EV Digest 6384
Topics covered in this issue include:
1) Re: Using GPS for measure performance (was Re: wind resistance (
was where to start )
by Tom Parker <[EMAIL PROTECTED]>
2) Re: Motor Controller for Capacitor Powered Vehicle
by "Bruce" <[EMAIL PROTECTED]>
3) Re: Speaking of Hybrids -rear wheel drive
by Jack Murray <[EMAIL PROTECTED]>
4) Re: Speaking of Hybrids
by "Bruce" <[EMAIL PROTECTED]>
5) Re: BBB pictures, Traction wiring inside the car.
by "Mike Harvey" <[EMAIL PROTECTED]>
6) RE: Getting juice from a light pole
by "Randy Burleson" <[EMAIL PROTECTED]>
7) When a controller fails... question
by "Darin - at - metrompg.com" <[EMAIL PROTECTED]>
8) Re: Motor Controller for Capacitor Powered Vehicle
by Danny Miller <[EMAIL PROTECTED]>
9) Re: Series Hybrid ( was RE: EV digest 6372)
by Danny Miller <[EMAIL PROTECTED]>
10) RE: When a controller fails... question
by Cor van de Water <[EMAIL PROTECTED]>
11) RE: Getting juice from a light pole
by Cor van de Water <[EMAIL PROTECTED]>
12) RE: Wiring a momentary voltage doubler for a contactor - diode?
by Cor van de Water <[EMAIL PROTECTED]>
13) FW: NOVA: Car of the Future -- Open Production
by Mike Willmon <[EMAIL PROTECTED]>
14) NOVA: Car of the Future -- Open Production
by Mike Willmon <[EMAIL PROTECTED]>
15) Re: BBB pictures
by Chip Gribben <[EMAIL PROTECTED]>
16) RE: BBB pictures, Traction wiring inside the car.
by "Shawn Waggoner, FLEAA" <[EMAIL PROTECTED]>
17) Re: When a controller fails... question
by "Darin - at - metrompg.com" <[EMAIL PROTECTED]>
18) RE:Jim Husted or other motor Guru's..
by "Mark Fisher" <[EMAIL PROTECTED]>
19) RE: Hub Motor Gear Ratio, was RE: EV digest 6380 (motor Guru)
by "Mark Fisher" <[EMAIL PROTECTED]>
20) Battronic of Boyertown, PA
by [EMAIL PROTECTED]
21) Re: Series Hybrid ( was RE: EV digest 6372)
by "David Roden" <[EMAIL PROTECTED]>
22) Re: Pot box issues - need a source for replacement resistive element for
PB-6
by Jeff Major <[EMAIL PROTECTED]>
23) Re: When a controller fails... question
by "Peter VanDerWal" <[EMAIL PROTECTED]>
--- Begin Message ---
On Mon, 2007-01-22 at 09:54 -0700, Peter VanDerWal wrote:
> The problem is, the altitude reading isn't stable. It cycles through
> readings that vary by up to ~70 feet. The swing takes maybe a minute to
> go from high to low and then starts up again. Not a big deal for a weather
> station, but getting the size of a hill wrong by 70 feet can really throw
> off your calculations when figuring EV performance.
My GPS with the antenna on the roof of the car doesn't seem to show
significant altitude variations, I've driven the same hills several
times and they were always close to the same height. I did try the built
in antenna with the unit by the windscreen on the dashboard, and this
produced large variations in height while driving the same hills. I
never explicitly checked the stationary case.
I've finished my analysis program, though currently it's a command line
thing, not a webpage. You can see the results for my car here:
http://carrott.org/cgi-bin/twiki/view/Main/RollingResistance
I'll make the program itself available shortly. It automatically detects
downhill sections and only displays those, so all I do is feed in my
track data, and I get a set of graphs, including the velocity-power plot
you can see above.
--- End Message ---
--- Begin Message ---
Lee, please explain more about how this standard switchmode power supply is
different from a DC-DC converter. Wouldn't it still have the same ~15%
efficiency loss?
Is there a way to eliminate the power supply or DC-DC converter entirely so
as to not incur the efficiency loss? That's why I thought you could add a
simple circuit to the controller to limit the current based on the voltage
level.
Are there any other approaches worth examining?
Thanks!
Bruce
----- Original Message -----
From: "Lee Hart" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Saturday, February 03, 2007 2:17 PM
Subject: Re: Motor Controller for Capacitor Powered Vehicle
> Bruce wrote:
> > How would you design a circuit to allow a constant number of Watts to be
> > available at any time from a capacitor bank?
>
> Any standard switchmode power supply already does this.
>
> Suppose you buy a supply with a "universal" input. They typically work
> from 85-265vac, which is the same as 120-370vdc. Say the output is 12v
> at 12a. If you connect a 1-ohm resistor to its output, it will deliver a
> constant 12v x 12a = 144 watts over the entire input voltage range,
> automatically adjusting its input current as needed.
>
> Some supplies of this sort can handle as much as a 4:1 input voltage
> range. They need design changes to cover a wider range or work with
> different input voltages, but the principle is the same.
>
> --
> Ring the bells that still can ring
> Forget the perfect offering
> There is a crack in everything
> That's how the light gets in -- Leonard Cohen
> --
> Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
>
>
--- End Message ---
--- Begin Message ---
There are other belts I could try, but they are rather expensive, seems
about $400-500 to get something else, which is a lot of expensive to
find out it won't work.
The issue using a planetary gear system is getting it to interface with
the half shafts and motor, they would take custom couplings that can
cost more than the gears. One thought I have is to take an existing
transaxle that already connects to the half shaft, and reduce it down to
just the differential portion with the final drive gear. At least on
the AXOD transaxle there is a planetary gearset that drive the
differential that connects to the half shafts.
If I can set it up to turn the input shaft to the differential, it would
be a good way to do it. A transaxle isn't particular inexpensive,
although if you buy a whole car they can come cheap.
Or perhaps use a complete manual transaxle, although it will add
significant weight, it can be put in neutral to eliminate the electric
motor drag and in fact not worry about over-reving the electric motor
when at 70mph freeway speeds under ICE power.
Jack
keith vansickle wrote:
try using a motorcycle belt drive from something like
a harley...they can take lots of torque and are
quiet...I also am thinking about a motor driven wheel
hook up that uses a planetary gear system...has anyone
done this...where do you get a planetary gear setup???
--- Frank John <[EMAIL PROTECTED]> wrote:
Jack, how well are the sprockets aligned? Also if
you use an o-ring chain it should be a bit quieter.
----- Original Message ----
From: Jack Murray <[EMAIL PROTECTED]>
To: ev@listproc.sjsu.edu
Sent: Saturday, February 3, 2007 8:37:57 PM
Subject: Speaking of Hybrids
I think a good way to do a plug-in hybrid is to take
a FWD car, and add
an electric motor to drive the rear wheels.
Then you can use the electric motor around town, and
use the gas motor
on the freeway.
I've been building just such a car, I've converted
one rear wheel into a
driven wheel powered by an electric motor.
However, I'm having trouble and could use some
suggestions. I
originally used a 1" wide belt drive to power the
wheel, but the belt would
slip when enough torque was applied to move the car.
So I've changed it to use a chain drive. The
problem now is the chain
makes a huge amount of noise! more noise than ICE
does.
Has anyone else done a chain or belt drive setup?
Are there chain
drives that are not so noisy? Or belts that can
handle a lot of torque.
A 3" wide belt?
I'm considering trying the snowmobile CVT setup, but
its a little
expensive for this project.
Thanks,
Jack
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--- End Message ---
--- Begin Message ---
Jack, in my experience, a chain driven motorcycle produces quite a bit of
noise. Perhaps the gas motor sound masks it a bit. Seems like the shaft
drive bikes are much quieter.
As to the Gilmer tooth belts used on Harleys, they are a little quieter, but
still make much more noise than a shaft drive. If I remember correctly, you
can still hear the blower drive noise over the exhaust noise on a
supercharged street rod.
My guess for the source of the noise is the rollers as they hit the sprocket
for a chain or the cogs hitting the grooves for a belt. I think there are
cog belt drives that use a chevron pattern for the cogs rather than the
straight perpendicular cogs. That would ensure that one cog is still
engaged before the last one released. Sort of like the difference between
straight cut gears and a hypoid drive differential.
As to other practical methods to reduce the chain noise in your car. I
would lube the chain very generously. Use that really sticky motorcycle
chain lube and slather it on, at least once. Also, you could enclose the
chain in a case, though that may not be easy. If it was in a chaincase, you
could run it in an oil bath and not have to lube it manually.
Hope this helps. I'd love to see a picture of the drive on your vehicle.
It sounds like this car could be really good.
Bruce
----- Original Message -----
From: "Jack Murray" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Sunday, February 04, 2007 7:32 PM
Subject: Re: Speaking of Hybrids
> I believe the sprockets are aligned correctly. I did notice when they
> were off a little it made a lot more noise, but with it straight it
> still makes way too much noise. I don't quite understand how it makes
> so much noise, a motorcycle with a chain does not make this kind of
> noise. Basically the noise seems to come from the sides of the chain
> slapping onto the sprocket at the drive end. I thought maybe the chain
> was too tight, loosened it and still same noise.
>
> What I think I might try next is using a nylon sprocket on the motor.
> I don't know if it can handle the torque or not, but at $21 it is an
> inexpensive option to try.
>
> Jack
>
> Frank John wrote:
> > Jack, how well are the sprockets aligned? Also if you use an o-ring
chain it should be a bit quieter.
> >
> > ----- Original Message ----
> > From: Jack Murray <[EMAIL PROTECTED]>
> > To: ev@listproc.sjsu.edu
> > Sent: Saturday, February 3, 2007 8:37:57 PM
> > Subject: Speaking of Hybrids
> >
> > I think a good way to do a plug-in hybrid is to take a FWD car, and add
> > an electric motor to drive the rear wheels.
> > Then you can use the electric motor around town, and use the gas motor
> > on the freeway.
> >
> > I've been building just such a car, I've converted one rear wheel into a
> > driven wheel powered by an electric motor.
> > However, I'm having trouble and could use some suggestions. I
> > originally used a 1" wide belt drive to power the wheel, but the belt
would
> > slip when enough torque was applied to move the car.
> > So I've changed it to use a chain drive. The problem now is the chain
> > makes a huge amount of noise! more noise than ICE does.
> > Has anyone else done a chain or belt drive setup? Are there chain
> > drives that are not so noisy? Or belts that can handle a lot of torque.
> > A 3" wide belt?
> > I'm considering trying the snowmobile CVT setup, but its a little
> > expensive for this project.
> >
> > Thanks,
> > Jack
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
____________________________________________________________________________
________
> > Do you Yahoo!?
> > Everyone is raving about the all-new Yahoo! Mail beta.
> > http://new.mail.yahoo.com
> >
> >
>
>
--- End Message ---
--- Begin Message ---
The +rev was done by Florida Instituteof Tech. They have a website at
http://my.fit.edu/rev/. Very impressive work.
----- Original Message -----
From: "Bruce Weisenberger" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Sunday, February 04, 2007 9:53 PM
Subject: Re: BBB pictures, Traction wiring inside the car.
The Solar 3 wheeler was 48 volts as described by the
website www.xlr8sun.com. A light weight production
vehicle no less. I looked it up as I thought it was
interesting. While 48 volts is not too bad it should
be covered.
Anyone want to fess up who owns the +rev it was
picture 23. I have some personal questions regarding
the frame and suspension system. Who ever can contact
me directly.
--- Bill Dube <[EMAIL PROTECTED]> wrote:
-Snip-
Of the drag race vehicles I did look at, the only one
that seemed like it might have exposed traction wiring
in the driver's compartment was the solar-powered
three-wheeled vehicle. I'm not sure what its voltage
was, however.
-Snip-
____________________________________________________________________________________
Do you Yahoo!?
Everyone is raving about the all-new Yahoo! Mail beta.
http://new.mail.yahoo.com
--- End Message ---
--- Begin Message ---
> I talked to the building manager and asked if there was any way I
> could pay to have an outlet installed on one of the dozens of light
> poles that can be found in the parking area surrounding the building.
> He said they might be able to get something like that approved but he
> doesn't know if it's technically feasable.
That's incredibly kind of him -- even if you do support the GFCI outlet
and hookup, your company foots the bill for juice.
I wish my company would pay for my fuel!
Randii
--- End Message ---
--- Begin Message ---
I understand that controllers can & do fail "on"... Full Monty.
But when a controller's smoke comes out, does it fail within its rated
amp limit, or does it send full pack juice to the motor?
IE "I, Curtis, being of sound mind and body, do hereby bequeath all my
worldly amps to thee (which I've been keeping from you until this very
moment. Enjoy!)"
Darin
--- End Message ---
--- Begin Message ---
A DC-DC converter does not have a "standard" efficiency loss.
The trouble is that, to meet a kilowatt spec requirement over a 4:1
input range, it might need to deliver say 20 amps @ 3000V and 80 amps @
750V. So you need both high voltage and high current transistors and
interconnects/PCB traces.
Ripple current is basically = 1/(freq*inductance). When the ratio of
input to output voltage is larger, the inductance of the motor may not
in itself be sufficient to make an acceptable ripple. This may mean the
converter may need to add its own inductance. Now we have a problem
because again we have to have a large inductance to handle the largest
vin/vout ratio, but it also has to have a current rating to handle the
high currents of the lowest vin/vout ratio.
Danny
Bruce wrote:
Lee, please explain more about how this standard switchmode power supply is
different from a DC-DC converter. Wouldn't it still have the same ~15%
efficiency loss?
Is there a way to eliminate the power supply or DC-DC converter entirely so
as to not incur the efficiency loss? That's why I thought you could add a
simple circuit to the controller to limit the current based on the voltage
level.
Are there any other approaches worth examining?
Thanks!
Bruce
----- Original Message -----
From: "Lee Hart" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Saturday, February 03, 2007 2:17 PM
Subject: Re: Motor Controller for Capacitor Powered Vehicle
Bruce wrote:
How would you design a circuit to allow a constant number of Watts to be
available at any time from a capacitor bank?
Any standard switchmode power supply already does this.
Suppose you buy a supply with a "universal" input. They typically work
from 85-265vac, which is the same as 120-370vdc. Say the output is 12v
at 12a. If you connect a 1-ohm resistor to its output, it will deliver a
constant 12v x 12a = 144 watts over the entire input voltage range,
automatically adjusting its input current as needed.
Some supplies of this sort can handle as much as a 4:1 input voltage
range. They need design changes to cover a wider range or work with
different input voltages, but the principle is the same.
--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in -- Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
Well, let's look at these claims.
80km/hr ~= 50mph
57kW/50mph=1.14kwh/mi.
(14.8miles/gal)*(1.14kwh/mi)=16.872 kwh/gal
(16.872 kwh/gal) / (0.746 kw/hp * 6 lb/gal) = 3.769 hp-hr/lb
reciprocal makes 0.265 lb/hp-hr
Now go to:
http://en.wikipedia.org/wiki/Specific_fuel_consumption
to put this in perspective. An Otto-cycle 4-stroke uses 0.5 lb/hp-hr.
0.265 is in line with the best designed and tuned engines ever, which
are not Ottos. It doesn't make sense that just running at one rpm and
throtttle would make it run better than these superengines. If so they
there would be no reason for that superengine to be designed! And we've
already erred here- to get that mpg, wow, the engine would need to be
better than 0.265 lb/hp-hr to make up for the generating losses. This
may well require the most efficient engine on record!
What am I saying? Well they either fudged their numbers or they've got
an extremely efficient prototype engine there (not completely
implausible). If they've got something magic going it's in the engine.
I'm maintaining that any off-the-shelf genny will not have a remarkable
lb/hp-hr consumption and no amount of amateur tuning is going to make it
jump up a lot.
Generator efficiencies are not hard to look up. At least you can just
look up tank capacity, power output, and specified runtime. For
example, EU3000i- a state-of-the-art inverter 4 stroke generator- is
3.43 gal tank, 2.8kva electrical output, 7.2 hr runtime per tank. I get
0.762 lb/hr-hr (note this includes electrical generator losses). It's
tuned to be a generator which operates at the optimum RPM for a given
load so it's not realistic to improve that device by tinkering. I know
there are industrial generators which get a bit better efficiency than
that (you'd certainly need a bigger one).
Danny
Aaron Quinto wrote:
I hope this isn't adding fuel to the fire, but I was somehow directed
to this site some months ago:
http://www.e-traction.com/whisper_2.htm
There's a graph at the bottom of the page that shows this company's
"series hybrid" bus getting 14.8 mpg on the highway, versus a standard
diesel bus that gets 3.5 mpg. Now granted, it does cost 240,000 Euros
or $311,000 US, but that also means that this 18,000 lb. bus has about
20% better fuel economy than my 5,000 lb. work van.
This is the type of vehicle I expect to see in the near future, but on
a smaller scale. Here was the quote that I remembered about the bus:
"maintain a speed of 80 km/hr with only 57 kW."
I didn't want to send this until I found the page referencing the
batteries: http://www.e-traction.com/technical_specifications.htm
"28 Lithium-Ion batteries @ 40Ah each," but "Super-capacitors are also
being considered."
Aaron Quinto
At 01:20 PM 02/02/2007, you wrote:
Joseph Lado wrote:
> Peter, you are mistaken. You are one of the people readers look to
for
answers on this list, however, you have got to get your numbers
straight
and really investigate your opinion on this mater, because you don't
have it
right. Series hybrids are less polluting and are more efficient than
using a
gasoline engine alone by a factor of three without counting regenerative
braking and the advantages of using batteries.
Joseph, can you please provide the literature/information that backs
up your
claims? I have only read a little bit (the research done by AC
Propulsion),
and they are getting about 30mpg with a genset. No so good...
--- End Message ---
--- Begin Message ---
Darin,
How do you think that rated amp limits are maintained normally?
Exactly - the controller switches off periodically.
If a controller fails full on, well - then it's full on.
In essence it is a dead short between battery input and motor
output. No more limits enforced - all the short-circuit current
the battery can deliver goes into torque to keep the motor moving
while you are braking to try to keep the vehicle under control.
If you have a way to disengage the battery input, this would be
a good time to active it. (for example a pull-cord on a breaker
or a knife-switch or even the throttle-microswitch which is in
the contactor's coil circuit, so to cut battery power you only
need to lift your foot from the accelerator.
If you have neither of these, then I hope your brakes are very
strong and you have something soft and cheap to run into nearby.
(Or a sand path that is loose enough to get stuck in, so the
driven wheels dig holes and you won't go anywhere anymore,
allowing you to get out and quickly disconnect a contact in the
battery pack or pull the fuse for the contactor circuit or
something like that....)
Cor van de Water
Systems Architect
Proxim Wireless Corporation http://www.proxim.com
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
Second Life: www.secondlife.com/?u=3b42cb3f4ae249319edb487991c30acb
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Behalf Of Darin - at - metrompg.com
Sent: Sunday, February 04, 2007 6:54 PM
To: Electric Vehicle Discussion List
Subject: When a controller fails... question
I understand that controllers can & do fail "on"... Full Monty.
But when a controller's smoke comes out, does it fail within its rated
amp limit, or does it send full pack juice to the motor?
IE "I, Curtis, being of sound mind and body, do hereby bequeath all my
worldly amps to thee (which I've been keeping from you until this very
moment. Enjoy!)"
Darin
--- End Message ---
--- Begin Message ---
Yup, no outside outlets, just lights.
Since our building is leased, it is not likely that something
dedicated will be installed.
There used to be door contacts and control boxes on some side-doors
which have left 1/2" holes in the alu profile frames.
That would be my preferred way to run power outside, though it may
not be seen as a safe solution.
The other way is to find a recepticle on the roof in a place where
you can drop an extension cord down that is not in plain sight and
can be tied down to something, then modify the cord to have a
non-standard plug - either twist-lock 110V if you still need 110
or use a NEMA 6-20 if you can use 240V - this won't allow plugging
in a standard plug.
In addition, you can put the system on timer to be only on during
work time, further reducing the possibility of problems.
Cor van de Water
Systems Architect
Proxim Wireless Corporation http://www.proxim.com
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
Second Life: www.secondlife.com/?u=3b42cb3f4ae249319edb487991c30acb
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Behalf Of Matt Kenigson
Sent: Sunday, February 04, 2007 3:34 PM
To: ev@listproc.sjsu.edu
Subject: Getting juice from a light pole
Howdy,
I work at one of those modern marble, steel, and glass office
buildings that have gotten popular of late. It was built with
absolutely no external outlets. I talked to the building manager and
asked if there was any way I could pay to have an outlet installed on
one of the dozens of light poles that can be found in the parking area
surrounding the building. He said they might be able to get something
like that approved but he doesn't know if it's technically feasable.
He said that in order to reduce conduction losses and use less
expensive wiring, the power to the poles is delivered at a high
voltage. I don't recall the exact voltage he said, but I think it may
have been around 480 volts. I have no idea what the amperage is.
I suppose I really need to find out the precise specs. I was hoping,
though, to be able to do a little research into transformers and get a
general idea of what the cost and physical dimensions might be before
engaging the building management in a more serious discussion about
the project. Plus, I'd like to find out if it's possible to do
something like this in a way that I could possibly take with me if I
change jobs sometime in the future.
If I can just get 5A for eight hours while I'm in the building, it
will give me the ability to go out for lunch and raise my range by
50%. To me, that's a slam-dunk.
Anyway, can you guys (and gals) give me any pointers on where to start
looking and what kinds of options I might have. Obviously, it would
help if I had precise specs but anything you can do to help me prepare
for the conversation would be really appreciated. Thanks!
Matt
--- End Message ---
--- Begin Message ---
Hi Lee,
No - I did not remember it, I re-created it by reasoning what a
voltage-doubler would need, in pencil on an envelope, then I
drew the ASCII art.
In fact, I started with the bare essential components: D2, R1, C1
and a short-circuited D1, so essentially C1 and D2 are in parallel
as shown in the alternative drawing by Paul 'neon' G.
Though there is no reason to switch the diode as his schematic
shows and that defeats the possible conversion to push-button, or
you need more than one hold-circuit.
BTW, I have a contactor with less than 1 Ohm resistance, it draws
well over 10A at a 12V battery. If your coil has such a small
resistance, you need a very large cap. Thanks for providing the
data on your contactor, it sounds like a more reasonable size
component. YMMV.
Cor van de Water
Systems Architect
Proxim Wireless Corporation http://www.proxim.com
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
Second Life: www.secondlife.com/?u=3b42cb3f4ae249319edb487991c30acb
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Behalf Of Lee Hart
Sent: Sunday, February 04, 2007 9:46 AM
To: ev@listproc.sjsu.edu
Subject: Re: Wiring a momentary voltage doubler for a contactor - diode?
Cor van de Water wrote:
> I don't recall the circuit...
But you remembered it perfectly! Here it is again, cleaned up a little.
As always, view this with a fixed-width font or you'll see cartoon swearing.
+-------------+------+----+
_|_ _|_ | |
D2 /_\ D1 /_\ < |
| | R2 < |_
| _____ | < _| contactor
+12v o--+-+--|_____|--+ _|_ _| coil
| R1 | D3 /_\ _|
| + --- |____|
| C1 --- |
| - | |
| o o
| \ S1 \ S2
+---------o \o o \o
on | | off
| |
GND o--------------------+------+
I agree with your additions of D2, D3, and R2 as well. They are matters
of finesse that improve operation and reliability.
Electrolytic capacitors can usually stand -0.6v without damage. A small
DC current will flow, which un-forms them a little, making their
capacitance and voltage rating go down and ESR go up. But they re-form
when the correct polarity is applied; so this does no damage if the
capacitor spends almost all of its time positive.
Without D2, you could have a situation where the only time C1 has a
positive voltage is for the 1 second between when you turned on the key
and when you switched S1 "on" to pull in the contactor.
D3 and R2 are a good idea, to relieve the voltage spike stress on switch S2.
> It is even possible to use a "Start" double-pole push-button to
> close S1 and S2 and have a helper-contact on the contactor closing
> in parallel to S2 to keep it energized. A second break-contact
> "Stop" push-button can break the helper-contact circuit, which
> de-energizes the contactor.
That's a clever addition. Might be desirable for some applications.
> The values of C1 and R1 determine how quick the capacitor C1
> recharges to 12V to energize the contactor again.
> For example a 10 Ohm, 10W resistor will allow to re-close the
> contactor after about 10 seconds with a 1 Farad capacitor.
> NOTE that the capacitor must be really big, around 1 Farad or more
> (that is 1,000,000 uF) otherwise it cannot deliver several amps
> for a fraction of a second.
It's not *that* big! A big contactor like the Albright SW200 has a 24v
32 ohm coil, and takes 40msec to pull in. T = RC, so the minimum value
of C = T/R = 0.04sec / 32ohms = 0.00125 farads or 1250 microfarads. A
2000uF capacitor is more than enough.
> This is the reason that commercial economizer circuits will usually
> either have a simple series resistor switched into the contactor
> coil circuit (for example in the helper contact), or use a PWM
> (Pulse Width Modulation) circuit to drop voltage.
Mostly, they do this because it's cheaper!
--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in -- Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net
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It appears the "open" production of this
film has been pushed to Fall 2007.
http://www.pbs.org/wgbh/nova/car/
However they have just added some featured
web content available now. Check out some
of the EV's in the "My Car of the Future,
Today" section
http://www.pbs.org/wgbh/nova/car/my.html
They had initially limited text to 50 words,
but I see others submitted much more than
that and the publisher said they'd let me
add to my posting.
join in their discussion column at
http://discussions.pbs.org/viewforum.pbs?f=178
Mike,
Anchorage, Ak.
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--- Begin Message ---
It appears the "open" production of this
film has been pushed to Fall 2007.
http://www.pbs.org/wgbh/nova/car/
However they have just added some featured
web content available now. Check out some
of the EV's in the "My Car of the Future,
Today" section
http://www.pbs.org/wgbh/nova/car/my.html
They had initially limited text to 50 words,
but I see others submitted much more than
that and the publisher said they'd let me
add to my posting.
join in their discussion column at
http://discussions.pbs.org/viewforum.pbs?f=178
Mike
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Thanks BB,
I decided to take the photos off the site.
After reading the discussions people were thinking some of the
vehicles were racing at the drag race part of the event and a few
vehicles had some safety things going on that would not pass tech for
the drags.
The pictures were actually of the Autocross and the other Saturday
activities not the drag race part.
So I took them down to avoid further confusion.
Chip Gribben
NEDRA Webmaster
http://www.nedra.com
On Feb 4, 2007, at 10:45 PM, Electric Vehicle Discussion List wrote:
From: "David (Battery Boy) Hawkins" <[EMAIL PROTECTED]>
Date: February 4, 2007 4:18:06 PM EST
To: "EV Discussion List" <ev@listproc.sjsu.edu>
Subject: BBB pictures
All,
I was looking at the pictures from the Battery Beach Burnout event
on the
NEDRA.com website and noticed a couple of things (thanks Chip for
putting
these up)...
BB
I'm wondering if these cars were drag raced under NEDRA, with the
traction
pack wiring and SB-350 disconnect in the vehicle?
http://ntensedsign.com/bbb/pages/PICT0014_JPG.htm
http://ntensedsign.com/bbb/pages/PICT0017_JPG.htm
Nice use of the handy man's secret weapon, duct tape!
http://ntensedsign.com/bbb/pages/PICT0025_JPG.htm
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Hi Bruce,
The REV is a college student team project currently under way at Florida
Institute of Technology (FIT). The car is still a work in progress and they
brought it out for display. The team's website is: http://my.fit.edu/rev
The competition that the students are preparing it for is one that has them
enter the same vehicle in 3 different events: acceleration (drag race),
range event and auto-crossing -- all with the same car, batteries and setup.
Shawn Waggoner
FLEAA
-----Original Message-----
From: Bruce Weisenberger [mailto:[EMAIL PROTECTED]
Sent: Sunday, February 04, 2007 9:54 PM
To: ev@listproc.sjsu.edu
Subject: Re: BBB pictures, Traction wiring inside the car.
<snip>
Anyone want to fess up who owns the +rev it was
picture 23. I have some personal questions regarding
the frame and suspension system. Who ever can contact
me directly.
<snip>
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Thanks, Cor.
Sometimes I've got to ask these blindingly obvious questions just to be
sure ;-).
If you have a way to disengage the battery input, this would be
a good time to active it. (for example a pull-cord on a breaker
or a knife-switch or even the throttle-microswitch which is in
the contactor's coil circuit
This was in fact the motivation for asking.
The plan is to activate the pack negative contactor through the ignition
key circuit, and pack positive contactor with the throttle microswitch.
Now I guess it's time to also plan a physical disconnect.
Related: the Curtis has a "Key Switch Input" (KSI) that turns on/off the
controller logic. If/when the controller fails, will removing the
voltage from KSI shut down a runaway controller?
IE is there any benefit (or drawback) to connecting KSI to the throttle
microswitch so it's effectively OFF each time the go pedal is released?
Darin
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Bill:
you said:
......I wonder if changing the brush timing a bit would help.
Just a thought.....
I was wondering about that. The comm plate is slotted, so timing can be
easily twiddled with, but I don't see how I could predict a better setting
while the hubmotor is disassembled. I certainly can't reach the comm plate
while the motor is running!
Mark
previos thread:
.........there is an odd wear pattern on the comm:
http://www.austinev.org/evalbum/img/822/822c.jpg
_________________________________________________________________
Talk now to your Hotmail contacts with Windows Live Messenger.
http://get.live.com/messenger/overview
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Jeff:
.....Can you reduce the diameter of the wheel it is in? That would have the
same effect........
It certainly would. However, the hubmotor casting is integral with the
wheel, and the scoot uses 3" x 10" vespa tires. I've never seen a lower
profile scooter tire.
In my dreaming mode, I've thought of a supplemental boost motor driving a
sprocket on the hubmotor, equipped with an overrunning clutch. I could gear
it for best thrust around 12 KH or so. I'd get chain noise, but the actual
extra drag at high speed should be small. It would be more efficient at low
speed than merely boosting voltage.
Mark
_________________________________________________________________
From predictions to trailers, check out the MSN Entertainment Guide to the
Academy Awards®
http://movies.msn.com/movies/oscars2007/?icid=ncoscartagline1
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I don't know if this has been discussed on the List but I just spent a fun
weekend hanging out in the Boyertown Museum of Historic Vehicles in
Pennsylvania. Every winter about 75 BMW bike enthusiasts get together on
Superbowl
weekend for "SuperTech 2007".... We put on seminars about caring for the
aircooled BMWs, built from 1970 to 1995. (Like the electric car, we feel this
model
line was "killed" to bring out more profitable models...) I taught:
"Ignition Systems" and "Wheel bearings"...
Anyway, the meeting place is the Museum and we could wander among the
vehicles when we weren't in sessions. Along with the "usual" old trucks, cars
and
motorcycles was a whole corner of the Museum devoted to EVs! Probably about
a dozen of them.... The building itself was the old plant for "Battronic of
Boyertown". They built delivery type electric trucks, up until 1975.
Apparently they closed simply because the owner wanted to retire! They have a
number of sales packets for the old products - they gave me one....
If you're in Pennsylvania Dutch country, it is definitely worth stopping by!
Matt Parkhouse
Colorado Springs, CO
BMW m/c-Golf Cart trike - 48 volts, 30mph on the flat, 35 mile range
1972 VW Van - to be converted this year!
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On 5 Feb 2007 at 0:34, Danny Miller wrote:
> It doesn't make sense that just running at one rpm and
> throtttle would make it run better than these superengines.
I think this is the heart of the matter.
Forty years ago, when automotive ICEs had point ignition with vacuum and
centrifugal advance, and simple carburetors, they were far less efficient
than today's microprocessor controlled, variable-everything engines. In
those days, tuning an ICE to operate at peak efficiency at one speed >would<
really gain you something. The improvement would significantly exceed the
losses of the series hybrid design.
No more. Engineers have developed ICEs impressively over the last 40 years.
Now they run with excellent efficiency at a wide range of loads and speeds.
As I understand it, they're approaching theoretical maximums for the
design. The efficiency could probably be improved even further, if it
weren't for the automakers' management's focus on smoothest possible running
and breakneck acceleration.
Today the ICE is about where the phono cartridge was in 1983, just before
the CD appeared on the scene. It's highly complex. There's more computer
power in the average automobile today than in the entire room-filling Univac
mainframe that my father worked with in 1966. The only reason that normal
people can afford this gross complexity is the miracle of mass production
with automation (and sometimes cheap overseas labor).
Today, fixing the speed of an ICE and thus gaining enough efficiency to
offset the losses of a series hybrid is a very daunting challenge. It's a
tribute to Toyota's engineers that they found a way to do precisely that in
the Prius. Very few shadetree mechanics (of which I'm one) can hope to
duplicate that success.
Using the very crudest of engines, as found in cheap Home Depot jobsite
gensets, is 'way on the other side of town. It makes far more sense in
every way to own a "beater" ICE (cheap insurance!) for the times when the EV
won't do.
David Roden - Akron, Ohio, USA
EV List Administrator
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Steve,
I replaced the pot in a PB-6 a while back. I think I got the replacement
from Curtis. I recall, it was pretty expensive for a pot, about half the price
of the PB-6. I am looking at the case from the failed pot which has been on my
desk all this time for some reason. Numbers are PMC98191, CM44675, 19-9035.
Looks like a special design for Curtis. Or check out Damacus Corp of Abingdon,
VA part EO22 for the equiv PB-6. Maybe they sell replacement pots.
Jeff
Steve Powers <[EMAIL PROTECTED]> wrote:
Looks like I need a new resistive element for my PB-6. You used to be able to
get just the element from Cloud EV, but they are closed. Anyone know where I
can get a new element for the 5k Curtis PB-6? Everything else looks god, just
the pot seems flakey.
Other than that, the Festiva works just fine. I got it all hooked up in the
car. Everything was fine, but the controller kept going full power. So, I
swapped out the pot with an elemet that I had on hand. Worked fine, but I need
one that actually fits into the PB-6 form factor.
I don't see a reason to get a whole new PB-6 when I can just change out the pot.
Steve
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> Related: the Curtis has a "Key Switch Input" (KSI) that turns on/off the
> controller logic. If/when the controller fails, will removing the
> voltage from KSI shut down a runaway controller?
Nope, when the 'FETs are blown the controller no longer has control of
them. Turning off the logic won't help.
>
> IE is there any benefit (or drawback) to connecting KSI to the throttle
> microswitch so it's effectively OFF each time the go pedal is released?
Seems to me like a bad idea.
IIRC one of the things the Curtis checks for in it's start up checks is to
see if the throttle is all the way off. If you don't start the controller
until the throttle is partially on (you know, when you've pushed the
throttle down enough to turn on the throttle switch), then it will fail
this test and the Curtis won't start.
You could redesign the pot box to get around this, but I also believe that
the Curtis has a few seconds time delay before it will start up.
Besides, I don't see any benifit to cycling the controller on and off all
the time.
--
If you send email to me, or the EVDL, that has > 4 lines of legalistic
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