EV Digest 6051
Topics covered in this issue include:
1) Re: Reattaching Magnets on PM Motors
by Jim Husted <[EMAIL PROTECTED]>
2) Playing with an EV-1 and/or GM... Any suggestions?
by "Arthur W. Matteson" <[EMAIL PROTECTED]>
3) Re: Playing with an EV-1 and/or GM... Any suggestions?
by "Arthur W. Matteson" <[EMAIL PROTECTED]>
4) Re: EV controllers? Practical parameters
by "Paul G." <[EMAIL PROTECTED]>
5) Re: Playing with an EV-1 and/or GM... Any suggestions?
by "[EMAIL PROTECTED]" <[EMAIL PROTECTED]>
6) Re: Source for GE EV-1s, Was: EV controllers? the 4th option...
by Steve Powers <[EMAIL PROTECTED]>
7) RE: EV controllers? the 4th option...
by James Massey <[EMAIL PROTECTED]>
8) Why does motor commutator not burn up with 350V battery?
by Cor van de Water <[EMAIL PROTECTED]>
9) Current multiplication, was: EV controllers? Practical parameters
by Cor van de Water <[EMAIL PROTECTED]>
10) Re: Current multiplication, was: EV controllers? Practical parameters
by Cory Cross <[EMAIL PROTECTED]>
11) Re: Ni-Cad Cell Reversal
by "jerryd" <[EMAIL PROTECTED]>
12) Re: Why does motor commutator not burn up with 350V battery?
by James Massey <[EMAIL PROTECTED]>
13) RE: Current multiplication, was: EV controllers? Practical parame
ters
by Cor van de Water <[EMAIL PROTECTED]>
14) Re: EV controllers? the 4th option...
by "Joseph H. Strubhar" <[EMAIL PROTECTED]>
--- Begin Message ---
Hey Mike
I've had good success with JB weld, used it for years
on ohio steer motors. You'll need 2 "C" clamps to
clamp it untill cured. I also use a cheap compass and
a small metal rod to determine polarity if multible
magnets are loose. I'd apply a little lip while in
there and set the others with a small bead around
their edges.
Hope this helps
Jim Husted
Hi-Torque Electric
--- Mike Chancey <[EMAIL PROTECTED]> wrote:
> Hi folks,
>
> I have a deck motor on my John Deere E90 electric
> riding mower that
> has one of the magnets loose in the shell. I am
> trying to get the
> mower operational for next year's yard work, and
> both deck motors
> were frozen. I was able to break both motors down
> completely so I
> can replace the bearing and brushes, but I will need
> to glue this
> magnet back on before one of them can be reused.
> So, what do kind of
> adhesive is recommended?
>
> Thanks,
>
> Mike Chancey,
> '88 Civic EV
> Kansas City, Missouri
> EV Photo Album at: http://evalbum.com
> My Electric Car at:
> http://www.geocities.com/electric_honda
> Mid-America EAA chapter at: http://maeaa.org
> Join the EV List at:
> http://www.madkatz.com/ev/evlist.html
>
> In medio stat virtus - Virtue is in the moderate,
> not the extreme
> position. (Horace)
>
>
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--- Begin Message ---
I rarely start threads here, but there was no question about this one.
As I may have mentioned before, I'm involved with the Solar Car Team at
Michigan State University (I'm the longest member). We've recently
learned that the race for 2007 may not happen because of a lack of
funding. Besides that, we've never had a car before and are finding it
difficult to get motivation and knowledge to build one from scratch.
So, the new advisor and I had a talk about other options.
A couple of years ago, the professor who I now work for in graduate
school took his class to visit MSU's EV-1. I wasn't in the class at the
time, but one of my friends who coincidentally got to test the car
(Delphi employee, now a Ph.D. in E.E.) called me and I tagged along. Of
course, I brought my camera. Pictures can be seen here:
http://mywebpages.comcast.net/awmatt/msuev1.html
The advisor and I came up with a suggestion of adding solar panels to it
and/or using it to experiment with. (GM of course wanted to design it
with a solar panel, but they found it would increase the cost too much.)
I just think it would be fun to see it go, no matter what we did. It
would be better than what we have now, that's for sure. I see this as a
huge opportunity that I don't want to pass up; how many of us would even
get this chance?
So I wrote an E-mail to two people that are in charge of taking care of
it, or giving access to it (I'm concealing their identities). Their
responses are shown below. We also have a hybrid car from a team that
existed a few years ago. Keep reading after this!
First message, from 'Shop-Supervisor':
> You are welcome to visit/view the EV-1 at your convenience. You may
> wish to let the folks at 'MSU-Building' (555-5555) know that you will
> be coming by and arrange a time when they can let you into the storage
> area.
>
> Please check with 'Assistant-Dean' about authorized uses for both the
> hybrid and the EV-1.
>
> My only thought is that there may be some space problems in the Solar
> cage if you are planning to have one or more of the cars in your cage
> at 'Solar-Car-Garage.'
>
> Let me know if you have any questions.
>
> Thanks,
>
> 'Shop-Supervisor'
Second message, from 'Assistant-Dean':
> Please see the attached letter from GM. They had us and other schools
> (Wisconsin got a red one) write a proposal to get an EV-1, and then GM
> got significant liability concerns. They put many restrictions on the
> use, removed the batteries, and took other measures to essentially
> make the car inoperable. So it has "zero" range. As we are paying for
> storage with essentially no use, we have been considering disposing of
> both cars, but I haven't had the heart to junk a classic collector's
> item.
>
> As I read the attached letter, the vehicle could be cannibalized for
> parts for another use, or use its components as visual aids in a
> class. The third bullet would suggest we can't get it running "as an
> EV-1".
>
> The hybrid is ours to use as we wish.
>
> Like 'Shop-Supervisor,' my primary concern is whether you have space
> to bring this vehicle to 'Solar-Car-Garage.' I suggest you and your
> team go out and take a further look, and have further conversations
> with 'Shop-Supervisor' about your intent.
>
> - 'Assistant-Dean'
Now I bet you all want to see the attached letter from GM. So I've
attached it here in HTML format. Just kidding!
I'll provide it in edited graphic and text format, but I'll need your
help to interpret it! (It was written long after MSU got the car, since
I saw it in November 2003.)
http://www.egr.msu.edu/~mattes12/ev1.gif
> 'Advanced Technology Vehicles' Letterhead
>
> November 7, 2005
>
> Dear Dr. Professor:
>
> We hope that you are enjoying the use of the GM EV1 for educational
> purposes and that it is providing a good learning opportunity for your
> students in automotive technology.
>
> We wanted to remind you that as part of the donation agreement that
> the university signed, the school and its representatives agreed that:
>
> - It would not sell, give away, donate or in any way transfer
> ownership of this vehicle or any parts or components therein.
> - If you find you no longer can use the vehicle and/or its components,
> the school will scrap them in an appropriate and environmental manner,
> and/or contact GM for assistance in scrapping.
> - The school will not attempt to get the vehicle running again as an
> EV1.
> - The school will not attempt to get EV1 parts for the vehicle from
> GM, a Saturn retailer, or any other source.
>
> We trust that you will continue to abide by this agreement. If you
> have any questions, please contact me.
>
> Thank you for your continued cooperation.
>
> Sincerely,
>
> 'EV-Program-Manager' (hand-signed)
I like how she says to contact GM for assistance in scrapping. Yeah,
they're awfully good at that. I guess if you're going to scrap an
electric car, you might as well do it environmentally!
Questions for the EV-List:
- Any ideas of what to do with the EV-1, that would be legal?
- Should I try to get in contact 'EV-Program-Manager' at all?
- What should I tell the Solar Car Team advisor, the 'Shop-Supervisor,'
and the 'Assistant-Dean'?
- The hybrid car MSU built from scratch (I think) can be seen at the
left of some of the EV-1 pictures. You might get a glimpse of its name,
"Spartan Challenger." Should we do anything with it? I think the EV-1
would be 100 times as fun.
- The team still wants to put effort into building a solar car, albeit
not much. How would I deal with having two projects? Any ideas on how
to connect the two so the team doesn't think we're giving up on the
solar car?
- I could easily build a three-phase motor controller to at least get
the car going (be forewarned: I'm not ready to sell controllers yet).
We can supply our own batteries, since we still have some money left.
- Also...the Solar Car Team's never-used, two-year-old pack of (8)
Trojan SG-50s died. I charged them once in a while; they never worked
particularly well. Where did I go wrong? Can they be revived? They
act like a leaky 100uF capacitor with a 16V zener diode across it, and
make lots of bubbling noises. (On the contrary, my Renault's flooded
marine batteries from Sears are still fine after six years.)
- Should I provide a showing of WKTEC to the Solar Car Team and our
advisor (he's already "green")? I haven't seen it yet.
- Any other comments or suggestions?
- Arthur Matteson
Master's candidate, Elec. Eng., MSU
--- End Message ---
--- Begin Message ---
Also, I found this on the Internet (see pages 6 and 7):
http://www.givingto.msu.edu/media/developments/partners_spring2002.pdf
or http://tinyurl.com/y99qf4
So, if it has a PIN instead of a key, how do we get in provided there
aren't any batteries? (Must we be careful not to lock it?)
- Arthur
--- End Message ---
--- Begin Message ---
On Oct 21, 2006, at 12:25 PM, Dave Wilker wrote:
The only way I know of is a step-down transformer.. Is that what you
mean? Or do you mean torque multiplication?
That is standard DC motor controller behavior. The watts in equals the
watts out. Watts is volts times amps. So if you controller is taking
120 volts at 100 amps in but the motor voltage is only 40 volts at part
throttle then the motor is getting 300 amps.
The catch is that the Curtis controller only limit motor current. Since
motor voltage will never exceed battery voltage the battery current
cannot exceed the motor current limit. Because of the motor current
limit there is a narrower peak power with a Curtis controller (one rpm,
when the motor is taking full voltage at max current and before it revs
any higher because then it won't take as much current.)
Separate motor and battery current limits allow for extra starting
torque and an extended power band. Lets say the motor current is 800
amps but the battery current is 400 amps. In this case the motor can
get 800 amps up to 1/2 pack voltage (400 battery amps), then the amps
drop as the motor voltage rises until the motor is getting 400 amps at
full pack voltage. That range of rpms is all at peak power. Extra
starting torque and a wider power band thanx to a better controller.
HTH,
Paul
--- End Message ---
--- Begin Message ---
I suggest you get it running again, but as an EV2
instead of an EV1!
Jay
--- "Arthur W. Matteson" <[EMAIL PROTECTED]> wrote:
> I rarely start threads here, but there was no
> question about this one.
> As I may have mentioned before, I'm involved with
> the Solar Car Team at
> Michigan State University (I'm the longest member).
> We've recently
> learned that the race for 2007 may not happen
> because of a lack of
> funding. Besides that, we've never had a car before
> and are finding it
> difficult to get motivation and knowledge to build
> one from scratch.
> So, the new advisor and I had a talk about other
> options.
>
> A couple of years ago, the professor who I now work
> for in graduate
> school took his class to visit MSU's EV-1. I wasn't
> in the class at the
> time, but one of my friends who coincidentally got
> to test the car
> (Delphi employee, now a Ph.D. in E.E.) called me and
> I tagged along. Of
> course, I brought my camera. Pictures can be seen
> here:
>
> http://mywebpages.comcast.net/awmatt/msuev1.html
>
> The advisor and I came up with a suggestion of
> adding solar panels to it
> and/or using it to experiment with. (GM of course
> wanted to design it
> with a solar panel, but they found it would increase
> the cost too much.)
> I just think it would be fun to see it go, no matter
> what we did. It
> would be better than what we have now, that's for
> sure. I see this as a
> huge opportunity that I don't want to pass up; how
> many of us would even
> get this chance?
>
> So I wrote an E-mail to two people that are in
> charge of taking care of
> it, or giving access to it (I'm concealing their
> identities). Their
> responses are shown below. We also have a hybrid
> car from a team that
> existed a few years ago. Keep reading after this!
>
>
> First message, from 'Shop-Supervisor':
>
> > You are welcome to visit/view the EV-1 at your
> convenience. You may
> > wish to let the folks at 'MSU-Building' (555-5555)
> know that you will
> > be coming by and arrange a time when they can let
> you into the storage
> > area.
> >
> > Please check with 'Assistant-Dean' about
> authorized uses for both the
> > hybrid and the EV-1.
> >
> > My only thought is that there may be some space
> problems in the Solar
> > cage if you are planning to have one or more of
> the cars in your cage
> > at 'Solar-Car-Garage.'
> >
> > Let me know if you have any questions.
> >
> > Thanks,
> >
> > 'Shop-Supervisor'
>
>
> Second message, from 'Assistant-Dean':
>
> > Please see the attached letter from GM. They had
> us and other schools
> > (Wisconsin got a red one) write a proposal to get
> an EV-1, and then GM
> > got significant liability concerns. They put many
> restrictions on the
> > use, removed the batteries, and took other
> measures to essentially
> > make the car inoperable. So it has "zero" range.
> As we are paying for
> > storage with essentially no use, we have been
> considering disposing of
> > both cars, but I haven't had the heart to junk a
> classic collector's
> > item.
> >
> > As I read the attached letter, the vehicle could
> be cannibalized for
> > parts for another use, or use its components as
> visual aids in a
> > class. The third bullet would suggest we can't get
> it running "as an
> > EV-1".
> >
> > The hybrid is ours to use as we wish.
> >
> > Like 'Shop-Supervisor,' my primary concern is
> whether you have space
> > to bring this vehicle to 'Solar-Car-Garage.' I
> suggest you and your
> > team go out and take a further look, and have
> further conversations
> > with 'Shop-Supervisor' about your intent.
> >
> > - 'Assistant-Dean'
>
>
> Now I bet you all want to see the attached letter
> from GM. So I've
> attached it here in HTML format. Just kidding!
>
> I'll provide it in edited graphic and text format,
> but I'll need your
> help to interpret it! (It was written long after
> MSU got the car, since
> I saw it in November 2003.)
>
> http://www.egr.msu.edu/~mattes12/ev1.gif
>
> > 'Advanced Technology Vehicles' Letterhead
> >
> > November 7, 2005
> >
> > Dear Dr. Professor:
> >
> > We hope that you are enjoying the use of the GM
> EV1 for educational
> > purposes and that it is providing a good learning
> opportunity for your
> > students in automotive technology.
> >
> > We wanted to remind you that as part of the
> donation agreement that
> > the university signed, the school and its
> representatives agreed that:
> >
> > - It would not sell, give away, donate or in any
> way transfer
> > ownership of this vehicle or any parts or
> components therein.
> > - If you find you no longer can use the vehicle
> and/or its components,
> > the school will scrap them in an appropriate and
> environmental manner,
> > and/or contact GM for assistance in scrapping.
> > - The school will not attempt to get the vehicle
> running again as an
> > EV1.
> > - The school will not attempt to get EV1 parts for
> the vehicle from
> > GM, a Saturn retailer, or any other source.
> >
> > We trust that you will continue to abide by this
> agreement. If you
> > have any questions, please contact me.
> >
> > Thank you for your continued cooperation.
> >
> > Sincerely,
> >
> > 'EV-Program-Manager' (hand-signed)
>
>
> I like how she says to contact GM for assistance in
> scrapping. Yeah,
> they're awfully good at that. I guess if you're
> going to scrap an
> electric car, you might as well do it
> environmentally!
>
>
> Questions for the EV-List:
>
> - Any ideas of what to do with the EV-1, that would
> be legal?
> - Should I try to get in contact
> 'EV-Program-Manager' at all?
> - What should I tell the Solar Car Team advisor, the
> 'Shop-Supervisor,'
> and the 'Assistant-Dean'?
> - The hybrid car MSU built from scratch (I think)
> can be seen at the
> left of some of the EV-1 pictures. You might get a
> glimpse of its name,
> "Spartan Challenger." Should we do anything with
> it? I think the EV-1
> would be 100 times as fun.
> - The team still wants to put effort into building a
> solar car, albeit
> not much. How would I deal with having two
> projects? Any ideas on how
>
=== message truncated ===
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--- Begin Message ---
As Roger wrote, the only one worth having in an unmodified form is the 84 - 144
V EV-1C used in a lot of the early 80's cars.
EV-1B's are available, local forklift salvage or the infamous e-bay. I
bought 2 last year. One was $50. The other was $35. I've seen them from $25
up to $100 on e-bay. But, they must have the most up to date card 24 - 84 V or
48 - 84 V. And, most come from 36 V lifts, so you have to change the coils on
the contactors, or use power resistors to step down the 84 V to about 18 V -
typical coil rating.
So, you get what you pay for - $50 may get your car rolling, but only a very
very light car. What I was talking about is buying several and using the parts
to build a monster controller. A little on the excessive side, but get 4 of
them. Put all 4 main SCRs in parallel. Let them split the current (total up
to about 800 A). That will keep them cool. Take 2 caps and put them in series
for an effective higher voltage rating. Take another set and put them in
series. Take the 2 groups and put them in parallel. That should take care of
the main cap bank. More capacity at a higher voltage. Then, go through the
rest and see what other mods are necessary. The control card is its own issue,
but a good electrical tech or engineer could figure this out.
That's my 2 cents on an inexpensive controller. But, if Zillas are
available, why re-invent the wheel. Go that route and save yourself the
headache. I just can't see spending $1200 - $1500 on a Curtis with early
1990's technology and performance. Would you buy a 286 computer? No.
Maybe if I ever get time, I'll try to boost my EV-1B. But, I still need a
new chasis for the Festiva, so why bother right now. Or, if I ever get the
mechanicals right, I'd love to have a Zilla.
Steve
Bruce <[EMAIL PROTECTED]> wrote:
Steve,
Could you please share with us your source for these low cost controllers? URL?
Steve Powers wrote: "Consider the used / surplus market where I can get a
complete GE EV-1 fully functional with pot box and contactors for $100 or less.
Or an EV-100 or even EV-200. All used, all cheap, all still very functional. "
---------------------------------
All-new Yahoo! Mail - Fire up a more powerful email and get things done faster.
--- End Message ---
--- Begin Message ---
At 12:55 AM 21/10/06 -0700, you wrote:
Hey Rich,
> What do we need in the way of Controllers and what
> would you folks pay for a new design?
What DC'ers need is a Curtis-killer, not something that tries to compete
with Otmar's already excellent offerings.
G'day Rich, and All
I agree with the comments of Raptor 600 capacity controller, and also the
"all in one box" charger and controller.
Maybe there is another option.
I know that this is a 'non-commercial' approach, and leaves the designer at
considerable risk of "loosing their shirt" by designing something that does
not have to be built by them. The Raptor and Zilla design strategy involves
specialised construction methods that almost prevent other people from
working on them. Being several thousand miles from the designer/builder I
am relying on the Zilla that I bought to be reliable, but buying the next
controller I'd look very closely at a controller that was designed to be
repaired by competent techs, anywhere, and also something that I could buy
in a partial assembled form to add the bits that I can get here, plus some
of my time to complete the controller:
A controller that is designed as a kit, using silicon that comes in a much
more expensive package than would be used in a commercial construction.
What I'm thinking of is isotop modules or something else that is industry
standard and would allow for a 600A controller to be built using maybe 2 or
4 modules. This gets around the 'can full of dead Fets' when designing a
controller. Yes, this will make it more expensive per unit in comparison to
a 1-design system, but it will allow for the builder to get E-bay or other
surplus components, and save money, or go high-voltage or high-spec and
build a megawatt controller if they have the cash.
What this will involve is to design a control board and power boards in a
manner that allows the assembly to go onto a flat surface, so the builder
can choose air or water cooling. Supply the controller as anywhere from a
pre assembled control board with bare power stages and no input DC/DC
converter up to a fully assembled and tested controller. This would allow
for the builder to put it together as any voltage he/she chooses, or to put
it together initially as a 450A controller and upgrade the power stage
later to whatever power level is desired. It may be possible for such a
system to be built as a sep-ex as some have requested with a single power
device in the field but measuring (and limiting) the curent from the armature.
Peripheral things like precharge control and reverse/valet mode etc would
need to be addressed on merit. Pre-charge control, current and RPM limit
I'd consider essential. Reverse and series/parallel may be able to be
designed as a 'tap-in' point in the controller for shift blanking and valet
mode power reduction (or reverse reduction) in the manner of open source
projects able to be added on as people need them.
For someone like Rich to take on a project like this, I feel that it would
take something like a subscription project. Everyone who thinks they will
want one (or more) puts up (for example) $250 to Rich. They get the value
of what they put up as a discount on their kit once they are ready and Rich
gets the cash to do the project.
What do people (and especially Rich, or anyone else who may be in a
position to design such a system) think?
Regards
[Technik] James
--- End Message ---
--- Begin Message ---
It has been bugging me for a while, but while writing the
previous post about current multiplication I suddenly
realized how you can limit motor voltage even while the
controller sends 350V from the battery to a motor that
cannot take more than 170V without dying from arcing
(See John Wayland's run where the burnout tricked the
Zilla in thinking it was time to switch to parallel
mode and full-on because of the high RPMs....
BIG SPARK under White Zombie.
Remember that a DC controller will send full pack
voltage to the motor and then switch off to have the
motor current loop around through the diodes?
I think that is the clue: as long as the controller is
not "full on" then the motor voltage will go to zero
every cycle, 15,000 times per second or so.
Any spark that is starting to fly because of the
excessive 350V motor voltage will extinguish as soon
as the voltage goes to zero again, in essence the
motor is seeing a one-sided AC voltage and as we all know
an AC voltage is much easier to break, even under load,
because it will not sustain the flash-over spark as soon
as the voltage goes down.
I am not intimately familiar with White Zombie, but I
expect that in parallel mode the motor voltage is limited
and there is no WOT (Wide Open Throttle) signal closing
a contactor to bypass the controller and send full pack
voltage to the parallelled motors, or else the pack
voltage could easily burn up the commutators in a
giant flashover (unless the pack is sagging so much
already that it protects the motors ;-) because in such
a case you would have the full DC pack voltage on the
motor, so any starting flashover is sustained.
By limiting the motor voltage, the controller takes an
averaged reading of its output and will continue to
switch the output on and off in a dutycycle to maintain
the average.
For example setting the motor voltage to max 170V with
350V batteries will make the controller switch on almost
50% of the time at maximum.
Added benefit of this switching is the previously mentioned
current multiplication.
NOTE that when the batteries sag, the average motor
voltage can be maintained by switching the output "on"
during a larger part of the cycle.
This will reduce current multiplication, so the batteries
get beaten twice as badly when they sag, not only are
they generating a lot of heat internally but also do they
need to dish out more current to keep the motor power
at the set level.
Cor van de Water
Systems Architect
Email: [EMAIL PROTECTED] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [EMAIL PROTECTED]
Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD# 25925
Fax: +1 408 731 3675 eFAX: +31-87-784-1130
Proxim Wireless Networks eFAX: +1-610-423-5743
Take your network further http://www.proxim.com
--- End Message ---
--- Begin Message ---
The modern switching controllers allow the *motor* current
to me many times larger than the *battery* current, in
particular at low motor RPM.
How? Simple - by sending battery voltage (and current) to
the motor for a very short period of time, which increases
the motor current quickly due to the low motor voltage at
low RPMs.
Then the majority of the time the controller disconnects
the battery from the motor, but since the motor acts as
an inductor, the current keeps flowing for a while, slowly
ramping down. The current flows through special diodes in
the controller output, which prevent the output voltage
from going negative by the motor current pushing through.
In low RPM situations the batteries may supply current
only 20% of the time, while the motor current loops around
through the diodes for the other 80% of the time.
Say the motor current is 500 Amps average, then the average
battery current is 20% or 100 Amps.
When you think this is impossible because energy cannot be
multiplied, it must come from somewhere then please think
about it as a transformer: low current and high voltage go
in at one side, high current at low voltage come out.
The above example may have a 200V battery pack while the
average motor voltage is around 36V.
(Yes, there is some loss in the controller and you can see
that the current goes from 20% to 100% while the voltage
goes from 100% to almost 20% - without loss it should be 40V)
Indeed - current multiplication is only effective when RPMs
are low, but then is exactly when you need it!
The motor current continuing to loop around can be thought of
as a wind-up toy: you can give it a quick turn, after which
is will run for a while, slowly losing speed. If you give it
a quick turn from time to time, it will continue going, just
like the controller giving the motor short bursts of battery
voltage to kick up the motor current, in between it will slowly
decay but as long as the ripple is small you will have a smooth
running motor at a much higher torque than the battery current
would suggest, because most current just loops around in the
motor and controller output diodes.
Hope this clarifies,
Cor van de Water
Systems Architect
Email: [EMAIL PROTECTED] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [EMAIL PROTECTED]
Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD# 25925
Fax: +1 408 731 3675 eFAX: +31-87-784-1130
Proxim Wireless Networks eFAX: +1-610-423-5743
Take your network further http://www.proxim.com
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Behalf Of Dave Wilker
Sent: Saturday, October 21, 2006 12:26 PM
To: [email protected]
Subject: Re: EV controllers? Practical parameters
The only way I know of is a step-down transformer.. Is that what you mean?
Or do you mean torque multiplication?
David C.. Wilker Jr.
USAF (RET)
----- Original Message -----
From: "Ryan Stotts" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Saturday, October 21, 2006 11:44 AM
Subject: Re: EV controllers? Practical parameters
> Steve Condie wrote:
>
>>current multiplication
>
> Hows that work?
>
--- End Message ---
--- Begin Message ---
Cor van de Water wrote:
>The modern switching controllers allow the *motor* current
>to me many times larger than the *battery* current, in
>particular at low motor RPM.
>
>
Nitpick -- they allow AVERAGE battery current to be lower. I recently
requested information (on the evtech list) on any experiments to see if
the high-frequency, low-duty-cycle draws consume at a Peukert's rate of
the average or motor currents, but there don't appear to be any studies.
Cory Cross
>How? Simple - by sending battery voltage (and current) to
>the motor for a very short period of time, which increases
>the motor current quickly due to the low motor voltage at
>low RPMs.
>Then the majority of the time the controller disconnects
>the battery from the motor, but since the motor acts as
>an inductor, the current keeps flowing for a while, slowly
>ramping down. The current flows through special diodes in
>the controller output, which prevent the output voltage
>from going negative by the motor current pushing through.
>
>In low RPM situations the batteries may supply current
>only 20% of the time, while the motor current loops around
>through the diodes for the other 80% of the time.
>Say the motor current is 500 Amps average, then the average
>battery current is 20% or 100 Amps.
>When you think this is impossible because energy cannot be
>multiplied, it must come from somewhere then please think
>about it as a transformer: low current and high voltage go
>in at one side, high current at low voltage come out.
>The above example may have a 200V battery pack while the
>average motor voltage is around 36V.
>(Yes, there is some loss in the controller and you can see
>that the current goes from 20% to 100% while the voltage
>goes from 100% to almost 20% - without loss it should be 40V)
>
>Indeed - current multiplication is only effective when RPMs
>are low, but then is exactly when you need it!
>
>The motor current continuing to loop around can be thought of
>as a wind-up toy: you can give it a quick turn, after which
>is will run for a while, slowly losing speed. If you give it
>a quick turn from time to time, it will continue going, just
>like the controller giving the motor short bursts of battery
>voltage to kick up the motor current, in between it will slowly
>decay but as long as the ripple is small you will have a smooth
>running motor at a much higher torque than the battery current
>would suggest, because most current just loops around in the
>motor and controller output diodes.
>
>Hope this clarifies,
>
>Cor van de Water
>Systems Architect
>Email: [EMAIL PROTECTED] Private: http://www.cvandewater.com
>Skype: cor_van_de_water IM: [EMAIL PROTECTED]
>Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD# 25925
>Fax: +1 408 731 3675 eFAX: +31-87-784-1130
>Proxim Wireless Networks eFAX: +1-610-423-5743
>Take your network further http://www.proxim.com
>
>
>-----Original Message-----
>From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
>Behalf Of Dave Wilker
>Sent: Saturday, October 21, 2006 12:26 PM
>To: [email protected]
>Subject: Re: EV controllers? Practical parameters
>
>
>The only way I know of is a step-down transformer.. Is that what you mean?
>Or do you mean torque multiplication?
>
>
>
>David C.. Wilker Jr.
>USAF (RET)
>----- Original Message -----
>From: "Ryan Stotts" <[EMAIL PROTECTED]>
>To: <[email protected]>
>Sent: Saturday, October 21, 2006 11:44 AM
>Subject: Re: EV controllers? Practical parameters
>
>
>
>
>>Steve Condie wrote:
>>
>>
>>
>>>current multiplication
>>>
>>>
>>Hows that work?
>>
>>
>>
>
>
>
--- End Message ---
--- Begin Message ---
Hi Mike, Nate and All,
----- Original Message Follows -----
From: "Mike Phillips" <[EMAIL PROTECTED]>
To: "England Nathan-r25543" <[email protected]>
Subject: Re: Ni-Cad Cell Reversal
Date: Sat, 21 Oct 2006 14:41:41 -0000
>When I can slow down a minute to stop enjoying all the
>driving I'm doing on them, I plan to put one cell in that
>is nearly discharged and then drive the truck to see what
>happens when it reverses. I'll report the results here.
Don't do that!!!
It's one thing to have a slightly out of balance cell
reverse for a short while as the pack voltage starts
dropping fast as the others go to 0, but to put a dead one,
then drive on it at higher amps for several miles is going
to put a lot of energy into that batt, melting it or worse.
Kind of depends on whether it boils it's water out first or
shorts!! Neither is good and will probably ruin the cell and
maybe melt things around it. BB600's are good but not
indestructable!!
Matched cells like the BB600 will stay balanced very
well if you follow their instruction or replace 105% more in
them than you took out, the best way.
The way to reduce watering is charge them to 95% for
4-5 days, then give them a 110-115% overcharge will cut
watering 1/2 to 2/3's I found on my SAFT cells like BB600's,
only smaller at 16 amphrs I use in my small bike/trike EV's.
They are over 30 yrs old and still putting out their rated
power.
I have 96vdc of BB600's I'm looking for a project to
put them in or use them and some more as a racing batt pack
for the Freedom EV. I just found my stash of copper bars
1/8"x 3/4" x 8'. Now just have to find a chrome place to
plate them of maybe try it myself.
I wonder if you could use SS as sacrificial metal to
plate it? What electrolyte?
BB600 are just about perfect for higher voltage
systems replacing YT's, Orbitals or the buddy paired Hawker
systems, costing much less than any of them while lasting
20+ yrs, added to no capacity loss in cold weather, able to
discharge deeper without life problems or let it sit without
charging without damage.
With good charging you shouldn't need to water but
every 2 months by under charging it a little most of the
time. If you design you battery boxes so it's easy to water,
make, get a cap removal tool, then it's little problem and
you get excellent, inexpensive batteries that last 20+ yrs
for a very low price, 1/4 of AGM's over 20 yrs!!
Jerry Dycus
>
>Mike
>
>
>
>--- In [EMAIL PROTECTED], "England
>Nathan-r25543" <[EMAIL PROTECTED]> wrote:
>>
>> What happens to a NiCad cell when it is reversed? I hear
>> this is bad so does it kill the cell dead to the point it
>> is useless?
>> Thanks,
>>
>> Nate
>>
>
>
>
--- End Message ---
--- Begin Message ---
G'day Cor, and All
At 05:05 PM 21/10/06 -0700, Cor van de Water wrote:
It has been bugging me for a while, but while writing the
previous post about current multiplication I suddenly
realized how you can limit motor voltage even while the
controller sends 350V from the battery to a motor that
cannot take more than 170V without dying from arcing
(See John Wayland's run where the burnout tricked the
Zilla in thinking it was time to switch to parallel
mode and full-on because of the high RPMs....
BIG SPARK under White Zombie.
I have a theory about that, when the S/P contactor changeover occurs, the
motors are momentarily open circuit, so the collapsing magnetic field has
nowhere to go (normally goes through the freewheel diodes) and generated a
high voltage spike, initiating the flashover that continued as soon as the
parallel contactors closed.
<snip>I am not intimately familiar with White Zombie, but I
expect that in parallel mode the motor voltage is limited
and there is no WOT (Wide Open Throttle) signal closing
a contactor to bypass the controller
IIRC Otmar stated in a post once that Zillas do not go 100% on, ever. The
maximum is something like 99.8%, with the power stage going off momentarily
every fraction of a second when WOT to make sure that it hasn't failed.
This may be a contributing factor to suppressing flash-overs at higher
voltages. Bypass contactors are for SCR controllers and once upon a time a
mad drag racer with a white Datsun had one for a while (and welded it shut).
and send full pack
voltage to the parallelled motors, or else the pack
voltage could easily burn up the commutators in a
giant flashover (unless the pack is sagging so much
Again, IIRC, John has stated that his battery pack sags to near or below
200V at maximum battery amps, so that yes, that protects the motors some.
By limiting the motor voltage, the controller takes an
averaged reading of its output and will continue to
switch the output on and off in a dutycycle to maintain
the average.
For example setting the motor voltage to max 170V with
350V batteries will make the controller switch on almost
50% of the time at maximum.
Correct. So the motors are seeing full pack voltage every on-pulse, and an
average voltage as per the limit programmed.
Hope this helps
Regards
[Technik] James
--- End Message ---
--- Begin Message ---
Hi Cory,
Good controllers have large capacitors at the battery input
for this very reason - to smooth out the short pulses into
a constant battery current with very small ripple.
It is indeed a measure of how good the controller is, with
most SCR controllers this smoothing is not present, so they
will peak the same batetry current as the motor sees, making
the Peukert effect take a larger toll, that is why Lee
suggested to add large capacitors at the input of an SCR
controller, to increase range by drawing a constant current
from the batteries instead of short high peaks.
So - it depends on the controller!
BTW, in my 700V 250A AC controller more than half the volume
of the controller is taken up by 8 huge capacitors.
I think they are switched as 2 series groups of 4 parallel
if they are using standard 400V electrolytes, but I have
not cut that deep into my controller yet.
I have a salvage VFD (Variable Frequency Drive) that is
specified for 600V 3 phase and it also has 2 banks of
capacitors switched in series to take the voltage.
Note that the higher the switching frequency, the smaller
the capacitors can be, as long as their internal resistance
is low enough to take the AC current of the charging and
in particular the discharging peaks.
Cor van de Water
Systems Architect
Email: [EMAIL PROTECTED] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [EMAIL PROTECTED]
Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD# 25925
Fax: +1 408 731 3675 eFAX: +31-87-784-1130
Proxim Wireless Networks eFAX: +1-610-423-5743
Take your network further http://www.proxim.com
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Behalf Of Cory Cross
Sent: Saturday, October 21, 2006 5:18 PM
To: [email protected]
Subject: Re: Current multiplication, was: EV controllers? Practical
parameters
Cor van de Water wrote:
>The modern switching controllers allow the *motor* current
>to me many times larger than the *battery* current, in
>particular at low motor RPM.
>
>
Nitpick -- they allow AVERAGE battery current to be lower. I recently
requested information (on the evtech list) on any experiments to see if
the high-frequency, low-duty-cycle draws consume at a Peukert's rate of
the average or motor currents, but there don't appear to be any studies.
Cory Cross
>How? Simple - by sending battery voltage (and current) to
>the motor for a very short period of time, which increases
>the motor current quickly due to the low motor voltage at
>low RPMs.
>Then the majority of the time the controller disconnects
>the battery from the motor, but since the motor acts as
>an inductor, the current keeps flowing for a while, slowly
>ramping down. The current flows through special diodes in
>the controller output, which prevent the output voltage
>from going negative by the motor current pushing through.
>
>In low RPM situations the batteries may supply current
>only 20% of the time, while the motor current loops around
>through the diodes for the other 80% of the time.
>Say the motor current is 500 Amps average, then the average
>battery current is 20% or 100 Amps.
>When you think this is impossible because energy cannot be
>multiplied, it must come from somewhere then please think
>about it as a transformer: low current and high voltage go
>in at one side, high current at low voltage come out.
>The above example may have a 200V battery pack while the
>average motor voltage is around 36V.
>(Yes, there is some loss in the controller and you can see
>that the current goes from 20% to 100% while the voltage
>goes from 100% to almost 20% - without loss it should be 40V)
>
>Indeed - current multiplication is only effective when RPMs
>are low, but then is exactly when you need it!
>
>The motor current continuing to loop around can be thought of
>as a wind-up toy: you can give it a quick turn, after which
>is will run for a while, slowly losing speed. If you give it
>a quick turn from time to time, it will continue going, just
>like the controller giving the motor short bursts of battery
>voltage to kick up the motor current, in between it will slowly
>decay but as long as the ripple is small you will have a smooth
>running motor at a much higher torque than the battery current
>would suggest, because most current just loops around in the
>motor and controller output diodes.
>
>Hope this clarifies,
>
>Cor van de Water
>Systems Architect
>Email: [EMAIL PROTECTED] Private: http://www.cvandewater.com
>Skype: cor_van_de_water IM: [EMAIL PROTECTED]
>Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD# 25925
>Fax: +1 408 731 3675 eFAX: +31-87-784-1130
>Proxim Wireless Networks eFAX: +1-610-423-5743
>Take your network further http://www.proxim.com
>
>
>-----Original Message-----
>From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
>Behalf Of Dave Wilker
>Sent: Saturday, October 21, 2006 12:26 PM
>To: [email protected]
>Subject: Re: EV controllers? Practical parameters
>
>
>The only way I know of is a step-down transformer.. Is that what you mean?
>Or do you mean torque multiplication?
>
>
>
>David C.. Wilker Jr.
>USAF (RET)
>----- Original Message -----
>From: "Ryan Stotts" <[EMAIL PROTECTED]>
>To: <[email protected]>
>Sent: Saturday, October 21, 2006 11:44 AM
>Subject: Re: EV controllers? Practical parameters
>
>
>
>
>>Steve Condie wrote:
>>
>>
>>
>>>current multiplication
>>>
>>>
>>Hows that work?
>>
>>
>>
>
>
>
--- End Message ---
--- Begin Message ---
Well, John, I need a controller for a conversion I am doing this winter.
Since it is for a customer, I would prefer a new one, but I can't wait 6
months on a Z1K. Anyone out there have a new Raptor that you would sell to
upgrade to a Zilla, and you can wait that long?
I may have to go with a Cursit, but I'd prefer not to; If I do, can someone
help me with a precharge circuit? I can build it, but not design it.
Joseph H. Strubhar
E-mail: [EMAIL PROTECTED]
Web: www.gremcoinc.com
----- Original Message -----
From: "John Wayland" <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Saturday, October 21, 2006 11:38 AM
Subject: Re: EV controllers? the 4th option...
> Hello to All,
>
> Roger Stockton wrote:
>
> >
> >What DC'ers need is a Curtis-killer, not something that tries to compete
> >with Otmar's already excellent offerings.
> >
> >
>
> Stop it Roger, that makes too much sense! Considering how lame the
> Curtis is, a 'Curtis Killer' isn't much of a challenge.
>
> >We need an updated Raptor 600. Forget the series-parallel shifting and
> >even the electric reverse; if someone is going direct drive or with dual
> >motors, they're probably going to want the extra oomph of at least a Z1K
> >anyway. Forget the 1000+ amps; if someone wants 1000A, they'll buy a
> >Z1K; if they want more, a Z2K.
> >
> >
>
> Stop it Roger, that makes too much sense!
>
> >96V to perhaps 192V is going to cover most anyone who
> >would have bought this controller instead of a Curtis or being pushed
> >into a Zilla due to choosing a pack voltage over 144V.
> >
> >
>
> Stop it Roger, that makes too much sense!
>
> >My essential spec/feature list for a Curtis-Killer is:
> >
> >- 600 adjustable battery amps
> >
> >- handles at least the range of 96-144V; 156V is almost essential, and
> >up to ~200V would be even better
> >
> >- precharge/contactor control
> >
> >- basic fault detection (open/short throttle, high pedal lockout)
> >
> >- rev limiter (and a tach drive output sure would be nice)
> >
> >- integrated heatsink (water-cooled is preferable
> >
> >- priced on par with 1231C + appropriate heatsink.
> >
> >- contactor failure detection
> >
> >- controller failure detection & auto contactor dropout
> >
> >
> >
> Roger, how on earth does one come up with such a wonderfully thought-out
> wish list, and leave out
> 'silent operation-no Curtis squeal!'???? Or, did you assume that no one
> in their right mind would ever again, design a road-going EV controller
> to make such an awful, irritating noise?
>
> From Mike Sandman:
>
> >I just ordered a kit from KTA using a 1231C-7701 for my 120v system.
>
> I'm curious Mike, did they tell you up front that this controller will
> cause your EV's drive motor to make an irritating non-varying squeal
> when you take off or cruise with a light throttle? Did they tell you
> that this controller has no safety features? Did they tell you it has no
> automatic precharge, and that if you don't design your own, it could
> blow up when the line contactor engages and send your EV off at full
> throttle? Did they tell you it cannot be adjusted for a battery input
> current limit to protect your battery pack investment? My guess is no to
> all the above.
>
> If it's not too late, you could save a bundle by purchasing a used
> Curtis 1221B controller. It's a bit less powerful at 400 amps, but it's
> silent and you could get one for maybe $300 if anyone has one available.
> The money saved would allow you to build a precharge circuit and pocket
> at least $500 cash, too. Better still, a used Raptor 600 could be found
> for maybe $800, is silent, properly cooled, has dip switch programming,
> and 900 amps motor loop current.
>
> I understand having to watch one's EV budget, but with one as high as
> $15k the last area I would have cut costs on would be on the all
> important motor controller. You may have saved $500-$600 by stepping
> w-a-ay down to the Curtis, but you gave up a lot of features that would
> have made your conversion more fun, far more pleasant, much smoother,
> more versatile, twice as powerful, and far safer, and...you gained a lot
> of negatives as described above.
>
> From Steve Powers:
>
> >When you get to more than 600 batt amps, you are really killing the pack.
>
>
>
> Is this one of those comments again, where one has to have read
> everything that came before and know that you might be talking about wet
> cell type batteries (and just didn't specify this), or do you really
> think that currents this low will harm powerful AGMs like Optimas,
> Hawkers, and Orbitals? Those of us using AGMs of higher quality know
> that the opposite is true, in that the high performance type AGMs
> actually give their best service life routinely dishing out BIG
> currents. 600 amps from the better AGMs is nothing. The Optimas in Blue
> Meanie lasted 6.5 years, and pretty close to each time it was taken out
> for a run, 1000 amps were sucked from them multiple times. Sure, under
> all out racing where you might suck 1000 amps from small 24.5 lb.
> batteries for 12 continuous seconds, it is stressful and sometimes fatal
> for the batteries, but for normal fun street driving 1000 amps for 5-6
> seconds from larger 40+ lb. AGMs is kid's stuff....besides, you're
> already well above the speed limit in that amount of time and will be
> off throttle and back to sub 100 amp levels.
>
> One more item to be added to Roger's list...compact size. Oat's Z1K's
> small near cube-shaped super compact size is not only amazing
> considering the thing cranks out 1000 full amps, it's also a blessing in
> an already crowded under-hood compartment. Though my experiences with
> the DCP Raptor 1200 were nothing but positive, its large bulky size was
> not a plus.
>
> See Ya......John Wayland
>
>
>
>
>
>
>
>
>
>
> --
> No virus found in this incoming message.
> Checked by AVG Free Edition.
> Version: 7.1.408 / Virus Database: 268.13.9/490 - Release Date: 10/20/2006
>
>
--- End Message ---
