EV Digest 4304
Topics covered in this issue include:
1) Re: Problem with T-Rex throttle setting
by Rich Rudman <[EMAIL PROTECTED]>
2) Re: Mechanical PWM Controllers
by James Massey <[EMAIL PROTECTED]>
3) Re: Gettting EVery word out
by Lock Hughes <[EMAIL PROTECTED]>
4) Any Th!nk NEVs and/or Th!nk Parts Around?
by "Mason Convey" <[EMAIL PROTECTED]>
5) much happier civic ev driver
by Iron Mountain Films <[EMAIL PROTECTED]>
6) Re: ICE for series hybrid
by Mike Chancey <[EMAIL PROTECTED]>
7) Re: Mechanical PWM Controllers
by Mike Chancey <[EMAIL PROTECTED]>
8) RE: Mechanical PWM Controllers
by "Stu and Jan" <[EMAIL PROTECTED]>
9) Charity EV Event In UK
by Electro Automotive <[EMAIL PROTECTED]>
10) For what it's worth...
by "Dave" <[EMAIL PROTECTED]>
11) Re: For what it's worth...
by "Lord Khaos" <[EMAIL PROTECTED]>
12) Aprilia trike in Maxim
by "Larry Hays" <[EMAIL PROTECTED]>
13) Value of electric 7 EV?
by Nick Austin <[EMAIL PROTECTED]>
14) Re: Aprilia trike in Maxim
by Ryan Stotts <[EMAIL PROTECTED]>
15) RE: Mechanical PWM Controllers
by "Stu and Jan" <[EMAIL PROTECTED]>
16) Re: Mechanical PWM Controllers
by Lee Hart <[EMAIL PROTECTED]>
17) Re: Pics of the Big Guy, mechanical questions (was Re: New EV Dragster)
by Seth Allen <[EMAIL PROTECTED]>
18) RE: Value of electric 7 EV?
by "Mark Fowler" <[EMAIL PROTECTED]>
19) Used Curtic controller
by TiM M <[EMAIL PROTECTED]>
20) RE: Value of electric 7 EV? Better body needed!!!
by jerry dycus <[EMAIL PROTECTED]>
21) Re: PV/EV workshop
by Jeff Shanab <[EMAIL PROTECTED]>
22) RE: Value of electric 7 EV? Better body needed!!!
by [EMAIL PROTECTED]
23) Re: Pics of the Big Guy,
mechanical questions (was Re: New EV Dragster)
by "Christopher Robison" <[EMAIL PROTECTED]>
--- Begin Message ---
The inductive pots were WHY we made them for the DCP controllers. Cheap and
last for ever.
Buy you need some brains and adjustments for everybody to get them right.
The adjustment pots are the pain not the main sensors.
Lee Hart wrote:
> Rich Rudman wrote:
> >> Yea, good quality gasketed Multi turns That would have been
> >> nice. and about $50s a pot.
>
> Yep; that's about right for a really good throttle pot.
>
> Myles Twete wrote:
> > EZ-GO golf cart ITS (Inductive Throttle Sensor) cost about $65
> > plus another $30 or so for the core... never will wear.
>
> That's about right, too. The pots are cheaper and still last forever, so
> that's what I use.
> --
> If you would not be forgotten
> When your body's dead and rotten
> Then write of great deeds worth the reading
> Or do the great deeds worth repeating
> -- Ben Franklin, Poor Richard's Almanac
> --
> Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
At 06:21 PM 22/04/05 -0400, Stu wrote:
I am intrigued by mechanical equivalents of PWM controllers.
I came across an old Mother Earth article in which a hybrid Opel was
described.
Hi Stu (and all)
I believe this was discussed on-list 12 to 18 months ago (but may have been
longer), with lots of reasons as to why this is a BAD idea. Not that it
wouldn't work, it just wouldn't work well enough to make a useable on-road
vehicle (If I remember correctly).
A search of the EVDL archives should find the thread.
James
--- End Message ---
--- Begin Message ---
Good Man Bob
I believe I had a little EV success today too. Heard through the
grapevine that a ban on EV's, perhaps the first ban of these vehicles
in Canada, has been dropped.
My EV is a kick scoot with power assist. My daily driver. Gets me
20-40km across the city on most work days.
A Toronto Parks Supervisor pronounced a ban on personal electrics in
"his park" last August. Some municipal by-laws across Canada may
effectively restrict our little EVs, but this was the first outright
ban (in Canada) that I am aware of.
Toronto is crossed with parklands making up over 12% of the city area,
so a ban in the parks sets up serious roadblocks to PEV travel and
sends out the wrong message about PEVs (the Supervisor pronounced two
(China-made cheap) scooters he saw in "his park" as
"environment-friendly, but that they "can go 70km/h and are a hazard".)
Toronto parklands feature many of the cities safest roads and pathways,
with a 20km/h speed max limit throughout. At the same time, acres of
parkland are paved as thousands of free parking spaces designed to
encourage travel by private car through the city (congested roads) and
into the parks. The actual Parks By-Law has no provision for the ban of
*any* vehicles at all! (Motorized vehicles are only restricted to the
roads and parking lots.)
Canadian cities don't have any real restrictive laws about powered kick
scooters yet, `cause PEVs are (still) illegal on roads and sidewalks
under Federal and Provincial laws, so rarely seen. Canadian Customs has
been diligent in turning back shipments at the borders.
Many young folk seem at least aware of the electrics, I think through
the TV etc. Older folk can assume the scoot is powered with a gas
motor. Actually, many older folks don't realize the scooter is powered
at all <grin>
I had to do a lot of writing but a City Councillor finally popped the
question to City staff about "PEVs in the Parks", and the General
Manager for Parks emailed back "of course we're not banning any
vehicles in the parks". So I'm guessing that's maybe when our Parks
Supervisor et al backed off? I hope someone shook him up a bit.
The best I can hope for at the moment is to keep up a little momentum
to get the City thinking more about PEVs. And eventually get the City
to send an endorsement to the Province to maybe move Provincial butts
in opening up restrictions that dictate pedals and seats on little
two-wheelers with electric power assist.
It's a bit of a race.
There are containers of e-bikes and e-scooters arriving now from China,
and Canadians can buy the powered kick scooters at the supermarket
(ignoring the fine printed labels that declare the vehicles as
"Restricted-Use Motorcycles"(RUM).) In Ontario, the RUMs are
restricted to anywhere that is not a road or a sidewalk...
Some PEVs w/pedals and seats are selling now, classed as mopeds, but
they too are coming in containers from China.
Hundreds of early adopters in Canada are being exposed to cheap junk,
bought in ignorance. Can't be good for EV's! But how to get any
*quality* scoots into the market when they are so restricted!
It's hard to promo the little scooters when they are so hard to acquire
(good ones, I mean.)
Anyway Bob... onwards and upwards <smile>
Lock Hughes
Chuckling along on my electric running machine
--- Bob Bath <[EMAIL PROTECTED]> wrote:
> Hi Friends,
> This was a great week for me; trying to EVangelize
> the masses.
> First, I've had a partnership with the local Junior
> College (JC). There's a mech-tech instructor there who
> hit it off really well with me 6 years ago, and I've
> demo'd the car there once or twice a year ever since.
> This time, I brought "Convert It", and the powerpoint
> presentation I put together. Usually the students are
> interested, but only to a point. _This_ year, I'm
> telling you, they were believers. Two of 8 took down
> the book info and are ready to start on their own
> conversions.
> Second, I wrote a letter to the editor. As always,
> they hacked it for space. (I had attacked GM for
> smashing the EV-1, of course). It is published in
> today's ORegonian.
> People, these are the steps we need to take. If
> _each_ of us shows up to a local JC with our cars, at
> 10 kids or better per class, it makes a difference.
> Another benefit: if you have an issue you lack
> expertise in, say, changing out a 1/2-shaft, it can be
> quid-pro-quo; you pay parts and do your demo, the
> students supply labor. I'd call that a win-win.
>
> Chuckling along in electric car
>
>
> I was one of probably 50 Oregonians to chuckle at your
> article, "Lack of fuel sources hurts West." The
> article asserts that because our state lacks refining
> capacity, all drivers are affected, to the tune of 30
> cents to 40 cents per gallon.
>
> My "fuel link" is about 20 steps to the garage. I
> simply plug my 1992 Honda Civic conversion into the
> wall to charge the 18 batteries that power it. Even
> with the added cost of purchasing electric power from
> wind power, my "fueling" cost is $6 per month.
>
> There are about 4,000 of us across the nation who have
> taken about $7,000 and some electronic and
> metal-fabricating know-how to break the addiction to
> oil. Most of our cars use lead-acid batteries and get
> a range of 40 miles -- ample for most of our
> commuting. Recent battery technology, however, would
> extend our range to more than 100 miles.
>
> Unfortunately, most people don't understand that
> alternatives to petroleum exist, if we just question
> the status quo.
>
> BOB BATH Grants Pass
>
> '92 Honda Civic sedan, 144V
> ____
> __/__|__\ __
> =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?
______________________________________________________________________
Post your free ad now! http://personals.yahoo.ca
--- End Message ---
--- Begin Message ---
I'll forward any replies sent to the EVDL, but contact me off-list if you so
desire (leave subject line the same, please)...
-----Original Message-----
Mason,
Can you post a message to your EV enthusiast list(s) to see if anyone has a
stash of Think NEVs or a collection of Think NEV parts? We're trying to work
a swap for a guy who has a bunch of Thinks but who needs parts.
THANKS
--- End Message ---
--- Begin Message ---
Thanks for all your suggestions on getting more range. I've been driving EV's
for almost 5 years but sometimes you need to have reminders.
I got a front end alignment, I turned my front rotors and replaced pads,
topped up my tire pressure, started revving out higher in each gear while
keeping amps as low as possible and brought my average AH usage from 3.2 per
mile to about 2.6 Not bad!
THIS LIST ROCKS
Thank You
-Mike Malmberg
92 Civic 96 volt, Sacramento, CA
---------------------------------
Do you Yahoo!?
Yahoo! Small Business - Try our new resources site!
--- End Message ---
--- Begin Message ---
And here I was just looking for a good Civic to put an '88 1.5 into.....
Actually, it would probably make a very good choice. As I recall they are
supposed to be about 265 pounds wet including the radiator. Couple that to
a large 3 phase AC motor wired as a generator and I think you could get a
very efficient generator setup. Alain St-Yves did something similar with
his S-10. He used a Ford Festiva engine on a trailer with a 15 HP AC motor
conversion. When I asked about it in Feb 2004 he sent this along.
"This trip was a 1500 km x 2 = 3000 km one. For this trip, I was equiped with
my 5000 watts Honda plus a 10 000 watts one on a trailer. (Twin generator
for power and safety). The 10 kw one is a 15 HP baldor with some 3 x 7 x 50
uf running capacitor at 14 $ each on a 100 amp. 3 phase bridge driven by a
Festiva motor at 3300 rpm. Lot of HP spare, could have put another induction
generator on it.
On the way back from this trip, I did the 1500 km return trip from the
friday 17 hr to the saturday 23 hr. (within some 30 hours).
There have been a 5 hour of sleep while the pick-up was plug on a 110 volts
circuit = nothing. So this 15 kw twin generator unit was enough to keep the
car on those road at an average speed between 70 and 90 km/hr. Speed was
verry low on hill climbing with something close to 6000 pounds equiped EV.
Did see some 120 to 130 km/hr on down hill. Battery stayed normal
temperature all the time because they were not much sollicitated. The curtis
has been use at it's maximum, only a good technicien and EV driver could
have make it without burning it..."
There is a write up on it in French at:
http://www.rocler.qc.ca/levehiculevert/recits.htm
Also a story on him using it to bring home a Cavalier EV conversion at:
http://www.rocler.qc.ca/levehiculevert/cavalier.htm
Someday I am going to get him to submit it to the Album.
Thanks,
Mike Chancey,
'88 Civic EV
'95 Solectria Force
Kansas City, Missouri
EV List Photo Album at: http://evalbum.com
My Electric Car at: http://www.geocities.com/electric_honda
Mid-America EAA chapter at: http://maeaa.org
Join the EV List at: http://www.madkatz.com/ev/evlist.html
Wasting imported oil is not an act of patriotism, conserving it is.
At 04:24 PM 4/22/2005, you wrote:
A quick question for the (illustrious) members of the EV list:
I may have the option to purchase a complete 1989 Honda Civic for $100.
How well would the 1.5l 16 valve 4-cylinder serve as the ICE side of a
generator for my series-hybrid Ranger? It is fuel injected, but only
throttle-body. Is this way too big of an engine, or would it be ok? How
about on the efficiency side of things?
Thanks for your input
-Matt Holthausen
--- End Message ---
--- Begin Message ---
Stu, I think the robot one could actually work, at least in principal,
though there would considerable challenges in reliability and
durability. Keep in mind at EV scales it is going to be seeing hundreds of
amps. The "controller" based on a fan motor and a modified Lucas starter
motor comm they mentioned in the Mother Earth News plans didn't even work
when their own crew built a car from the plans they were selling. See
http://www.motherearthnews.com/library/1980_September_October/Mother_s_Own_Hybrid_Car_
FWIW, I bought those plans new in 1979 and it is really what started me
into EVs. I started a Renault 10 conversion at the time but never finished
it. I finally built my own EV 20 years later.
Thanks,
Mike Chancey,
'88 Civic EV
'95 Solectria Force
Kansas City, Missouri
EV List Photo Album at: http://evalbum.com
My Electric Car at: http://www.geocities.com/electric_honda
Mid-America EAA chapter at: http://maeaa.org
Join the EV List at: http://www.madkatz.com/ev/evlist.html
Wasting imported oil is not an act of patriotism, conserving it is.
--- End Message ---
--- Begin Message ---
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of James Massey
Sent: Friday, April 22, 2005 7:30 PM
To: [email protected]
Subject: Re: Mechanical PWM Controllers
At 06:21 PM 22/04/05 -0400, Stu wrote:
>I am intrigued by mechanical equivalents of PWM controllers.
>
>I came across an old Mother Earth article in which a hybrid Opel was
>described.
Hi Stu (and all)
I believe this was discussed on-list 12 to 18 months ago (but may have been
longer), with lots of reasons as to why this is a BAD idea.
The question as President Clinton used to say; "It depends on what 'this'
is?"
I will look at eh archives to determine whether or not the concepts are the
same.
Thanks,
Stu
--- End Message ---
--- Begin Message ---
I am passing this on to anyone on the list who is interested. I don't have
any personal knowledge of this person or the event, so do your own due
diligence. This is a fellow from the UK interested in putting on an EV
event to raise money for charity. At this point, it is still in the very
early stages and he is looking for businesses/sponsors to
participate. Please direct any communication directly to him. Below are
exerpts of my email from him.
Shari Prange
>It Will Be An Exhibition Show to invite people to bring their custom
>vehicles and conversions to show the Public what can be achieved with a
>little imagination and creativity hard work and love of their
>vehicles,
>That's the first thing, next its finding company's who would like to
>contribute and support,
>entry fees will got to terminally ill children,
>And yes it is the UK I wasn't to sure where you were based but i had to
>start some where you understand,
>The show Will Be Over two Days, People Can Arrive and Stay Over Night In
>The Park and the festival would start on The Saturday and Finish on the
>Sunday Evening Some can stay and leave on the Monday, These Festival/shows
>are very successful as TV, Radio Road shows and local and National Papers
>do get involved also in some of these shows, the venue is very well suited
>for these type of shows, i hope this helps!
Mike Bowler
Chairman
Daniel Bowlers Memorial Trust Fund
Reg Charity 1102506
Office No:08707 601 200
[EMAIL PROTECTED]
--- End Message ---
--- Begin Message ---
My neighbor gave me a motor today for a table saw he gave me last week. I just
looked at the ID plate, and realised it is 230/460 VAC 3-Phase. I have no use
for it. Does anyone here want it? Would it make a good EV motor? It is rated at
2 HP @ 460VAC
David C. Wilker Jr. USAF (RET)
Children need love, especially when they do not deserve it.
- Harold S.
Hulbert
--- End Message ---
--- Begin Message ---
Not sure where your located, but I have a band saw that motor would make
rather happy.
----- Original Message -----
From: "Dave" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Friday, April 22, 2005 6:19 PM
Subject: For what it's worth...
My neighbor gave me a motor today for a table saw he gave me last week. I
just looked at the ID plate, and realised it is 230/460 VAC 3-Phase. I have
no use for it. Does anyone here want it? Would it make a good EV motor? It
is rated at 2 HP @ 460VAC
David C. Wilker Jr. USAF (RET)
Children need love, especially when they do not deserve it.
- Harold S.
Hulbert
----------------------------------------------------------------------------
----
No virus found in this incoming message.
Checked by AVG Anti-Virus.
Version: 7.0.308 / Virus Database: 266.10.2 - Release Date: 4/21/2005
--- End Message ---
--- Begin Message ---
In the may Maxim theres a scetch or two of an Aprilia hybrid leaning trike
that is very cool. It has those impossible looking hubless wheels, a 500 cc
v-twin and two electric powered wheels. Its a prorotype...I hope they build
a zilion of them
--- End Message ---
--- Begin Message ---
Hello,
I'm thinking about buying a Birkin or Caterham 7 kit and building an EV with
Lipoly batteries and an AC motor around it.
Then I thought, this would be a really cool car, could I sell a car like this?
What do you think the value of a vehicle like this is? Do you think there is
money to be made doing this?
I've seen the electric7.com site, and his car looks very nice.
Just a thought.
Thanks!
--- End Message ---
--- Begin Message ---
Larry wrote:
> In the may Maxim theres a sketch or two of an Aprilia hybrid leaning trike
> that is very cool. It has those impossible looking hubless wheels,
They put wheels like this on an Aprilia?!!
http://img228.echo.cx/img228/2481/hubless3it.jpg
;)
--- End Message ---
--- Begin Message ---
Mike,
Congratulations on you EV projects!
Thanks for your input. I read the article in Mother Earth.
The author said the following: " Our experience with the "chopper" used by
Dave on his prototype Opel hybrid indicated that the system might have a
limited lifetime as a result of the sometimes extreme currents that passed
through its brushes while in operation."
Notice the word 'might'.
My thinking is thus:
You have a DC motor with 4 brushes with a total contact area to the
commutator of x square inches. I visualize a mechanical controller with
brushes and contact area equal to or greater than that of the motor.
Is there any reason why a mechanical controller as I have just described
would not outlive the motor?
I see a way for to eliminate the drive motor completely. I see the
controller as integral part of the vehicle motor.
Stu
P.S. See my $100 elevator, etc at: www.stulieberman,com
I am building a hybrid recumbent trike that can lean in turns.
It is a 1F2R delta with foot steering.
--- End Message ---
--- Begin Message ---
Stu and Jan wrote:
> Is there any reason why a mechanical controller as I have just
> described would not outlive the motor?
Welcome, Stu. Sounds like you have some interesting projects!
First, you should recognize that electric motors have been around for
well over 100 years. Some truly brilliant engineering minds have applied
themselves to designing them (Edison, Tesla, etc.). The motors we use
today are the result of over a century of experimentation and
optimization.
All motors are fundamentally AC motors. DC motors always have some kind
of switch to switch the current on/off to the coils to produce the AC
that the motor needs to run.
Until the last few decades, these switches were always mechanical. A
"commutator" is just a big rotary switch, switching power to each coil
in turn as the motor rotates. It produces AC in the coils so the motor
runs.
But we now have a few options to the mechanical commutator. Successful
motors have used SCRs, bipolar transistors, IGBTs, and MOSFETs in place
of the commutator. These devices are used to produce "brushless DC"
motors (really AC motors with electronic commutators).
One thing the early experimentors found is that when you interrupt
current in an inductive circuit (like motor windings), you get a lot of
arcing. The arcing rapidly destroys the switch. To combat this, HUNDREDS
of schemes have been used. In the end, all this experimentation led to
the commutators we use today. All the other schemes proved inferior.
The commutator works because a) it always provides a path for the
inductive current i.e. it never open-circuits any coil, b) all coils are
always powered so they share the load equally, c) the brushes,
commutator bars, and coils are all carefully positioned so the voltage
is almost zero as the brush crosses over from one commutator bar to the
next.
With a commutator, you adjust motor speed via field current. You don't
want to do it with the commutator because you will degrade the delicate
balance that minimizes arcing. Here again, vast amounts of
experimentation and optimization has been done to learn exactly how to
alter the field current without affecting brush life. A wide speed range
usually requires not just a simple field winding, but also compensating
windings (interpoles, face windings, etc.).
The scheme described in the Mother Earth News article is what people
used over 100 years ago, before Edison and Tesla, and before the
commutator was invented. It suffers from all these problems; no path for
inductive current, it does open-circuit coils, and it doesn't switch at
zero volts. As a result, it is rapidly destroyed by arcing problems.
My impression is that the designer was a bright but naive backyard
experimenter. He had never studied any of the history of motors, didn't
understand how they worked, and so was basically "starting from scratch"
and re-inventing the motor speed controls of 100+years ago.
If you *really* want to get this type of mechanical switch speed
controller to work, you'll need to study the designs of Edison and
others. They were familiar with these problems, and you can see what
they did to solve them.
--
If you would not be forgotten
When your body's dead and rotten
Then write of great deeds worth the reading
Or do the great deeds worth repeating
-- Ben Franklin, Poor Richard's Almanac
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
Ok, before I start, I will make a few assumptions and such:
1: You don't want to greatly increase cost, so a material that doesn't
need a rough machining, heat treat and grind to size is desirable
2: You need some plunge on the output
3: a standard interface is nice
4: you want it sized for fatigue life at peak torque (many dragstrip
runs)
5: you will not be getting it plated
If all this is right, then a suggestion for a steel might be a
pre-hardened AISI 4140 which is fairly common and fairly easy to
machine. It won't be fully hard, but you won't have to do the heat
treat and grind to size.
As for an output. I have done standard yokes with slip joint
driveshafts for trucks. Not sexy, but they work. But your torque is
actually quite low if this is direct drive to the rear diff. A CV joint
can easily handle this torque and requires no alignment of the yokes or
concern over driveshaft angle. A CV flange on the output of the motor
with whay would normally be an IRS halfshaft could work quite well. It
is what I would do, but some people really refer U-joints. If that is
the case, then at www.roadranger.com there are loads of U-joint specs
there. ANd they will specify the spline options. Let me know what your
preference is (CV joint or U-joint) and we can wade through the options
and once a spline is found, see if it will work. Your torque is so low
that with half-hard 4140 and an easily cut involute spline on a ~2"
diameter that I think there will be no problem with fatigue life, even
after effects like corrosion are figured in.
Seth
On Apr 22, 2005, at 12:52 AM, Christopher Robison wrote:
Seth,
Verizon wouldn't allow me to send directly to your email address (the
bounce says I'm not on their whitelist?) so I'm forwarding this to the
EVDL...
Moderators: I will respect your wishes to discontinue this discussion
on
this list, however it is very much in the interest of getting a cool
EV on
the road, and is in reference to issues encountered with the sole
cause of
gonzo electric torque... :o)
--chris
---------------------------- Original Message
----------------------------
Subject: Re: Fwd: Pics of the Big Guy, mechanical questions (was
Re:
From: "Christopher Robison" <[EMAIL PROTECTED]>
Date: Thu, April 21, 2005 11:37 pm
To: "Seth Allen" <[EMAIL PROTECTED]>
Cc: "Keith Richtman" <[EMAIL PROTECTED]>
-----------------------------------------------------------------------
---
Thanks guys for your input here ... I am definitely at a disadvantage
having no education in mech. engineering, so I apologize in advance for
any tedious explanations that may be necessary going forward.
I guess my main question is, what information can I provide that will
make
the answer more certain?
Keith, I think that 1600 ft-lbs is probably a good working number,
especially given that I have no real data beyond 1400A on the older
Warp
13, and no data at all on the newer version I'll be getting. Should an
extra proportion also be added to handle torsional shock loads (speed
bumps, potholes etc)? Such driveline shock will be transmitted
directly
to the motor -- no clutch disk springs or other dampeners will be
present
(unless it's decided I can't do without it).
Please let me know how I can help you help me. I'd like to get
Netgain an
answer in the next few weeks, as they've waited for me to figure this
out
for quite some time now... :o)
Thanks for your time!
--Christopher Robison
Seth Allen said:
Begin forwarded message:
From: Seth Allen <[EMAIL PROTECTED]>
Date: April 21, 2005 9:46:56 PM EDT
To: [email protected]
Subject: Re: Pics of the Big Guy, mechanical questions (was Re: New
EV
Dragster)
I did the mechanical engineering for the Super7 Kenworth hybrid at
Solectria. For the moment, not enough is known to say if 1144 is
acceptable. I can tell you that either an end milled or sled runner
keyway is not acceptable in that diameter and torque, regardless of
material.
I specified 4340 with a heat treat, but I had a slightly smaller
diameter. The input shaft on the transmission was a 10 spline at 1.75"
diameter made of some quite hard stuff, and it was rated for 860 ft-lb
for 500,000 miles. (This was a 32,000 lb hybrid with 1000 lbs of AC
induction motors) That's 860 ft-lbs but with lots of ripple that is
difficult to characterize. I can tell you what I did, the asssumptions
I made and what worked, what we tested and where the predicted failure
was. If you want. If I get sniped at then we can take it off list.
The vehicle:
http://www.solectria.com/news/17sept03.html
Seth
P.S. I think the F.O.S. for an involute spline is lower than 2, but I
don't recall off the top of my head what I did use or how I reached the
number I used.
On Apr 21, 2005, at 7:39 PM, Keith Richtman wrote:
I am not a mechanical engineer, but I will be in December.
Here are my numbers:
Torque = 1600 ft-lb = 19200 in-lb
Polar Moment of Inertia (J) = (pi*dia^4)/32 = 1.57
Outer Radius = 1"
Shear Stress = (T*r)/J = (19200 * 1)/1.57 = 12.2 ksi
I do not know the stress concentration factor for splines (and I am
sure it depends on the style), but we'll say 2 for now. The yield
stress for 1144 steel is ~90 ksi.
Shear Yield Strength = .577 * Tensile Yield Strength = .577 * 90 =
51 ksi
Safety Factor = Strength / (Stress * Stress Conc. Factor) =
51/(12.2*2) = 2.09
Unless you can better quantify the materials, loads, and the effect
the spline has on the peak stress I wouldn't trust the shaft as is.
Easiest option is to find better steel, but you could also find a way
to attach the drive shaft that doesn't involve a spline (queue Seth to
mention Loctite 620).
Keith
Philip Marino wrote:
From: "Christopher Robison" <[EMAIL PROTECTED]>
Reply-To: [email protected]
To: [email protected]
Subject: Pics of the Big Guy, mechanical questions (was Re: New EV
Dragster)
Date: Thu, 21 Apr 2005 15:55:47 -0500 (CDT)
e.
The
motor is supplied with a 2" shaft of untreated 1144 steel (LaSalle
calls
it "Stressproof").
This brings me to my main question ... from what should the shaft
be
made?
Should I choose a different material, or is 1144 sufficient? If I
stay
with 1144, should I have it heat treated? If so, to what extent
(what
hardness, etc)? How should dimensional instability during the
hardening
process be handled?
"Stressproof" 1144, at least according the the only references to
it
I could find, is a LaSalle Steel trademark, and is not "untreated"
but is coldworked to a yield strength of 100 kpsi, and a tensile
strength of 120 kpsi, and a Rockwell hardness of C23.
This is already a moderately high strength steel - roughly double
the
strength of untreated low carbon steel.
If you have a reasonable idea of the maximum torque expected, you
could bring your design ( or, even, just a sketch of your ideas) to a
mechanical engineer - preferably a stress analyst , to try to get a
prediction of what will happen under load. ( and, what strength steel
you need, if 1144 is not adequate.)
Try contacting the mechanical engineering department of a local
university ( if any) - you may get some leads as to who can help with
this.
Phil Marino
--- End Message ---
--- Begin Message ---
Hi Nick,
Building a Lotus 7 kit based EV is a great way to go.
A couple of us have done it.
Could you sell a car like this? of course!
Could you sell it for more than it cost to build? Dunno.
Li-Poly plus AC (I assume you've looked through Victor's site
www.metricmind.com or the Electric Imp site www.proev.com ) is going to
cost a large chunk of money - probably about double what the Lotus 7 kit
costs.
(Victor, were you selling 3.7V Kokams for about US$5 per Ah?)
In Australia (where I built my Birkin based EV) that comes to about
AU$100K.
Now that's more than a BMW Z4 ($81K), an MG TF 160 ($52K), Mazda MX5 SE
($45K), Toyota Prius ($38K) or a Toyota MR2 Spyder ($50K).
Admittedly, this car would be in the serious sports car performance
league.
Who would spend that sort of money on a car that doesn't even have
doors?
Someone with lots of spare money, an environmental image, but likes to
go fast.
A celebrity.
I suggest you find someone that wants a car like this and get them to
pay you to build it rather than spending the big bucks to build an
amazing car, just to have no-one buy it.
Mark
-----Original Message-----
From: Nick Austin [mailto:[EMAIL PROTECTED]
Sent: Saturday, 23 April 2005 11:43 AM
To: [email protected]
Subject: Value of electric 7 EV?
Hello,
I'm thinking about buying a Birkin or Caterham 7 kit and building an EV
with
Lipoly batteries and an AC motor around it.
Then I thought, this would be a really cool car, could I sell a car like
this?
What do you think the value of a vehicle like this is? Do you think
there is
money to be made doing this?
I've seen the electric7.com site, and his car looks very nice.
Just a thought.
Thanks!
--- End Message ---
--- Begin Message ---
I'm looking to upgrade my truck, it's @ 96V right now,
the batteries are ready to be replaced and the Curtis
1231C-77xx is good for up to 120V I was thinking I'd
be happier @ 144V or better. What is a used 1231C-77xx
worth? I'd like to sell it to offset the cost of a new
Zilla 1k.
Thanks,
TiM
'61 Electric Rampside
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
--- End Message ---
--- Begin Message ---
Hi Mark, Nick and Al,
They have an Aero CD of about .65 which is
really bad if you intend to go faster than 50 mph,
range will be terrible.
Build the chassis and put a more aero body
on it!
Put say a Ferrari Daytona or Ford GT-40,
ect, body on it and you could easily get really good
money for it in the US.
Go for a Locost 7 chassis to keep costs low
for more profit.
HTH's,
Jerry Dycus
--- Mark Fowler <[EMAIL PROTECTED]> wrote:
> Hi Nick,
>
> Building a Lotus 7 kit based EV is a great way to
> go.
> A couple of us have done it.
>
> Could you sell a car like this? of course!
> Could you sell it for more than it cost to build?
> Dunno.
>
> Li-Poly plus AC (I assume you've looked through
> Victor's site
> www.metricmind.com or the Electric Imp site
> www.proev.com ) is going to
> cost a large chunk of money - probably about double
> what the Lotus 7 kit
> costs.
> (Victor, were you selling 3.7V Kokams for about US$5
> per Ah?)
>
> In Australia (where I built my Birkin based EV) that
> comes to about
> AU$100K.
> Now that's more than a BMW Z4 ($81K), an MG TF 160
> ($52K), Mazda MX5 SE
> ($45K), Toyota Prius ($38K) or a Toyota MR2 Spyder
> ($50K).
>
> Admittedly, this car would be in the serious sports
> car performance
> league.
>
> Who would spend that sort of money on a car that
> doesn't even have
> doors?
> Someone with lots of spare money, an environmental
> image, but likes to
> go fast.
> A celebrity.
>
> I suggest you find someone that wants a car like
> this and get them to
> pay you to build it rather than spending the big
> bucks to build an
> amazing car, just to have no-one buy it.
>
> Mark
>
>
> -----Original Message-----
> From: Nick Austin [mailto:[EMAIL PROTECTED]
> Sent: Saturday, 23 April 2005 11:43 AM
> To: [email protected]
> Subject: Value of electric 7 EV?
>
>
> Hello,
>
> I'm thinking about buying a Birkin or Caterham 7 kit
> and building an EV
> with
> Lipoly batteries and an AC motor around it.
>
> Then I thought, this would be a really cool car,
> could I sell a car like
> this?
>
> What do you think the value of a vehicle like this
> is? Do you think
> there is
> money to be made doing this?
>
> I've seen the electric7.com site, and his car looks
> very nice.
>
> Just a thought.
>
> Thanks!
>
>
__________________________________
Do you Yahoo!?
Yahoo! Small Business - Try our new resources site!
http://smallbusiness.yahoo.com/resources/
--- End Message ---
--- Begin Message ---
I didn't borrow to get the money but I see how this could work out if
financed over 10 years.
My system is only 2.5Kw ( really need 5kw) and the system price was
~$18,000 installed of which the state of ca rebate program payed ~$9000.
(rebate direct to approved contractor so $1000 deposit $8192 on completion.
In the summer in fresno it drops my pg&e $100/month if I use my AC
The sun came out in march and the electricity I use dropped in half.
~$21.00 :-)
The meter on the inverter about matches the new digital meter
installed in november of 1400kwh
But, if I had 5kw, it would be better than twice as good. Once I am
making more than I use in the peak hours i switch over to "Time of use"
metering and pay/sell power at $.35/kwh(while I am at work) peak and
$.08 (after 7pm) off-peak
Eitherway, I will be getting a seperate meter set for the EV that is
valid from midnight to 7am for $.05/kwh
5kw, check at end of year from pg&e, no gas, no oil cahnges was my plan
this year but a trip to the hospital set me back a bit. :-(
--- End Message ---
--- Begin Message ---
<< Hi Mark, Nick and Al,
They have an Aero CD of about .65 which is
really bad if you intend to go faster than 50 mph,
range will be terrible.
Build the chassis and put a more aero body
on it!
Put say a Ferrari Daytona or Ford GT-40,
ect, body on it and you could easily get really good
money for it in the US.
Go for a Locost 7 chassis to keep costs low
for more profit.
HTH's,
Jerry Dycus >>
Looking at http://www.teknett.com/pwp/drmayf/tbls.htm (I've now linked this on
the EV Calculator page), a Catherham Super 7 is .62 and 15.8sq ft for a 9.81
CdA (10% more than a Camaro convertible). The Birkin and other Super 7 clones
aren't a style you easily "convert" to lower that value, but you'd have to have
your heart set on a convertible to not choose something "slicker". For example,
the entry for an MG RV8 is 9.02 vs anequivalent coupe, an MGB, is 7.09. But, if
the CdA was the only determining factor, conversions would all be MR2s!
Peruse the other models to compare, but when it comes to drains on the system
and stressing the components, driving on city streets gets hit by stop-and-go
demands, while freeway speeds are where you really worry about aero drag.
--- End Message ---
--- Begin Message ---
Seth Allen said:
> Ok, before I start, I will make a few assumptions and such:
>
> 1: You don't want to greatly increase cost, so a material that doesn't
> need a rough machining, heat treat and grind to size is desirable
I agree with this (I've got plenty of other parts of the truck that are
also demanding my money), though I'm not sure even what kind of
neighborhood to shoot for. Am I looking at a thousand bucks no matter what
I do, or am I just trying to save a hundred or so? I've already spent a
few grand; a couple hundred well-placed dollars aren't so much of an
issue, but adding half the cost of the motor would be difficult.
> 2: You need some plunge on the output
I'm not sure what this means. Are you referring to the need for a slip
yoke, or sliding element somewhere along the driveline? If so, yes -- I am
not willing to lock down the rear end (at least not permanently); I need
to allow for some suspension travel.
> 3: a standard interface is nice
I have bought from Inland Empire in the past; they make a wide variety of
slip yokes. In general though, yes, standard == good.
> 4: you want it sized for fatigue life at peak torque (many dragstrip
> runs)
Agreed. The motor will be heavy and expensive to ship, making the cost of
replacing the shaft pretty high, if I'm to have Netgain doing it. Warfield
has a location in Dallas I'm told, but they don't work on the Warps. All
in all, I'd like the shaft to last. :o) I'm willing to spend a little
more now to help with this.
> 5: you will not be getting it plated
I can't say without more information. What would be the benefit of
plating, and with what material? Is it expensive? Would it be worth it? If
you're talking about aesthetics (chrome plating or whatever), then no. I
just don't want it rusting. :o)
> If all this is right, then a suggestion for a steel might be a
> pre-hardened AISI 4140 which is fairly common and fairly easy to
> machine. It won't be fully hard, but you won't have to do the heat
> treat and grind to size.
I will make a note of this -- thank you!
> As for an output. I have done standard yokes with slip joint
> driveshafts for trucks. Not sexy, but they work. But your torque is
> actually quite low if this is direct drive to the rear diff.
Compared to the potential if I had a transmission, yes, the torque is
pretty low. It seemed high to me, but that was during my search for a
suitable manual transmission. On the other hand, the existing driveshaft
on my truck probably doesn't even see a third as much torque, flooring it
in first gear. The input shaft on my transmission is only rated for 175
ft-lbs; I don't have the ratios handy but output torque can't be too
spectacular. In fact, in 1st I guess I probably get less peak torque at
the *wheels* today than I'll eventually get out of this motor. In that
sense, it's not so bad. :o)
> A CV joint
> can easily handle this torque and requires no alignment of the yokes or
> concern over driveshaft angle. A CV flange on the output of the motor
> with whay would normally be an IRS halfshaft could work quite well.
I am not quite familiar with the setup you're referring to. Is it possible
to get something like this that is long enough, and lightweight? I have
been assuming the need for a traditional driveshaft and a slip-yoke on the
motor, in part because of the arrangement of the motor and differential.
I'm planning on putting the motor under the passenger compartment, between
the seats, where the transmission is now. I would put it further back, but
I'd like to put battery boxes between the frame rails. I've been planning
on using a large diameter aluminum or carbon fiber shaft between the
battery boxes to reduce spinning mass. Can I have this same arrangement
with CV joints?
When you speak of CV joints, I'm imagining the three rollers at the end of
a shaft which fits in a cup with three deep corresponding grooves,
allowing both the CV torque transfer as well as a small amount of sliding
motion. Is this the sort of thing you're referring to?
> It
> is what I would do, but some people really refer U-joints.
At this point, I don't think I have enough knowledge to have a valid
preference. I have come to certain conclusions based on what I've learned
so far, but of course nothing is really concluded until I start actually
acquiring the parts. Until then, the more I can learn, the better. I'm OK
with CV joints (actually, I like the idea of the smooth torque transfer,
and not having to worry about matching angles and such), I just don't know
what else about my driveline plans would have to change.
> If that is
> the case, then at www.roadranger.com there are loads of U-joint specs
> there. ANd they will specify the spline options. Let me know what your
> preference is (CV joint or U-joint) and we can wade through the options
> and once a spline is found, see if it will work. Your torque is so low
> that with half-hard 4140 and an easily cut involute spline on a ~2"
> diameter that I think there will be no problem with fatigue life, even
> after effects like corrosion are figured in.
What are the corrosion properties of 4140? What kind of degradation can I
expect, mechanically and aesthetically, assuming this will be subjected to
water and road grime? For the most part though, this sounds like what I'm
looking for. Can we say that 1144 is out of the picture? I understand it
responds well to heat treating, though I don't know if this will give me
what I want.
I will see what info I can dig up on CV joints used in this application.
Although I'm hesitant about using techniques that aren't popular in
racing, I realize the operating parameters here are a bit different and
may call for an unusual solution. Mainly, if we can plan a driveline
that's lightweight, can span from the cab to the differential, can
tolerate the torque and the RPM (I'll be running a 5.0-5.3 or so rear end
ratio, not quite sure yet), then I won't have much rational cause to
disagree.
--chris
--- End Message ---
