EV Digest 6856
Topics covered in this issue include:
1) Re: Tesla roadster motor philsophy
by Victor Tikhonov <[EMAIL PROTECTED]>
2) RE: Tesla roadster motor philsophy
by "Dale Ulan" <[EMAIL PROTECTED]>
3) Re: Battery - Fuel Cell Hybrid Idea
by "(-Phil-)" <[EMAIL PROTECTED]>
4) RE: Siamese8 rub pics up
by James Massey <[EMAIL PROTECTED]>
5) Woohoo! just finished homemade capacitive discharge spot battery tab welder
by Tony Hwang <[EMAIL PROTECTED]>
6) Rolling resistance going from 165 to 195...
by Bob Bath <[EMAIL PROTECTED]>
7) Re: Battery - Fuel Cell Hybrid Idea
by Lee Hart <[EMAIL PROTECTED]>
8) Re: Thundersky and calculations
by "Richard Acuti" <[EMAIL PROTECTED]>
9) Re: NEDRA Featured in July Hemmings Motor News!
by Chip Gribben <[EMAIL PROTECTED]>
10) Re: Tesla roadster motor philosophy
by Bill Dube <[EMAIL PROTECTED]>
11) RE: Rolling resistance going from 165 to 195...( and, rotational mass)
by "Phil Marino" <[EMAIL PROTECTED]>
12) Re: Rolling resistance going from 165 to 195...
by "Roland Wiench" <[EMAIL PROTECTED]>
13) RE: Thundersky and calculations
by "David S" <[EMAIL PROTECTED]>
14) RE: Tesla roadster motor philsophy
by "Dale Ulan" <[EMAIL PROTECTED]>
15) RE: Rolling resistance going from 165 to 195...( and, rotational mass)
by Bob Bath <[EMAIL PROTECTED]>
16) Re: aluminum wire for EVs?
by "joe" <[EMAIL PROTECTED]>
17) Re: Rolling resistance going from 165 to 195...( and, rotational mass)
by "Marty Hewes" <[EMAIL PROTECTED]>
18) Re: Tesla roadster motor philsophy
by "Peter VanDerWal" <[EMAIL PROTECTED]>
19) Re: Tesla roadster motor philsophy
by Dan Frederiksen <[EMAIL PROTECTED]>
20) Re: Motor Adapter plate
by "Marty Hewes" <[EMAIL PROTECTED]>
21) Re: Tesla roadster motor philosophy
by Danny Miller <[EMAIL PROTECTED]>
--- Begin Message ---
John Wayland wrote:
David, there's a brand of DC controller that protects against the
above. Every single Zilla controller cannot run without and is mated
to, a Hairball interface that provides absolute protection against the
full-on runaway you describe. For the record, there's never been a
single occurance of this kind of failure in a Zilla, old or new, but
just in case in the very unlikely scenario of a Zilla's power stage
going into full failure mode and it 'were' to happen, the Hairball's
advanced protection features would instantly shut down all power
contactors and the vehicle would simply cease to operate...
John, what David meant, the AC inverter itself inherently cannot
run AC motor if it's connected directly to it and to the battery
(no contactors) in case power stage fails. If DC controller's power
stage fails it will run the motor attached to it full speed, and the
contactors you mention which hairball drops off is something extra
(outside controller) you must have in order to deal with failed
power stage, unlike AC inverter which doesn't have to rely on external
contactors (which may get stuck by the way).
Point is AC inverter will not run AC motor period.
DC motor WILL run DC motor unless you add extra mechanical
hardware to prevent it from happening.
...
> On the other hand, a siamesed DC motor and a Zilla Z2K would
right now, effortlessly deliver 0-60 in 3.5 seconds in that car,
Not to spoil it John, but as Roger usually puts it you "conveniently
forgetting" (tm) that, unlike Tesla, WZ has really two motors.
They want to build very good performance car, but not the purposely
race car like yours. It's like comparing different classes.
So it's not quite apples to apples, you know.
... and
likely the same 200 miles range because of the DC controller's higher
efficiency over the AC inverter's wasteful use of electricity as it
passes through 6 times the silicon on its way to making three phase
juice for that high revving motor :-)
To let you know, these 6 times more waste represent perhaps 1-2% of
overall energy "wasted" to move the car. With 6 times more waste
(which is, say 600 watts instead of DC controller's 100 watts while you
keep supplying ~10,000 watts to move along) your range may get shorter
by a few feet.
Care to calculate exact number?
See Ya....John Wayland
Victor
'91 ACRX - something different
--- End Message ---
--- Begin Message ---
>AC motors are generally less complex than DC motors. DC controllers are
>generally less complex than AC controllers. Seesaw: you are trading
>mechanical complexity for electronic complexity.
Very well-written post (and good follow-ups). My (humble) opinion....
Cost to manufacture mechanicals always seems to go up with time.
Cost of silicon historically has gone down.
-Dale
--- End Message ---
--- Begin Message ---
My point is, You *lose* power by doing this, not gain any. If it did gain
any "free" power, you have a perpetual motion machine!!!
It takes energy to split the hydrogen out, if you leave that energy in the
battery you lose less. Add a resistor across your battery, and that's
effectively what such a system would be doing.
-Phil
----- Original Message -----
From: "Michael Wendell" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Friday, June 08, 2007 12:59 PM
Subject: RE: Battery - Fuel Cell Hybrid Idea
mark asked:
1. Manufacture battery to *maximize* generation of
Hydrogen when cycling, instead of maximizing
recombination as SLAs do.
2. Route the Hydrogen to the fuel cell side of the
device, which then generates more power.
3. Route waste water from fuel cell back into battery.
4. Charge battery with any excess electrical output
from fuel cell (like when's there's no other
application demand on fuel cell). Of course also
charge battery from wall as needed.
phil replied:
This won't do any good, as it costs electrical energy
in the first place to split (electrolysis) the hydrogen
out. When you put it back in later, and with efficiency
losses, you end up in the negative.
i don't think mark was proposing perpetual motion, just the idea of
capturing the hydrogen released from the battery and using a fuel cell to
process it for a little bit more power.
m.
--- End Message ---
--- Begin Message ---
At 07:40 PM 8/06/07 -0700, Jim wrote:
Now I will admit that this shaft has some flex to it
as opposed to a brittle shaft so it could be that
plain and simple. But then it blows my mind to pull
the shaft and lathe it and it's dialed at .002-!
<snip>
Well isn't this the bitch now isn't it, 8^) LMAO Okay
now chew on this, if that shaft was warping enough to
hit this hard it seems to me that the armature would
distort being it's made up of thin laminations and
soft copper wire and there isn't any issue there, lol.
G'day Jim, All
Here is my take on what is going on:
It has to be one of two things, the drive end of the housing is moving,
allowing the bearing position to move off-center of the body tube, or the
shaft is flexing.
The body tube is not likely to be bending/flexing. The aluminium where the
brush windows are may well be bending/flexing, though, as it is much less
rigid than the tube. If that's the case, just supporting the end of the
body tube will make no difference, it will be necessary to lock the drive
CE plate into it's position relative to the body tube.
The other possibility is that the shaft is flexing enough that outside the
motor the shaft goes "left" pivots through the end plate making the rotor
go "right" and rub the poles with the armature. I doubt this is going on,
as I haven't read any reports of vibration, and that'd make the tailshaft
vibrate like there was no tomorrow.
So, motor twin, which is the likely possibility? My vote is the aluminium
of the drive end CE plate brush windows, but I'm not the "motor dog". A
close look at the aluminium where it sits on the steel of the body tube may
show chafe marks, giving the game away if there are.
Regards
The Less Evil twin, [Technik] James
--- End Message ---
--- Begin Message ---
Gonna test it now and will provide more info on how well it works.
Pretty simple, just some caps, two voltage regulators, a pot, a relay,
and some resistors. Haven't actually used it yet... :) - Tony
--- End Message ---
--- Begin Message ---
I'm still mulling over a set of alloy rims.
One pair I'm eyeing is 15", and currently 195s are
mounted. That means 30 mm x 4 tires, or 120 mm more
cross section to be dragged over the pavement.
Any real-world data of whether this will affect my
range substantially?
Thanks,
Converting a gen. 5 Honda Civic? My $20 video/DVD
has my '92 sedan, as well as a del Sol and hatch too!
Learn more at:
www.budget.net/~bbath/CivicWithACord.html
____
__/__|__\ __
=D-------/ - - \
'O'-----'O'-'
Would you still drive your car if the tailpipe came out of the steering wheel?
Are you saving any gas for your kids?
____________________________________________________________________________________
Sick sense of humor? Visit Yahoo! TV's
Comedy with an Edge to see what's on, when.
http://tv.yahoo.com/collections/222
--- End Message ---
--- Begin Message ---
(-Phil-) wrote:
This is called a "reversible fuel cell", and it's basically what a
normal fuel cell does, but will also work in reverse.... The
efficiency is horrible for all existing devices. So far, Not even on
the same planet as a good old SLA.
In a manner of speaking, the nimh (nickel - metal hydride) cell is a
reversible fuel cell. One electrode is nickel, and the other is
hydrogen. The hydogen is created during charging and stored in the
spongy matrix of the metal hydride plate. On discharge, this hydrogen is
converted back into water.
--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in -- Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
Ian,
Thanks a lot for answering my questions. That's quite a price spread;.
.50-$1.60...
Do you happen to have a point of contact for PHET and Valence?
Rich
Here are some costs per watt hour for various brands of lithium:
- ThunderSky and Liteway cost about $0.50/Wh
- Valence Saphions are about $1.60/Wh, including BMS
- A123 M1 cells cost $1.40/Wh
- PHET cost about $0.65/Wh or $1/Wh in packs with BMS
Multiply by 13000 to calculate the cost of your equivalent pack (since
128V @ 100Ah = 13kWh). A BMS will set you back about $1K on top of this
for those without.
Prices for A123 are if you pull apart DeWalt 9360 packs, which is sadly
the cheapest way for individuals to get them! A123 continue to disappoint
me with their reluctance to sell to the public. PHET were far more
welcoming of private enquiries, and it sounds like their high power cells
aren't all that far short of A123 in performance - very promising! (My
soapbox comment for the day!)
-Ian
_________________________________________________________________
Dont miss your chance to WIN $10,000 and other great prizes from Microsoft
Office Live http://clk.atdmt.com/MRT/go/aub0540003042mrt/direct/01/
--- End Message ---
--- Begin Message ---
Hey John!
Thanks for sending this out. Our local bookstore still has the June
issue so I guess I'll have to check back later.
Having Hemmings give us a "plug" validates the work NEDRA and our
members are doing out on the track, almost every week now. That's a
pretty cool honor. Just keep getting those vehicles out and racing!!
It's also cool to see a major automotive news publication actually
taking notice of the website itself. Kind of put a ray of sunshine on
things after the deluge last weekend at PODC.
The Photo Gallery is a new thing I started this year. I've been
thinking about it for awhile but didn't want to compete or duplicate
what was already done with the EV Photo Album but it's apparent
visitors to the site want to see more information and pictures of the
vehicles making the news. This is evident from the hits that both the
White Zombie Photo Page and the KillaCycle Photo Pages get each
month. Including the YouTube videos on the pages really makes them
more interesting too.
It's a bit involved gathering up the photos and the specs. Matt's
photo page and OJ is going up next. And I have a list of more
people's vehicles to go up including Jack's Chevelle, AGNuS, the
Maniac Mazda, Current Eliminator, Father Time's machines, some high
school NEDRA racers and a whole bunch more. I'm starting with the
more active vehicles and hope to fill in with the rest.
The NEDRA site could be a full-time job with all the cool stuff
happening.
Chip Gribben
NEDRA
http://www.nedra.com
On Jun 8, 2007, at 2:42 PM, Electric Vehicle Discussion List wrote:
From: John Wayland <[EMAIL PROTECTED]>
Date: June 8, 2007 12:06:41 AM EDT
To: ev@listproc.sjsu.edu
Subject: NEDRA Featured in July Hemmings Motor News!
Hello to All,
So I'm at work, in my forklift wrench mode, and walking past an
army of heavy lifting equipment, when one of the warehouseman guys
says to me, "Hey, nice write-up on you guys in Hemmings!" I of
course, know nothing about what he's talking about, so it comes at
me out of left field. The next day, he brings in his July copy of
the 3/4 inch thick 'bible' to all gearheads and lovers of
collectible cars, and there in living color (a big detailed screen
capture of the NEDRA home page takes up a good portion of the page)
is a wonderfully written full page story by Mike McNessor, all
about the NEDRA web site and electric drag racers entitled 'Fast As
Lightning', with the sub-title caption 'National Electric Drag
Racing Association's site deserves a plug'
It's surprisingly upbeat and accurate in the details, with well-
deserved Kudos to Chip Gribben (though he's not mentioned in name)
for the site being 'nicely constructed with professional-looking
graphics and logical navigation'. They were jazzed about
Killacycle's 8.16 ET, as well as Current Eliminator IV's 8.8 ET.
They take the time to info everyone, 'they prefer to be known as
ampheads instead of gearheads'. Their only gripe was the 'just two'
photos of racing machines currently listed under the photo
gallery...they're hungry for more!
They gave the NEDRA web site a four star rating, and the four red
stars look impressive even if I don't know how many stars one can
earn :-)
Word is getting out!
See Ya.....John Wayland
--- End Message ---
--- Begin Message ---
I agree with Victor on this one. An AC system is inherently much
safer than a DC system. A dropped wrench in the right spot can
connect the motor to the battery in a DC system and result in full
throttle. Shorted silicon will launch the car before the safety logic
has a chance to realize what has happened and drop out the main
contactors. The contactors open quickly, but far from "instantly."
In an AC system, the controller must be 100% functional for
the motor to even turn.
There is only twice the loss in the controller, not six
times the loss. There are indeed six switches, but the current flows
through just two in series. The voltage is typically twice as high as
it is in DC systems, so the current is half as much and thus the
losses turn out to be about the same. (The motors folks use in DC
cars just can't take the 300+ volts that the AC systems thrive on.)
AC systems often fail in "plug braking" not "lock up". Plug
braking is regen. A typical motor in a typical EV is not quite beefy
enough to lock up the wheels in plug braking except in icy weather.
The plug braking failures are probably going to be one phase rather
than three-phase so the plug braking would be typically 1/3 the
maximum torque.
GM dumped the two-motor set-up for a bunch of very good
reasons. One inverter is cheaper than two and has half the mean time
between failures. Plug braking on one side will jerk the car out of
control, even if the wheel doesn't lock up. A failed controller on
one side that gives zero torque can cause the car to go out of
control if you punch the throttle and give full torque to the
remaining good motor.
As for range, the lack of regen in the Zilla would obviously
allow the AC system (that always has regen) to provide greater range.
The acceleration is just a matter of how powerful you make the drive
package relative to the weight of the car. There is no inherent
limitation on an AC system HP. Ask Bob Rice about the 5,000 HP AC
drive systems in locomotives.
Of the DC systems, the Zilla is the finest available by a
large margin. However, AC systems have some inherent advantages over
DC systems. Safety is one of them. (Cost is not one of them.) If
there were not some advantages of an AC system, Otmar would not
bother developing one.
We have wanted to get an AC drive on the KillaCycle for
years because they have many advantages over DC systems. Moving the
commutation out o the motor is the biggest advantage for us. This
would allow us to go to much higher voltages and also higher motor
RPM. These two advantages would allow us to take a significant amount
of weight out of the motor and perhaps off the bike.
Bill Dube'
At 10:35 PM 6/8/2007, you wrote:
John Wayland wrote:
David, there's a brand of DC controller that protects against the
above. Every single Zilla controller cannot run without and is
mated to, a Hairball interface that provides absolute protection
against the full-on runaway you describe. For the record, there's
never been a single occurance of this kind of failure in a Zilla,
old or new, but just in case in the very unlikely scenario of a
Zilla's power stage going into full failure mode and it 'were' to
happen, the Hairball's advanced protection features would instantly
shut down all power contactors and the vehicle would simply cease to operate...
John, what David meant, the AC inverter itself inherently cannot
run AC motor if it's connected directly to it and to the battery
(no contactors) in case power stage fails. If DC controller's power
stage fails it will run the motor attached to it full speed, and the
contactors you mention which hairball drops off is something extra
(outside controller) you must have in order to deal with failed
power stage, unlike AC inverter which doesn't have to rely on external
contactors (which may get stuck by the way).
Point is AC inverter will not run AC motor period.
DC motor WILL run DC motor unless you add extra mechanical
hardware to prevent it from happening.
...
> On the other hand, a siamesed DC motor and a Zilla Z2K would
right now, effortlessly deliver 0-60 in 3.5 seconds in that car,
Not to spoil it John, but as Roger usually puts it you "conveniently
forgetting" (tm) that, unlike Tesla, WZ has really two motors.
They want to build very good performance car, but not the purposely
race car like yours. It's like comparing different classes.
So it's not quite apples to apples, you know.
... and likely the same 200 miles range because of the DC
controller's higher efficiency over the AC inverter's wasteful use
of electricity as it passes through 6 times the silicon on its way
to making three phase juice for that high revving motor :-)
To let you know, these 6 times more waste represent perhaps 1-2% of
overall energy "wasted" to move the car. With 6 times more waste
(which is, say 600 watts instead of DC controller's 100 watts while
you keep supplying ~10,000 watts to move along) your range may get shorter
by a few feet.
Care to calculate exact number?
See Ya....John Wayland
Victor
'91 ACRX - something different
--- End Message ---
--- Begin Message ---
Bob
Wider tires don;t necessarily have higher rolling resistance. What is more
important is the particular tire model ( and it's rolling resistance) and
the pressure you run in them.
Can you tell us why are you considering changing to alloy rims? Is it to
reduce rotational mass?
The added rotational inertia due to the rims is pretty small. A few weeks
ago I measured the rotational inertia of my Echo's OEM steel wheels and the
low-RR tires I just bought ( Bridgestone B381's) using a bifilar pendulum.
Here are the results:
Tire ( Bridgestone B381 195/65-14)
Weight ( each) - 16 lbs.
Rotational inertia ( lb- in -in) : 1712
Radius of gyration ( effective inertial radius of the mass) : 10.34 inches
Equivalent extra weight due to rotational mass : 13.2 lbs
Rims ( each) Toyota 5 x 14 OEM steel:
Weight : 12.7 lbs.
Rotational inertia ( lb- in -in) : 490
Radius of Gyration ( effective inertial radius of the mass) : 6.22 inches
Equivalent extra weight due to rotational mass : 3.8 lbs.
So, the rotational mass effects of the rims ( 3.8 lbs/rim) is small - much
smaller than for the tires - because the weight of the rims is concentrated
close to the axle center. For every 1 pound reduction in rim weight, you
will reduce the car's effective inertia by about another 1/3 pound. This
ratio will vary slightly depending on your tire's aspect ratio and the
particular rims.
And, this rotational mass effect only hurts range and performance while
accelerating - not hill climbing, or traveling at constant speed.
The benefits of low RR tires are there at all speeds, under all conditions.
I would put my money into the lowest RR tires you can find that will work
for your car, and don't worry about the rims.
Phil Marino
Reply-To: ev@listproc.sjsu.edu
To: ev@listproc.sjsu.edu
Subject: Rolling resistance going from 165 to 195...
Date: Sat, 9 Jun 2007 05:40:32 -0700 (PDT)
I'm still mulling over a set of alloy rims.
One pair I'm eyeing is 15", and currently 195s are
mounted. That means 30 mm x 4 tires, or 120 mm more
cross section to be dragged over the pavement.
Any real-world data of whether this will affect my
range substantially?
Thanks,
Converting a gen. 5 Honda Civic? My $20 video/DVD
has my '92 sedan, as well as a del Sol and hatch too!
Learn more at:
www.budget.net/~bbath/CivicWithACord.html
____
__/__|__\ __
=D-------/ - - \
'O'-----'O'-'
Would you still drive your car if the tailpipe came out of the steering
wheel? Are you saving any gas for your kids?
____________________________________________________________________________________
Sick sense of humor? Visit Yahoo! TV's
Comedy with an Edge to see what's on, when.
http://tv.yahoo.com/collections/222
_________________________________________________________________
Make every IM count. Download Messenger and join the im Initiative now.
Its free. http://im.live.com/messenger/im/home/?source=TAGHM_June07
--- End Message ---
--- Begin Message ---
This depends on the tire lug spacing, load rating and at a specific tire
PSI. I have a sports car that is design by the manufacture to have 12 inch
wide tires on the rear and 8 inch wide tires in the front. They are mounted
on magnesium heavy duty rims with a 1.5 inch thick centers.
The rear lug spaces are about 1/2 inch apart and the front lug spaces are
1/4 inch apart and also the tire compound is different in the front than the
rear.
The rear foot print is only 2 inches wide by 12 inches, while the front foot
print is 3 inches wide by 8 inches. This allows the same psi down force on
the tire surface to be about equal from rear to front, even though the rear
suspension has 80 percent of the weight of the vehicle on it, but it feels
like a 50/50 weight distribution.
The tires on my EV are 235's x 15 inch which are about 30 inch in diameter
rated at 65 PSI at 2600 lbs load rating which are mounted on a 3500 lb
rating wheel. If you look at your light weight alloys rims, many of these
have only a load rating of 1500 lbs or less. You should design a 1.50%
service factor for weight on any wheels or tires. A load rating of 1000 lbs
should be about the maximum on at 1500 lbs tire and wheel rating.
Also if you are only driving on very flat smooth roads with a year around
average temperature of 70 degrees, you can get by with those low profile
tires with a 2 inch side wall. This type of tire on one car only lasted 10
minutes of driving on very rough roads, that broke the alloy rims, because
the tires had too much deflection.
Roland
----- Original Message -----
From: "Bob Bath" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Saturday, June 09, 2007 6:40 AM
Subject: Rolling resistance going from 165 to 195...
> I'm still mulling over a set of alloy rims.
> One pair I'm eyeing is 15", and currently 195s are
> mounted. That means 30 mm x 4 tires, or 120 mm more
> cross section to be dragged over the pavement.
> Any real-world data of whether this will affect my
> range substantially?
> Thanks,
>
> Converting a gen. 5 Honda Civic? My $20 video/DVD
> has my '92 sedan, as well as a del Sol and hatch too!
> Learn more at:
> www.budget.net/~bbath/CivicWithACord.html
> ____
> __/__|__\ __
> =D-------/ - - \
> 'O'-----'O'-'
> Would you still drive your car if the tailpipe came out of the steering
> wheel? Are you saving any gas for your kids?
>
>
>
> ____________________________________________________________________________________
> Sick sense of humor? Visit Yahoo! TV's
> Comedy with an Edge to see what's on, when.
> http://tv.yahoo.com/collections/222
>
>
--- End Message ---
--- Begin Message ---
Ian Hooper said
>- ThunderSky and Liteway cost about $0.50/Wh
>- Valence Saphions are about $1.60/Wh, including BMS
>- A123 M1 cells cost $1.40/Wh
>- PHET cost about $0.65/Wh or $1/Wh in packs with BMS
>Prices for A123 are if you pull apart DeWalt 9360 packs, which is
>sadly the cheapest way for individuals to get them! A123 continue to
>disappoint me with their reluctance to sell to the public. PHET were
>far more welcoming of private enquiries, and it sounds like their
>high power cells aren't all that far short of A123 in performance -
>very promising! (My soapbox comment for the day!)
>-Ian
What is the Home Depot brand Rigid using in their 48 volt tools?
--- End Message ---
--- Begin Message ---
To let you know, these 6 times more waste represent perhaps 1-2% of
overall energy "wasted" to move the car. With 6 times more waste
(which is, say 600 watts instead of DC controller's 100 watts while you
keep supplying ~10,000 watts to move along) your range may get shorter
by a few feet.
A little nit-pick here, but actually the energy 'wasted' in silicon
is only double, not times six, if you compare apples to apples (ie
the same type of transistor). The voltage drop between the motor
and the battery is only that of two IGBT's or MOSFETs, not six.
-Dale
--- End Message ---
--- Begin Message ---
> Can you tell us why are you considering changing to
> alloy rims? Is it to
> reduce rotational mass?
No, it is to improve the looks, and get more air to
the rotors. While I can stop just fine, let's face
it: it's like driving with a full load of passengers
each time. And my plastic hubcaps are starting to
flake paint off. I show the car often, and it just
looks sharper.
>
>
> The added rotational inertia due to the rims is
> pretty small. A few weeks
> ago I measured the rotational inertia of my Echo's
> OEM steel wheels and the
> low-RR tires I just bought ( Bridgestone B381's)
> using a bifilar pendulum.
>
> Here are the results:
>
>
> Tire ( Bridgestone B381 195/65-14)
>
> Weight ( each) - 16 lbs.
>
> Rotational inertia ( lb- in -in) : 1712
>
> Radius of gyration ( effective inertial radius of
> the mass) : 10.34 inches
>
> Equivalent extra weight due to rotational mass :
> 13.2 lbs
>
>
>
> Rims ( each) Toyota 5 x 14 OEM steel:
>
> Weight : 12.7 lbs.
>
> Rotational inertia ( lb- in -in) : 490
>
> Radius of Gyration ( effective inertial radius of
> the mass) : 6.22 inches
>
> Equivalent extra weight due to rotational mass : 3.8
> lbs.
>
>
>
>
>
> So, the rotational mass effects of the rims ( 3.8
> lbs/rim) is small - much
> smaller than for the tires - because the weight of
> the rims is concentrated
> close to the axle center. For every 1 pound
> reduction in rim weight, you
> will reduce the car's effective inertia by about
> another 1/3 pound. This
> ratio will vary slightly depending on your tire's
> aspect ratio and the
> particular rims.
>
>
> And, this rotational mass effect only hurts range
> and performance while
> accelerating - not hill climbing, or traveling at
> constant speed.
>
> The benefits of low RR tires are there at all
> speeds, under all conditions.
> I would put my money into the lowest RR tires you
> can find that will work
> for your car, and don't worry about the rims.
>
>
> Phil Marino
>
>
>
>
> >Reply-To: ev@listproc.sjsu.edu
> >To: ev@listproc.sjsu.edu
> >Subject: Rolling resistance going from 165 to
> 195...
> >Date: Sat, 9 Jun 2007 05:40:32 -0700 (PDT)
> >
> >I'm still mulling over a set of alloy rims.
> >One pair I'm eyeing is 15", and currently 195s are
> >mounted. That means 30 mm x 4 tires, or 120 mm
> more
> >cross section to be dragged over the pavement.
> >Any real-world data of whether this will affect my
> >range substantially?
> >Thanks,
> >
> >Converting a gen. 5 Honda Civic? My $20 video/DVD
> >has my '92 sedan, as well as a del Sol and hatch
> too!
> >Learn more at:
> >www.budget.net/~bbath/CivicWithACord.html
> > ____
> > __/__|__\ __
> > =D-------/ - - \
> > 'O'-----'O'-'
> >Would you still drive your car if the tailpipe came
> out of the steering
> >wheel? Are you saving any gas for your kids?
> >
> >
> >
>
>____________________________________________________________________________________
> >Sick sense of humor? Visit Yahoo! TV's
> >Comedy with an Edge to see what's on, when.
> >http://tv.yahoo.com/collections/222
> >
>
>
_________________________________________________________________
> Make every IM count. Download Messenger and join the
> im Initiative now.
> Its free.
>
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>
>
Converting a gen. 5 Honda Civic? My $20 video/DVD
has my '92 sedan, as well as a del Sol and hatch too!
Learn more at:
www.budget.net/~bbath/CivicWithACord.html
____
__/__|__\ __
=D-------/ - - \
'O'-----'O'-'
Would you still drive your car if the tailpipe came out of the steering wheel?
Are you saving any gas for your kids?
____________________________________________________________________________________
Got a little couch potato?
Check out fun summer activities for kids.
http://search.yahoo.com/search?fr=oni_on_mail&p=summer+activities+for+kids&cs=bz
--- End Message ---
--- Begin Message ---
The real problem with aluminum wire is the expansion factor, and the effect
it has on connections, as well as the corrosion issue.
Do not even consider using aluminum wire in an EV!!!!!!
Joseph H. Strubhar
Web: www.gremcoinc.com
E-mail: [EMAIL PROTECTED]
----- Original Message -----
From: "chad plantenberg" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Thursday, June 07, 2007 9:44 PM
Subject: Re: aluminum wire for EVs?
one of the reasons aluminum has fallen out of disuse in the
construction industry (aside from the larger guages) was bending
fatigue. someone may have some better knowledge - but in a vehicle
with constant road vibrations - i would think that aluminum would be
expected to have a shorter servicable life (possibly premature
failure?).
chad
On 6/7/07, Marcin Ciosek <[EMAIL PROTECTED]> wrote:
Sure, you can use aluminum but to compensate lower conductivity you need
to
increase wire thickness. I use factor of 1.4 to for replacing copper with
aluminum. If you use to thin wire you will loose some of energy on heat.
Marcin
--- End Message ---
--- Begin Message ---
Anybody tried using heat sink compound between the rotors and aluminum
wheels in order to conduct the heat out of the brakes and dissipate it with
those big spinning heat sinks? I suppose the biggest problem is getting the
rotors to conduct the heat to the wheel mounting area without cooking all
the grease out of the wheel bearing.
OK, old age test, who here remembers the Pontiac aluminum brake drums that
were also the wheel centers? I wonder how much better they dissipated heat?
Marty
----- Original Message -----
From: "Bob Bath" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Saturday, June 09, 2007 9:29 AM
Subject: RE: Rolling resistance going from 165 to 195...( and, rotational
mass)
Can you tell us why are you considering changing to
alloy rims? Is it to
reduce rotational mass?
No, it is to improve the looks, and get more air to
the rotors. While I can stop just fine, let's face
it: it's like driving with a full load of passengers
each time. And my plastic hubcaps are starting to
flake paint off. I show the car often, and it just
looks sharper.
The added rotational inertia due to the rims is
pretty small. A few weeks
ago I measured the rotational inertia of my Echo's
OEM steel wheels and the
low-RR tires I just bought ( Bridgestone B381's)
using a bifilar pendulum.
Here are the results:
Tire ( Bridgestone B381 195/65-14)
Weight ( each) - 16 lbs.
Rotational inertia ( lb- in -in) : 1712
Radius of gyration ( effective inertial radius of
the mass) : 10.34 inches
Equivalent extra weight due to rotational mass :
13.2 lbs
Rims ( each) Toyota 5 x 14 OEM steel:
Weight : 12.7 lbs.
Rotational inertia ( lb- in -in) : 490
Radius of Gyration ( effective inertial radius of
the mass) : 6.22 inches
Equivalent extra weight due to rotational mass : 3.8
lbs.
So, the rotational mass effects of the rims ( 3.8
lbs/rim) is small - much
smaller than for the tires - because the weight of
the rims is concentrated
close to the axle center. For every 1 pound
reduction in rim weight, you
will reduce the car's effective inertia by about
another 1/3 pound. This
ratio will vary slightly depending on your tire's
aspect ratio and the
particular rims.
And, this rotational mass effect only hurts range
and performance while
accelerating - not hill climbing, or traveling at
constant speed.
The benefits of low RR tires are there at all
speeds, under all conditions.
I would put my money into the lowest RR tires you
can find that will work
for your car, and don't worry about the rims.
Phil Marino
>Reply-To: ev@listproc.sjsu.edu
>To: ev@listproc.sjsu.edu
>Subject: Rolling resistance going from 165 to
195...
>Date: Sat, 9 Jun 2007 05:40:32 -0700 (PDT)
>
>I'm still mulling over a set of alloy rims.
>One pair I'm eyeing is 15", and currently 195s are
>mounted. That means 30 mm x 4 tires, or 120 mm
more
>cross section to be dragged over the pavement.
>Any real-world data of whether this will affect my
>range substantially?
>Thanks,
>
>Converting a gen. 5 Honda Civic? My $20 video/DVD
>has my '92 sedan, as well as a del Sol and hatch
too!
>Learn more at:
>www.budget.net/~bbath/CivicWithACord.html
> ____
> __/__|__\ __
> =D-------/ - - \
> 'O'-----'O'-'
>Would you still drive your car if the tailpipe came
out of the steering
>wheel? Are you saving any gas for your kids?
>
>
>
____________________________________________________________________________________
>Sick sense of humor? Visit Yahoo! TV's
>Comedy with an Edge to see what's on, when.
>http://tv.yahoo.com/collections/222
>
_________________________________________________________________
Make every IM count. Download Messenger and join the
i'm Initiative now.
It's free.
http://im.live.com/messenger/im/home/?source=TAGHM_June07
Converting a gen. 5 Honda Civic? My $20 video/DVD
has my '92 sedan, as well as a del Sol and hatch too!
Learn more at:
www.budget.net/~bbath/CivicWithACord.html
____
__/__|__\ __
=D-------/ - - \
'O'-----'O'-'
Would you still drive your car if the tailpipe came out of the steering
wheel? Are you saving any gas for your kids?
____________________________________________________________________________________
Got a little couch potato?
Check out fun summer activities for kids.
http://search.yahoo.com/search?fr=oni_on_mail&p=summer+activities+for+kids&cs=bz
--- End Message ---
--- Begin Message ---
> An elaborate answer and I tend to agree but aren't you forgetting (if I
> understand correctly) the advantage that comes from the high rpm where
> you can supply the power more in the voltage and less in the current.
> which is good since all the loss is in the current side. and also why
> they can make it smaller (less heat)
RPM vs voltage is only tied together for a given motor design. By that I
mean, high voltage does NOT necessarily mean high RPM.
There are motors that spin at 20,000 rpm on 12V, likewise there are 300V
motors that spin at 1800 rpm.
>
> in principle you could have an apple sized super high speed motor of
> 100+kW that doesn't get hot.
> even without superconductors
Can you explain how this would be accomplished? Even if the motor was 99%
efficient, that still means that your apple size motor has to dissipate
1kw.
In order NOT to get hot, it would need to be something like 99.99%
efficient. How are you going to do that without superconductors? And
probably magnetic bearings and a vacuum enviroment?
> batteries suck somewhat though. something like eestor would change
> things if it becomes real though
>
>
> David Roden wrote:
>> AC induction and brushless DC motors move the job of commutation from
>> the
>> motor (mechanical) to the controller (electronic and/or microprocessor
>> controlled). Voltage drop in carbon brushes is replaced with voltage
>> drop
>> in semiconductors. Mechanical wear on brushes goes away. Carbon dust
>> in
>> the motor goes away. Maintenance thus is reduced (though brush service
>>
> ...
>
>
--
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 VanDerWal wrote:
RPM vs voltage is only tied together for a given motor design. By that I
mean, high voltage does NOT necessarily mean high RPM.
sure.
Can you explain how this would be accomplished? Even if the motor was 99%
efficient, that still means that your apple size motor has to dissipate
1kw. In order NOT to get hot, it would need to be something like 99.99%
efficient. How are you going to do that without superconductors? And
probably magnetic bearings and a vacuum enviroment?
magnetic bearings and vacuum might be needed :)
Granted I am extrapolating on very limited knowledge but it's my
impression that for a given (frictionless) motor that as you increase
the rpm, a given power will be increasingly provided through the voltage
and at lower rpm more so through current. the upper extreme of which is
nearly no current and very high voltage at which point there is very
little energy loss. is that correct? a consequence of P=RII
since vacuum is not nice to have to deal with, various trickery will be
needed to deal with airflow/drag in the motor. but at least
theoretically 10000V at 10A
there is an unfortunate drawback to a high gearing approach (as I
understand the mechanics), that such a setup doesn't lend itself well
to 'direct drive' but maybe it's just a matter of very well crafted
gear. it would be nicer to have an ultra light and powerful hub motor
but those two seem contradictory as it is
--- End Message ---
--- Begin Message ---
Hey Jeff (and Roland), someone on the same wavelength :). We're either on
to something, or we're all nuts :). I'm surprised the large Chevy crank
flange hasn't become more of a standard in the EV world. You can bolt a
world of goodies to it, thanks to the various race parts suppliers out
there. Once my motor looks like a Chevy crank, I can bolt in a manual trans
with stock, lightweight race, or no flywheel or clutch, or to one of a
number of automatics with or without a torque converter, all without
changing the hub. And a huge variety of transmissions are all cheap and
available. And information, and parts for modifications to those
transmissions is plentiful.
What did you do for a pilot bearing, bore the hub center for it? My motor
just has a bolt hole in the end of the shaft.
I could sure use those drawings. Did you make your hub? Are you in a
position to make me one?
I'd go with Roland's idea of just cutting the end off a Chevy crank and
boring it for a taper lock except that forged steel Chevy cranks are
relatively rare and expensive, most Chevy cranks are cast nodular iron. By
the time it's bored, I'd be a little leary of the strength.
Anybody got a junk Chevy steel crank around that suffered a thrown rod or
something?
Marty
----- Original Message -----
From: "Jeff Shanab" <[EMAIL PROTECTED]>
To: "Electric Vehicle Discussion List" <ev@listproc.sjsu.edu>
Sent: Friday, June 08, 2007 8:33 PM
Subject: Re: Motor Adapter plate
Funny you should mention that.
My taperlock presents the pre-"one piece rear seal" chevy 350 crank
pattern.
Which I mount a button flywheel and tilton racing clutch. Then I order
disks with the nissan splines in it since all the racing clutches are
the same.
If I dust off my old server and transfer the files to a host (I lost my
free SDSL connection when I changed jobs) I could provide drawings of it.
MY complete adapters for sale idea was simple. (I just don't have money
to start this buisness)
warp 9 to 350 chevy taper lock adapter
for use with tilton or quartermaster clutch off ebay
A series of bells that mounts to the 9" that sets back the assembly
and adds a 12" diameter register.
A flat plate with a 12" hole in the middle and a standard bolt pattern.
To make a kit I pull the proper depth bell off the shelf and put it
in the box with the crank adapter and clutch
I throw the blank plate into the fixture on the cnc
it puts in all the tranny mounting holes and the dowels
I take it over to the waterjet guy and he cuts the outside profile.
I have since decided that a dual motor setup would be better.
--- End Message ---
--- Begin Message ---
There is an additional issue though. AC drive systems are affected by
skin effect, DC systems are not.
In addition to the skin effect issue, fundamentally the power is not
moving through all the copper at the same time and this increases the
effective resistance for a motor made of a given mass of copper. Motor
winding resistance is a significant issue at these power levels. Well
that's only the simplest observation of the difference in AC vs DC
sizing and efficiency. I don't have the experience to know much more
about the differences.
I think the overriding benefit of AC remains the regen capability (if
the controller supports it). This significantly benefits in-town driving.
Danny
Bill Dube wrote:
I agree with Victor on this one. An AC system is inherently much safer
than a DC system. A dropped wrench in the right spot can connect the
motor to the battery in a DC system and result in full throttle.
Shorted silicon will launch the car before the safety logic has a
chance to realize what has happened and drop out the main contactors.
The contactors open quickly, but far from "instantly."
In an AC system, the controller must be 100% functional for
the motor to even turn.
There is only twice the loss in the controller, not six times
the loss. There are indeed six switches, but the current flows through
just two in series. The voltage is typically twice as high as it is in
DC systems, so the current is half as much and thus the losses turn
out to be about the same. (The motors folks use in DC cars just can't
take the 300+ volts that the AC systems thrive on.)
--- End Message ---
