EV Digest 2664
Topics covered in this issue include:
1) Re: Motor, surprise!
by Peter VanDerWal <[EMAIL PROTECTED]>
2) Re: Motor, surprise!
by Lee Hart <[EMAIL PROTECTED]>
3) Re: Motor, surprise!
by Peter VanDerWal <[EMAIL PROTECTED]>
4) Re: ZAP RAP FEVER: page to sell or trade your EV
by Roderick Wilde <[EMAIL PROTECTED]>
5) Re: Motor, surprise!
by Peter VanDerWal <[EMAIL PROTECTED]>
6) Re: ADC 8" testing
by Peter VanDerWal <[EMAIL PROTECTED]>
7) Permanent heibao-ev.com url
by Bruce EVangel Parmenter <[EMAIL PROTECTED]>
8) Re: ADC 8" testing
by "Roy LeMeur" <[EMAIL PROTECTED]>
9) Advice: drum to disk rear brakes for Civicwithacord
by Bob Bath <[EMAIL PROTECTED]>
10) Re: ZAP RAP FEVER: page to sell or trade your EV
by "Roy LeMeur" <[EMAIL PROTECTED]>
11) Re: ZAP RAP FEVER: page to sell or trade your EV
by Bruce EVangel Parmenter <[EMAIL PROTECTED]>
12) Re: Motor, surprise!
by "garry" <[EMAIL PROTECTED]>
13) Re: Motor, surprise!
by "garry" <[EMAIL PROTECTED]>
14) Re: Advice: drum to disk rear brakes for Civicwithacord
by "garry" <[EMAIL PROTECTED]>
15) Re: Advice: drum to disk rear brakes for Civicwithacord
by Mike Chancey <[EMAIL PROTECTED]>
16) FW: charging interlock - Reality closing in - LeSled wiring and universal input
relays
by "Chris Tromley" <[EMAIL PROTECTED]>
17) RE: Motor, surprise!
by "Andre Blanchard" <[EMAIL PROTECTED]>
18) Re: Non-profit would never fly (was RE: ZAP RAP FEVER: page to sell or trade your
EV)
by "1sclunn" <[EMAIL PROTECTED]>
19) Re: ZAP RAP FEVER: page to sell or trade your EV
by "damon henry" <[EMAIL PROTECTED]>
20) Re: Motor, surprise!
by "garry" <[EMAIL PROTECTED]>
21) RE: ZAP RAP FEVER: page to sell or trade your EV
by "James Jarrett" <[EMAIL PROTECTED]>
--- Begin Message ---
On Thu, 2003-03-20 at 16:34, garry wrote:
> Hi Peter,
>
> "Back EMF is NOT a loss. All Back EMF does is limit how much current the
> motor draws. Without Back EMF a typical EV motor would draw thousands
> of Amps all of the time."
>
> I think if you changed your interpretation of this to back emf and its
> associated current limit the amount of input power that can be converted to
> shaft output, you will be on a better track.
>
> "One more time Back EMF is NOT a loss. It doesn't figure into motor
> losses at any point. It is simply a function of how motors work."
>
> Good sales pitch, bad science, see the post in this group in reply to victor
> by me prior to this one.
I saw the post, your analogy was flawed. The rest was correct and if
you think about it hard enough you will understand why you can't remove
back EMF from the equation, not if you want to build a motor that
actually works.
It's not bad science it's science fact. It is a fact that has not
changed in over 150 years, this is regardless of the thousands of people
who, like you, think their lack of understanding somehow means they can
violate the laws of physics.
Go to the library and check out a book on how motors work, you will get
a clearer understanding of what's happening.
>
> "Windage losses go up as the square of the RPM, this can be a significant
> portion of your losses."
>
> Aren't you confusing windage losses in a motor with aerodynamic losses of a
> vehicle at speed here ?
No, windage losses ARE aerodynamic losses. They are simply inside the
spinning motor.
--- End Message ---
--- Begin Message ---
Lee Hart wrote:
>> More specifically, it is the VOLTAGE generated across a coil
>> when it moves in a magnetic field.
Garry Stanley replied:
> You are spot on here but I suspect for the wrong reason; back emf
> is the magnetic resistance to rotation caused by the current
> movement in a wire.
I think you are still having a problem with terminology.
"Reluctance" is the magnetic equivalent of electrical resistance; not
back emf. In fact, magnetic circuits and electric circuits are complete
twins.
electrical magnetic
---------- --------
emf (volts) mmf (ampere-turns)
current (amps) flux (webers)
resistance (ohms) reluctance (ampere-turns/weber)
The units for electric circuits are pretty well standardized; everyone
uses standard metric units (volts, amps, and ohms). Unfortunately, the
units for magnetic circuits are a confusing mess of english and metric
units. This means there are lots of different units being used for mmf,
flux, and reluctance, requiring lots of oddball conversion factors (We
Americans have the same problem with length, width, volume, etc.)
Ohm's law for electric circuits is:
emf = current / resistance
For magnetic circuits, it becomes:
mmf = flux / reluctance
>> EMF is FORCE, not power. If the current is zero, the power is zero.
> This is also spot on but if you check your motor you will find you
> have a closed circuit to the battery for 360 degrees of rotation so
> it doesn't apply to a motor.
Yes, it does. The coils in a motor are all in pairs. The DC current in
every wire is zero. They are connected in a loop, but opposite pairs of
coils have opposite polarities (because they are under opposite poles of
the magnetic field). The equivalent electric circuit is a bunch of 1.5v
batteries, all in series, with half of them facing one way, and half
facing the other. The net current is zero, because the voltages of the
two halves are identical and cancel out.
>> The direction of current flow determines whether the coil is
>> producing energy, or consuming energy.
> Spot on, but if I've laid this out properly, you will know that
> current is in fact traveling in both directions in the coil and
> it is only that the current in, is exceeding the current out,
> that causes the device to be a motor not a generator.
Current is a flow of electrons; it can't be "traveling in both
directions" at once. Thomas Edison initially thought that AC was
worthless because the electricity travelled both ways at once. Nikola
Tesla showed Edison his mistake (and he never forgave him :-)
--
Lee A. Hart Ring the bells that still can ring
814 8th Ave. N. Forget your perfect offering
Sartell, MN 56377 USA There is a crack in everything
leeahart_at_earthlink.net That's how the light gets in - Leonard Cohen
--- End Message ---
--- Begin Message ---
> The current is what is doing the work and a motor is about work, so why
> would you want to reduce the current ?
Because otherwise you end up with thousands of amps flowing through the
motor and your coils melt down.
The internal resistance of an EV size motor is a fraction of an Ohm,
usually something like 0.1 Ohm or less.
In a series motor when you initially apply 100 volts to s stalled motor
it wants to draw something like 1,000 amps. The motor quickly starts
spinning and back EMF comes up and limits the current. This continues
until the back EMF is high enough to limit the current to exactly how
much is needed to overcome the load on the motors shaft. The motor is
now at a stable RPM and stays there until either the voltage changes or
the load does.
Without Back EMF the motor would continue to draw 1,000 amps and the
coils would melt in a matter of seconds.
>
> Eventually the load will stop the motor from doing more work as it equals
> the input so why do motors internally self regulate the amount of work
> output for a given input ?
>
It's called physics. Specifically the laws of thermodynamics.
You can't get more power out than you put in, in fact you can't even
break even. there will always be some losses (one more time Back EMF is
NOT one of them)
Back EMF is part of how motors work and makes it so motors nicely fit
into the laws of physics.
> Torque may not increase with rpm but horsepower sure does.
HP only increases if torque remains the same (or increases). With most
EVs, HP is stable across a wide range of RPMs until the controller comes
out of current limit. Once the controller comes out of current limit
torque falls off as RPM increases and HP typically falls.
--- End Message ---
--- Begin Message ---
I was recently contacted by Zap. They wanted to buy our Street Rod
with stock that the sales person said would be skyrocketing because
they have a new battery that the government wants but they won't sell
them the technology. This salesperson then told me that this battery
would take a car over 250 miles on a charge and could be charged
fully in an hour. First I tried to explain to him the feasability of
replacing this much energy so quickly and how much energy it takes to
move a vehicle down the road. I finally gave up trying to educate a
salesperson who may or may not have graduated from grade school. I
further told him, and I quote. "There is no way in hell that I would
take your stock for this car" Don't they know that we know who they
are.
Roderick
Bruce EVangel Parmenter wrote:
---------------------------------
http://www.zapworld.com/rapcars.htm
Offering pre-owned Sparrows, Force, conversions, nEVs, scooters.
It sort of says to contact them to sell your EV through them
(like a broker?).
Has anyone used their service?
---------------------------------
After buying and selling many, many vehicles over the years, I
_never_ call on an ad that doesn't list an asking price. With rare
exceptions, people who do not list a price think their *stuff* don't
stink and is always too high priced.
Not one vehicle at this site/page has an asking price, even the conversions.
Buyer beware!
IMHO
Roy LeMeur Seattle WA
My Electric Vehicle Pages:
http://www.angelfire.com/ca4/renewables/evpage.html
Informative Electric Vehicle Links:
http://www.angelfire.com/ca4/renewables/evlinks.html
_________________________________________________________________
MSN 8 helps eliminate e-mail viruses. Get 2 months FREE*.
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--
--- End Message ---
--- Begin Message ---
> "More specifically, it is the VOLTAGE generated across a coil when it
> moves in a magnetic field."
>
> You are spot on here but I suspect for the wrong reason, back emf is the
> magnetic resistance to rotation caused by the current movement in a wire.
No, EMF stands for Electro Motive Force. It IS voltage not the magnetic
force. The magnetic field created by the back EMF is a secondary product
of the voltage flowing in the coils.
> This is also spot on but if you check your motor you will find you have a
> closed circuit to the battery for 360 degrees of rotation so it doesn't
> apply to a motor.
It does if you disconnect the battery. He was pointing that out to show
that Back EMF does not resist the turning of the motor by itself. It is
not a loss. It is simply a property of motors (and generators since
they are both the same thing).
>
> "The direction of current flow determines whether the coil is producing
> energy, or consuming energy"
>
> Spot on, but if ive laid this out properly, you will know that current is in
> fact traveling in both directions in the coil and it is only that the
> current in, is exceeding the current out, that causes the device to be a
> motor not a generator.
Current is only actually flowing in one direction. Which direction
depends on whether the Back EMF is higher or lower than the applied
voltage.
A motor can switch to being a generator by simply forcing it to spin
faster than it wants to with the applied voltage, for example going down
hill with a PM motor. It works as a motor going up the hill and as soon
as you go down hill, and pick up some speed, it works as a generator and
slows you down.
--- End Message ---
--- Begin Message ---
On Thu, 2003-03-20 at 16:57, Lawrence Rhodes wrote:
> I have the ADC 8" out in the open. It seems to spin freely. A2 & S2 are
> shunted together normally. A1 is positive and S1 is negative. With a
> multimeter what resistance values would I look for in a normal motor at rest
> and while spinning by hand . What values from connection to connection.
> Can I hook up a batterycharger and spin a non loaded motor with it?
> Lawrence Rhodes........
The normal values of a good motor are too small to test with a
multimeter. It will appear as a short. Typically what you are looking
for is something like 0.1 ohms or less. The actual reading will vary
depending on the brush position.
Spinning the motor by hand 'may' generate some voltage IF there is any
residual magnetism. If you have the meter set to measure resistance you
might burn it out doing this.
--- End Message ---
--- Begin Message ---
David Li of HeiBao let me know that Heibao has set up
their website domain. Their permanent url is
http://www.heibao-ev.com
I have advised David about how to put a refresh on his
temporary tripod site to point to the heibao-ev.com site.
The http://heibao-ev.com site lists a contact email that
uses that domain [EMAIL PROTECTED]
So this is a little polish for their operations.
I pray that partners will work with them to make their
production EV available to the Americas.
=====
' ____
~/__|o\__
'@----- @'---(=
. http://geocities.com/brucedp/
. EV List Editor & RE newswires
. (originator of the above ASCII art)
=====
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Yahoo! Platinum - Watch CBS' NCAA March Madness, live on your desktop!
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--- End Message ---
--- Begin Message ---
Lawrence Rhodes wrote:
I have the ADC 8" out in the open. It seems to spin freely. A2 & S2 are
shunted together normally. A1 is positive and S1 is negative. With a
multimeter what resistance values would I look for in a normal motor at
rest
and while spinning by hand . What values from connection to connection.
Can I hook up a batterycharger and spin a non loaded motor with it?
Lawrence Rhodes........
Just hook any 12-24V battery/batteries to it. Spin it and look for
overheating/bad smells/smoke.
I suspect the problem is not the motor.
Roy LeMeur Seattle WA
My Electric Vehicle Pages:
http://www.angelfire.com/ca4/renewables/evpage.html
Informative Electric Vehicle Links:
http://www.angelfire.com/ca4/renewables/evlinks.html
_________________________________________________________________
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--- End Message ---
--- Begin Message ---
Hi All,
Just got my e-meter wired (well, on the one end)
into the dash, and am contemplating beefing up the
rear brakes to handle that extra lead, at least
knowing that disk is better than drum!
There is a dead Civic at the salvage yard near me,
and the caliper assy. and rotors are still intact.
I'm contemplating pulling them off, and using them.
My rig is originally a DX, which means drum in the
back. If my (limited) knowledge serves me right, the
master cylinder proportionally makes the front do most
of the stopping. Ok-- cut to chase, Bob...
1) Any ideas if the rear calipers are just the same
as the front? (Haven't checked the Helm manual yet,
sorry).
2) Is there anything major that would need to be done
to make the changeover that I am just too clueless on?
Appreciatively,
__________________________________________________
Do you Yahoo!?
Yahoo! Platinum - Watch CBS' NCAA March Madness, live on your desktop!
http://platinum.yahoo.com
--- End Message ---
--- Begin Message ---
Roderick Wilde wrote:
---------------------
I was recently contacted by Zap. They wanted to buy our Street Rod
with stock that the sales person said would be skyrocketing because
they have a new battery that the government wants but they won't sell
them the technology. This salesperson then told me that this battery
would take a car over 250 miles on a charge and could be charged
fully in an hour. First I tried to explain to him the feasability of
replacing this much energy so quickly and how much energy it takes to
move a vehicle down the road. I finally gave up trying to educate a
salesperson who may or may not have graduated from grade school. I
further told him, and I quote. "There is no way in hell that I would
take your stock for this car" Don't they know that we know who they
are.
Roderick
---------------------------
Who exactly are "they" Rod?
Tilley's little brother?
:^D
Roy LeMeur Seattle WA
My Electric Vehicle Pages:
http://www.angelfire.com/ca4/renewables/evpage.html
Informative Electric Vehicle Links:
http://www.angelfire.com/ca4/renewables/evlinks.html
Bruce EVangel Parmenter wrote:
---------------------------------
http://www.zapworld.com/rapcars.htm
Offering pre-owned Sparrows, Force, conversions, nEVs, scooters.
It sort of says to contact them to sell your EV through them
(like a broker?).
Has anyone used their service?
---------------------------------
After buying and selling many, many vehicles over the years, I _never_ call
on an ad that doesn't list an asking price. With rare exceptions, people
who do not list a price think their *stuff* don't stink and is always too
high priced.
Not one vehicle at this site/page has an asking price, even the
conversions.
Buyer beware!
IMHO
Roy LeMeur Seattle WA
My Electric Vehicle Pages:
http://www.angelfire.com/ca4/renewables/evpage.html
Informative Electric Vehicle Links:
http://www.angelfire.com/ca4/renewables/evlinks.html
_________________________________________________________________
Protect your PC - get McAfee.com VirusScan Online
http://clinic.mcafee.com/clinic/ibuy/campaign.asp?cid=3963
--- End Message ---
--- Begin Message ---
Thanks Roderick for sharing that.
It sheds new light on their operation.
ZAP sure seems to have the energy in their sales team
to promote their nEV (high schoolers hopped up on sugar?).
I hope their new high power battery EV is not vaporware.
That would do the EV cause harm.
Slimy-sales is as slimy-sales does.
=====
' ____
~/__|o\__
'@----- @'---(=
. http://geocities.com/brucedp/
. EV List Editor & RE newswires
. (originator of the above ASCII art)
=====
__________________________________________________
Do you Yahoo!?
Yahoo! Platinum - Watch CBS' NCAA March Madness, live on your desktop!
http://platinum.yahoo.com
--- End Message ---
--- Begin Message ---
Hi Peter,
"No, EMF stands for Electro Motive Force. It IS voltage not the magnetic
force. The magnetic field created by the back EMF is a secondary product
of the voltage flowing in the coils."
OK EMF is driving the motor so back emf is what ...driving the motor
too...nope, sorry back EMF is anti EMF if you like, if it was aiding the
motor they would call it forward EMF.
"It does if you disconnect the battery. He was pointing that out to show
that Back EMF does not resist the turning of the motor by itself. It is
not a loss. It is simply a property of motors (and generators since
they are both the same thing)."
Yes I se that point here but mine is equally valid that there is never a
time when power is applied to a motor that there is not a closed circuit and
therefore there is always back EMF.
"Current is only actually flowing in one direction. Which direction
depends on whether the Back EMF is higher or lower than the applied
voltage."
Yup I will agree with this one my point here is how much current is flowing,
when the switch turns on and you comprehend what im saying here you will see
that I am not trying to get more out than in, im simply trying to say that
you can get more out from what you put in.
"A motor can switch to being a generator by simply forcing it to spin
faster than it wants to with the applied voltage, for example going down
hill with a PM motor. It works as a motor going up the hill and as soon
as you go down hill, and pick up some speed, it works as a generator and
slows you down."
Yes precisely, but if you remove the back EMF, it will no longer generate
when it is being over run.
Garry Stanley
Cable.net.nz
--- End Message ---
--- Begin Message ---
Thanx Lee,
Sorry if im using the wrong terms to describe this, but im serious about
what im trying to impart to you all and I believe its worth following
through on, even if I don't understand it the way some do.
"Yes, it does. The coils in a motor are all in pairs. The DC current in
every wire is zero. They are connected in a loop, but opposite pairs of
coils have opposite polarities (because they are under opposite poles of
the magnetic field). The equivalent electric circuit is a bunch of 1.5v
batteries, all in series, with half of them facing one way, and half
facing the other. The net current is zero, because the voltages of the
two halves are identical and cancel out."
Your description here is brilliant I wish I had though of it and of course
its exactly what im trying to explain here.
The problem is that if this is true then, when spun by an external means
with a closed circuit your motor can not make any power and if this is the
way motors are built then what im trying to say here is wasting everyone's
time, not to mention the hours ive spent already developing it to a working
prototype.
"Current is a flow of electrons; it can't be "traveling in both
directions" at once. Thomas Edison initially thought that AC was
worthless because the electricity traveled both ways at once. Nicola
Tesla showed Edison his mistake (and he never forgave him :-)"
This is what I would call text book correct, but it is not always true.
To use your own analogy here if you take 3 batteries of 2 volts ( seeing
most of us are working with 2 volt cells ) and wire them so that one is
facing opposite the other 2, + - -+ +- then measure the voltage you will
find you only have 2 volts (you might be surprised that current can flow
through the reversed battery without damaging it, along with some other
interesting side effects, but this is another story probably for another
group ).
So current can indeed be flowing in both directions in a wire at the same
time, if you don't believe me just try it for yourself ...run a 2 volt motor
or bulb from the above setup.
This means that the true statement is that current flowing in a wire is the
sum of any currents flowing in said wire and the direction will always be
that of the greater voltage (pressure) but will only be the amount of
pressure minus the counter pressure ... ( Peter read counter pressure as
what im calling back emf in other posts).
Garry Stanley
Cable.net.nz
--- End Message ---
--- Begin Message ---
Hi Bob,
The bear minimum you need is the proportioning valve from the vehicle you
are getting the disc read end from.
The in-depth requirement would be to make sure your front discs have the
same sized pistons as the ones on the car you are getting the rear from.
If they don't then your best shot is either change the fronts as well or get
an adjustable proportioning valve as used in race cars to vary the front /
rear pressure till you find the right setting.
Garry Stanley
Cable.net.nz
--- End Message ---
--- Begin Message ---
Hi Bob,
If you really want to go to rear disc brakes, you will need to find a Civic
or Integra with the rear disc system. Front and rear calipers are
completely different animals. The rears include the parking brake. As I
recall you are converting a 5th generation Civic. Complete instructions
for doing the rear disc conversion can be found at:
http://tech.hybridgarage.com/tech/brakeswap.html
You will need quite a bit more than just the brake calipers and discs. You
will also need most of the rear suspension and the parking brake cables as
well as the master cylinder and proportion valve.
Personally, I wouldn't bother. The real advantage of disc brakes is their
ability to loose heat more rapidly and thus resist fading. On the minus
side, they do cause slightly more drag than a drum system, and the parking
brakes are much more complex.
I originally intended to do the rear disc conversion on my Civic EV (4th
generation), but it has proven completely unneeded. The rear brakes only
contribute about 30-40% of the braking and even with the increased loads of
an EV conversion, they are still apparently not working very hard. There
has been no significant brake wear and they stay cool and don't
fade. Overall, the brakes feel great.
I did upgrade to the front larger calipers, discs, and spindles with those
from a Civic EX, as well as the matching master cylinder. As I recall on
the 5th generation Civics, the DX and EX both had the same front brakes to
begin with, so you wouldn't need to do this swap either.
If you want to be nice to yourself, while you are poking about in the
salvage yards, get a rear stabilizer bar if your Civic doesn't already have
one. Yes, the low mounted batteries may actually lower your center of
gravity, but the added weight can mean there is more roll to
control. Bigger or added stabilizer bars are easy to install and really
make a difference. My Civic was a base model so it had none. I added the
front bar from an EX sedan and the rear bar and lower control arms from an
Si. The results are delightful.
I noticed Solectria added very large stabilizer bars on the Force
conversions. They appear to be after market units, as they look too big to
be Geo items.
Thanks,
Mike Chancey,
'88 Civic EV
Kansas City, Missouri
EV List Photo Album at: http://evalbum.com
My Electric Car at: http://www.geocities.com/electric_honda
Mid-America EAA chapter at: http://maeaa.org
Join the EV List at: http://www.madkatz.com/ev/evlist.html
--- End Message ---
--- Begin Message ---
Here's another good idea from Doug Hartley (who's having trouble posting
to the list):
> My Skoda has a safe and automatic arrangement:
> To charge, you unplug the plug of the car's coil cord from a
> "parking" socket/dead outlet (under the hood in the Skoda's
> case) and plug it into the charging power outlet (240V 20 amp
> circuit is what I have). When done, you plug it back in to
> the outlet in the car, which holds the plug nicely in a known
> place. If you don't, the car doesn't run. How? The
> charging coil cord plug has a grounding pin connected to the
> car ground which is of course the aux . 12V battery negative.
> The ground of the parking outlet is connected to the
> negative side of a control relay switching Key + 12V to the
> (now) Curtis controller. If the relay does not "see" the
> ground pin of the charging plug safely stowed in the right
> place, it keeps the circuit open and the controller does not
> see its enabling signal. So it is impossible to forget to
> unplug or leave the plug dangling.
I wanted to pass this on because I think it's a very clever and reliable
solution. It won't work for me though, because I will probably have the
ability to use a standard cord plugged into a 14-50 outlet *and* an
Avcon receptacle that accepts the cord from the Avcon charging outlet
(at some later date).
Chris
--- End Message ---
--- Begin Message ---
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Behalf Of garry
Sent: Friday, March 21, 2003 2:39 AM
To: [EMAIL PROTECTED]
Subject: Re: Motor, surprise!
< Thanx Lee,
<
< Sorry if im using the wrong terms to describe this, but im serious about
< what im trying to impart to you all and I believe its worth following
< through on, even if I don't understand it the way some do.
<
< "Yes, it does. The coils in a motor are all in pairs. The DC current in
< every wire is zero. They are connected in a loop, but opposite pairs of
< coils have opposite polarities (because they are under opposite poles of
< the magnetic field). The equivalent electric circuit is a bunch of 1.5v
< batteries, all in series, with half of them facing one way, and half
< facing the other. The net current is zero, because the voltages of the
< two halves are identical and cancel out."
<
< Your description here is brilliant I wish I had though of it and of course
< its exactly what im trying to explain here.
<
< The problem is that if this is true then, when spun by an external means
< with a closed circuit your motor can not make any power and if this is the
< way motors are built then what im trying to say here is wasting everyone's
< time, not to mention the hours ive spent already developing it to a
working
< prototype.
<
Think of the loop as 2 series strings of batteries (for a 2 poll
motor/generator) connected in parallel. The brushes on the commutator would
be on the 2 loops of wire between the series strings of batteries. The hard
part to visualize is that the loop (armature) rotates but the batteries
remain stationary relative to the field. That is why the need for the
commutator and the brushes, so that the loop can be tapped at the points
where the voltage difference is greatest for a generator and/or the current
can have its greatest effect for a motor.
This point changes a little bit depending on the amount and direction of the
current, because the magnetic fields of the armature and the field magnets
push each other a little out of position. So on better motors/generators
the positions of the brushes can be adjusted either manually or
automatically.
< "Current is a flow of electrons; it can't be "traveling in both
< directions" at once. Thomas Edison initially thought that AC was
< worthless because the electricity traveled both ways at once. Nicola
< Tesla showed Edison his mistake (and he never forgave him :-)"
<
< This is what I would call text book correct, but it is not always true.
<
< To use your own analogy here if you take 3 batteries of 2 volts ( seeing
< most of us are working with 2 volt cells ) and wire them so that one is
< facing opposite the other 2, + - -+ +- then measure the voltage you will
< find you only have 2 volts (you might be surprised that current can flow
< through the reversed battery without damaging it, along with some other
< interesting side effects, but this is another story probably for another
< group ).
<
Very few here would be surprised we put current backwards through our
batteries every time we recharge them. You might be surprised how fast
reversed current flow can damage a fully charged battery.
< So current can indeed be flowing in both directions in a wire at the same
< time, if you don't believe me just try it for yourself ...run a 2 volt
motor
< or bulb from the above setup.
<
< This means that the true statement is that current flowing in a wire is
the
< sum of any currents flowing in said wire and the direction will always be
< that of the greater voltage (pressure) but will only be the amount of
< pressure minus the counter pressure ... ( Peter read counter pressure as
< what im calling back emf in other posts).
I think you have the concept here but there is only one current flowing and
it can only flow in one direction at any one time. Its direction is
determined by the greater EMF that of the motor/generator or that of the
battery. The amount of current is determined by the magnitude of the
difference between the motor/generator and battery EMFs and the resistance
in the path of the current.
<
< Garry Stanley
<
< Cable.net.nz
If you assume a perfect motor, as one with zero resistance.
And a perfect battery, as one with zero internal resistance.
Then connect them with wire that has zero resistance.
Any time the back EMF of the motor did not exactly match the EMF of the
battery there would be an infinite current flowing. Since motor torque is
determined by current there would be an infinite torque which would be
enough to speed up the rotation of the earth to the point we would all fly
off into space.
So back EMF is a good thing.
Andre' B. [EMAIL PROTECTED]
If something cannot be defined, it does not exist.
Isaac Newton
--- End Message ---
--- Begin Message ---
----- Original Message -----
From: "Edward Ang" <[EMAIL PROTECTED]>
>
> I often think about EV companies that failed over the years. Guess what?
> They ran out of money. If they don't make money, they are forced to close
> the door.
Just because they don't make money dose not mean they failed. Have you
noticed that when some one starts driving an EV it's not long before they
want to start a EV bis. Even people who don't have an EV want to start a EV
bis . I don't think its becuse they see alot of money being made.
May be its just me but more that 1/2 the people I
know who drive EV's are trying to figure there way into the jEV bissness.
And this is
fine with me . Must be one of the stages of "EV madness" It say's
something about the product when the people using it like it enough to wants
to sell it .
> Then, I think about how a company could make money in this EV business.
> And, the only conclusion I could draw is they have to get a large profit
> margin. This way, they survive to do further research and development.
I like that , so a nice state of the art conversion for 25k with you
supplying the car. I was listening to one of my EV friends talking about the
money end of EV's and I said "look if its money your want to make ,,,,,,,,"
I think that at the heart of any EV bis is a person that's doing it because
they feel it needs to be done. Yes they will get tired and run out of money
and stop but this is not failing.
> And, one day, they might just have enough money to deal with the "economy
of
> scale". Rich, Otmar, Lee, and others might agree with me on this. Let
the
> early adopters (us?) pay a premium price for a good product in low volume
> production. Only if the companies stay in business and make money for a
few
> years, we could hope for higher volume production.
That's how I look at buying EV parts , your helping some bis stay afloat
> Sometimes, I think of small used ICE car dealers. They make some money
and
> survive. But, with all these free websites providing free used EV
postings,
> how is a company going to make money from selling used EVs?
By being there in a town where they are the only EV garage in town and
buying a used
EV from them means there is somebody who knows how
to repair it. Being able to have it fixed is what I hear people ask about
allot.
> May be we
> should let ZAP and others make some money so that they stay in business to
> move us forward. If they fix these things and resell them in working
order,
> we could see more EVs on the road. At least, a lot of members on this
list
> would just buy one from them instead of converting or fixing their own.
It would be nice if there was some way we could measure EV profit. 10 to 1
or 10 dollars spent to 1 made . then we could see some progress . how
about this . we take the next 10 cars sold on EV trading post , we give
each car a real value like what the parts cost and time spent on the car-
wear and divide it by what they got . Now we have a number which can be
updated with each car that sells ( with the owner's permission) . Could
have
Rich, Otmar, and Lee set the "fair price" . This would be a number I'd
be watching. off the top of my head that Porsche that just sold for what
1900 might have weighed in at $38,000 ( 20 /hour labor ect) so that's 1/20
or .05
> Let's face it. If you ain't making money, you are out of here.
yep .That's why I'm not selling my Mazda pick up at a loss.
lets see best offer so far 2k , RV (real value reflecting 200 120 minute
hours and parts) 10k so that's 1/5 or .2
,,,Looking better. It reminds me a little of overunity ,selling ev's for a
profit. The quest .
Steve Clunn
>May be I am
> way off on this. But, I doubt it.
>
> Ed Ang
>
> > -----Original Message-----
> > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
> > Behalf Of Bruce EVangel Parmenter
> > Sent: Thursday, March 20, 2003 3:30 PM
> > To: [EMAIL PROTECTED]
> > Subject: ZAP RAP FEVER: page to sell or trade your EV
> >
> >
> > http://www.zapworld.com/rapcars.htm
> > Offering pre-owned Sparrows, Force, conversions, nEVs, scooters.
> > It sort of says to contact them to sell your EV through them
> > (like a broker?).
> >
> > Has anyone used their service?
> >
> >
> >
> >
> > =====
> > ' ____
> > ~/__|o\__
> > '@----- @'---(=
> > http://geocities.com/brucedp/
> > EV List Editor & RE newswires
> > (originator of the above ASCII art)
> > =====
> >
> > __________________________________________________
> > Do you Yahoo!?
> > Yahoo! Platinum - Watch CBS' NCAA March Madness, live on your desktop!
> > http://platinum.yahoo.com
> >
>
>
--- End Message ---
--- Begin Message ---
It's too bad that the government didn't get in on Victor's group buy of this
new battery technology, then they wouldn't be stymied by ZAP :-)
From: Roderick Wilde <[EMAIL PROTECTED]>
Reply-To: [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Subject: Re: ZAP RAP FEVER: page to sell or trade your EV
Date: Thu, 20 Mar 2003 21:09:37 -0800
I was recently contacted by Zap. They wanted to buy our Street Rod with
stock that the sales person said would be skyrocketing because they have a
new battery that the government wants but they won't sell them the
technology. This salesperson then told me that this battery would take a
car over 250 miles on a charge and could be charged fully in an hour. First
I tried to explain to him the feasability of replacing this much energy so
quickly and how much energy it takes to move a vehicle down the road. I
finally gave up trying to educate a salesperson who may or may not have
graduated from grade school. I further told him, and I quote. "There is no
way in hell that I would take your stock for this car" Don't they know that
we know who they are.
Roderick
Bruce EVangel Parmenter wrote:
---------------------------------
http://www.zapworld.com/rapcars.htm
Offering pre-owned Sparrows, Force, conversions, nEVs, scooters.
It sort of says to contact them to sell your EV through them
(like a broker?).
Has anyone used their service?
---------------------------------
After buying and selling many, many vehicles over the years, I _never_
call on an ad that doesn't list an asking price. With rare exceptions,
people who do not list a price think their *stuff* don't stink and is
always too high priced.
Not one vehicle at this site/page has an asking price, even the
conversions.
Buyer beware!
IMHO
Roy LeMeur Seattle WA
My Electric Vehicle Pages:
http://www.angelfire.com/ca4/renewables/evpage.html
Informative Electric Vehicle Links:
http://www.angelfire.com/ca4/renewables/evlinks.html
_________________________________________________________________
MSN 8 helps eliminate e-mail viruses. Get 2 months FREE*.
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--- End Message ---
--- Begin Message ---
Hi Andre,
"Very few here would be surprised we put current backwards through our
batteries every time we recharge them. You might be surprised how fast
reversed current flow can damage a fully charged battery."
This is one of those things that I call "misinterpretation by assumption".
Because we have all charged batteries and discharged them we know that we
put the power in and take it out and from this we assume that it comes out
one way and goes back in the other, this is of course not true.
You can prove this for yourself by taking a motor, a battery and its battery
charger and connecting the motor to the battery, if you now note the
direction of the rotation of the motor and which wires are connected to
positive and which are connected to negative and then remove the battery and
replace it with the battery charger, so that the battery charger has
positive going to the wire that the batteries positive terminal was
connected to and also the negative to the wire that the batteries negative
terminal was connected to and check the direction of rotation you will see
that they are the same.
What this shows is that a battery does not charge by having current forced
into it in the opposite direction to the current that came out, but rather
that it is in parallel with the charger and a cascade effect is the cause of
charge as the energy "cascades" into the battery so that it comes up to the
same level as the charger.
You can further test this by placing a flat battery in line with a charged
battery and leaving them over night, the following morning you will have 2
half charged batteries as the charged one has cascaded into the flat one
until equilibrium has been reached.
"I think you have the concept here but there is only one current flowing and
it can only flow in one direction at any one time. Its direction is
determined by the greater EMF that of the motor/generator or that of the
battery. The amount of current is determined by the magnitude of the
difference between the motor/generator and battery EMFs and the resistance
in the path of the current."
Isn't this exactly what I said "that the shaft output of a motor can be
defined as a/v in, minus a/v out, minus resistance" ?
I can see that you all seem to be able to grasp that back emf is in one way
or another, slowing your motors yet you all seem to think this is a good
thing.
Garry Stanley
Cable.net.nz
--- End Message ---
--- Begin Message ---
I went to Zap's page in response to this thread and saw two vehicles there
I'd be interested in if the price is right. Since, I feel the same way
about pages that don't post their prices I sent them the below e-mail...
**BEGIN SENT MESSGE***
Hi,
I just saw your used EV web page. There are a number of them I might be
interested in depending on price and availiblity. The problem is, you don't
list either of those things on your web page. I know you say "call for
pricing".
Let me get to the point. My first job was working in a shark tank
(telemarketing room). I have seen, heard, and shook my head at every phone
scam in existance to get someone to pay more for something. It is a waste
of everyone's time.
I am NOT saying that this is what you do, you may have a valid reason for
not listing the prices of your cars, but frankly, to me (and serveral others
I have spoken with) this comes across as a "danger" signal.
Saying that, I am still intersted in several of the cars. Specificly, The
two tone blue/purple bug, the white 93 electric wagon, and the "flame job"
sparrow.
Could you please contact me with price/availibility information on these
vehicles?
James F. Jarrett
Information Systems Associate
Charlotte Country Day School
**END SENT MESSAGE***
I'll let the list know what (if anything) they say to me.
James
James F. Jarrett
Information Systems Associate
Charlotte Country Day School
(704)943-4562
Do not meddle in the affairs of dragons, for you are crunchy and taste good
with ketchup.-- Anon.
>>Bruce EVangel Parmenter wrote:
>>---------------------------------
>>http://www.zapworld.com/rapcars.htm
>>Offering pre-owned Sparrows, Force, conversions, nEVs, scooters.
>>It sort of says to contact them to sell your EV through them
>>(like a broker?).
>>
>>Has anyone used their service?
>>---------------------------------
>>
>>After buying and selling many, many vehicles over the years, I _never_
>>call on an ad that doesn't list an asking price. With rare exceptions,
>>people who do not list a price think their *stuff* don't stink and is
>>always too high priced.
>>
>>Not one vehicle at this site/page has an asking price, even the
>>conversions.
>>
>>Buyer beware!
>>
>>IMHO
>>
>>
>>
>>
>>
>>
>>
>>Roy LeMeur Seattle WA
>>
>>My Electric Vehicle Pages:
>>http://www.angelfire.com/ca4/renewables/evpage.html
>>
>>Informative Electric Vehicle Links:
>>http://www.angelfire.com/ca4/renewables/evlinks.html
>>
>>
>>
>>
>>_________________________________________________________________
>>MSN 8 helps eliminate e-mail viruses. Get 2 months FREE*.
>>http://join.msn.com/?page=features/virus
>
>
>--
>
_________________________________________________________________
Add photos to your messages with MSN 8. Get 2 months FREE*.
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--- End Message ---
