EV Digest 5031
Topics covered in this issue include:
1) FW: RPM, brushes and commutators, was: RE: CVT transmission for E V
by Tim Humphrey <[EMAIL PROTECTED]>
2) Re: I want to build a PWM DC motor controller
by "Mark Hanson" <[EMAIL PROTECTED]>
3) Re: refractometer vs hydrometer...
by "Andre' Blanchard" <[EMAIL PROTECTED]>
4) Re: Ovonics licenses expired? Matter? and OT, My Letter to Editor
by "jerryd" <[EMAIL PROTECTED]>
5) Range in Rudman, was Re: Units of EV merit
by "Michaela Merz" <[EMAIL PROTECTED]>
6) Re: RPM, brushes and commutators, was: RE: CVT transmission for EV
by "Roland Wiench" <[EMAIL PROTECTED]>
7) Re: EV acceptance idea
by Aaron NMLUG-EV <[EMAIL PROTECTED]>
8) Re: EV acceptance idea
by Aaron NMLUG-EV <[EMAIL PROTECTED]>
9) EV acceptance idea-Positive spin
by paul wiley <[EMAIL PROTECTED]>
10) Re: I want to build a PWM DC motor controller
by Jeff Shanab <[EMAIL PROTECTED]>
11) EV configurations, Re: EV acceptance idea
by "jerryd" <[EMAIL PROTECTED]>
12) Re: EV acceptance idea, Battery comments
by "Bob Rice" <[EMAIL PROTECTED]>
--- Begin Message ---
The snowmobile CVT's that you were originally considering are bi-directional.
Both of my sleds have reverse, one reverses the via a gearbox, the other
reverses the engine rotation.
Stay Charged!
Hump
Original Message -----------------------
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Dewey, Jody R ATC (CVN75 IM3)
Sent: Wednesday, December 28, 2005 6:48 AM
To: '[email protected]'
Subject: RE: RPM, brushes and commutators, was: RE: CVT transmission for E V
Ooooh I never thought of that. Not good. Also with the slipper clutch - no
reverse in EV mode. Not good. Probably stuck with a 1:1 chain driven ratio
using motorcycle sprockets and chain. That way I don't over rev the
electric while in gas mode and the creation of the driveline adapter is
greatly simplified. Maybe I could even get one CNC milled as one piece for
strength. I thought about an electric actuated clutch to disconnect the
motor from the driveline, maybe a clutch from an air conditioning
compressor. The drawbacks I see with that is it would have to take some
serious torque and also would draw power the entire time the car was in
electric mode. Not very efficient.
-----Original Message-----
From: Mark Grasser [mailto:[EMAIL PROTECTED]
Sent: Tuesday, December 27, 2005 1:42 PM
To: [email protected]
Subject: Re: RPM, brushes and commutators, was: RE: CVT transmission for EV
I have already changed my mind on the slipper clutch thing. During
normal-electric operation if you are cruising say 30 mph and you take your
foot out of the throttle the motor stops. When you step on it again it revs
up then slams. BAD IDEA. Sorry I brought it up! Other options would be a
clutch or band. I think the easiest might be parts from a lower unit of an
out drive or outboard motor. They are called "Shift Dogs" purely mechanical
and controlled by cable.
Mark Grasser
----- Original Message -----
From: "Dewey, Jody R ATC (CVN75 IM3)" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Tuesday, December 27, 2005 11:51 AM
Subject: RE: RPM, brushes and commutators, was: RE: CVT transmission for EV
> Mark,
>
> That is my current thinking. Comet makes a CVT torque converter
> that will handle 200 HP. I think it will work but spending $400 for
> something that DOESNT work is kinda pointless. I have to do some serious
> research before forking over the dough.
>
> Jody
>
> -----Original Message-----
> From: Mark Grasser [mailto:[EMAIL PROTECTED]
> Sent: Tuesday, December 27, 2005 10:23 AM
> To: [email protected]
> Subject: Re: RPM, brushes and commutators, was: RE: CVT transmission for
> EV
>
>
> Why not create... or buy, a slipper clutch and let the electric motor be
> motionless when not being used. I don't know if they are comercially
> available but I do know that most automatics have them, I think in the 1st
> gear assembly. Don't worry they should be able to handle the torque, but
> you
>
> would have to design and build a suitable housing. Nice part about this is
> you could then gear it for higher motor rpm.
>
>
> Mark Grasser
> ----- Original Message -----
> From: "Roland Wiench" <[EMAIL PROTECTED]>
> To: <[email protected]>
> Sent: Tuesday, December 27, 2005 9:57 AM
> Subject: Re: RPM, brushes and commutators, was: RE: CVT transmission for
> EV
>
>
>>
>> ----- Original Message -----
>> From: Dewey, Jody R ATC (CVN75 IM3)<mailto:[EMAIL PROTECTED]>
>> To: '[email protected]'<mailto:'[email protected]'>
>> Sent: Tuesday, December 27, 2005 5:42 AM
>> Subject: RE: RPM, brushes and commutators, was: RE: CVT transmission for
>> EV
>>
>>
>> My question though is this:
>>
>> My plan is to connect my electric motor to my rear end pumpkin directly
>> via
>> a gear and chain. The reason I am asking for max RPM is that I will be
>> running a gas motor at highway speeds. Right now it looks like my
>> driveshaft speeds will not exceed 5000 RPM but if I gear down the
>> electric
>> motor for good city driving the highway speeds will drive the electric
>> motor
>> to about 6 or 7,000 rpm. The electric motor will NOT be energized
>> during
>> this time but will be freewheeling. I just want to make sure the
>> electric
>> motor is not going to be damaged when in gas mode. I have thought about
>> using a comet torque converter. They have a model that can take 200 HP.
>> The only thought I have is can I adapt the driven pulley to have a
>> driveshaft connection on each end so I can bolt it to the pumpkin and
>> have a
>> PTO connection for the driveshaft of the gas engine.
>>
>> Your electric motor rpm will be lower then the engine rpm.
>>
>> Lets say the engine is at 4000 rpm and drive line is at 4000 rpm, if the
>> differential gear is 4 to 1 ratio, then the axle rpm is 1000 rpm.
>>
>> If you connect a 3 inch sprocket on the drive line and a 9 inch sprocket
>> on the motor, this is a 3 to 1 ratio. For every 3 rpm that the driveline
>> rotates the motor will rotate 1 rpm.
>>
>> The maximum rpm of the engine at 5000 rpm would be 5000/3:1 = 1666 rpm.
>>
>> Therefore the overall gear ratio to the axles is 4:1 x 3:1 when motor is
>> running would be 12:1 ratio.
>>
>> The formula for speed of vehicle:
>>
>> RPM x Wheel Circumference
>> MPH = ---------------------------------
>> Overall Axle Ratio x 1056
>>
>> RPM is the electric motor RPM
>> Wheel Circumference is the rolling circumference in inches by marking
>> the
>> tire and rotate it one revolution on a
>> flat grade.
>> Overall Axle Ratio is the transmission gear ratio or any other gear
>> reduction
>> ratio times the differential gear.
>>
>> 1056 is a constant to convert the axle rpm which is in inches per
>> minute
>
>> to
>> feet per minute and than to miles per hour or:
>>
>> 5280 ft per mile x 12 inches per ft.
>> 1056 = ---------------------------------------
>> 60 minutes per hour
>>
>> Therefore the mph at 4000 electric motor rpm would be with a wheel
>> circumference of 85 inches using a 4:1 axle ratio and a sprocket ratio of
>> 3:1 would be:
>>
>> 1000 RPM x 85 inches
>> MPH = ----------------------------- = 6.7 Mph
>> 12:1 ratio x 1056
>>
>>
>> Therefore for every 1000 RPM, you have 6.7 Mph
>>
>> At 7000 electric motor RPM than you will have 7 x 6.7 = 46.9 Mph.
>>
>> In my EV, my 2nd gear ratio is about 13.5:1 which is about 35 Mph. I
>> therefore can shift from 19.5:1 1st gear to a 5.57:1 gear which gives me
>> about 92 MPH at 6000 Rpm with a 90 inch wheel circumference.
>>
>> I normally have to stay in 2nd gear for any speed under 35 mph which
>> keeps the RPM up and motor amperes down to 150 amps and battery amps to
>> 50.
>>
>> If your EV weight is at 3000 lbs than a 3:1 sprocket gear ratio for a
>> overall ratio of 9:1 will work for about 100 motor amperes. For every
>> 1000 lbs of weight its about a 3:1 ratio increase, so a 4000 lb EV should
>> be at 12:1 and 5000 lb at 15:1 and etc.
>>
>> Roland
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> -----Original Message-----
>> From: James Massey [mailto:[EMAIL PROTECTED]
>> Sent: Friday, December 16, 2005 5:50 PM
>> To: [email protected]<mailto:[email protected]>
>> Subject: RPM, brushes and commutators, was: RE: CVT transmission for EV
>>
>>
>> At 06:23 AM 16/12/05 -0500, Jody wrote:
>> >What is the maximum RPM limit of the WarP 9" ???? Is the limit because
>> the
>> >brushes will pull away from the commutator or the bearings won't take
>> it?
>>
>> Hi Jody
>>
>> Your question reveals a misconception or a misunderstanding you seem to
>> have with brush/commutator assembly. If the commutator is not perfectly
>> round, or not 'true' to the rotation of the rotor, the brushes will
>> bounce
>> at speed, arc and die. This will happen very quickly, so a great deal of
>> effort is placed in making sure that the brushes do not bounce, i.e. the
>> commutator is truly round.
>>
>> Once the brushes are running on a round commutator, sheer speed cannot
>> harm
>> them, there is no centrifical or other forces being put onto the to the
>> brushes from the comutator. There comes a point where with enough volts
>> and
>> enough amps, the gaps between the commutator bars cannot clear the
>> energy
>> and then an arc occurrs that goes brush-to-brush over the surface of the
>> commutator.
>>
>> The commutator itself is the weakest link. It IS affected by centrifical
>> force, so that high RPMs are trying very hard to throw the commutator
>> (and
>> the windings, but they are held in a different, stronger, manner) away
>> from
>> the rotor.
>>
>> The voltage and power requirements of the commutator prevents the
>> commutator from being made in really small diameters, so we will always
>> have this limitation, one way or another.
>>
>> The limits to a commutators' RPMs are due to the material that it is
>> constructed from. In ye olde days of double-breasted sandshoes and
>> leather
>> flywheels (as my electronics instructor of 20-odd years ago used to put
>> it)
>> commutators were constructed mechanically. The commutator bars were
>> insulated with mica sheet and held in place by steel rings each end. The
>> limit on RPMs with this method is when the copper of the bar 'bows out'
>> enough to allow the mica to come loose or cause brush problems, or the
>> copper bar breaks.
>>
>> In more recent decades, commutator bars are held in by a hard plastic of
>> some description - generally 'bakelite' or a similar product. If this
>> gets
>> too hot, or exceeds its' mechanical strength, a single bar is loosened
>> first, and nothing is there to stop it flying out, so EVERYTHING gets
>> smashed, brush gear, all the other comm bars (which as soon as the first
>> bar is loose quickly follow).
>>
>> Madman pointed out on-list a couple of years ago that racer-EVers had
>> placed kevlar banding onto their commutators to prevent this wholesale
>> destruction in the event of comm failiure. I don't know how common this
>> method is, or how effective it is, so if anyone (Rich?) knows, please
>> post
>> it. Until Jim Husted recognised my commutator for a steel-ring type, I
>> had
>> planned on Kevlar banding my commutator, but there would be no benefit.
>>
>> Hope this helps
>>
>> James
>>
>
--- End Message ---
--- Begin Message ---
Actually, there are literally millions of EV, golf cart and fork lift
controllers out there in use with the Motorola MC68HC05 when I worked at
GE-EV (and now the flash series Freescale MC68HC908). They are easier to
program than the PIC using www.pemicro.com multilink programmer and have
been reliable in my controllers since the early 80's. You need to do common
point grounding and keep the uP 5V stuff shielded or partitioned away from
the power stuff but it's all done in the same enclosure. All the presently
sold motor speed controls use a uP or uController.
BTW, it's a hellova lot easier to buy a controller from Curtis or Otmar than
re-inventing the wheel (unless you like to experiment, spend money & blow up
stuff :-)
Have a Renewable Energy Day, Mark
----- Original Message -----
From: "Danny Miller" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Tuesday, December 27, 2005 10:53 PM
Subject: Re: I want to build a PWM DC motor controller
> I don't follow the reasoning against them, a uC can be built with better
> protection than possible with discrete components. Modern uC have
> features for detecting brownouts and execution errors and can be made
> extremely reliable. Of course software bugs are still an obvious
> additional problem.
>
> I could agree there's a possible issue if you have a setup like a
> fullwave bridge or synchronous rectifier where a temporary failure of
> the controller for even a brief moment before it resets itself could
> result in an destructive output state that shorts the power supply.
> Still I wouldn't necessarily say it's less reliable than another
> implementation. The other option is of course to implement some sort of
> protection in hardware against the destructive conditions.
>
> As far as your choice of controller, why this one? PIC and Atmel are
> far more common and very well developed, documented, and supported.
> Most DIY'ers are going to recommend PICs and I'm one of them.
>
> Danny
>
> Lee Hart wrote:
>
> >>It was recently suggested that I use the Freescle MC68HC908QY4 IC.
> >>
> >>
> >
> >I would avoid using a micro, except perhaps as a remotely-mounted system
> >monitor. The noise levels are so high, and the consequences of a computer
> >"crash" so hideous that it is better to keep them OUT of the main control
> >loop.
> >
> >
>
--- End Message ---
--- Begin Message ---
At 09:25 PM 12/27/2005, you wrote:
I was all set to order a misco refractometer because I was getting tired
of spending 20-30 minutes once or twice a day to check my batts... Then I
thought to ask my wife who has used refractometers in the lab, She said
her experience has been they are difficult to read and the dilenation is
not sharp more gradual from light thru grey and then dark requiring
eperience/guesswork to interpolate the proper reading.
So is anyone currently using a refractometer? How simple/difficult is it
to read?
One other downside it seems to me would be stratification of the acid in
the battery. with a hydrometer I take my reading on the 3rd bulbful.
whereas the refractometer uses only a drop or two of liquid and would only
be reading the very top layer of acid...
thanks,
dave
We have a refractometer for check in concentration of soluble oil coolant
in machine tools. With fresh clean coolant you get a nice sharp easy to
read line. Once the coolant has been in use for a while (homogenized tramp
oil, metal fines, and new forms of life) usually all you get is the gradual
grey scale. I can not see battery acid getting so dirty as to cause that
problem but the stratification could defiantly be a problem.
__________
Andre' B. Clear Lake, Wi.
--- End Message ---
--- Begin Message ---
Hi Reverend and All,
That may have been me as the original NIMH
patents are about or have expired, maybe someone could look
them up who are better at that. I believe they just have 17
yr exclusive on them before they expire but some things have
changed in the last few yrs..
But that's not really relivent anymore as
the materials to make them will always be expensive, Nickel,
ect, added to the little 1.2vdc/cell they make means they
will be outclassed by Li-ions much cheaper basic materials
of lithium, magnesium plus their 3.7vdc/cell means it has a
hugh advantage in costs, capacity, NiMH can never overcome.
Lead's 2.12vdc/cell is what has kept it from disappearing
long ago.
Once the Lithium chemical's production are
ramped up and they have competition, most of the other batts
will be history. There are many new plants coming online
this yr, next to do just that.
For those interested I got a letter to the
editor printed this morning on fuel subsidies, oil wars and
US jobs.
<http://tampatrib.com/opinion/MGBBU15XQHE.html>
They changed it slightly but basicly intact.
Please don't comment on this list as OT but directly to me
if you want or one of the other energy, vehicle lists I'm
on.
In the paper they mentioned I was an EV
designer, alt energy experimenter but doesn't show online.
The title is their's but not bad.
Thanks,
Jerry Dycus
Big Oil Takes American Hostages
By JERRY DYCUS
Published: Dec 28, 2005
Your editorial on biodiesel fuel subsidies ("Foreign Fuel
Subsidy Burns Taxpayers, Dec. 26) misses the real problem,
which is the huge subsidies we give international oil
companies.
Subsidies come in two forms: direct and indirect, such as
deploying our military in the Middle East. Do you think we
would care about the people of that region if they didn't
have oil?
If the price of oil reflected the true cost of these
subsidies, we wouldn't need any for other fuels. Shortly we
would be energy-independent with a rational energy policy.
We could remove our military from the Middle East and let
those nations settle things among themselves, instead of
sending our soldiers to die and spending billions from our
treasury to support despotic regimes.
By depending on Big Oil instead of diversified U.S. energy
sources, our country will remain hostage to that unstable
region.
Our support of Big Oil has installed dictators like Saddam
and the Saudi rulers who have created the problems we are
now paying for.
If instead we became energy-independent by basing energy
policy on real free markets, we could increase U.S. jobs by
millions and, by causing the price of oil to drop, starve
dictators and terrorists of the funds they need to stay in
power and terrorize us. That would be the cheaper, smarter
way to fight terrorism.
We have plenty of energy here from so many sources - coal,
nuclear, tar sands/oil shales and wind, as well as U.S. oil
and natural gas - that can make millions of jobs and
increase our national security
Without the demands of the Middle East, we would need a much
smaller military. We could lower taxes and make government
smaller, more than making up for the extra cost of oil.
Florida, with its great biomass potential, could be in the
forefront of this energy solution, making biofuels and
growing well-paying jobs.
Or we can make OPEC's members richer.
Your choice: Which would be more patriotic and better for
our kids and for our country?
--------------------------------------------------------------------------------
----- Original Message Follows -----
From: Reverend Gadget <[EMAIL PROTECTED]>
To: [email protected]
Subject: Ovonics licenses
Date: Tue, 27 Dec 2005 22:30:38 -0800 (PST)
>A while back there was a post talking about the
>limitations of the Ovonics licenses for nickel metal
>hydride batteries. I believe the post said that the
>licenses limits the size of batteries to those too
>small for use in BEV's if you wrote the post or
>remember who did, please email me off list ASAP. or
>call me at 310-908-0604
>
> Thanks in advance
>
> Gadget
>
>visit my websites at www.reverendgadget.com,
>gadgetsworld.org, leftcoastconversions.com
>
--- End Message ---
--- Begin Message ---
Rich Rudman wrote:
> All our measuremnts can be made using normal units.
> so lets keep them that way.
AFAIK, there is no 'normal' unit to define the range of an EV. This is why
I suggested to agree on some new formula that takes (almost) all factors
into account and is relatively easy to measure, even for newbies. DOD
could be measured by drop in voltage (all we need is a handy spreadsheet
that shows approx. DOD percentages in regard to battery voltage).
Range sure is an issue for me (and maybe for others). And it would be nice
to have some form of measurement (it doesn't need to be called 'Rudman'
though).
I'd like to spark a discussion about how that formula would look like and
how one would be able to measure it. Let's mute personal feelings for a
moment and think (and talk) about it. Maybe, after some more scientific
evaluations, we find that we don't really need it. However. maybe we come
up with something that makes sense.
Michaela
--- End Message ---
--- Begin Message ---
----- Original Message -----
From: Dewey, Jody R ATC (CVN75 IM3)<mailto:[EMAIL PROTECTED]>
To: '[email protected]'<mailto:'[email protected]'>
Sent: Wednesday, December 28, 2005 4:48 AM
Subject: RE: RPM, brushes and commutators, was: RE: CVT transmission for EV
Ooooh I never thought of that. Not good. Also with the slipper clutch - no
reverse in EV mode. Not good. Probably stuck with a 1:1 chain driven ratio
using motorcycle sprockets and chain. That way I don't over rev the
electric while in gas mode and the creation of the driveline adapter is
greatly simplified. Maybe I could even get one CNC milled as one piece for
strength. I thought about an electric actuated clutch to disconnect the
motor from the driveline, maybe a clutch from an air conditioning
compressor. The drawbacks I see with that is it would have to take some
serious torque and also would draw power the entire time the car was in
electric mode. Not very efficient.
On second thought, you could run in 1:1 ratio, because if your run your
engine in a series hybrid mode, where the engine is always at idle to take the
start up away from the motor. This is what I did, but did it a little
different.
I mounted my motor after a engine with a standard clutch only and before the
transmission. I attach a 12 volt activator that can push 600 lbs, which I got
from a Power Transmission Bearing and Gear company that sells either Dodge or
Browning gears, bearings, clutches, etc.
I design a accelerator linkage that can either operated the motor pot box and
the fuel system on the engine or both at the same time or seperated. I used a
Square D industrial vacuum switch with has multiple sets of N.O. and N.C.
contacts that sense the engine vacuum. I adjusted the vacuum switch so any
time the engine vacuum drop below 15 in.hg. the accelerator linkage would
unlock from the engine and lock in position to the pot box. It would than turn
on the 12 volt control to the controller at this time.
It was a very smooth transition between the two prime movers. My motor start
up amperes never went over 200 amps as it did before, it stay between 50 to 100
amperes.
This unit work fine, if I was driving a longer distance of 10 miles or more
where the engine had a chance to warm up. I could keep the engine which would
normally do 22 mpg at 33 mpg if I was moving above 30 mph.
I used a 400 amp current relay between the controller and motor. When the
ampere went over 400 amps, this would cut out the controller and lock up the
engine fuel accelerator which would bring in the engine to help out the
electric motor. At the console of switches I have, I could program the engine
to help out the motor if current gets to high or motor helps out the engine if
the vacuum gets too low. I find this was the best operating mode to keep it
in.
For my short trips, which I am doing now, I using full time electric car.
There is another method of connecting up a electric motor which a electrical
engineer did back in the 70's in Florida. He left the engine, transmission,
drive line as it was, and connected the motor to the front of the engine. He
connect a flexible coupler that connected to the face of the fan belt pulley
which mounts onto the damper wheel on the engine. He could slide the motor from
the spline coupler back for changing the engine belts. This was a full time
connection. In this method, the engine and motor was used together at all
times, which reduce the engine in.hg or vacuum for increase mpg.
You could with your drive line method, used a industrial electric clutch unit
that can be attach to the sprocket. My Dodge power transmission hand book,
which I pick up from the Bearing Sales Company, shows different type of
electric brake and clutch disconnects that can be connected to one of there
gear sprockets or couplers. They show HP ratings going up to close to 1000 hp
or even more for the big rigs.
You could then use a gear reduction if you did a disconnect.
Roland
-----Original Message-----
From: Mark Grasser [mailto:[EMAIL PROTECTED]
Sent: Tuesday, December 27, 2005 1:42 PM
To: [email protected]<mailto:[email protected]>
Subject: Re: RPM, brushes and commutators, was: RE: CVT transmission for
EV
I have already changed my mind on the slipper clutch thing. During
normal-electric operation if you are cruising say 30 mph and you take your
foot out of the throttle the motor stops. When you step on it again it revs
up then slams. BAD IDEA. Sorry I brought it up! Other options would be a
clutch or band. I think the easiest might be parts from a lower unit of an
out drive or outboard motor. They are called "Shift Dogs" purely mechanical
and controlled by cable.
Mark Grasser
----- Original Message -----
From: "Dewey, Jody R ATC (CVN75 IM3)" <[EMAIL PROTECTED]<mailto:[EMAIL
PROTECTED]>>
To: <[email protected]<mailto:[email protected]>>
Sent: Tuesday, December 27, 2005 11:51 AM
Subject: RE: RPM, brushes and commutators, was: RE: CVT transmission for EV
> Mark,
>
> That is my current thinking. Comet makes a CVT torque converter
> that will handle 200 HP. I think it will work but spending $400 for
> something that DOESNT work is kinda pointless. I have to do some serious
> research before forking over the dough.
>
> Jody
>
> -----Original Message-----
> From: Mark Grasser [mailto:[EMAIL PROTECTED]
> Sent: Tuesday, December 27, 2005 10:23 AM
> To: [email protected]<mailto:[email protected]>
> Subject: Re: RPM, brushes and commutators, was: RE: CVT transmission for
> EV
>
>
> Why not create... or buy, a slipper clutch and let the electric motor be
> motionless when not being used. I don't know if they are comercially
> available but I do know that most automatics have them, I think in the 1st
> gear assembly. Don't worry they should be able to handle the torque, but
> you
>
> would have to design and build a suitable housing. Nice part about this is
> you could then gear it for higher motor rpm.
>
>
> Mark Grasser
> ----- Original Message -----
> From: "Roland Wiench" <[EMAIL PROTECTED]<mailto:[EMAIL PROTECTED]>>
> To: <[email protected]<mailto:[email protected]>>
> Sent: Tuesday, December 27, 2005 9:57 AM
> Subject: Re: RPM, brushes and commutators, was: RE: CVT transmission for
> EV
>
>
>>
>> ----- Original Message -----
>> From: Dewey, Jody R ATC (CVN75 IM3)<mailto:[EMAIL
PROTECTED]<mailto:[EMAIL PROTECTED]>>
>> To:
'[email protected]'<mailto:'[email protected]'<mailto:'[email protected]'<mailto:'[email protected]'>>
>> Sent: Tuesday, December 27, 2005 5:42 AM
>> Subject: RE: RPM, brushes and commutators, was: RE: CVT transmission for
>> EV
>>
>>
>> My question though is this:
>>
>> My plan is to connect my electric motor to my rear end pumpkin directly
>> via
>> a gear and chain. The reason I am asking for max RPM is that I will be
>> running a gas motor at highway speeds. Right now it looks like my
>> driveshaft speeds will not exceed 5000 RPM but if I gear down the
>> electric
>> motor for good city driving the highway speeds will drive the electric
>> motor
>> to about 6 or 7,000 rpm. The electric motor will NOT be energized
>> during
>> this time but will be freewheeling. I just want to make sure the
>> electric
>> motor is not going to be damaged when in gas mode. I have thought about
>> using a comet torque converter. They have a model that can take 200 HP.
>> The only thought I have is can I adapt the driven pulley to have a
>> driveshaft connection on each end so I can bolt it to the pumpkin and
>> have a
>> PTO connection for the driveshaft of the gas engine.
>>
>> Your electric motor rpm will be lower then the engine rpm.
>>
>> Lets say the engine is at 4000 rpm and drive line is at 4000 rpm, if the
>> differential gear is 4 to 1 ratio, then the axle rpm is 1000 rpm.
>>
>> If you connect a 3 inch sprocket on the drive line and a 9 inch sprocket
>> on the motor, this is a 3 to 1 ratio. For every 3 rpm that the driveline
>> rotates the motor will rotate 1 rpm.
>>
>> The maximum rpm of the engine at 5000 rpm would be 5000/3:1 = 1666 rpm.
>>
>> Therefore the overall gear ratio to the axles is 4:1 x 3:1 when motor is
>> running would be 12:1 ratio.
>>
>> The formula for speed of vehicle:
>>
>> RPM x Wheel Circumference
>> MPH = ---------------------------------
>> Overall Axle Ratio x 1056
>>
>> RPM is the electric motor RPM
>> Wheel Circumference is the rolling circumference in inches by marking
>> the
>> tire and rotate it one revolution on a
>> flat grade.
>> Overall Axle Ratio is the transmission gear ratio or any other gear
>> reduction
>> ratio times the differential gear.
>>
>> 1056 is a constant to convert the axle rpm which is in inches per
>> minute
>
>> to
>> feet per minute and than to miles per hour or:
>>
>> 5280 ft per mile x 12 inches per ft.
>> 1056 = ---------------------------------------
>> 60 minutes per hour
>>
>> Therefore the mph at 4000 electric motor rpm would be with a wheel
>> circumference of 85 inches using a 4:1 axle ratio and a sprocket ratio of
>> 3:1 would be:
>>
>> 1000 RPM x 85 inches
>> MPH = ----------------------------- = 6.7 Mph
>> 12:1 ratio x 1056
>>
>>
>> Therefore for every 1000 RPM, you have 6.7 Mph
>>
>> At 7000 electric motor RPM than you will have 7 x 6.7 = 46.9 Mph.
>>
>> In my EV, my 2nd gear ratio is about 13.5:1 which is about 35 Mph. I
>> therefore can shift from 19.5:1 1st gear to a 5.57:1 gear which gives me
>> about 92 MPH at 6000 Rpm with a 90 inch wheel circumference.
>>
>> I normally have to stay in 2nd gear for any speed under 35 mph which
>> keeps the RPM up and motor amperes down to 150 amps and battery amps to
>> 50.
>>
>> If your EV weight is at 3000 lbs than a 3:1 sprocket gear ratio for a
>> overall ratio of 9:1 will work for about 100 motor amperes. For every
>> 1000 lbs of weight its about a 3:1 ratio increase, so a 4000 lb EV should
>> be at 12:1 and 5000 lb at 15:1 and etc.
>>
>> Roland
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> -----Original Message-----
>> From: James Massey [mailto:[EMAIL PROTECTED]
>> Sent: Friday, December 16, 2005 5:50 PM
>> To:
[email protected]<mailto:[email protected]<mailto:[email protected]<mailto:[email protected]>>
>> Subject: RPM, brushes and commutators, was: RE: CVT transmission for EV
>>
>>
>> At 06:23 AM 16/12/05 -0500, Jody wrote:
>> >What is the maximum RPM limit of the WarP 9" ???? Is the limit because
>> the
>> >brushes will pull away from the commutator or the bearings won't take
>> it?
>>
>> Hi Jody
>>
>> Your question reveals a misconception or a misunderstanding you seem to
>> have with brush/commutator assembly. If the commutator is not perfectly
>> round, or not 'true' to the rotation of the rotor, the brushes will
>> bounce
>> at speed, arc and die. This will happen very quickly, so a great deal of
>> effort is placed in making sure that the brushes do not bounce, i.e. the
>> commutator is truly round.
>>
>> Once the brushes are running on a round commutator, sheer speed cannot
>> harm
>> them, there is no centrifical or other forces being put onto the to the
>> brushes from the comutator. There comes a point where with enough volts
>> and
>> enough amps, the gaps between the commutator bars cannot clear the
>> energy
>> and then an arc occurrs that goes brush-to-brush over the surface of the
>> commutator.
>>
>> The commutator itself is the weakest link. It IS affected by centrifical
>> force, so that high RPMs are trying very hard to throw the commutator
>> (and
>> the windings, but they are held in a different, stronger, manner) away
>> from
>> the rotor.
>>
>> The voltage and power requirements of the commutator prevents the
>> commutator from being made in really small diameters, so we will always
>> have this limitation, one way or another.
>>
>> The limits to a commutators' RPMs are due to the material that it is
>> constructed from. In ye olde days of double-breasted sandshoes and
>> leather
>> flywheels (as my electronics instructor of 20-odd years ago used to put
>> it)
>> commutators were constructed mechanically. The commutator bars were
>> insulated with mica sheet and held in place by steel rings each end. The
>> limit on RPMs with this method is when the copper of the bar 'bows out'
>> enough to allow the mica to come loose or cause brush problems, or the
>> copper bar breaks.
>>
>> In more recent decades, commutator bars are held in by a hard plastic of
>> some description - generally 'bakelite' or a similar product. If this
>> gets
>> too hot, or exceeds its' mechanical strength, a single bar is loosened
>> first, and nothing is there to stop it flying out, so EVERYTHING gets
>> smashed, brush gear, all the other comm bars (which as soon as the first
>> bar is loose quickly follow).
>>
>> Madman pointed out on-list a couple of years ago that racer-EVers had
>> placed kevlar banding onto their commutators to prevent this wholesale
>> destruction in the event of comm failiure. I don't know how common this
>> method is, or how effective it is, so if anyone (Rich?) knows, please
>> post
>> it. Until Jim Husted recognised my commutator for a steel-ring type, I
>> had
>> planned on Kevlar banding my commutator, but there would be no benefit.
>>
>> Hope this helps
>>
>> James
>>
>
--- End Message ---
--- Begin Message ---
> On 27 Dec 2005 at 10:50, jerryd wrote:
>
> > one thing I won't be targeting is economy as it is a
> > loser conjuring up cheap images and lowering the sellability
> > of the Freedom EV.
Does Mr. Woodbury (Tango) have the little itty bitty
vehicle, one (or more?) seat(s) BEHIND the other with low mounted
batteries all patented up?
I think that the basic Tango design... low batteries,
very small frontal area, very small car is the right way
to go for a low-cost electric.
Although I wonder if a tadpole with rear-wheel-drive
would be stable and practical.
I understand the marketing problem with such an unusual
shape, but as an engineer, it seems to be the RIGHT design.
Just curious.
I have no desire to try to influence the evolution of the
Freedom EV.
aaron
--- End Message ---
--- Begin Message ---
On Tue, 2005-12-27 at 13:57, Stefan T. Peters wrote:
> Joel Shellman wrote:
> > And to me (though I know not
> > everyone looks at it this way), I only care about the range when I
> > might be going 75 mph. In other words, we need some kind of "worse
> > case range" or "full highway use range" so we can have a good idea of
> > what the range means when used as a typical car might be used.
> >
> > -joel shellman
> >
> >
>
> Typical? That can't be right... if the typical car was "full highway
> use", they would all be parking lots. Since comments like these pop up
> regularly, I think our little EV community is slanted towards those who
> are not suburban (am I right?). Please realize that the vast majority of
> people in this country live in a large city, close to work and services.
I dunno about that.
EVs will certainly be a bit of a toy and 2nd car, at first.
I bet that much of the potential market is suburban.
However, I don't think you necessarily want to chase
the big market initially.
I am an urbanite.
I HATE driving our SUV and Nissan Maxima around town.
Hard to maneuver. Hard to park.
I relly enjoyed our Honda Civicc and Solectria (Metro)
for all my in-town trips.
Do you think focusing marketing on this being a "City Car" might
attract the desired niche market?
aaron
--- End Message ---
--- Begin Message ---
Here is some positive news!
Over the family gathering, my 19yr old nephew got a chance to ride the
electric interceptor. His first impression was hard to read, but later i
overheard a conversation with his 20yr old cousin. He was impressed by the
smoothness and enjoyed the quietness. Even talked about building a car for
himself to get to the university in. Hard to beleive from a kid whom normally
has the bass so loud that you couldn't hear a bigblock with uncorked headers!
Point is, the younger kids may not be so afraid of these electric cars, might
look thru the pitfalls and see a better place.
Happy "motoring!"
---------------------------------
Yahoo! Photos
Ring in the New Year with Photo Calendars. Add photos, events, holidays,
whatever.
--- End Message ---
--- Begin Message ---
I have to agree with both lee,danny, and stefen, and no, I am not crazy.
What the freescale salesman trys to sell is a certain degree of
crashwortheniss and pseudo crashworthiness. They let the programmer lock
out the ability for someone to change the code, they provide watchdog
and reset circuits and default port levels.
But there are people making advances in this area, in aviation, military
and space programs they go to great lengths to reduce the mean time to
failure of computerized control systems.
Space shuttle has 5 computers for the control system on a special buss
where no one computer can pull the buss down and prevent inter-processor
communication failure. (nasa came and gave a talk at our local college,
one of the professors worked at the space center)
IIRC these computers run the same program and when a result like
"actuate flap up" output is decided upon they VOTE. it takes a majority
of the computers to agree for an action to take place. If a computer is
making wrong decisions it can be voted off the bus. the computer
confidence light goes from green to yellow. when it gets down to 3
computers it goes to manual override.
In space applications the stray bit errors created by cosmic rays are
considered. They use special "radiation hardened" versions of the same
chips.
if I have 3 items each with a 99% chance of success and they are
dependent or detrimental , then I actually have a 97% chance of sucess
this gets bad quick
if I have 3 items each with a 90% chance of success and they are
dependent or detrimental, then I only have a 73% chance of sucess.
When we use this the other way and these 3 items are independent or
re-enforcing we get 1 in 10,000 chance of failure.
Our idea of a charger per battery are an example of the detrimental type
of situation, and our example of more than one disconnect in series is
an example of the re-enforcing scenario.
Part of the design process is to consider every component one at a
time then in combinations and make sure they can only fail in a safe
way. it is not an either or situation, never rely only on the micro to
ensure the analog circuits fail safe, never design the analog circuit to
depend on a signal from micro for safety. Since the analog side is the
interface to the physical world, the burden falls there.
"There are more modes of failure in heaven and earth than are dreamed of
by an engineer"
--- End Message ---
--- Begin Message ---
Hi Aaron and All,
----- Original Message Follows -----
From: Aaron NMLUG-EV <[EMAIL PROTECTED]>
To: [email protected]
Subject: Re: EV acceptance idea
Date: Wed, 28 Dec 2005 08:16:57 -0700
>> On 27 Dec 2005 at 10:50, jerryd wrote:
>>
>> > one thing I won't be targeting is economy as it is a
>> > loser conjuring up cheap images and lowering the
>> > sellability of the Freedom EV.
>
>Does Mr. Woodbury (Tango) have the little itty bitty
>vehicle, one (or more?) seat(s) BEHIND the other with low
>mounted batteries all patented up?
He too has 2 seats. I don't know if it is or could be
patentable.
>I think that the basic Tango design... low batteries,
>very small frontal area, very small car is the right way
>to go for a low-cost electric.
I really like it and think it's a great EV design.
But it has the problem of comforming to the 4wh USDOT regs
which cost big bucks in order to get into production as a
finished product. I only chose the 3wh design so I could go
into production at a much lower cost thru MC DOT regs though
since I have learn much more about it, have come to really
love it too.
I hope someone comes up with the money so Rick can
get the Tango into production as it would be a great
addition to our transport system and solve some of it's
problems of parking space, fuel costs, pollution.
>Although I wonder if a tadpole with rear-wheel-drive
>would be stable and practical.
Especially with an EV version where you can
correctly place the CG, it can actually be more stable,
better handling from it's much quicker steering response,
lower weight with good design. On the other hand, with bad
design, very bad handling as it is more unforgiving of it.
Luckily it isn't that hard to design correctly.
>I understand the marketing problem with such an unusual
>shape, but as an engineer, it seems to be the RIGHT design.
With my E woody I've found it can be a plus, greatly
lowering advertising expenses and it puts it in a whole new
catagory so one can define it rather than it being compared
to economy cars.
Kind of like doing SUV's until recently instead of
Station wagons/minivans, both name which are the kiss of
death though all 3 do the same job.
Especially the new "SUV"s" crossovers which are
really station wagons but will never be called that.
>
>Just curious.
>I have no desire to try to influence the evolution of the
>Freedom EV.
No problem doing that as it is basicly set in stone
now as the tooling is built. Any different thought would go
into a new EV instead.
Thanks,
Jerry Dycus
>
> aaron
>
--- End Message ---
--- Begin Message ---
----- Original Message -----
From: "Aaron NMLUG-EV" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Wednesday, December 28, 2005 10:23 AM
Subject: Re: EV acceptance idea
> On Tue, 2005-12-27 at 13:57, Stefan T. Peters wrote:
> > Joel Shellman wrote:
> > > And to me (though I know not
> > > everyone looks at it this way), I only care about the range when I
> > > might be going 75 mph. In other words, we need some kind of "worse
> > > case range" or "full highway use range" so we can have a good idea of
> > > what the range means when used as a typical car might be used.
> > >
> > > -joel shellman
> > >
> > > Hi All;
Typicalcar? Yeah, right<g>! As for range there is no way to
accurately predict that. Beyond how- heavy- is -your- right- foot? My Rabbit
HAS done 100 miles ,not really on a charge, but an evening outing, driving
to Hartford, about 40 miles, plugitin at the motel, where I stopped off to
meet an old Army buddy, chat a while, I suggested dinner at a nice Italion
place a few miles away. We went over there, YES! They had a nice outdoor
outlet in the bushes outside the door.Plugged it in, cranked the Variac up
to 10 amps, as I did at the motel, earlier. We went in and ate, over an
hour. Came out, went on our way, dropped John off at the motel, he had to
get an early start in the AM, and hopped on the freeway for home. TRIED to
stay below 200 amps, but there are points where you HAVE to do bursts of
reasonable speed to, say, get on.I REFUSE to dragass down the On Ramp at 30
mph, in ANY kind of car or truck!So you do 50-60 or what EVer the wheels
will turn! This is a safety thing anyhow. Why should the guy already on even
let you on if you're doggin' it? YOU are the hazard, here! Back to the
story, got on, dignity intact, and cruised at 50-60 depending on the hills.
There are NO, AZ type flat roads in CT, you are always going up or down,
more UP than down, it seems!Stoplights? Yeah, I swear they can sense an EV
coming and they go RED when you get there!Or when yur early for work and you
sweep through, all green, and guyz say " What are YOU doing so early?"I have
made that commute run at RUSH Hour at posted speed ALL the way, arriving
half an hour early, what with the built in time for stop and go shit.
Back to the story, cruised home with 115 volts on the meter, this is /was
with a fairly new set of T 145's Best batteries I EVer had! 20 of them,
stuffed in the Rabbit. Got home with about 70 miles on the clock. So I
thought, lets go for 100, I drove about on local roads, 35-40 mph to burn up
excess fuel as the flying machine guyz say. Till I saw a noticiable drop in
voltage, headed home. Up the driveway at about 100 volts. All done! At 101
miles. I was impressed, better than the mid day charge gig, where I had
charged at lunchtime after an intense errand run in the AM then my usual
Train Run in the PM, another 50 miles. Sooo I had run up about 120 E miles
that day. After all yur car is only as good as your charger,, anyhow.And
this is in a crappy home made conversion. NOT a purpose built EV and
infrastructure to support it, like outlets all over the place, although my
above Hartford run was a beginning, to show how batteries will dio if fed a
snack as you go about. Now If I cioulda used my PFC -20 and 240 volts
chargin' at EVery stop? Well you coulda gone on all day!
In reality, my Rabbit has a useful range of , 40-50 miles at IDEAL
conditions, warm weather is the biggie, here. NOW with 30 degrees, I'm lucky
to go 26 miles on the freeway. Yes we need better batteries. IF I had heated
battery boxes, but they they would OVER heat in the tropical summers we have
been having. So I let it go, batteries are open to whatever temps are that
day!Driving the car daily in the winter keeps things sorta warmed up, plus
my relatively unheated garage. The PFC -20 is a great garage heater!Plan to
pipe that INTO the car someday, when it is built into the car.
So, how far will my conversion go? Good question. You hafta just build
it and drive it. After carefully breaking in your new batteries. Funny,
NOBODY gets into breaking in batteries! They just dump the new cells into
the car, Wheeee! Drive like hell, til the car will hardly move. EV grin
intact. But early on too early on it doesn't go as far, and cells start
dying, reversing too soon. Figure on at first driving only a few miles,
recharge, a few miles, charge, a few more miles, next flight. No squeeling
out or racing!This is YOUR bankroll on the roll here! Be patient, the
little red hearts of "I Love You" bubbling up from the batteries. If they
could tell you that, they would. But they can't cry out in pain, ether, when
ya are beating them to death, ether.Cycle them! A bit more each day.
Golightly for a few weeks! As you go longer distances the cells will cycle
and build up power. I don't know WHY, they just DO. Maybe a battery Garu can
tell why, but in the real world it just happens. If you did it right you
feel like you're hooked to Niagra Falls as you glide along for miles.
This will have to do till we get some REAL batteries, not tied up in
patent stuff, we all know about that. In a totally irellivent thing here,
the Music Racket, I mean recording industry is trying to get copyright
protection for almost EVERY recording MADE in the last 110 years of
records.I'm on the 78 rpm record List, too. Soon , if they have their way, I
wouldn't be legally allowed to, on line, send ya a copy of, say, " Come,
Josephine, in My Flying Machine" Ada Jones and Billy Murray, released in
1911 or so.So it 'aint just batteries, anymore!You all knew about the Sony
incripted CD discs with the "Copyright" protection that crapped up
everybodies computer, til they has to offer a fix and an apologie to folks
that bought their crap.
I sound a bit bitter, not wanting to step over the Politically Correct,
line stuff here, except to make a point.
Seeya at BBB
Bob
>
>
--- End Message ---
