EV Digest 6874
Topics covered in this issue include:
1) Re: Doers vs talkers, was Otmar is getting rich?
by Dan Frederiksen <[EMAIL PROTECTED]>
2) Re: Safety of inverter/controller or whole system?
by "(-Phil-)" <[EMAIL PROTECTED]>
3) RE: Tesla roadster motor philsophy AC vs. DC
by Cor van de Water <[EMAIL PROTECTED]>
4) RE: Tesla roadster motor philsophy
by "Peter VanDerWal" <[EMAIL PROTECTED]>
5) Re: Any disadvantage to 1 big blade? (mower)
by "Joe Smalley" <[EMAIL PROTECTED]>
6) Re: thinking about cost
by "Peter VanDerWal" <[EMAIL PROTECTED]>
7) Re: Safety of inverter/controller or whole system?
by Thomas Ward <[EMAIL PROTECTED]>
8) Pavlov's Troll
by Tom Gocze <[EMAIL PROTECTED]>
9) Re: Tesla roadster motor philsophy
by Dan Frederiksen <[EMAIL PROTECTED]>
10) Question about DMV
by [EMAIL PROTECTED]
11) Re: Tesla roadster motor philsophy plain text
by John Wayland <[EMAIL PROTECTED]>
12) RE: Question about DMV
by "Dewey, Jody R ATC COMNAVAIRLANT, N422G5G" <[EMAIL PROTECTED]>
13) Re: Weights and Mesasures, WAS Tesla Motor thing.
by "Bob Rice" <[EMAIL PROTECTED]>
14) Re: Grass Roots charging infrastructure Was: Quick VEVCS poll
by Jeff Shanab <[EMAIL PROTECTED]>
15) Re: Embarrassing Moments , Was: EV's are less maintenance?
by "Bob Rice" <[EMAIL PROTECTED]>
16) Re: Is it just monday, or did the list size change?
by "Michaela Merz" <[EMAIL PROTECTED]>
17) RE: Tesla roadster motor philsophy
by Cor van de Water <[EMAIL PROTECTED]>
18) RE: open source motor controller
by "Britt MSN" <[EMAIL PROTECTED]>
19) Mt Washington Alternative Vehicle Days 17-18 June
by lyle sloan <[EMAIL PROTECTED]>
--- Begin Message ---
James Massey wrote:
Dan, All
Knowing the device numbers will not help you.
then why not tell me
--- End Message ---
--- Begin Message ---
I'm not sure what you mean exactly, but what I am talking about is to put
the contactor across the motor or battery, but PAST the main system fuse.
This is basically a "blow the fuse" contactor and will definitely interrupt
power to a faulted controller or whatever.
As far as what models... Really, any of those will work as long as you
insure that the interlocks are such that it never closes during normal
operation. Anything reasonably beefy, even if it's not rated to interrupt
DC. It won't be exposed to interrupt current.
If the contactor burns contacts a bit during the fault, it's ok. as it will
definitely blow the fuse.
-Phil
----- Original Message -----
From: "Thomas Ward" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Monday, June 11, 2007 1:40 PM
Subject: Re: Safety of inverter/controller or whole system?
could the power to the normally closed contactor also be delivered through
a fuse which shorts in the event of motor runaway or other such fault?
Phil,
when you say cheap contactor do you mean ev200 cheap or potter and
brumfield 240V AC cheap or GE 48V contactor off ebay cheap ?
(-Phil-) wrote:
A simple (but not cheap) backup DC safety measure would be to put a
normally closed contactor across the motor. If the power is interrupted
then the contactor closes and shorts the motor. The power to this
contactor would be maintained by a separate safety monitor
microcontroller acting as a watchdog. In the event of a fault, it opens
the main contactor, and drops power to the motor shunt contactor. After
the aforementioned 2 faults on my little EV during controller testing,
this is basically what I did. (I used a SPDT relay that cut power and
shorted the motor) The contacts on such a device may not enjoy ever
being used, but it would add no resistance or loss if there was no fault.
You could also use a cheap contactor w/o arc suppression.
--- End Message ---
--- Begin Message ---
Power is power, no doubt.
What I see happening (my own EV included) is that
- AC drive has much higher voltage and lower current limit
(my controller has 700V but only 250A ratings)
- AC runs at much higher RPMs, which can lead to higher
losses in the transmission - my gearbox is noticeable
warmer after driving just a little distance and I
checked its fill level, but a 8,000 RPM at freeway
speed will meet a lot of oil (it is fixed in second gear).
Another point, but not specific to AC, is the loss of power
at high RPM due to the small difference between back EMF
and max voltage the controller (batteries) can supply.
I see that I can't get my battery current up any more
once I reach near redline, so the acceleration is very
minimal - with a slightly higher battery voltage, the
car would be able to pick up speed better than with the
current 312V. (Or be able to change gears, reducing the
motor RPMs).
What I am trying to say is that even with equal motor
power, the motor drive may limit the power at higer or
lower RPM levels due to current or voltage limits, for
example an AC drive may be more limited by its controller's
max current, while a series wound DC motor at low RPMs
can have a large torque, but run out of steam due to
max voltage at higher RPM, so in this example the DC
drive may be faster off the line while the AC system goes
stronger at higher speeds, though the AC drive can be
voltage limited as well, it all depends on the design
of the entire system - voltage and current limits,
gearing, back EMF in the motor at certain RPMs and so on.
Cor van de Water
Systems Architect
Proxim Wireless Corporation http://www.proxim.com
Email: [EMAIL PROTECTED] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [EMAIL PROTECTED]
Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD# 25925
Fax: +1 408 731 3675 eFAX: +31-87-784-1130
Second Life: www.secondlife.com/?u=3b42cb3f4ae249319edb487991c30acb
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Tehben Dean
Sent: Monday, June 11, 2007 10:27 AM
To: ev@listproc.sjsu.edu
Subject: Re: Tesla roadster motor philsophy AC vs. DC
Ok. so I have a question for John and Victor (and anyone who wants) Can we
compare say 2 45kw motors and their controllers. One AC and the other DC.
What are the hp and torque at what rpms and what is the efficiency of the
controller and motor.
Forget about cost.
The argument that a DC motor is more powerful doesn't make sense to me if
the 2 motors are the same hp/whatever. If it requires lower gearing that
does not mean it is not going to have the same performance or torque in the
end????
Tehben
--- End Message ---
--- Begin Message ---
> Dan,
>
> Sorry to burst your bubble, but there is no free lunch.
>
> If you have a motor with a high RPM redline, it will
> require a higher voltage simply because it generates
> a higher back-EMF that counter-acts the voltage
> that the controller applies to the motor.
Really? I've seen 12V 10,000 rpm motors, if your theory is true (which
apparently it isn't) then how would you explain that?
The RPM vs voltage is a characteristic of the motor design and can be
almost anything the designer wants it to be.
> If the controller does not provide a high enough
> voltage, then the motor will lack power at high
> RPMs, there will not be enough current flow through the
> motor due to the lack of voltage difference between the
> applied voltage and back EMF.
>
> Another issue with high voltage controllers is that the
> higher the voltage, the lower the current that can be
> carried by a certain amount of silicon.
> Now you may say that it won't matter - the power is still
> the same if the voltage is double and the current half.
> Correct - but the motor is not always turning at optimal
> RPMs. Starting torque is linear with current through the
> motor, so half the current is half the starting torque.
>
> Since the max RPMs of an AC motor can be double the speed
> of a DC motor, you can adjust the gearing to double the
> starting torque again (half the gear ratio) but now you
> have gained nothing: the motor is running at double speed
> and it is immediately reduced to half, so you have the same
> power and torque, no matter if you have a high voltage
> or low voltage setup. Main drawbacks of high voltage are
> the large nr of batteries required and the high wear of
> the gearbox (or an impossible to find diff ratio).
> What can give you higher low speed torque is a large
> ratio between battery current and maximum motor current,
> in other words: much more silicon than needed for the
> average drive current.
> I think that is what Otmar did with the Zilla.
>
> Regards,
>
> Cor van de Water
> Systems Architect
> Proxim Wireless Corporation http://www.proxim.com
> Email: [EMAIL PROTECTED] Private: http://www.cvandewater.com
> Skype: cor_van_de_water IM: [EMAIL PROTECTED]
> Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD# 25925
> Fax: +1 408 731 3675 eFAX: +31-87-784-1130
> Second Life: www.secondlife.com/?u=3b42cb3f4ae249319edb487991c30acb
>
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
> Behalf Of Dan Frederiksen
> Sent: Friday, June 08, 2007 2:09 PM
> To: ev@listproc.sjsu.edu
> Subject: Tesla roadster motor philsophy
>
> given the weight and power of their motor it seems they are choosing the
> right technology with getting their power through the voltage rather than
> the current by going high rpm (phase velocity). seemingly a pure win win
> other than perhaps a little higher gear ratio needed. am I understanding
> that right or is there more to it?
>
> is high rpm AC the certain way forward?
>
>
--
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 ---
The longer blade can be pushed faster than a shorter blade but the
difference is probably insignificant on a push mower.
The disadvantage of the longer blade is it requires a longer wheelbase on
the mower to clear the blade housing. The longer wheelbase is a disadvantage
because it increases the turning radius. Multiple short blades are usually
used to reduce the turning radius.
I don't believe there is any significant difference in the power required as
long as the blades have similar lift and have the same tip velocity.
My Craftsman riding mower uses 3 times as much fuel spinning the high lift
(bagger) blades that it does with the mulching blades.
Joe Smalley
Rural Kitsap County WA
Fiesta 48 volts
NEDRA 48 volt street conversion record holder
[EMAIL PROTECTED]
----- Original Message -----
From: "Mark Hastings" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Monday, June 11, 2007 7:45 AM
Subject: Any disadvantage to 1 big blade? (mower)
> I recently came across a 26" yazoo mower which I could
> use as an updgrade to my 22" mower, though I'd
> probably need to use a bigger motor compared to the
> 22" one. The yazoo has nice 20" rear wheels and is
> pretty heavy duty compared to my 22" old sears mower
> which is straining under the weight of a couple
> batteries.
>
> The question I have is the yazoo uses one 26" blade
> and I'm wondering how much power I'm going to lose
> turning one blade vrs say two smaller blades? When I
> look at those robotic mowers they use 3 tiny blades
> and I wonder if that helps them last longer on a
> charge then 1 larger blade.
>
--- End Message ---
--- Begin Message ---
True, the cheapest way to drive is probably to buy a clunker for $200 and
drive it until it drops and then buy another.
Not counting the cost of gasoline, you could probably keep this up for 30
years or more on just the initial cost of converting a vehicle to
electric.
> Sure, but it's even cheaper (still) to keep buying
> gasoline (unless you drive Hummer). So if money is
> absolute top priority, conversion makes no sense at all.
>
> At least today.
>
> Victor
>
> Peter VanDerWal wrote:
>> True enough, however the number of people interested in EVs shoots up
>> whenever gas prices jump up. This indicates that for many people it's
>> more about economics than the enviroment.
>>
>> Many folks think they will save a bundle by building an EV, and this
>> simply isn't true. You might save a little in the loong run, but you
>> have
>> to spend a bundle up front.
>> A lot of folks (most) choke on this and decide to the cheaper route,
>> which
>> currently means DC.
>
>
--
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 ---
thanks Phil,
Sorry, my suggestion wasn't phrased very clearly... I'll try again...
"Is there a simple way of wiring up the shorting contactor so that a
microcontroller/watchdog is not needed?"
I have another question; if the motor is shorted out like this does that
apply plug braking? If so will the braking be violent or gentle?
(-Phil-) wrote:
I'm not sure what you mean exactly, but what I am talking about is to
put the contactor across the motor or battery, but PAST the main system
fuse. This is basically a "blow the fuse" contactor and will definitely
interrupt power to a faulted controller or whatever.
As far as what models... Really, any of those will work as long as you
insure that the interlocks are such that it never closes during normal
operation. Anything reasonably beefy, even if it's not rated to
interrupt DC. It won't be exposed to interrupt current.
If the contactor burns contacts a bit during the fault, it's ok. as it
will definitely blow the fuse.
-Phil
----- Original Message ----- From: "Thomas Ward"
<[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Monday, June 11, 2007 1:40 PM
Subject: Re: Safety of inverter/controller or whole system?
could the power to the normally closed contactor also be delivered
through a fuse which shorts in the event of motor runaway or other
such fault?
Phil,
when you say cheap contactor do you mean ev200 cheap or potter and
brumfield 240V AC cheap or GE 48V contactor off ebay cheap ?
(-Phil-) wrote:
A simple (but not cheap) backup DC safety measure would be to put a
normally closed contactor across the motor. If the power is
interrupted then the contactor closes and shorts the motor. The
power to this contactor would be maintained by a separate safety
monitor microcontroller acting as a watchdog. In the event of a
fault, it opens the main contactor, and drops power to the motor
shunt contactor. After the aforementioned 2 faults on my little EV
during controller testing, this is basically what I did. (I used a
SPDT relay that cut power and shorted the motor) The contacts on
such a device may not enjoy ever being used, but it would add no
resistance or loss if there was no fault. You could also use a cheap
contactor w/o arc suppression.
--- End Message ---
--- Begin Message ---
Sorry I fed the troll, I can see it is a lose/lose thing.
Gone to ignore mode.
--- End Message ---
--- Begin Message ---
Cor van de Water wrote:
Dan,
Sorry to burst your bubble, but there is no free lunch.
the only buble you can burst is yourself
If you have a motor with a high RPM redline, it will
require a higher voltage simply because it generates
a higher back-EMF that counter-acts the voltage
that the controller applies to the motor.
didn't I several times say that I wanted higher voltage!
Another issue with high voltage controllers is that the
higher the voltage, the lower the current that can be
carried by a certain amount of silicon.
what is the basis for that conclusion?
Now you may say that it won't matter - the power is still
the same if the voltage is double and the current half.
the max current will be max current. the voltage higher. there is no
double the voltage half the current here. unless you compare it to the
zilla but it sounds like you are trying to make a technical point and
not a reference to a zilla
Since the max RPMs of an AC motor can be double the speed
of a DC motor, you can adjust the gearing to double the
starting torque again (half the gear ratio) but now you
have gained nothing
but that's simply not true (what a surprise). by powering more through
the voltage you gain far better thermal conditions. P=RII loses have
been cut to a quarter!
thinner wires, less silicon, smaller motor.. but who's counting
--- End Message ---
--- Begin Message ---
Hello to everyone on the list,
I am new to the scene and have been lurking on the list and reading the
conversion manuals available to me. After some research, I found a car
to convert and am going to start in a few months. I am interested in
knowing more about the registration process for this car now. I never
thought much about it until the discussion about the DMV came up.
I currently have this car registered and am driving it. Do I need to let
the DMV know that it have been converted to electric when I am done?
What are the benefits to letting them know? There is very little
emissions testing in Virginia, only select areas and I am not in one of
them, so that is not an issue.
Also, does anyone know of any tax credits, incentives, etc for
converting a vehicle to electric? I know my mom got some kind of tax
credit for buying her Prius, but do they offer anything for conversions?
Where would I find this kind of info?
thanks in advance for any input.
Corbett
--- End Message ---
--- Begin Message ---
Hello to Don and All,
[EMAIL PROTECTED] wrote:
As a past owner of a Solectria Force...I averaged around 10 to 15 percent
additional miles in the Portland area.
I believe this. There are a lot of hills around here, some of them
pretty steep, so yes, in our beautiful urban area (we are the only major
city in the USA with an extinct volcano within the city limits) regen is
a nice feature. HEL--LOW everyone...I've 'never' said I don't like
regen! In fact, I think it's great.
In my first version of Blue Meanie, waaaay back in 1980, I used a
primitive aircraft starter generator as the traction source. It was a
very inefficient motor, and thus ran very hot all the time, but it was a
versatile compound wound type beast with its selectable windings. In
addition to having the acceleration power of the mighty series-wound
motor within, you could also excite the shunt windings of its generator
soul and get mondo regen, the kind that would try to through you through
the windshield if you got carried away! Some where in cyber space
there's my detailed post of a trip I took from my east Portland home
westward across the city, up and over the steep Sylvan hills (6% grade
for nearly 4 miles), out to Beaverton where the car was put on charge
but because of time restraints (high output constant current PFC
chargers didn't exist back then) it didn't get fully charged...then
reverse the process back home. This was when my little Datsun ran at a
heady 48 volts, folks, just 8 6V golf car batteries! Anyway...I barely
made it up the west side grade to the summit of Sylvan hill as the
batteries were exhausted from their not-so-great recharge...the car
crawled to the top and was at a tepid human's walking gate as it rolled
over the crest...whew! I kicked on full regen which held the car to a
slow 15 mph or so down the hill, but hundreds of amps were jammed into
the poor abused batteries (my formative years, so give me a break for
committing battricide). I could have coasted down the hill, but after
the lowest point as you re-enter Portland, there's a big ass bridge you
have to transverse that arches high up and over the Willamette River
that's part of the freeway system that outs you onto I-84 East. Had I
merely coasted, the car 'might' have had enough momentum to make it up
and over the bridge, but it surely would have died afterwards on the
l-o-n-g ramp that winds to the I-84 and I would have found myself stuck
alongside the crazy freeway. However, because of the high current, long
duration regen I employed, the car had a burst of power in its battery
pack and I was able to make the ~ 9 mile trek (all a gradual uphill
route) all the way back to my driveway! Yes, it was a 100% discharge,
yes the batteries were streaming-hot, yes, I should have been shot for
the abuse I did to those poor batteries....but, what a great memory it
is! Sooooo, yes, I like regen!
To add regen to a DC motor is this not
the cost near the price of an AC drive if both bought new? If one was to
recapture this much energy with a DC motor. Would you have to be replacing
brushes more and having to turn the commutator? Any maintenance on the DC motor
should be considered as additional cost or savings.
No argument from me on this. AC is better than DC if regen is high on
your list and you don't mind paying a lot to get it. A road going EV
power level Sep-Ex DC system would be pretty close tot he price of one
of Victor's nice AC setups, and yes, you'd still have brush arcing to
contend with.
John your point regen is not best used all the time is true. I have found it
is always better to retain as much of the momentum as possible...
Thanks for acknowledging this. Yes, I know I'm right about it. I have
logged too many miles behind the wheel of EV1s to not know this, and
yes, I've even driven Solectria's vehicles (their twin rear motor
pickups and unfortunately, their s-l-o-w Geo Metros).
The Solectria Force is not a fast vehicle but It is fun to
drive using one pedal.
My opinion...the Solectria Geo Metro Force has absolutely no soul, it is
boring, it was way overpriced for what you got, and for me, it was an
embarrassment to the EV movement when introduced. The automotive press
got a good laugh when Solectria's outrageously priced $40,000 Metro was
introduced. After road testing the car and reporting on its anemic
acceleration, poor hill climbing capabilities, limited top speed, ~ 30
road-tester mile range, mundane handling, and well...its Geo Metro
spartan personality, they all pretty much said, "You get all this, for
just $40,000!" Some may argue it was cutting edge, and even faced with
its 1950's VW bug performance, will still rave about its AC drive
system...I will not.
The city of Portland bought a few of these. They never did get the
claimed 40-45 mile range from them around here...more like 25-30 miles,
and the East Penn sealed gel cell battery packs failed early on. There
were several embarrassing newspaper articles and radio and TV
interviews, where using their hands-on experience with the Geo Force
cars, city employees proclaimed that electric cars were not meant for
the freeway because they didn't have adequate passing power. They also
warned people that EVs could not pull hills. Great! What wonderful PR
these things generated. Can you tell I'm not a fan? All while these
proclamations were being made, I was whirring around Portland in Blue
Meanie with its DC system kicking out 100+ hp, delivering 0-60 in about
6-7 seconds, and a top speed in excess of 100 mph. It could eat Sylvan
hill alive and actually pass gas cars on that steep grade, and with a
lighter weight lead acid battery pack, at reduced speeds and a more
conservative driving style, it delivered nearly the same actual range as
the $40,000 Metros, a bit less at 25 miles per charge. Thankfully, 'The
Oregonian' newspaper caught onto what I was up to and ran a lively story
called 'Socket Rocket' that was all about an electric car (Blue Meanie)
that did not fit the mold that the city employees had described.
John I agree with you about building a vehicle that only was for 100 miles
on a flat freeway. Unless there were very significant hills you will actually
decrease your range using the regen. You would have less maintenance though
on the AC motor in the long term. I know this is a minor point to you.
Again, thanks for admitting this. Yes, the maintenance is a minor point
when the power levels are 'average' in scope. The DC drive motor in Red
Beastie never needed any attention in its entire 9 years of service,
over probably 80,000 actual road miles between myself and Tony Ascrizzi,
its last and final owner.
My point is that a vehicle that can go
fairly fast and long distance would be more fun for everyday use.
I don't disagree with you here. My point, was to correct your assertion
that the tZero and the absolutely goofy Wrightspeed deliver the above
'fairly fast and long distance' largely because they use AC drive...it
simply is a false premise. They do it, because they are minimalist
vehicles (an understatement when considering the tube frame door-less
roof-less Wrightspeed) and because they have state of the art, VERY
expensive lithium batteries. Fitted with a DC drive system at
dramatically less cost compared to the high dollar AC drives, the
vehicles would have even higher acceleration performance, and range
within 3-5% of the AC versions. In heavy up and downhill conditions,
that gap would widen in favor of the AC system due to regen.
Regardless the chemistry of the pack building a vehicle with an AC drive for everyday use
has advantages.
Not if the cost of the vehicle goes way up.
If both vehicles were priced the same and delivered the same overall
performance, AC would win, hands down. As Victor said, no one in their
right mind would choose DC over AC...that includes me. The forklift
industry is a perfect example. The new AC forklifts, pallet jacks, and
stock pickers are all going the AC route, and yet, are priced pretty
close to the DC systems they are replacing. At the same price point, the
AC trucks (how we refer to forklifts, pallet jacks, and stock pickers)
blow away the DC ones.
Your statement the expensive electric AC cars are overpriced diminishes
their achievements.
Yes, it does...precisely my point. It's not impressive at all, that it
takes $150,000 and some twisted metal tubing and four tires to match the
performance of my $15,000 full bodied car with its cave man DC system.
Yes, range cannot be argued, but that's all in the lithium pack and the
extreme weight reduction making a car without 'anything' one expects a
real car to have.
If a vehicle can go 30 or 40 miles and regen adds 4 or 6
miles that is significant.
Yes, it is. But if the car costs twice as much and or is priced out of
reach, then it's a stupid idea.
An AC drive could
have been used in the Red beastie it would just need the right gearing. With
all that weight a lot of energy could be recovered. Of course under the right
conditions.
No, it couldn't have been used. You keep giving me great ammunition,
here Don :-)
I co-designed and built this historic vehicle with my dear friend Dick
Finley, a practical and determined man. At the time, he was in his late
70's. The cost of the DC motor and controller was about $3000 of the
total of about $9000 put into the making this truck. Victor wasn't yet
immersed in providing more affordable AC drives back then, but even if
he had, asking Dick to spend an amount 'more' than the entire cost of
Red Beastie, about $10,000 just to have an AC power plant, would never
have flied with this guy! I wouldn't have wanted to be in the same room
with Dick after I had asked him to shell out that kind of money, all to
get relatively small gains in return.
In fact, after proving an electric car needn't act like a golf car with
his tire-shredding 'Rocket Renault' (Dick was well known around here for
blowing off unsuspecting muscle cars in stoplight drags), Dick's goal
with Red Beastie was to show it didn't take a lot of money or anything
exotic to do 100 miles per charge in an EV...he was right. An expensive
AC drive would have been soundly rejected by him.
I drive a 4500 hundred pound AC vehicle and it has the ability of 0 to 50 in
less that 10 seconds with lead or NiMH batteries.
Hate to pop your bubble on this, but 0-50 is way different than 0-60,
and a 0-50 time of 10 seconds is s-l-o-w! Solectria used to play the
game of citing their horribly performing over-priced cars' 0-50
times...never a 0-60 time. I called them on it, wrote about it, and
finally got them to admit that 0-50 was far different than 0-60 and that
their 0-50 claims translated into a 0-60 of about 18 seconds!
With NiMH batteries. I can go to Costco, Home Depot or any where else with 7 or 8 hundred pounds
loaded on. It is a multi purpose vehicle that can haul 2 or 3 if needed and has a
50 mile range. Same running gear as the EV1
you drove but using the Tech2 GM tool for the live readings.
I've driven the same truck, many times. Not impressed with the
outrageous original price (a consistent theme of mine), and the only
reason you like it, is because it was a good value at 1/4 the price. As
to the 50 mile range...again, hardly anything to do with it having an AC
power train, and almost everything to do with it having an exotic NiMH pack.
Were you not impressed with the EV1 AC drive for street use?
Yes, absolutely! If you haven't yet read it, go to my web page 'Links'
section, find and read 'Living in the Past, getting Beat by the Future!"
I don't know how many times I have to say this...I am a fan of AC. I am
involved with AC. I work on AC electric vehicles every day now. I've had
vast experience with AC vehicles over the years. My Insight has an AC
motor. Yes, the EV1 with its AC induction motor was awesome and fun to
drive. It's range per charge however, was largely due to other factors
(slippery drag coefficient) and in the case of the one I rented and
drove over great distances, largely due to its large volume NiMH pack.
The regen was great, but only added about 5-10% range in most of the
driving I did with it.
Let's get this clear....I like AC and feel it is superior to DC, when
priced the same and delivering similar performance. I'd love to have a
high power AC setup for my drag car, and I would switch to one in a
heartbeat if one were available at a reasonable price...one is not, at
present.
Unlike others who salivate over high tech AC, drool over 'creations'
like the tZero and Wrightspeed, then give all the range and acceleration
performance credit to the AC drive these vehicles have, I can see what
they evidently can't. I see ridiculously priced, ridiculously built
fringe type machines unfit for the masses, that are mere caricatures of
real cars. I see ultra-light weight minimalist machines with VERY
expensive and VERY powerful lithium packs, and I see that the light
weight platform coupled with the lithium packs are the main reason for
their stellar range performance, not the AC drive system. In fact, I
think that going to these extremes to get the performance numbers they
have to showcase their AC drives, is a bad idea. A lot of the gearheads
at the track know about these two vehicles. These are guys who
understand power and performance, believe me! I routinely hear comments
like, "Yeah, but anything without doors or a roof or a real body can be
fast...is that what they had to do to make their electric car go fast?"
I also hear a lot about the extreme dollars these vehicles cost in order
to perform the way they do, and again, it's all negative, not positive.
On the other hand, these same guys are impressed with my steel bodied
recognizable 'car' that runs low 12s. They are even more impressed when
I tell them they can make one for about $15,000.
See Ya.....John Wayland
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Corbett,
Where in Virginia are you? You might have difficulty with your
state inspection. I think the registration won't be a problem but the
inspection might. I haven't tried it yet in Virginia Beach since my EV
isn't finished yet.
Jody
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of [EMAIL PROTECTED]
Sent: Tuesday, June 12, 2007 8:39
To: ev@listproc.sjsu.edu
Subject: Question about DMV
Hello to everyone on the list,
I am new to the scene and have been lurking on the list and reading the
conversion manuals available to me. After some research, I found a car
to convert and am going to start in a few months. I am interested in
knowing more about the registration process for this car now. I never
thought much about it until the discussion about the DMV came up.
I currently have this car registered and am driving it. Do I need to let
the DMV know that it have been converted to electric when I am done?
What are the benefits to letting them know? There is very little
emissions testing in Virginia, only select areas and I am not in one of
them, so that is not an issue.
Also, does anyone know of any tax credits, incentives, etc for
converting a vehicle to electric? I know my mom got some kind of tax
credit for buying her Prius, but do they offer anything for conversions?
Where would I find this kind of info?
thanks in advance for any input.
Corbett
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----- Original Message -----
From: "Beth Silverman" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Monday, June 11, 2007 1:31 PM
Subject: RE: Weights and Mesasures, WAS Tesla Motor thing.
The New York Times article about the Solectria Sunrise's Boston-to-NYC
run was published on October 24, 1997, page B3.
************************
Thanks Beth! Seems like only yesterday! Sigh.
Bob
-----Original Message-----
From: Bob Rice [mailto:[EMAIL PROTECTED]
Sent: Monday, June 11, 2007 11:29 AM
To: ev@listproc.sjsu.edu
Subject: Weights and Mesasures, WAS Tesla Motor thing.
Blah Blah Blah!
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Yes I agree there are many variations, that was indeed my second idea.
the first was an internet connection so availability and scheduling and
ability to check on progress with web enabled phone while you are in
that restaurant or mall.
This variation was thought up as one to keep the kiosk cheap and
unattractive to vandals. A how low can we go. It also is simple for us
early adopters.
AS a matter of fact, I think there was a cell phone to sms in a recent
circuit celler. and cell phones are damn chaep nowadays
But a short range control and monitoring network like zigbee to a base
station inside the building, maybe an option also.
Zigbee might be a great way of having a handshaking between the car
charger and the box in the future.
You are right about the hard part.
And I will add one more. The legal/safety requirements for higher
power charging plugs that we went through a while back.
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----- Original Message -----
From: "Michael Barkley" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Monday, June 11, 2007 8:46 AM
Subject: Embarrassing Moments , Was: EV's are less maintenance?
Had my first embarrassing moment - Drove all over town
this weekend, showing off the car, breaking in the
battery pack, after the local television station did a
story on it. Thought, I'll go to the bank, and cash a
check, no big deal.
When I went to leave the drive through, which every
teller drop, had about 5 cars deep in line, the EV
wouldn't budge. Had to troubleshoot the EV in the
middle of several onlookers, finding my relay, I was
using to switch on the controller had fried it's coil.
Jumpered across it, and went home to recover from the
embarrassment. Note: Never use a ford starter relay,
as a simple aux relay, seems they don't like to be
energized for extended periods - Another lesson
learned.
Has anyone else had such experiences like Bruce and I?
It might help me recover, verses having to go for
therapy.....
Hi Mike;
Good show! And for finding/fixing yur issue, dignity intact. They DO make
solenoid type relays that LOOK like Ford ones, but made for golf carts, and
won't burn up on you, being used continuously.
My early contacter controller did the disapearing act thing at a light,
years ago! Light turned, one of those 3 second jobs where people have to
MOVE to make it or wait a few weeks for the next one. Of course the Rabbit
wouldn't go! Jumped out, waved the irate folks by me to make the 3 seconder
light, then had to PUSH the godamn car OVER the curb and onto the sidewalk
to clear the lane. Do ya think anybody would help me? Hah! Titanic's coming
in Thursday! DID get in the clear and found my issue: Wire to run the
contacter sequence to GO was loose to the ignition(hot) wire. Tightened that
and went on my way!At least with a contacter controller, YOU built YOU can
fix it! Not so when a squalid state one shits out! I REALLY should wire in a
maybe 2 step contacter thing to be able to limp home WITHOUT a tow. But as
Rich sez" Keep yur dues up with the Auto Club!!"
Seeya
Bob
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> On 11 Jun 2007 at 18:57, Jeff Shanab wrote:
>
>> I got what seemed like a bunch of smaller digests today, Did those
>> survey quantities take effect already?
>
> Monday was an unusually high traffic day for the EVDL. Lots of rather
> warm
> threads are open right now.
Must be the high gas prices :)
mm./
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Dan Frederiksen wrote:
>the only buble you can burst is yourself
You're insisting on trying to insult someone?
>> If you have a motor with a high RPM redline, it will require a higher
>> voltage simply because it generates a higher back-EMF that
>> counter-acts the voltage that the controller applies to the motor.
>
>didn't I several times say that I wanted higher voltage!
I am trying to explain that higher voltage and higher RPM go hand in hand,
at higher RPM you *have* to provide higher voltage, otherwise it won't
work - I am also trying to say that higher RPM does reduce the current,
so the total power will not double when voltage doubles if also the
RPM is going up.
>> Another issue with high voltage controllers is that the higher the
>> voltage, the lower the current that can be carried by a certain amount
>> of silicon.
>
>what is the basis for that conclusion?
Physics.
Higher voltage devices require a lower dotation to get a larger
distance between the edges of the depleted area, otherwise you
will simply get a breakdown of material, causing a short.
With the lower dotation comes a higher resistance, so you get
a lower current spec, because the higher resistance results in
more power loss. It is quite elementary after you have studied
properties of semiconductor device material.
BTW - I have never done too much on modern FETs, maybe they can
keep the same dotation, but need a longer channel to allow the
higher voltage, which also causes a linearly higher resistance
due to geometry, not dotation of the material.
But take any spec overview of high power transistors and see how
the current varies with voltage for the same package and you
will see a trend....
>> Now you may say that it won't matter - the power is still the same if
>> the voltage is double and the current half.
>
>the max current will be max current. the voltage higher.
>there is no double the voltage half the current here.
>unless you compare it to the zilla but it sounds like
>you are trying to make a technical point and not a reference
>to a zilla
Correct, this is simply physics.
Using the same amount and type of transistor packages, you will
get lower current at higher voltage device specs from the
increased "ON" resistance.
There is a second reason that you will get higher losses that
I will describe after your next statement:
>> Since the max RPMs of an AC motor can be double the speed of a DC
>> motor, you can adjust the gearing to double the starting torque again
>> (half the gear ratio) but now you have gained nothing
>but that's simply not true (what a surprise).
>by powering more through the voltage you gain far
>better thermal conditions. P=RII loses have been
>cut to a quarter! thinner wires, less silicon,
>smaller motor.. but who's counting
I have been an EE for 20+ years, so please explain
Ohm's law to me. It may be more effective to ask
why I make this statement, to create an opportunity to
learn why the effect of Ohms law is not contributing
much to the efficiency here. I'll give the reason anyway:
- true that at higher voltage, lower current the resistive
losses are reduced - that is the reason why there are
high voltage lines in the first place.
- BUT, I already explained that the resistance in the
silicon increases, so the effect of the reduction of
losses is already less (probably half iso quart)
- in addition, with increasing voltage, you also have
higher switching losses: every time the transistor
switches on and off, the capacitances need to be
charged and discharged, these switching losses at the
speeds of motor controller switching, are typically
around the same amount of loss as the resistive loss
in the transistors in "ON" state.
By increasing the voltage, you also increase the
switching losses and these are not linear.
They vary by the capacitance of the device and are
multiplied by the voltage change and the internal resistance,
so they may be more than twice as large when doubling the voltage
due to the higher internal resistance.
Hope this clarifies,
Cor.
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--- Begin Message ---
Is there a list somewhere of the existing commercial suppliers of AC and DC
motors and controllers. Most interested in 50-250kw solutions. Thanks in
advance.
britt
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Kaido Kert
Sent: Tuesday, June 12, 2007 3:44 AM
To: ev@listproc.sjsu.edu
Subject: open source motor controller
with all the fuss going on about open designs for motor controller,
why not take and improve on whats already out there ?
OSMC project has been open source with its circuits, board layouts and
construction from the very beginning
http://www.robotpower.com/osmc_info/
http://www.robotpower.com/products/osmc_info.html
Yes, it does only 50Volts and 160Amps continous, thats 8KW , but its a
start. Workable design that you can scale up from.
All the designs are out there, you can put one together yourself, buy
a kit or preassembled. Questions are answered in its yahoo discussion
group.
-kert
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The Mt Washington Alternative Vehicle Days seems to be
still scheduled for this coming 17-18 June. If any of
you New Englanders go to this event, would you mind
doing some good pics of both Charles Macarthur and his
em-cycle? He said he was planning on bringing it. I
kinda got too enthusiastic about his Corbin cycle and
scared him off....Pretty please. I am on my knees
begging for some pics.
BTW in case ppl forgot here is the info for the event.
http://www.mountwashingtonautoroad.com/index.php?module=StaticContent&func=display&scid=176
____________________________________________________________________________________
Boardwalk for $500? In 2007? Ha! Play Monopoly Here and Now (it's updated for
today's economy) at Yahoo! Games.
http://get.games.yahoo.com/proddesc?gamekey=monopolyherenow
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