a kart on the drag strip.
It isn't at all simple, is it? That is why NEDRA originally
allowed karts, because we didn't know any better in the beginning.
Bill Dube'
At 11:13 AM 5/24/2007, you wrote:
All this excitement over the AGNS minibike reminded me of the
gokart that was in the same league (12.102 sec. at 102.71mph) a few
years back that blew my mind, and in tracking it down found that
the NEDRA website says the gokart class has been dropped for safety
reasons. Can it be any different than for minibikes? BTW, I'm
certainly not thinking that the minibike class should also be
dropped!! Rather the other way round.
--
Michael Haseltine
--
Michael Haseltine
--- End Message ---
--- Begin Message ---
I have several that are rated over 2Hp, but as Lee
says, how are you going to get 2HP out of a normal
wall socket anyhow. So the rating is for low duty
cycles.
Anyhow, these treadmill motors are new, if you need
one paypal $20 plus $10 shipping in the US
Rod
--- "Dewey, Jody R ATC COMNAVAIRLANT, N422G5G"
<[EMAIL PROTECTED]> wrote:
> I haven't tried a treadmil motor. I agree that they
> would work if one
> could be found that matched the pack voltage closely
> enough. Since mine
> is a 120V system I found one on ebay that was for
> 130V with a low
> voltage spec of 95V. They had it for $50. Item #
> is 120123978153. I
> think 1 1/2 horsepower should be enough for a power
> steering pump.
>
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] On
> Behalf Of Tim Humphrey
> Sent: Thursday, May 24, 2007 9:06
> To: EV
> Subject: RE: Electric motor for air conditioning or
> power steering
>
>
>
>
> There are 90vdc 1.5+hp PM treadmill motors on EBay
> all the time. Usually
> less than 50 bucks. Why wouldn't one of those work?
>
> I was on my tread for 1.5hrs the other day, when I
> got off it my wife
> got on for another 30mins. I don't think duty-cycle
> will be a problem.
>
> --
> Stay Charged!
> Hump
> I-5, Blossvale NY
> >
> > -----Original Message-----
> > From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED]
> > On Behalf Of Dustin Stern
> > Sent: Wednesday, May 23, 2007 3:09 PM
> > To: ev@listproc.sjsu.edu
> > Subject: Re: Electric motor for air conditioning
> or power steering
> >
> >
> > That's cheaper and lighter than the one offer by
> ElectroAutomotive -
> > or that I've found anywhere else, as I've also
> been looking.
> >
> > By the way have you seen the electric compressor
> units at
> > http://www.masterflux.com/ ?
> > Although I can't seem to get an email reply, they
> have some ideal
> units.
> >
> > Dustin
> >
> > On May 23, 2007, Dewey, Jody R ATC COMNAVAIRLANT,
> N422G5G wrote:
> >
> >> Does anyone think that this motor will work to
> drive a power steering
>
> >> pump or an AC pump?
> >>
> >>
> >>
> >
>
http://www.e-motorsonline.com/emotors/viewproduct_dcm.php?catid=2&Pid=
> > DC
> >> M00116
>
>
--- End Message ---
--- Begin Message ---
Hey Shawn! Please don't break anything else before the race. And
save us a few records too :-)
Actually, this is probably good. You are getting all the bugs worked
out before the event. So OK, that's fine.
Good luck!
Chip
On May 24, 2007, at 12:59 PM, Electric Vehicle Discussion List wrote:
From: [EMAIL PROTECTED]
Date: May 24, 2007 8:03:16 AM EDT
To: ev@listproc.sjsu.edu
Subject: AGNS misses 168 record
Wednesday was a day of anomalies.
1. The Electropolitan twists up her driveshaft at 50 MPH.
2. A Bat reg catches fire.
3. Perfect weather in Thompson OH wih no wind, no clouds, and 87
degrees.
4. AGNS runs a 12.888 at 103, a 12.818 at 103, and a 12.888 at 103.
5. AGNS runs 95 MPH in the 1/8 only to fall on her face 3 times and
limp to 103 MPH in the 1/4
5. A Zilla hairball fails after run 2 with a bad internal connection.
All in all just a weird but fun day. About the 168 runs:
It became apparent after 1 run that the 2 batteries I stole from
the Metro to bump AGNS' volts to 168 were not on the same cycle
path as the other 12. I cycled them through and brought up to temp
3 times before we went to track but after run #1 when I talked to
Denis, looked at the time slip, measured battery temp, and watched
the bats fill back up it was painfully clear they were not up to
snuff. AGNS roared out to 95 in the 1/8th them fell asleep 3 times
to finish at 103. Compare this to Saturday when she only ran 81 in
the 1/8th and pulled all the way to 106 in the 1/4. My fault. We
finished our first two runs at 7:30, recharged and were in line for
eliminations when the hairball connection failed. We checked
everything but could not get the main contactor off light to glow.
By the time I found that the plug for the 2 voltage inputs was
loose it was too late, we missed our turn and were out. Too bad
because with times of 12.888, 12.817 , and 12.888 I would say we
were dead consistent. We finally got a consolation run at 10:30
pm. I taped up the hairball to put enough pressure on the input
plug to make it work and we ran exactly the same time again. Who
wants consistently slow? Not me. Give me a 1/2 second breakout any
day! A real life lesson that once again proves....
IT'S THE BATTERIES STUPID!
Shawn
--- End Message ---
--- Begin Message ---
I don't have a clue what was said in the video, but I hope it went
something like this: "This new Thorr roadster looks so cool, even at
slower speeds, that I do not have to be bothered with racing any gas
eating, pollution making........." "Look, with only 12 volts of lead
acid, I can cruise along at...."
Alan
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of MIKE WILLMON
Sent: Thursday, May 24, 2007 1:50 PM
To: ev@listproc.sjsu.edu
Subject: Re: New EV - Thorr roadster
I'm a little rusty on my Norwegian, but in the video it looks like the
Subaru won the test race.
Was there something in the interview that stated this was a lead acid
pack and that the lithium pack would kick the Subaru's butt?
Mike,
Anchorage, Ak.
--- End Message ---
--- Begin Message ---
I didn't see any explanation. It was also unclear to me what the
distance was, perhaps they hit the upper speed limit of the EV, 112mph
On 5/24/07, MIKE WILLMON <[EMAIL PROTECTED]> wrote:
I'm a little rusty on my Norwegian, but in the video it looks like the Subaru
won the test race.
Was there something in the interview that stated this was a lead acid pack and
that the lithium pack would kick the Subaru's butt?
Mike,
Anchorage, Ak.
--
www.electric-lemon.com
--- End Message ---
--- Begin Message ---
I have a 4 brush 24 volt 1.5 PM motor on my 22" mower.
I had run it initially on 24 volts but it got far too
hot. I now run it at 18 volts and it worked for a
couple mows.
However now it just has no power at all. Any tall
grass and it bogs down incredibly like the batteries
are dead. I even tried putting it back to 24 volts and
get the same results. Does this sound like I ruined
the motor in my initial runs at 24 volts? It is almost
as if the batteries are dead. They are freshly charged
batteries along with a brand new set of freshly
charged batteries I just purchased.
It had been cutting wonderfully but now I can hardly
use it.
--- End Message ---
--- Begin Message ---
Hey all
I wanted to take a minute and post a couple pics of
this years Power of DC's raffle motor. I finally got
her done and am shipping it to Chip today. Nothing to
fancy but hopefully capable of causing a few EV grins
to the one whos name gets pulled 8^)
Chip wanted an electric blue so I chose a flourecent
blue (she might glow at night or under a black light,
hehe) The camera doesn't show it's true color which
I'm really digging actually 8^)
Chip my man this is for you as honestly I had to cram
this little guy in, lol. I could'nt stand the thought
of letting down someone who does so much for EVeryone.
On that, I hope she adds a little flavor and a touch
of green to help you pay for all that goes into an
EVent like this and keeps you motivated to continue
being such a valuable member of the community. I hope
maybe she'll also motivate those close arm chair
lurkers to come on out and help support your efforts.
As I look at this motor about to ship, I'm wondering
if maybe I can throw 20 bucks at this via mail as I
wouldn't mind having this one myself, LMAO!
Anyway the pics are here.
http://www.hitorqueelectric.com/
Got to run.
Smack the winner up side his head and tell them they
better not scratch my motor, hehehe. 8^P
Cya
Jim Husted
Hi-Torque Electric
Much success!
____________________________________________________________________________________
8:00? 8:25? 8:40? Find a flick in no time
with the Yahoo! Search movie showtime shortcut.
http://tools.search.yahoo.com/shortcuts/#news
--- End Message ---
--- Begin Message ---
If the motor was REALLY hot on 24Vdc there's a good
chance you demagnetized the PM field or at least
weakened it to the point of having much less
performance. If this is the case, I would think it
still gets pretty warm at 18Vdc. Also make sure that
the brushes are properly seated on the commutator and
not sticking in the holder.
Rod
--- Mark Hastings <[EMAIL PROTECTED]> wrote:
> I have a 4 brush 24 volt 1.5 PM motor on my 22"
> mower.
> I had run it initially on 24 volts but it got far
> too
> hot. I now run it at 18 volts and it worked for a
> couple mows.
> However now it just has no power at all. Any tall
> grass and it bogs down incredibly like the batteries
> are dead. I even tried putting it back to 24 volts
> and
> get the same results. Does this sound like I ruined
> the motor in my initial runs at 24 volts? It is
> almost
> as if the batteries are dead. They are freshly
> charged
> batteries along with a brand new set of freshly
> charged batteries I just purchased.
> It had been cutting wonderfully but now I can
> hardly
> use it.
>
>
--- End Message ---
--- Begin Message ---
Not this again!! There are very good reasons why we limit this list to plain
text, so Please desist making these suggestions to move or change it!!
Joseph H. Strubhar
Web: www.gremcoinc.com
E-mail: [EMAIL PROTECTED]
----- Original Message -----
From: "Tehben Dean" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Wednesday, May 23, 2007 7:30 PM
Subject: Re: Solectra/Azure - A123 response + A Great Idea!!
Maybe this list should be moved over to yahoo or something so it can
handle things besides plain text...??? Or is plain text to keep peoples
old computers from using up to much disk space?
On May 23, 2007, at 3:06 PM, Matt Kenigson wrote:
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--- Begin Message ---
Solectria may be, but this is certainly not how Siemens systems work.
You get true regen
current up to the lowest speed limit. I watch battery current during
regen - it remains negative (e.g. current flowing into the battery)
at all times.
Victor
Lee Hart wrote:
One alternative is to switch to plug braking below some speed. The
inverter can also be programmed to *short* the motor, or apply straight
DC to it. This isn't regen (it *consumes* power from the batteries); but
it still brakes the motor. I believe this is what Solectria does.
--- End Message ---
--- Begin Message ---
> ..aren't very good diodes, so if a controller uses them, the maximum regen
> current won't be as high as the maximum motoring current.
>
> Unless you use synchronous rectification - which uses the MOSFET in
> reverse. You probably want to do that anyways to lower the losses.
Can you explain this? The few synchoronous rectification designs I've
studied used a second MOSFET to relace the diode. I haven't seen any that
use a single MOSFET for both functions.
I.e. for a PMDC motor controller, instead of one FET and one diode, they
use a high side FET and a low side FET.
I had assumed they'd do the same thing with three phase synchronous
rectifiers.
--
If you send email to me, or the EVDL, that has > 4 lines of legalistic
junk at the end; then you are specifically authorizing me to do whatever I
wish with the message. By posting the message you agree that your long
legalistic signature is void.
--- End Message ---
--- Begin Message ---
Peter,
Peter Gabrielsson wrote:
It's Norwegian.
Thank you.
The article is sparse on details, range 300 km, 190 miles. 180km/h top
speed, recharges in 3 hours. 0-100km/h in 6 seconds, 272hp, cost
990.000 kr = $160.000
This is certainly production version with LiP battery.
"- Damer liker smarte menn. Og smarte menn kjører jo elbil,
understreker han." -Ladies like smart men and smart men drive electric
cars.
I only understood last three words :-)
Victor
--- End Message ---
--- Begin Message ---
MIKE WILLMON wrote:
I'm a little rusty on my Norwegian, but in the video it looks like
the Subaru won the test race. Was there something in the interview
that stated this was a lead acid pack and that the lithium pack would
kick the Subaru's butt?
Mike, Anchorage, Ak.
Yes, Subaru won this race because again this was lead acid version
supplied to Norway and looks like someone (not Thorr supplier)
decided to arrange this test in private.
The demo was not to prove that Thorr win (you can always find
more powerful ICE and make even t-zero or Tesla loose if you
determined). It shows one more option for us and that it is real
one, not on paper or "may be in future".
Victor
--- End Message ---
--- Begin Message ---
Hi all,
The Skunk is now officially an award winning conversion. I was in a parade
last Saturday and was awarded 1st place in the motorcycle division. I just
received the plaque today so its official. Just a small town parade, but
lots of viewers and many comments and discussions afterwards with the
spectators. There was a car show in conjunction with the parade and I was
parked with them afterwards where I got the comments.
Also I'm almost up to 500 mi on the bike as an electric.
respectfully,
John
The Skunk, 58 Harley servicar conversion.
http://www.austinev.org/evalbum/751
--- End Message ---
--- Begin Message ---
--- jerryd <[EMAIL PROTECTED]> wrote:
>> ...that works out to 52 miles range. Not too bad
>> for a 12 second drag car!
> You forgot an important number, it took only
> 140-150
> wthr/mile for it's trip!! Not bad for an EV
> breathing down
> the 11sec 14 mile bracket!! This is an important
> item for
> you to mention as it's the equivilent of 300mpg cost
> wise or
> between 100-300mpg energy wise depending on your
> electric
> costs hile putting muscle cars to shame at the track
> ;^D.
Hey John, Jerry, all
And that was on a pretty hurt motor to boot! There's
one holder that's been melted almost completely
through the holders length, so no sweat John, just
take it on a 30 mile Sunday drive with its guts
hanging out the rear end! Anyway I just wanted you
to know that I just reread that and well... shame on
you. I guess what I'm saying is she wasn't getting
the best commutation she's seen.
Just thought I'd add to the pot. You know it's just
another reason why Cheryl keeps the Zombie keys, BTW
John did Cheryl know about this? She will, LMAO!
Cya
Jim Husted
Hi-Torque Electric
____________________________________________________________________________________
No need to miss a message. Get email on-the-go
with Yahoo! Mail for Mobile. Get started.
http://mobile.yahoo.com/mail
--- End Message ---
--- Begin Message ---
Chip,
As you know the ev drag racing bugs are like those on a windshield in
Florida in May.
Solving new and different problems is really part of the allure to me.
Speaking of records, after last night I have even more respect for that
168 volt MT #.
I told Rudman he would eat his hat and I got mine handed to me.
Weds night???
Shawn
-----Original Message-----
From: Chip Gribben <[EMAIL PROTECTED]>
To: ev@listproc.sjsu.edu
Sent: Thu, 24 May 2007 5:05 pm
Subject: Re: AGNS misses 168 record
Hey Shawn! Please don't break anything else before the race. And save
us a few records too :-)
Actually, this is probably good. You are getting all the bugs worked
out before the event. So OK, that's fine.
Good luck!
Chip
On May 24, 2007, at 12:59 PM, Electric Vehicle Discussion List wrote:
From: [EMAIL PROTECTED]
Date: May 24, 2007 8:03:16 AM EDT
To: [EMAIL PROTECTED]
Subject: AGNS misses 168 record
Wednesday was a day of anomalies.
1. The Electropolitan twists up her driveshaft at 50 MPH.
2. A Bat reg catches fire.
3. Perfect weather in Thompson OH wih no wind, no clouds, and 87 >
degrees.
4. AGNS runs a 12.888 at 103, a 12.818 at 103, and a 12.888 at 103.
5. AGNS runs 95 MPH in the 1/8 only to fall on her face 3 times and >
limp to 103 MPH in the 1/4
5. A Zilla hairball fails after run 2 with a bad internal connection.
All in all just a weird but fun day. About the 168 runs:
It became apparent after 1 run that the 2 batteries I stole from >
the Metro to bump AGNS' volts to 168 were not on the same cycle > path
as the other 12. I cycled them through and brought up to temp > 3 times
before we went to track but after run #1 when I talked to > Denis,
looked at the time slip, measured battery temp, and watched > the bats
fill back up it was painfully clear they were not up to > snuff. AGNS
roared out to 95 in the 1/8th them fell asleep 3 times > to finish at
103. Compare this to Saturday when she only ran 81 in > the 1/8th and
pulled all the way to 106 in the 1/4. My fault. We > finished our first
two runs at 7:30, recharged and were in line for > eliminations when
the hairball connection failed. We checked > everything but could not
get the main contactor off light to glow. > By the time I found that
the plug for the 2 voltage inputs was > loose it was too late, we
missed our turn and were out. Too bad > because with times of 12.888,
12.817 , and 12.888 I would say we > were dead consistent. We finally
got a consolation run at 10:30 > pm. I taped up the hairball to put
enough pressure on the input > plug to make it work and we ran exactly
the same time again. Who > wants consistently slow? Not me. Give me a
1/2 second breakout any > day! A real life lesson that once again
proves....
IT'S THE BATTERIES STUPID!
Shawn
________________________________________________________________________
AOL now offers free email to everyone. Find out more about what's free
from AOL at AOL.com.
=0
--- End Message ---
--- Begin Message ---
On 24 May 2007 at 15:11, joe wrote:
> ... plain text ...
(and a few other choice words ;-)
SJSU listservers will probably never distribute html mail or attachments, and
for good reasons. But Mailman is coming. It handles html rather well : it
simply removes it, tweaks the headers so they say "plain text only," and
distributes the mail sans formatting.
David Roden
EVDL Administrator
http://www.evdl.org/help/
--- End Message ---
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Can you explain this? The few synchoronous rectification designs I've
studied used a second MOSFET to relace the diode. I haven't seen any that
use a single MOSFET for both functions.
You are using two MOSFET's - it's just that both MOSFET's
need to be there anyways. Which MOSFET is a rectifier and
which one is a switch depends on the applied duty
cycle and the direction of current flow. At a 50% duty
cycle, with an ACIM stationary, each part will act as
a diode, then will switch to acting like a 'normal' MOSFET
switch half-ways through a PWM cycle.
IGBT's don't do rectification nicely - they need separate
diodes. But IGBT's are usually used in higher-voltage
applications so the added semiconductor losses are less of
an issue, and low-resistance MOSFET's are rare much above
200 volts.
-Dale
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There was a mention on nbc news tonight that C. Rice rode in an electric
car, no pictures or information about which car it was.
http://sparklepony.blogspot.com/
Bill
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Efficiency in physics is defined as power out/power in. To increase
the figure by 5% implies that you are getting 5% more work for energy
in.
Car comparisons do this all the time where the marketing techniques
are developed already. Technologies for new engines claiming energy
improvements (20% more efficient) really are maybe only 2% overall
more efficient thermodynically in terms of heat energy in vs useful
kinetic energy out e.g 20% for an ICE means that the overall
efficiency may now only be 22% for the overall engine.
I think that the above is a lie simply due the definition my
university physics textbook suggests. It should say we are getting 20%
more work compared to before, not that it is 20% more efficient which
in case would be a 100% increase in work compared to useful work we
were getting before. It is correct if you say what you are comparing
to though, don't compare apples with oranges.
On 5/25/07, Peter VanDerWal <[EMAIL PROTECTED]> wrote:
> Peter VanDerWal wrote:
>
>> Anyway you slice it, 99% is approximately 5% more efficient than 94%
>
> Really? How do you figure? Is it because 94+5=99? I really want to know.
Efficiency is very well defined; output divided by input. When expressed
as a percentage you multiply the result by 100.
(99-94)/99 =~ 5%
99% - 94% = 5%
The rules of math are very simply. Twice means to multiply by 2,
increasing something by 5 means to add 5.
Perhaps the rules are different where you were educated, however, I
thought the rules of mathematics where universal.
As has already been pointed out, by your rules if someone was to claim
they had produced a solar cell that was twice as efficient as a 10%
efficient cell, it would have to be 55% efficient.
After all the losses on a 10% cell are 90%, so 1/2 of 90% = 45%, since you
are claiming that doubleing efficiency means the same thing as cutting
losses in 1/2
Unless you are claiming that the rules change depending on your mood or
desired outcome? I find it hard to believe that any system of mathematics
has rules like that though.
>
> So what happens if I improve already 99% efficient design and make it
> yet 5% more efficient [5% improvement of that 99% gadget]?
But that is NOT possible, at least not in this universe.
99% + (.05 * 99) =~ 104%
There is no way you can improve a 99% efficient gadget by 5%.
You can reduce it's losses by 5%. But that is NOT THE SAME as improving
it's efficency 5%.
1/2 does NOT equal 2
1/5 does NOT equal 5
> It's percentage of percentage Peter. Unless I misunderstood you, indeed
> appears like common misconception but on your part. Please re-think
> or elaborate.
I don't know how I can put it more clearly. If you are still having
trouble with these concepts, I'd suggest visiting a library and reading a
textbook on percentages
--
If you send email to me, or the EVDL, that has > 4 lines of legalistic
junk at the end; then you are specifically authorizing me to do whatever I
wish with the message. By posting the message you agree that your long
legalistic signature is void.
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Sorry guys. I wasn't sure, if I was treading on sacred ground ;)
Maybe there are a lot of new members or something, but there seem to
be a lot of emails that are not getting through.
Cheers,
Tehben
On May 24, 2007, at 2:11 PM, joe wrote:
Not this again!! There are very good reasons why we limit this list
to plain text, so Please desist making these suggestions to move or
change it!!
Joseph H. Strubhar
Web: www.gremcoinc.com
E-mail: [EMAIL PROTECTED]
----- Original Message ----- From: "Tehben Dean" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Wednesday, May 23, 2007 7:30 PM
Subject: Re: Solectra/Azure - A123 response + A Great Idea!!
Maybe this list should be moved over to yahoo or something so it
can handle things besides plain text...??? Or is plain text to
keep peoples old computers from using up to much disk space?
On May 23, 2007, at 3:06 PM, Matt Kenigson wrote:
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* ---REMAINDER OF MESSAGE TRUNCATED--- *
* This post contains a forbidden message format *
* (such as an attached file, a v-card, HTML formatting) *
* Lists at sjsu.edu only accept PLAIN TEXT *
* If your postings display this message your mail program *
* is not set to send PLAIN TEXT ONLY and needs adjusting *
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Mark Karatovic wrote:
Efficiency in physics is defined as power out/power in. To increase
the figure by 5% implies that you are getting 5% more work for energy
in.
Or the same work for 5% less energy in. We already settle on this.
I only associate efficiency with losses because they are always
inversely dependent: more losses = less work for the same input
= less efficiency. Halving losses does not double efficiency
mathematically, but it gets you exactly half way between current
efficiency and 100% efficiency. If it was 90% it becomes 95%.
You halved your losses. Of course you didn't double output,
but you got it half way (to 95%) to the ideal maximum it can
theoretically be (100%).
My math is simple: 100% in and 90% out means 10% losses.
Half the losses to 5%. Now 5% more can contribute to the useful
output, and output is 90+5=95% of the input. 95% is HALF WAY
between former 90% and ideal 100%. Half way is 50% of what
you can ever do, (going 100% would be adding entire 10% to useful
output and so have 0% losses which is impossible). I didn't use
physical definition of efficiency, which is strictly speaking a mistake.
Sorry, it's difficult to express exact way of thinking let alone
assuring grasping by others.
Peter wrote:
But that is NOT possible, at least not in this universe.
99% + (.05 * 99) =~ 104%
There is no way you can improve a 99% efficient gadget by 5%.
There is - you can improve any efficiency gadget by anything from
near 0% to near 100% *of what it takes to make it 100% efficient*.
Depends how you define it:
In your example your gadget is 99% efficient. 1% is losses.
Make this obvious: you feed 100W in and get 99W out. 1W is loss.
I was implying *this 1W* is 100% to work with (not entire input is
100% as is correct per physical definition): if you convert
entire lost watt to useful output you removed 100% (all possible) losses.
So you certainly can recover less than 100% of possible 1W recovery,
for instance 5% or 50% or whatever. Again, 100% is only remaining 1 watt
(1% of original input), not entire input, I was trying to describe it
that way.
So if you remove 5% losses you removed 50mW. If you removed 50% (of that
watt) you removed 500mW which is 50% "improvement" compare to what it
can possibly be.
In physical terms improvement is 0.5% because you take whole input as
100%. Again, I was trying to explain that I took only losses as 100% to
work with. I could sure stick to second way to look at the same thing
(strict physical definition that 100% is entire input, not remaining
losses, but chose not to. Doesn't mean I don't know about it it or don't
understand it. I agree: difficult to express this, let alone assure
others can grasp it.
But this is not important since no one on this list cares how I
(or anyone for that matter) think; it's a place to discuss EVs,
not personalities. Why am I trying to convince you that I know this
stuff well enough that it serves me flawlessly for years? I really
shouldn't.
You're right, I'm wrong. No problem.
Let it die.
Victor
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Don't worry too much about it. It happens when the price of gas spikes.
People figure it out though when they find this list has
good information. It seems this list has been going plain text longer than
some of the other "fancy" boards I watch. Its just
pure unadulterated EV info. (OK maybe a little bit adulterated at times)
Mike,
Anchorage, Ak.
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
> Behalf Of Tehben Dean
> Sent: Thursday, May 24, 2007 10:54 PM
> To: ev@listproc.sjsu.edu
> Subject: Re: plain text
>
>
> Sorry guys. I wasn't sure, if I was treading on sacred ground ;)
> Maybe there are a lot of new members or something, but there seem to
> be a lot of emails that are not getting through.
> Cheers,
> Tehben
>
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Dale Ulan wrote:
The guy who thinks he can take a PIC, a little 1amp gate driver IC, and
a dozen MOSFETS and build a controller will have a bucket full of dead
parts
use every snubbing capacitor shown in the application notes exactly as shown in the app notes.
I wouldn't even attempt it if I didn't have a 100 MHz + 'scope.
Slowly ramp the input voltage and current up and watch for little
'hairs' during the switching periods. That is oscillation that'll
kill MOSFET's and IGBT's.
tame all parasitics, then ramp up, repeat taming
the parasitics, etc.
-Dale
Dale,
Are you saying
1. your first attempt did not follow the application notes and resulted
in blown parts then a subsequent attempt followed the application notes
and was successful?
or
2.
your followed the application notes and still blew up parts then tested
with an oscilloscope and tweaked the design so that it worked?
This may be a stupid question - I am a proto novice..... What do you
mean by "tame the parasitics"? Do you mean that the switching of the
IGBT causes noise in the control signal?
Tom Ward.
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Greetings all-
The site for my Lancia Scorpion Elettrico is finally ready for prime-
time. You can find it here:
www.plugzen.com
After finally making it to a SEVA meeting last month, I had new found
inspiration to get this thing completed. It includes a journal that I
try to update regularly and photo galleries I will continue to expand
(especially with Gasless on Greenwood picks). I could also use some
help filling out the links section if there are good EV info sources
I've undoubtedly missed. There's also an RSS feed for those of you
into the automated info thing.
Please check it out and let me know what you think...and send it
along to anyone else you think might be interested.
-t
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MOSFETs will conduct either direction when ON. One direction when OFF due
to the body diode.
So Whenever you want to improve efficiency by taking the body diode voltage
drop out, you can just switch the gate on and let it bypass the body diode.
Software can do this at the right time and you get synchronous behavior.
-Phil
----- Original Message -----
From: "Peter VanDerWal" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Thursday, May 24, 2007 5:46 PM
Subject: RE: How regen works
..aren't very good diodes, so if a controller uses them, the maximum
regen
current won't be as high as the maximum motoring current.
Unless you use synchronous rectification - which uses the MOSFET in
reverse. You probably want to do that anyways to lower the losses.
Can you explain this? The few synchoronous rectification designs I've
studied used a second MOSFET to relace the diode. I haven't seen any that
use a single MOSFET for both functions.
I.e. for a PMDC motor controller, instead of one FET and one diode, they
use a high side FET and a low side FET.
I had assumed they'd do the same thing with three phase synchronous
rectifiers.
--
If you send email to me, or the EVDL, that has > 4 lines of legalistic
junk at the end; then you are specifically authorizing me to do whatever I
wish with the message. By posting the message you agree that your long
legalistic signature is void.
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