Electric motor with no tranny for conversion

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Re: Electric motor with no tranny for conversion

storm connors
Tesla had a 2 speed, didn't it?

On Sat, May 24, 2008 at 3:20 PM, EVDL Administrator <[hidden email]> wrote:

> On 24 May 2008 at 12:26, Lee Hart wrote:
>
>> But essentially *all* EVs designed from scratch have no transmission.
>> The exceptions are the rare ones.
>
> I can think of two more or less recent examples offhand : the Comuta-Van and
> the Chrysler TEVan.  The C-van had a 3-speed Borg Warner transmission that
> Jim Tervort once told me had originally been designed for a 1930s vintage
> Dodge (!).  The Chrysler had a 2-speed gearbox about which I know nothing
> more.  Rod Hower had one and was involved in designing the vehicle, so he
> might know more details, if you care.
>
> No doubt there are other examples, but my impression is in accord with
> Lee's; most factory EVs (not conversions) in recent years have had single
> speed drives.  The obviation of the need for a multispeed transmission was
> (and is)  considered a significant advantage of electric motors over ICEs.
>
> David Roden - Akron, Ohio, USA
> EVDL Administrator
>
> = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
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> reach me.  To send a private message, please obtain my
> email address from the webpage http://www.evdl.org/help/ .
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>
>
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>



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Storm

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Re: Electric motor with no tranny for conversion

David Nelson-5
On Sat, May 24, 2008 at 7:18 PM, storm connors <[hidden email]> wrote:
> Tesla had a 2 speed, didn't it?

Yes, against the wishes of the original founder. It is now back to a
"Fixed Gear" 2 speed until a replacement 1 speed is finished. The two
speed was to keep their 0-60 time under 4 sec without having to
increase the power to the motor.

--
David D. Nelson

http://evalbum.com/1328

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Re: Electric motor with no tranny for conversion

Richard Marks
In reply to this post by storm connors
    I am new but I follow the EV world very closely.  I have been in
automotive for 36 years and have good understanding on how to design
vehicles and EV's.
    Tesla's mainstream is a two speed transmission. Low gear is for the
breathtaking acceleration and high gear is to get you to 150 mph.  They have
had problems getting this 2-spd transmission to work and are supposedly
going to build some early models with a single speed and later re-fit these
with the right transmissions.  If Tesla can't do 100 year old technology
right, what makes them think they can do high tech EV technology right?  I
think Tesla may not survive through the end of the year, unfortunately.
They are way too far out on the limb and don't understand automotive very
well.  Their VC investors are getting nervous about their inability to
deliver on their promises.  Look out!
    All EV's have some form of "transmission."  Some are single speed and
these usually use AC induction motors or DC brushless motors because both
motors are capable of 10,000 rpms.  With DC brush motors, you are typically
limited to about 5,000 to 6,000 rpms.  You need a transmission to have
acceleration and hill climbing ability and then a lower (numerically) to
have high speed ability (say 60-70 mph).
    Rich
----- Original Message -----
From: "storm connors" <[hidden email]>
To: "Electric Vehicle Discussion List" <[hidden email]>
Sent: Saturday, May 24, 2008 10:18 PM
Subject: Re: [EVDL] Electric motor with no tranny for conversion


> Tesla had a 2 speed, didn't it?
>
> On Sat, May 24, 2008 at 3:20 PM, EVDL Administrator <[hidden email]>
> wrote:
>> On 24 May 2008 at 12:26, Lee Hart wrote:
>>
>>> But essentially *all* EVs designed from scratch have no transmission.
>>> The exceptions are the rare ones.
>>
>> I can think of two more or less recent examples offhand : the Comuta-Van
>> and
>> the Chrysler TEVan.  The C-van had a 3-speed Borg Warner transmission
>> that
>> Jim Tervort once told me had originally been designed for a 1930s vintage
>> Dodge (!).  The Chrysler had a 2-speed gearbox about which I know nothing
>> more.  Rod Hower had one and was involved in designing the vehicle, so he
>> might know more details, if you care.
>>
>> No doubt there are other examples, but my impression is in accord with
>> Lee's; most factory EVs (not conversions) in recent years have had single
>> speed drives.  The obviation of the need for a multispeed transmission
>> was
>> (and is)  considered a significant advantage of electric motors over
>> ICEs.
>>
>> David Roden - Akron, Ohio, USA
>> EVDL Administrator
>>
>> = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
>> EVDL Information: http://www.evdl.org/help/
>> = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
>> Note: mail sent to "evpost" or "etpost" addresses will not
>> reach me.  To send a private message, please obtain my
>> email address from the webpage http://www.evdl.org/help/ .
>> = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
>>
>>
>> _______________________________________________
>> For subscription options, see
>> http://lists.sjsu.edu/mailman/listinfo/ev
>>
>
>
>
> --
> http://www.austinev.org/evalbum/1059
> http://stormselectric.blogspot.com/
> Storm
>
> _______________________________________________
> For subscription options, see
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Re: Electric motor with no tranny for conversion

Richard Marks
In reply to this post by David Nelson-5
Suggestion, go to CafeElectric and read Otmar's comments on why you need
multiple speeds.  While he is focusing mostly on series DC motors, it also
applies to AC motors, too.  You want as small a motor to get the job done
and a transmission helps greatly.  Why are ICE's all behind transmissions?
Think about it.
    Rich
----- Original Message -----
From: "David Nelson" <[hidden email]>
To: "Electric Vehicle Discussion List" <[hidden email]>
Sent: Saturday, May 24, 2008 10:28 PM
Subject: Re: [EVDL] Electric motor with no tranny for conversion


> On Sat, May 24, 2008 at 7:18 PM, storm connors <[hidden email]>
> wrote:
>> Tesla had a 2 speed, didn't it?
>
> Yes, against the wishes of the original founder. It is now back to a
> "Fixed Gear" 2 speed until a replacement 1 speed is finished. The two
> speed was to keep their 0-60 time under 4 sec without having to
> increase the power to the motor.
>
> --
> David D. Nelson
>
> http://evalbum.com/1328
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>

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Re: Electric motor with no tranny for conversion

jwolfe@doitnow.com
In reply to this post by chazersize
>The Chrysler had a 2-speed gearbox about which I know nothing
> more

The Chrysler TEVan used a "Gear Vendors" 2 speed transaxle. They mention it
on their website.

It has only High and Low, Reverse is accomplished by switching the field on
the SepEx motor and of course locking you out of high range. The "Park"
position mechanically locks the gears together. I don't know what the gear
ratio's are but "low" is not used over 40 Mph, and at that speed the motor
is probably turning about 6K. There is no method to govern top speed but
I've had mine up to slightly over 80 and motor speed was probably 6K.

HTH

Jim
www.evalbum.com/425
www.evalbum.com/804
www.evalbum.com/1703

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Re: Electric motor with no tranny for conversion

Roger Stockton
In reply to this post by Lee Hart
Lee Hart wrote:

> Hmm... you need to look at the situation under a 'Vette. The frame
> doesn't come anywhere near the transmission. The steel frame rails are
> way out in the rocker panels, about 5 feet apart, and the fiberglass
> floor dips down close to the road between them. The closest frame to the
> rear is 3 feet away, at the differential. The closest frame in front is
> about 2 feet forward, at the engine mounts.
>
> Chevy used the engine to mount the front of the transmission, and the
> torque tube to mount the rear of it.

Yes, I understand.  This is why it seems obvious to me that the easiest approach would have been to use a manual tranny (Vette or otherwise), with some sort of adapter to couple it to the torque tube (if not a Vette tranny) and a conventional adapter plate on the front.  This would have supported the rear of the motor/tranny as originally intended and spaced the motor forward enough for it to be supported on the front using the original motor mounts.

The tranny would have allowed the use of a smaller motor and controller, and if a tranny were chosen that is compatible with the commonly available S10 adapter plate/coupler this could be cheaper than being the first to have an adapter plate and coupler made for the Vette tranny.

It seems so obvious to me, but I appreciate that we all have our own visions of how to perform our conversions.  I'm sure there are things I did on my EV that others shake their heads over! ;^>

As long as Michael is pleased with the outcome, that's really all that matters, isn't it?

Cheers,

Roger.


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Re: Electric motor with no tranny for conversion

Roger Stockton
In reply to this post by EVDL Administrator
David Roden wrote:

> On 24 May 2008 at 12:26, Lee Hart wrote:
>
> > But essentially *all* EVs designed from scratch have no transmission.
> > The exceptions are the rare ones.
>
> I can think of two more or less recent examples offhand : the Comuta-Van
> and
> the Chrysler TEVan.  The C-van had a 3-speed Borg Warner transmission that
> Jim Tervort once told me had originally been designed for a 1930s vintage
> Dodge (!).  The Chrysler had a 2-speed gearbox about which I know nothing
> more.  Rod Hower had one and was involved in designing the vehicle, so he
> might know more details, if you care.
>
> No doubt there are other examples, but my impression is in accord with
> Lee's; most factory EVs (not conversions) in recent years have had single
> speed drives.  The obviation of the need for a multispeed transmission was
> (and is)  considered a significant advantage of electric motors over ICEs.

I think there have been so few OEM on-road EVs produced that it is a bit of a stretch to suggest that one or the other approach is the norm.  e.g. 3 out of 5 examples allows one to say "most" are trannyless, but it hardly establishes a convincing trend.

Another point to consider is how many of these trannyless OEM EVs use series DC drivetrains?  With the typical 5000RPM-ish useful redline of our common series DC motors, a 5:1 fixed reduction limits the vehicle to about 65-70mph max *theoretical* top speed.  One still needs a rather large motor and controller to have decent hill climbing ability and acceleration (2nd gear on a typical car results in an overall reduction of about 8:1 in comparison), and without a highish voltage pack (200-300V), it is unlikely that the vehicle will be able to attain even this theoretical max speed.

The EV allows for the possibility of not using a multispeed transmission, but just because one *can* leave the tranny out doesn't mean one *should*.  Perhaps if the any of the OEMs had produced multiple EV models for enough years of production we would see more variety in the drivetrain approaches as they figured out what offered the best overall cost/benefit/performance compromise.

Cheers,

Roger.


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Re: Electric motor with no tranny for conversion

Mark Grasser
In reply to this post by Roger Stockton
 

It seems so obvious to me, but I appreciate that we all have our own visions
of how to perform our conversions.  I'm sure there are things I did on my EV
that others shake their heads over! ;^>

Roger,
Sorry but it is apparently not so obvious. :-) Your approach uses the tunnel
and a substantial part of the engine compartment for the drive train leaving
not so much for the batteries. The method used mounts the motor directly to
the differential. This makes the drive train about 3 feet long in total
length and being flipped to the rear it leaves the entire tunnel and front
engine bay for batteries.

Being well versed in the Porsche 928 (took one apart and put it back
together. http://members.rennlist.com/mgrasser Still have the web page but
sold the car) I would have considered morphing either a 924 transaxle or a
new C6 transaxle into the project and mounted a single or dual 8 inch motor
directly to the front of the transmission. This would have put the motor in
the tunnel freeing up the entire front and rear of the car for batteries and
given the added benefit of having a transmission.

Mark Grasser


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Re: Electric motor with no tranny for conversion

kEVs
In reply to this post by Roger Stockton
both of these were factory conversions. they were not
designed as ev  first they were gas powered.  just
something to think about
--- Roger Stockton <[hidden email]> wrote:

> David Roden wrote:
>
> > On 24 May 2008 at 12:26, Lee Hart wrote:
> >
> > > But essentially *all* EVs designed from scratch
> have no transmission.
> > > The exceptions are the rare ones.
> >
> > I can think of two more or less recent examples
> offhand : the Comuta-Van
> > and
> > the Chrysler TEVan.  The C-van had a 3-speed Borg
> Warner transmission that
> > Jim Tervort once told me had originally been
> designed for a 1930s vintage
> > Dodge (!).  The Chrysler had a 2-speed gearbox
> about which I know nothing
> > more.  Rod Hower had one and was involved in
> designing the vehicle, so he
> > might know more details, if you care.
> >
> > No doubt there are other examples, but my
> impression is in accord with
> > Lee's; most factory EVs (not conversions) in
> recent years have had single
> > speed drives.  The obviation of the need for a
> multispeed transmission was
> > (and is)  considered a significant advantage of
> electric motors over ICEs.
>
> I think there have been so few OEM on-road EVs
> produced that it is a bit of a stretch to suggest
> that one or the other approach is the norm.  e.g. 3
> out of 5 examples allows one to say "most" are
> trannyless, but it hardly establishes a convincing
> trend.
>
> Another point to consider is how many of these
> trannyless OEM EVs use series DC drivetrains?  With
> the typical 5000RPM-ish useful redline of our common
> series DC motors, a 5:1 fixed reduction limits the
> vehicle to about 65-70mph max *theoretical* top
> speed.  One still needs a rather large motor and
> controller to have decent hill climbing ability and
> acceleration (2nd gear on a typical car results in
> an overall reduction of about 8:1 in comparison),
> and without a highish voltage pack (200-300V), it is
> unlikely that the vehicle will be able to attain
> even this theoretical max speed.
>
> The EV allows for the possibility of not using a
> multispeed transmission, but just because one *can*
> leave the tranny out doesn't mean one *should*.
> Perhaps if the any of the OEMs had produced multiple
> EV models for enough years of production we would
> see more variety in the drivetrain approaches as
> they figured out what offered the best overall
> cost/benefit/performance compromise.
>
> Cheers,
>
> Roger.
>
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>



     

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Re: Electric motor with no tranny for conversion

insndrvr
In reply to this post by chazersize
>Tesla's mainstream is a two speed transmission. Low gear is for the
>breathtaking acceleration and high gear is to get you to 150 mph.  They have
>had problems getting this 2-spd transmission to work and are supposedly
>going to build some early models with a single speed and later re-fit these
>with the right transmissions.  

Actually, the original Tesla founder, Martin Eberhard, wanted to do a single gear ratio, but Elon Musk, the primary VC wanted a two speed to improve the accleration.  The early model cars are actually sent out with the original two speed, locked in 2nd gear and will be retrofitted with a single speed later.  The problem they were having wasn't in house, they assumed, much like the rest of us, that transmissions aren't hard to design.  The problem came when they were looking for a transmission that could handle the low speed torque and the 13,500 rpm redline of their AC motor.  They ran into lubrication issues at these rpms, not torque problems.  So the transmissions were failing due to running without lubrication.  To clarify, Tesla was using an outside transmission designer and didn't think there would be issues.

>If Tesla can't do 100 year old technology
>right, what makes them think they can do high tech EV technology right?

Tesla actually did the EV part very well, their controller for the later model single speed drive train is producing 850 amps at the motor, reaching the goal of sub 4 second 0-60 time, and still pushing over 120 mph with a 200+ mile range.  Again, they did not design the transmission, they had left that too the "automotive experts", but that didn't work out. So now they are designing their own.


 Chris Leone
University of Florida
Student of Mechanical Engineering
352-278-1176



----- Original Message ----
From: Richard Marks <[hidden email]>
To: Electric Vehicle Discussion List <[hidden email]>
Sent: Saturday, May 24, 2008 11:35:51 PM
Subject: Re: [EVDL] Electric motor with no tranny for conversion


    Rich
----- Original Message -----
From: "storm connors" <[hidden email]>
To: "Electric Vehicle Discussion List" <[hidden email]>
Sent: Saturday, May 24, 2008 10:18 PM
Subject: Re: [EVDL] Electric motor with no tranny for conversion


> Tesla had a 2 speed, didn't it?
>
> On Sat, May 24, 2008 at 3:20 PM, EVDL Administrator <[hidden email]>
> wrote:
>> On 24 May 2008 at 12:26, Lee Hart wrote:
>>
>>> But essentially *all* EVs designed from scratch have no transmission.
>>> The exceptions are the rare ones.
>>
>> I can think of two more or less recent examples offhand : the Comuta-Van
>> and
>> the Chrysler TEVan.  The C-van had a 3-speed Borg Warner transmission
>> that
>> Jim Tervort once told me had originally been designed for a 1930s vintage
>> Dodge (!).  The Chrysler had a 2-speed gearbox about which I know nothing
>> more.  Rod Hower had one and was involved in designing the vehicle, so he
>> might know more details, if you care.
>>
>> No doubt there are other examples, but my impression is in accord with
>> Lee's; most factory EVs (not conversions) in recent years have had single
>> speed drives.  The obviation of the need for a multispeed transmission
>> was
>> (and is)  considered a significant advantage of electric motors over
>> ICEs.
>>
>> David Roden - Akron, Ohio, USA
>> EVDL Administrator
>>
>> = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
>> EVDL Information: http://www.evdl.org/help/
>> = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
>> Note: mail sent to "evpost" or "etpost" addresses will not
>> reach me.  To send a private message, please obtain my
>> email address from the webpage http://www.evdl.org/help/ .
>> = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
>>
>>
>> _______________________________________________
>> For subscription options, see
>> http://lists.sjsu.edu/mailman/listinfo/ev
>>
>
>
>
> --
> http://www.austinev.org/evalbum/1059
> http://stormselectric.blogspot.com/
> Storm
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>

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Re: Electric motor with no tranny for conversion

jason solivais-2
In reply to this post by chazersize
CVT (constantly variable) trannys are the latest and greatest thing in the auto world. Wouldn't it make sense to use this type of tranny?

-----Original Message-----
From: Chris Leone <[hidden email]>
Sent: Sunday, May 25, 2008 5:07 PM
To: Electric Vehicle Discussion List <[hidden email]>
Subject: Re: [EVDL] Electric motor with no tranny for conversion

>Tesla's mainstream is a two speed transmission. Low gear is for the
>breathtaking acceleration and high gear is to get you to 150 mph.  They have
>had problems getting this 2-spd transmission to work and are supposedly
>going to build some early models with a single speed and later re-fit these
>with the right transmissions.  

Actually, the original Tesla founder, Martin Eberhard, wanted to do a single gear ratio, but Elon Musk, the primary VC wanted a two speed to improve the accleration.  The early model cars are actually sent out with the original two speed, locked in 2nd gear and will be retrofitted with a single speed later.  The problem they were having wasn't in house, they assumed, much like the rest of us, that transmissions aren't hard to design.  The problem came when they were looking for a transmission that could handle the low speed torque and the 13,500 rpm redline of their AC motor.  They ran into lubrication issues at these rpms, not torque problems.  So the transmissions were failing due to running without lubrication.  To clarify, Tesla was using an outside transmission designer and didn't think there would be issues.

>If Tesla can't do 100 year old technology
>right, what makes them think they can do high tech EV technology right?

Tesla actually did the EV part very well, their controller for the later model single speed drive train is producing 850 amps at the motor, reaching the goal of sub 4 second 0-60 time, and still pushing over 120 mph with a 200+ mile range.  Again, they did not design the transmission, they had left that too the "automotive experts", but that didn't work out. So now they are designing their own.


 Chris Leone
University of Florida
Student of Mechanical Engineering
352-278-1176



----- Original Message ----
From: Richard Marks <[hidden email]>
To: Electric Vehicle Discussion List <[hidden email]>
Sent: Saturday, May 24, 2008 11:35:51 PM
Subject: Re: [EVDL] Electric motor with no tranny for conversion


[The entire original message is not included]

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Re: Electric motor with no tranny for conversion

Peter VanDerWal
While CVTs are improving, they are still much lower in efficiency than a
standard transmission.

ICE's tend to have a very narrow band where they are near maximum
efficiency.  With an ICE it can make sense to loose a little efficiency in
the tranmission if you are going to gain efficiency in the motor by
keeping it at it's max efficiency point.

Electric motors tend to be efficient over a very wide band of RPMs.  They
gain little if any advantage from the CVT, but end up loosing efficiency
over all.

> CVT (constantly variable) trannys are the latest and greatest thing in the
> auto world. Wouldn't it make sense to use this type of tranny?
>
> -----Original Message-----
> From: Chris Leone <[hidden email]>
> Sent: Sunday, May 25, 2008 5:07 PM
> To: Electric Vehicle Discussion List <[hidden email]>
> Subject: Re: [EVDL] Electric motor with no tranny for conversion
>
>>Tesla's mainstream is a two speed transmission. Low gear is for the
>>breathtaking acceleration and high gear is to get you to 150 mph.  They
>> have
>>had problems getting this 2-spd transmission to work and are supposedly
>>going to build some early models with a single speed and later re-fit
>> these
>>with the right transmissions.
>
> Actually, the original Tesla founder, Martin Eberhard, wanted to do a
> single gear ratio, but Elon Musk, the primary VC wanted a two speed to
> improve the accleration.  The early model cars are actually sent out with
> the original two speed, locked in 2nd gear and will be retrofitted with a
> single speed later.  The problem they were having wasn't in house, they
> assumed, much like the rest of us, that transmissions aren't hard to
> design.  The problem came when they were looking for a transmission that
> could handle the low speed torque and the 13,500 rpm redline of their AC
> motor.  They ran into lubrication issues at these rpms, not torque
> problems.  So the transmissions were failing due to running without
> lubrication.  To clarify, Tesla was using an outside transmission designer
> and didn't think there would be issues.
>
>>If Tesla can't do 100 year old technology
>>right, what makes them think they can do high tech EV technology right?
>
> Tesla actually did the EV part very well, their controller for the later
> model single speed drive train is producing 850 amps at the motor,
> reaching the goal of sub 4 second 0-60 time, and still pushing over 120
> mph with a 200+ mile range.  Again, they did not design the transmission,
> they had left that too the "automotive experts", but that didn't work out.
> So now they are designing their own.
>
>
>  Chris Leone
> University of Florida
> Student of Mechanical Engineering
> 352-278-1176
>
>
>
> ----- Original Message ----
> From: Richard Marks <[hidden email]>
> To: Electric Vehicle Discussion List <[hidden email]>
> Sent: Saturday, May 24, 2008 11:35:51 PM
> Subject: Re: [EVDL] Electric motor with no tranny for conversion
>
>
> [The entire original message is not included]
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>


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Re: Electric motor with no tranny for conversion

EVDL Administrator
In reply to this post by kEVs
On 25 May 2008 at 11:51, keith vansickle wrote:

> both of these were factory conversions. they were not
> designed as ev  first they were gas powered.

This is true of the TEVan; it was an ordinary Dodge Caravan with an EPTO.

Not the Comuta-van, however.  It was born an EV.  Not a very well optimized
one, mind you, but it was an EV from the start.  To my knowledge, Commuter
Vehicles did not produce any ICE-powered Comuta-Vans.

David Roden - Akron, Ohio, USA
EVDL Administrator

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Re: Electric motor with no tranny for conversion

Roger Stockton
In reply to this post by Mark Grasser
Mark Grasser wrote:

> Sorry but it is apparently not so obvious. :-) Your
> approach uses the tunnel and a substantial part of
> the engine compartment for the drive train leaving
> not so much for the batteries. The method used mounts
> the motor directly to the differential. This makes
> the drive train about 3 feet long in total length
> and being flipped to the rear it leaves the entire
> tunnel and front engine bay for batteries.

You seem to have mixed up the 'Vette and Sunrise and combined elements of both ;^>

The 'Vette, as I understand Lee, mounts the Transwarp 11 (a motor that is designed to connect to a *driveshaft*) where the original tranny used to live, and connects to the 'Vette diff using a driveshaft.  The tunnel is used anyway.  However, since the 'Vette had no tranny mount, what sounds like a rather large crossmember had to be fabricated to hold the motor here.  Yes, it freed up more space in the engine bay for batteries, but it still seems obvious to me that it would have been easier/neater/cheaper to have used a tranny in the stock location so the motor and tranny could be supported as originally intended instead.

The Sunrise, on the other hand, does use a flipped diff in the rear, with the motor hanging directly off it.  This does allow the battery box that runs down the tunnel to extend further forward.  Lee has indicated that the original Sunrise was a little tail heavy, but had the car remained FWD, the battery box could presumably have been lengthened by the same 12" if allowed to extend further rearward instead.

I do like your thought of the 924/928, etc. transaxles.

My "obvious" comments were directed at the 'Vette, not the Sunrise.

Cheers,

Roger.


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Re: Electric motor with no tranny for conversion

Richard Marks
In reply to this post by insndrvr
Everybody is interested in seeing Tesla succeed.  The question is, do they
know enough about automotive test and validation to do it properly.  I  live
in Detroit and Tesla decided they needed more automotive experience to
design the roadster and the White/Blue Star future models.  They set up a
facility here and then laid off half of the people last Fall.  I have spoken
to several of them, I one thing seems clear.  The Tesla management does not
understand automotive technology.  The fact that most of management came out
of software is a real worry.  Software people sell products everyday knowing
it works most of the time and they can release patches to fix things that
their customers complain about or sell you new software that fixes the old
bugs and provide new features.  Great in IT, but that does not work in
automobiles.  You buy a new car today and do not expect to have any problems
for 10 years.  Everybody remembers the Bill Gates/Microsoft jokes 10 years
ago about if MS built cars.  You remember?  Your car would periodically stop
and you would have to reboot...etc...
Today's car manufacturers build quality to the tune of 10 defects per
million parts.  Elon Musk about 2 years ago said if you build electronics
you don't do it in Detroit, you do it in Silicon Valley.  How little he
knows.  Today's cars are more complex electrically than any single computer
that uses PayPal.  And they are extremely reliable!
My biggest concern is their choice of battery technology. Li-ion with cobalt
is considered universally the wrong technology for transportation products.
They probably realize this now, but are they too stubborn to make a change?
The other issue is life cycle testing.  If a battery is supposed to last 10
years, how do you get 10 years of testing at a pack level?  You don't.  It
takes more time and everytime you make an improvement you start the testing
all over.
But let's not speculate, time will tell if they can be successful.
    Richard
----- Original Message -----
From: "Chris Leone" <[hidden email]>
To: "Electric Vehicle Discussion List" <[hidden email]>
Sent: Sunday, May 25, 2008 6:07 PM
Subject: Re: [EVDL] Electric motor with no tranny for conversion


> >Tesla's mainstream is a two speed transmission. Low gear is for the
>>breathtaking acceleration and high gear is to get you to 150 mph.  They
>>have
>>had problems getting this 2-spd transmission to work and are supposedly
>>going to build some early models with a single speed and later re-fit
>>these
>>with the right transmissions.
>
> Actually, the original Tesla founder, Martin Eberhard, wanted to do a
> single gear ratio, but Elon Musk, the primary VC wanted a two speed to
> improve the accleration.  The early model cars are actually sent out with
> the original two speed, locked in 2nd gear and will be retrofitted with a
> single speed later.  The problem they were having wasn't in house, they
> assumed, much like the rest of us, that transmissions aren't hard to
> design.  The problem came when they were looking for a transmission that
> could handle the low speed torque and the 13,500 rpm redline of their AC
> motor.  They ran into lubrication issues at these rpms, not torque
> problems.  So the transmissions were failing due to running without
> lubrication.  To clarify, Tesla was using an outside transmission designer
> and didn't think there would be issues.
>
>>If Tesla can't do 100 year old technology
>>right, what makes them think they can do high tech EV technology right?
>
> Tesla actually did the EV part very well, their controller for the later
> model single speed drive train is producing 850 amps at the motor,
> reaching the goal of sub 4 second 0-60 time, and still pushing over 120
> mph with a 200+ mile range.  Again, they did not design the transmission,
> they had left that too the "automotive experts", but that didn't work out.
> So now they are designing their own.
>
>
> Chris Leone
> University of Florida
> Student of Mechanical Engineering
> 352-278-1176
>
>
>
> ----- Original Message ----
> From: Richard Marks <[hidden email]>
> To: Electric Vehicle Discussion List <[hidden email]>
> Sent: Saturday, May 24, 2008 11:35:51 PM
> Subject: Re: [EVDL] Electric motor with no tranny for conversion
>
>
>    Rich
> ----- Original Message -----
> From: "storm connors" <[hidden email]>
> To: "Electric Vehicle Discussion List" <[hidden email]>
> Sent: Saturday, May 24, 2008 10:18 PM
> Subject: Re: [EVDL] Electric motor with no tranny for conversion
>
>
>> Tesla had a 2 speed, didn't it?
>>
>> On Sat, May 24, 2008 at 3:20 PM, EVDL Administrator <[hidden email]>
>> wrote:
>>> On 24 May 2008 at 12:26, Lee Hart wrote:
>>>
>>>> But essentially *all* EVs designed from scratch have no transmission.
>>>> The exceptions are the rare ones.
>>>
>>> I can think of two more or less recent examples offhand : the Comuta-Van
>>> and
>>> the Chrysler TEVan.  The C-van had a 3-speed Borg Warner transmission
>>> that
>>> Jim Tervort once told me had originally been designed for a 1930s
>>> vintage
>>> Dodge (!).  The Chrysler had a 2-speed gearbox about which I know
>>> nothing
>>> more.  Rod Hower had one and was involved in designing the vehicle, so
>>> he
>>> might know more details, if you care.
>>>
>>> No doubt there are other examples, but my impression is in accord with
>>> Lee's; most factory EVs (not conversions) in recent years have had
>>> single
>>> speed drives.  The obviation of the need for a multispeed transmission
>>> was
>>> (and is)  considered a significant advantage of electric motors over
>>> ICEs.
>>>
>>> David Roden - Akron, Ohio, USA
>>> EVDL Administrator
>>>
>>> = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
>>> EVDL Information: http://www.evdl.org/help/
>>> = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
>>> Note: mail sent to "evpost" or "etpost" addresses will not
>>> reach me.  To send a private message, please obtain my
>>> email address from the webpage http://www.evdl.org/help/ .
>>> = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
>>>
>>>
>>> _______________________________________________
>>> For subscription options, see
>>> http://lists.sjsu.edu/mailman/listinfo/ev
>>>
>>
>>
>>
>> --
>> http://www.austinev.org/evalbum/1059
>> http://stormselectric.blogspot.com/
>> Storm
>>
>> _______________________________________________
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>>
>
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Re: Electric motor with no tranny for conversion

Neon John
On Tue, 27 May 2008 12:20:02 -0400, "Richard Marks" <[hidden email]>
wrote:


>Today's car manufacturers build quality to the tune of 10 defects per
>million parts.  Elon Musk about 2 years ago said if you build electronics
>you don't do it in Detroit, you do it in Silicon Valley.  How little he
>knows.  Today's cars are more complex electrically than any single computer
>that uses PayPal.  And they are extremely reliable!

Yep.  Automotive electronics are on par with and in some cases better than
aerospace.  All quietly done by the companies that so many on this list love
to hate.

>My biggest concern is their choice of battery technology. Li-ion with cobalt
>is considered universally the wrong technology for transportation products.
>They probably realize this now, but are they too stubborn to make a change?
>The other issue is life cycle testing.  If a battery is supposed to last 10
>years, how do you get 10 years of testing at a pack level?  You don't.  It
>takes more time and everytime you make an improvement you start the testing
>all over.

All true.  I just marvel that an outfit like that can run through over $25
million dollars and have practically nothing to show for it.  The car itself
is built for them by Lotus.  The drive system is AC Propulsion.  I'm not sure
just what it is they've spent all that money on.  My mind races at the thought
of what I could do in the EV world with a tenth that much money.

>But let's not speculate, time will tell if they can be successful.

Here's a good place to keep track.

http://www.thetruthaboutcars.com/category/news-blog/tesla-death-watch/

This is some pretty good reporting by folks who haven't drank the Kool-Aid on
Tesla's activities up to allegedly delivering the first "production" (sic) car

http://www.thetruthaboutcars.com/category/news-blog/tesla-birth-watch/

Note the next to last entry where they report on Larry Sonsini, the scandalous
M&A shark, joining the board.  Sounds like the "dump" part of "pump'n'dump" is
being planned for.

John
--
John De Armond
See my website for my current email address
http://www.neon-john.com
http://www.johndearmond.com <-- best little blog on the net!
Tellico Plains, Occupied TN
If the letters PhD appear after a person's name, that person will
remain outdoors even after it's started raining.

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Re: Electric motor with no tranny for conversion

David Dymaxion
In reply to this post by chazersize
This is a bit of a nitpick, but you need 1500 ft*lbs to spin the rear wheels (2 wheels with 750 lbs each of weight on them), so 965 ft*lbs won't quite do it. It'll still be a fast car and able to climb almost any hill you'd see on a U.S. public road. If you want max acceleration with this setup you'll need either a transmission, or more electrical power (maybe even 2 motors), or give up some top speed with a lower rear end gear ratio, or a lighter car (A123 batteries).

This is a fine point primarily of interest to the racers: Weight transfer to the rear wheels in a RWD car can significantly raise the weight on the rear wheels. For example, my gas car statically has 42% of its weight on the rear wheels, but it can accelerate at 0.7 g on street tires in 1st gear, due to weight transfer during acceleration. This can get even more extreme with race tires and a sticky track. So if you want the fastest car, you should assume all the car's weight is on the rear wheels for your calculations (indeed, really fast drag racers do a wheelie, truly putting 100% of the weight on the rear wheels). All out drag racers, with drag slicks and a sticky track, should assume even more weight, as they accelerate faster than 1 g.

----- Original Message ----
From: Lee Hart <[hidden email]>
To: Electric Vehicle Discussion List <[hidden email]>
Sent: Tuesday, May 27, 2008 1:48:27 PM
Subject: Re: [EVDL] Electric motor with no tranny for conversion

...
5. Calculate how much wheel torque this will produce, by multiplying
    by the differential ratio: 225 ft.lbs x 4.29 = 965 ft.lbs

6. Is this "enough"? Well, any torque in excess of what it takes to
    spin the tires is pointless; it is traction limited, not motor
    limited. A tire produces about 1 lbs thrust for every 1 lbs of
    weight on it. Say your EV weighs 3000 lbs, with 750 lbs per tire.
    So a 1-foot radius tire "breaks loose" over 750 ft.lbs; we have
    enough torque with this motor, controller, and differential to
    spin the tires and can climb any possible hill.
...


     

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Re: Electric motor with no tranny for conversion

Mark Grasser
I would think it to be 750 ft*if if the differential is of the open type and
1,500 if it is a posi unit. Also depending on how the suspension is setup I
would think the effect of weight transfer might be negligible. Of course
these are opinions and I have based nothing on fact. :-)

Mark  Grasser
Eliot, ME

 
This is a bit of a nitpick, but you need 1500 ft*lbs to spin the rear wheels
(2 wheels with 750 lbs each of weight on them), so 965 ft*lbs won't quite do
it. It'll still be a fast car and able to climb almost any hill you'd see on
a U.S. public road. If you want max acceleration with this setup you'll need
either a transmission, or more electrical power (maybe even 2 motors), or
give up some top speed with a lower rear end gear ratio, or a lighter car
(A123 batteries).

This is a fine point primarily of interest to the racers: Weight transfer to
the rear wheels in a RWD car can significantly raise the weight on the rear
wheels. For example, my gas car statically has 42% of its weight on the rear
wheels, but it can accelerate at 0.7 g on street tires in 1st gear, due to
weight transfer during acceleration. This can get even more extreme with
race tires and a sticky track. So if you want the fastest car, you should
assume all the car's weight is on the rear wheels for your calculations
(indeed, really fast drag racers do a wheelie, truly putting 100% of the
weight on the rear wheels). All out drag racers, with drag slicks and a
sticky track, should assume even more weight, as they accelerate faster than
1 g.

----- Original Message ----
From: Lee Hart <[hidden email]>
To: Electric Vehicle Discussion List <[hidden email]>
Sent: Tuesday, May 27, 2008 1:48:27 PM
Subject: Re: [EVDL] Electric motor with no tranny for conversion

...
5. Calculate how much wheel torque this will produce, by multiplying
    by the differential ratio: 225 ft.lbs x 4.29 = 965 ft.lbs

6. Is this "enough"? Well, any torque in excess of what it takes to
    spin the tires is pointless; it is traction limited, not motor
    limited. A tire produces about 1 lbs thrust for every 1 lbs of
    weight on it. Say your EV weighs 3000 lbs, with 750 lbs per tire.
    So a 1-foot radius tire "breaks loose" over 750 ft.lbs; we have
    enough torque with this motor, controller, and differential to
    spin the tires and can climb any possible hill.
...


     

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Re: Electric motor with no tranny for conversion

David Dymaxion
In reply to this post by chazersize
Right you are about open vs. posi.

It turns out weight transfer is fundamental from the geometry. Even a go kart with no suspension, or even a cardboard box, will get weight transfer to the rear upon acceleration, as the cg is above the floor. Suspension tuning can enhance this effect further.

Note for my gas car, weight transfer was not negligible. It went from 42%, to 70%. That's 1.7 times the weight on the rear wheels, and this was a daily driver car with a bone stock suspension on good street tires, and a stock limited slip differential.

If want to accelerate really fast, plan to push all the car's weight with the rear wheels (or all wheel drive) at about 1 g for the street, and as high as about 3 g for an all out drag racer at the strip. 1 g is Ferrari levels of acceleration.

----- Original Message ----
From: Mark Grasser <[hidden email]>
To: Electric Vehicle Discussion List <[hidden email]>
Sent: Tuesday, May 27, 2008 3:31:59 PM
Subject: Re: [EVDL] Electric motor with no tranny for conversion

I would think it to be 750 ft*if if the differential is of the open type and
1,500 if it is a posi unit. Also depending on how the suspension is setup I
would think the effect of weight transfer might be negligible. Of course
these are opinions and I have based nothing on fact. :-)

Mark  Grasser
Eliot, ME


This is a bit of a nitpick, but you need 1500 ft*lbs to spin the rear wheels
(2 wheels with 750 lbs each of weight on them), so 965 ft*lbs won't quite do
it. It'll still be a fast car and able to climb almost any hill you'd see on
a U.S. public road. If you want max acceleration with this setup you'll need
either a transmission, or more electrical power (maybe even 2 motors), or
give up some top speed with a lower rear end gear ratio, or a lighter car
(A123 batteries).

This is a fine point primarily of interest to the racers: Weight transfer to
the rear wheels in a RWD car can significantly raise the weight on the rear
wheels. For example, my gas car statically has 42% of its weight on the rear
wheels, but it can accelerate at 0.7 g on street tires in 1st gear, due to
weight transfer during acceleration. This can get even more extreme with
race tires and a sticky track. So if you want the fastest car, you should
assume all the car's weight is on the rear wheels for your calculations
(indeed, really fast drag racers do a wheelie, truly putting 100% of the
weight on the rear wheels). All out drag racers, with drag slicks and a
sticky track, should assume even more weight, as they accelerate faster than
1 g.

----- Original Message ----
From: Lee Hart <[hidden email]>
To: Electric Vehicle Discussion List <[hidden email]>
Sent: Tuesday, May 27, 2008 1:48:27 PM
Subject: Re: [EVDL] Electric motor with no tranny for conversion

...
5. Calculate how much wheel torque this will produce, by multiplying
    by the differential ratio: 225 ft.lbs x 4.29 = 965 ft.lbs

6. Is this "enough"? Well, any torque in excess of what it takes to
    spin the tires is pointless; it is traction limited, not motor
    limited. A tire produces about 1 lbs thrust for every 1 lbs of
    weight on it. Say your EV weighs 3000 lbs, with 750 lbs per tire.
    So a 1-foot radius tire "breaks loose" over 750 ft.lbs; we have
    enough torque with this motor, controller, and differential to
    spin the tires and can climb any possible hill.
...


     

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Re: Electric motor with no tranny for conversion

Roland Wiench
In reply to this post by David Dymaxion



----- Original Message -----
From: "David Dymaxion" <[hidden email]>
To: "Electric Vehicle Discussion List" <[hidden email]>
Sent: Tuesday, May 27, 2008 2:38 PM
Subject: Re: [EVDL] Electric motor with no tranny for conversion


> This is a bit of a nitpick, but you need 1500 ft*lbs to spin the rear
> wheels (2 wheels with 750 lbs each of weight on them), so 965 ft*lbs won't
> quite do it. It'll still be a fast car and able to climb almost any hill
> you'd see on a U.S. public road. If you want max acceleration with this
> setup you'll need either a transmission, or more electrical power (maybe
> even 2 motors), or give up some top speed with a lower rear end gear
> ratio, or a lighter car (A123 batteries).
>
> This is a fine point primarily of interest to the racers: Weight transfer
> to the rear wheels in a RWD car can significantly raise the weight on the
> rear wheels. For example, my gas car statically has 42% of its weight on
> the rear wheels, but it can accelerate at 0.7 g on street tires in 1st
> gear, due to weight transfer during acceleration. This can get even more
> extreme with race tires and a sticky track. So if you want the fastest
> car, you should assume all the car's weight is on the rear wheels for your
> calculations (indeed, really fast drag racers do a wheelie, truly putting
> 100% of the weight on the rear wheels). All out drag racers, with drag
> slicks and a sticky track, should assume even more weight, as they
> accelerate faster than 1 g.


This is true about the weight transfer, normally call thrust.  When I order
my axle set from www.markwilliams.com, they recommended a 4000 lb thrust
axle and bearing set for a rear wheel weight of 2000 lbs.  Each wheel are
rated for a load rating of 3500 lbs and the tires are rated for 2600 lbs at
65 psi.

At static load, there is only a 0.375 inch deflection of the tire face.

Roland

 

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