EV Digest 4136
Topics covered in this issue include:
1) Re: 3 phase PM
by Ryan Stotts <[EMAIL PROTECTED]>
2) RE: 3 phase PM
by "Myles Twete" <[EMAIL PROTECTED]>
3) Re: Question: Max efficiency charging with 3 phase alternator
by "Peter VanDerWal" <[EMAIL PROTECTED]>
4) Re: If series regen's not a good idea, what about plug braking?
by Tim Clevenger <[EMAIL PROTECTED]>
5) RE: 3 phase PM
by "Myles Twete" <[EMAIL PROTECTED]>
6) re: Dave Cloud's Rules ideas.
by "Rich Rudman" <[EMAIL PROTECTED]>
7) Re: Accuracy of voltmeters, revisited
by Victor Tikhonov <[EMAIL PROTECTED]>
8) Re: Question: Max efficiency charging with 3 phase alternator
by Victor Tikhonov <[EMAIL PROTECTED]>
9) Re: 3 phase PM
by "Rich Rudman" <[EMAIL PROTECTED]>
10) RE: 3 phase PM
by "Andre' Blanchard" <[EMAIL PROTECTED]>
11) RE: Accuracy of voltmeters, revisited
by "Don Cameron" <[EMAIL PROTECTED]>
12) Re: Accuracy of voltmeters, revisited
by Seth Allen <[EMAIL PROTECTED]>
13) AC vs. DC / 100 mph club with AC?
by Ryan Stotts <[EMAIL PROTECTED]>
14) Re: If series regen's not a good idea, what about plug braking?
by Ryan Stotts <[EMAIL PROTECTED]>
15) Re: Dave Cloud's Rules ideas.
by "Roderick Wilde" <[EMAIL PROTECTED]>
16) Motor Efficiency
by "Raymond Knight" <[EMAIL PROTECTED]>
17) Re: Accuracy of voltmeters, revisited
by Otmar <[EMAIL PROTECTED]>
18) Re: Dave Cloud's Rules ideas. correction
by "Roderick Wilde" <[EMAIL PROTECTED]>
19) Re: 3 phase alternator-why not an induction machine?
by Lee Hart <[EMAIL PROTECTED]>
20) Re: Question: Max efficiency charging with 3 phase alternator
by "Rich Rudman" <[EMAIL PROTECTED]>
21) Re: Question: Max efficiency charging with 3 phase alternator
by Lee Hart <[EMAIL PROTECTED]>
--- Begin Message ---
> >Myles Twete wrote:
>
> > And I've been waiting months to comment on these---thanks for the
> > opportunity.
> >
> > No matter which alternator we
> > tried, all we could ever get was about 20amps into the nom. 12.5v, i.e. only
> > around 250watts max.
>
How about one of these "300 amp" alternators?
http://www.powermastermotorsports.com/spl_alternators.html
Bunch of "200 amp" ones too..
http://www.powermastermotorsports.com/mustangs.html
--- End Message ---
--- Begin Message ---
Ryan suggested:
> Would one of these work any better?
> http://www.performancedistributors.com/alternator.htm
Maybe...who knows?
We've tried 60amp and 100amp alternators.
Neither put out much more than 20amps at full-out steam rate.
And while we could boost the steam pressure and rate, the engine's already
going like a bat-outta-hell to drive the generator fast enough.
We increased the belt drive ratio also, from perhaps 1:4 to 1:6 -- my guess.
We can probably do 2400RPM at the alternator, but not much more.
At much over 300RPM the steam engine gets loud.
Ideally, I'd like to see it spin much less.
Hence, driving an ETEK at (13.2v+.025*60amp)*(75RPM/volt) = 1103RPM ,
we should expect (with 1:6 belt drive) a steam engine speed of only 183RPM.
That'll be much better---even if we have to increase the steam regulator
pressure, which I doubt we'd have to do.
Now, if I can only get my friend to cough up $400 for an ETEK...
-Myles
--- End Message ---
--- Begin Message ---
> Rich Rudman wrote:
>> The best in the Buisness are PM windturbine power sections.
>> They use FETs and Diodes. The top of the 3 phase bridge is Diodes,
>> Low voltage, low conduction losses. Ultra fast soft recovery.
>
> Who cares if they are fast or soft recovery? We're only dealing with low
> audio frequencies. I would think they would choose the diodes based on
> forward voltage drop (probably schottkys).
>
>> The bottoms are FETS that can be PWMed. This allows normal
>> rectification when there is enough windblowing.
>
> Presumably by using the MOSFET's body diode? This is a high-drop diode.
>
I don't think that's what he meant, I think he meant they were doing
synchronous rectification (sort of).
They are probably using fast diodes as much as freewheeling diodes as well
as rectifiers.
I'm thinking you could probably set it up to do buck/boost with MPPT to
maximize power output over a variety of windspeed vs. battery SOC.
At least that's what I would try to do.
--- End Message ---
--- Begin Message ---
I would probably drill through the shifter and install an on/off
button, similar to what Honda used to do with their Overdrive
on/off switches on the side of their automatic shifters. That way
you can control plug braking completely independently of the
service brake, but still keep your hand on the shifter.
Tim
-------
> Date: Tue, 01 Mar 2005 09:28:15 -0800
> From: Lee Hart <[EMAIL PROTECTED]>
> To: ev@listproc.sjsu.edu
> Subject: Re: If series regen's not a good idea, what about plug braking?
>
> [EMAIL PROTECTED] wrote:
>
> > I'd like to be able to say, tap the brakes to initiate plug
> > braking, and tap the accelerator pedal to turn it off. Has
> > anyone implemented such?
>
> That's an interesting idea, and sounds workable. You'd have to get used
> to it, though. I think it would feel like the brakes are sticking.
>
__________________________________
Do you Yahoo!?
Yahoo! Mail - now with 250MB free storage. Learn more.
http://info.mail.yahoo.com/mail_250
--- End Message ---
--- Begin Message ---
Peter suggested:
> I suspect he didn't buy the 'optional' cooling fan.
> Pretty much required on these alternators and an additional reduction in
> efficiency.
On the contrary, he did indeed by the 'optional' cooling fan.
And guess what it is?
It's virtually identical to the shaft fan you get with any ordinary
alternator. And that's what you get for $30 extra!
What a racket.
I'm a big fan of cooling.
I force-air cool my Permag (PM) ETEK on my 26ft outboard-powered wooden
boat.
All it takes is a Pabst 7inch 48v muffin fan running on 36v with perhaps
0.3amp (?) and the ETEK is at most, warm to the touch to 100amps. At
150amps it's quite warm on the case, but still not a worry.
Contrast this with these PM alternators from Thermodyne.
These units get EXTREMELY HOT at only 20amps, even with their 'optional'
fan.
It doesn't matter what speed or voltage, with approx. 0.6ohm internal
resistance, 240watts is lost to heat at 20amps.
The ETEK won't generate this much heat until it hits 100amps---and even
then, it only drops 2.5v compared to the Thermodyne unit which drops 12v
internally at only 20amps!
Spend your money on something that really is efficient---not something which
claims to be so without offering any evidence or support.
-Myles
--- End Message ---
--- Begin Message ---
Rich:
Would you please post this for me on the EV Discussion List?
Thanks. Dave
02/27/05
My name is Dave Cloud (not Steve/Dave Cloud). My brother and I are not
connected at the brain and never have been. We are not in business together
and don't always have the same opinions.
I have never proposed a NEDRA rule change that would benefit only me as
Rich Madman posted (although he later apologized to me on the phone).
I have discussed my ideas with Rich and others about class divisions
based on voltage. I believe the potential quarter mile time difference between
a 72V system and a 360V setup is less than 0.5 seconds. I realize that this is
a controversial point of view, but I expect to prove it at the racetrack.
Obviously, if this were the case, I hope we would all be in agreement that 10
separate divisions within a 0.5 second difference would be ridiculous.
I have pondered the idea of classes divided based on battery weight
(never wattage). I believe it would have more validity than voltage and would
be much easier to verify. [A cheater could more easily move a wire than hide
a battery.]
If I were to propose a new way to separate class divisions, it would be
based on money, a standard claimer system used in many forms of racing. What
makes a vehicle go faster is more money, not more voltage. Dragster class might
have something like 6 divisions: $5K, $10K, $20K, $50, $100K, Unclaimable.
For example, it you entered your vehicle in the $10K category, you would have
to sell it at the end of the event for that price. The vehicle would have to
be in the same condition and have the same contents (less driver & driver's
gear) as when it crossed the quarter mile light.
Records would be rewarded in each division based on low ET. If someone
had a better ET than in any division above, they would be awarded that record
also. I believe claimer divisions would have several benefits. The concern
that someone with unlimited funding could sweep all the records would be
eliminated since they would not put their expensive vehicle at risk in a lower
$$ class.
I believe competition would be tighter than voltage classes since vehicle
built with similar funding are more likely to have similar performance.
Looking at past performance NEDRA records, it is true that generally the higher
voltage vehicles are faster. However, these same vehicles also are much more
expensive.
Claimer classes would also result in more competitors. More spectators
would come to the races with the idea of possibly claiming a vehicle so then
the original owner would have to build a new one. This would help the
development of low cost EV's in general.
If you think voltage by itself is still a good way to define class
divisions, why not let low voltage record holders with better ET's than the
higher voltage in the same class have the higher record also? This change
would probably benefit me greatly, but I believe it is the most fair and
logical approach which treats everyone equally.
It has been suggested that a 20 second minimum ET be enforced. This
sounds like a good idea to me, but we should also let all voltage classes
including the 96V and under run the full quarter mile under this limitation if
they so choose.
If any of you NEDRA members (Rich, Otmar, Lee, Bill, Dennis) think this
post was written by a lunatic, please print this, save for one year and then
read again.
This message has been approved by Dave Cloud.
--- End Message ---
--- Begin Message ---
Don,
Two (or all three) voltmeters are out of calibration then.
The way to check your meters it is to measure voltage on a band-gap
voltage reference you can ger from digikey or others.
Say, 10V is convenient value. For example, you can use:
0.05% accurate: LT1236ACN8-10 or AD587KN both $6.14
0.1% accurate: ADR01AR %2.93 or LM4040 - $2.39
You can check all your meters against it.
Use spec's temp (usually room 25'C) when you do this.
That above is valid for pure DC measurements though.
When you measure voltage while on charge, results will vary
because of the waveform (not pure DC). Unless you use the scope
to see what you're measuring or you know what the voltmeter
error is, it will be a guess. Knowing the error exactly is near
impossible since the load changes the duration of voltage pulses
present on top of DC voltage, and that skews the measurements for
different voltmeters to different degrees.
Victor
Don Cameron wrote:
Good question. I have three DVMs, I measured the same battery with each:
Radio Shack: 12.78
Meterman: 12.82
OTC: 12.7
I thought maybe the leads have an effect, so I tried each with each other
leads and get the same results. I wonder, what can be used as an accurate
voltage reference?
Victoria, BC, Canada
See the New Beetle EV Conversion Web Site at
www.cameronsoftware.com/ev/
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Bob Bath
Sent: February 28, 2005 6:11 PM
To: ev@listproc.sjsu.edu
Subject: Accuracy of voltmeters, revisited
In setting up my charger, either I trust that the e-meter is accurate,
(shows 186V) or the Gardner-Bender voltmeter is accurate (shows 179V).
I suppose this has to do with ripples in the DC, that is, that the
voltmeter is spending more time seeing 179V, and the E-meter is seeing the
186V at the points it is sampling?
=====
'92 Honda Civic sedan, 144V
____
__/__|__\ __
=D-------/ - - \
'O'-----'O'-'
Would you still drive your car if the tailpipe came out of the steering
wheel? Are you saving any gas for your kids?
__________________________________
Do you Yahoo!?
Yahoo! Sports - Sign up for Fantasy Baseball.
http://baseball.fantasysports.yahoo.com/
--- End Message ---
--- Begin Message ---
Sync rectigication with lousy body diodes in MOSFETs isn't worth
the effort. You must use conduction of the mosfer itself to take
advantage of it. Regular Si rectifier will yield beter efficiency
that synchronous with body diodes (not that anyone would do it
that way).
FYI, a "body diode" is by-product of manufacturing these devices,
and will be there even if manufacturer doesn't want it.
This has to do with doping certain areas on the silicon substrate
and using inevitably resulting p-n junctions to your advantage, but
the parameters of these diodes are never optimized.
They just happen to be there.
Some devices nay have specifically built diodes conected in
parallel to the body ones, this is different story. These diodes
have their target ratings.
Victor
Peter VanDerWal wrote:
Rich Rudman wrote:
The best in the Buisness are PM windturbine power sections.
They use FETs and Diodes. The top of the 3 phase bridge is Diodes,
Low voltage, low conduction losses. Ultra fast soft recovery.
Who cares if they are fast or soft recovery? We're only dealing with low
audio frequencies. I would think they would choose the diodes based on
forward voltage drop (probably schottkys).
The bottoms are FETS that can be PWMed. This allows normal
rectification when there is enough windblowing.
Presumably by using the MOSFET's body diode? This is a high-drop diode.
I don't think that's what he meant, I think he meant they were doing
synchronous rectification (sort of).
They are probably using fast diodes as much as freewheeling diodes as well
as rectifiers.
I'm thinking you could probably set it up to do buck/boost with MPPT to
maximize power output over a variety of windspeed vs. battery SOC.
At least that's what I would try to do.
--- End Message ---
--- Begin Message ---
Why don't you spin the Alternators a bit faster??? It's pretty clear that
you are not getting anywheres near the RPM that they want.
The reference to the "Air 403" is to SouthWest Windpower's alternators. I
know they will make real amps at low RPMs.
But... isn't the "403" only a 400 watt device?
Keep in mind that a alternator that is supposed to run at 18,000 rpm is
going to have some thermal issues at %10 of it's rated RPM.
I have 1/2 a dozzen stator and rotor flavors for the Airex frame
alternator... Believe me... with 6000 rpm they can make some pretty
impressive watt numbers.
Stuffing 8000 watts into them as a BLDC motor will yank your head off. They
make E-teks look like toys.
----- Original Message -----
From: "Myles Twete" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Monday, February 28, 2005 10:13 PM
Subject: RE: 3 phase PM
> Incidentally, before you buy anything from Thermodyne Systems, read this
> Sept. 14th, 2001 article by Paul Gipe, former board member of the American
> Wind Energy Association ("Stirring Up a Hornet's Nest: New Turbine
Generates
> Controversy"): http://www.wind-works.org/articles/sm_hornet.html regarding
> Thermodyne's claims.
>
> a snippet:
> >At 5 mph, the web site claims the Hornet will produce 640% of the power
> >available in the wind; at 12 mph, 117%; at 22 mph, 49%; at 28 mph, 35%.
The
> >Hornet's performance at 22 mph and 28 mph would make it one of the most
> >efficient small wind turbines ever built--even exceeding the aggressive
> >performance advertised for the Air 403 of 31%. The Hornet's performance
at
> >5 mph and 12 mph is clearly impossible according to our understanding of
> >physical laws governing the power available in the wind.
> >
> >Such wild claims for the Hornet could come back to sting Thermodyne in
> >litigious California.
>
> Again, I wouldn't trust any of the claims made by Thermodyne and wouldn't
> recommend them to anyone. Their PMA generators will only perform
> efficiently for high output voltage relative to load current. You're
better
> off buying a low internal resistance alternator---rotor losses are likely
> nil compared to that lost in the stator windings anyway.
>
--- End Message ---
--- Begin Message ---
Is is possible that the steam engine is giving all it can at the pressure
and speed you are running?
Is the 1.5HP a calculated or measured value?
Based on how often I see your name around the web related to steam I am
guessing you know how fast the torque can drop off at high speeds just
because you can't get the steam in and out fast enough.
_____________
Andre' B.
At 12:00 PM 3/1/2005, you wrote:
Ryan suggested:
> Would one of these work any better?
> http://www.performancedistributors.com/alternator.htm
Maybe...who knows?
We've tried 60amp and 100amp alternators.
Neither put out much more than 20amps at full-out steam rate.
And while we could boost the steam pressure and rate, the engine's already
going like a bat-outta-hell to drive the generator fast enough.
We increased the belt drive ratio also, from perhaps 1:4 to 1:6 -- my guess.
We can probably do 2400RPM at the alternator, but not much more.
At much over 300RPM the steam engine gets loud.
Ideally, I'd like to see it spin much less.
Hence, driving an ETEK at (13.2v+.025*60amp)*(75RPM/volt) = 1103RPM ,
we should expect (with 1:6 belt drive) a steam engine speed of only 183RPM.
That'll be much better---even if we have to increase the steam regulator
pressure, which I doubt we'd have to do.
Now, if I can only get my friend to cough up $400 for an ETEK...
-Myles
--- End Message ---
--- Begin Message ---
Victor - great idea. I will get one and use it as a reference.
thanks
Don
Victoria, BC, Canada
See the New Beetle EV Conversion Web Site at
www.cameronsoftware.com/ev/
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Victor Tikhonov
Sent: March 1, 2005 10:28 AM
To: ev@listproc.sjsu.edu
Subject: Re: Accuracy of voltmeters, revisited
Don,
Two (or all three) voltmeters are out of calibration then.
The way to check your meters it is to measure voltage on a band-gap voltage
reference you can ger from digikey or others.
Say, 10V is convenient value. For example, you can use:
0.05% accurate: LT1236ACN8-10 or AD587KN both $6.14 0.1% accurate: ADR01AR
%2.93 or LM4040 - $2.39
You can check all your meters against it.
Use spec's temp (usually room 25'C) when you do this.
That above is valid for pure DC measurements though.
When you measure voltage while on charge, results will vary because of the
waveform (not pure DC). Unless you use the scope to see what you're
measuring or you know what the voltmeter error is, it will be a guess.
Knowing the error exactly is near impossible since the load changes the
duration of voltage pulses present on top of DC voltage, and that skews the
measurements for different voltmeters to different degrees.
Victor
Don Cameron wrote:
> Good question. I have three DVMs, I measured the same battery with each:
>
> Radio Shack: 12.78
> Meterman: 12.82
> OTC: 12.7
>
> I thought maybe the leads have an effect, so I tried each with each
> other leads and get the same results. I wonder, what can be used as
> an accurate voltage reference?
>
>
>
>
>
> Victoria, BC, Canada
>
> See the New Beetle EV Conversion Web Site at
> www.cameronsoftware.com/ev/
>
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
> On Behalf Of Bob Bath
> Sent: February 28, 2005 6:11 PM
> To: ev@listproc.sjsu.edu
> Subject: Accuracy of voltmeters, revisited
>
> In setting up my charger, either I trust that the e-meter is accurate,
> (shows 186V) or the Gardner-Bender voltmeter is accurate (shows 179V).
> I suppose this has to do with ripples in the DC, that is, that the
> voltmeter is spending more time seeing 179V, and the E-meter is seeing
> the 186V at the points it is sampling?
>
>
> =====
> '92 Honda Civic sedan, 144V
> ____
> __/__|__\ __
> =D-------/ - - \
> 'O'-----'O'-'
> Would you still drive your car if the tailpipe came out of the
> steering wheel? Are you saving any gas for your kids?
>
>
>
> __________________________________
> Do you Yahoo!?
> Yahoo! Sports - Sign up for Fantasy Baseball.
> http://baseball.fantasysports.yahoo.com/
--- End Message ---
--- Begin Message ---
One thing to remember. If you self calibrate, you get what you pay for.
Assuming that there is zero offset error and the error is only in the
slope, and then calibrating, then measuring a voltage 18X as high (180V
pack on charge) may work. Or it may not.
Calibration of a modest DMM shouldn't be more than $40. Of course it
will only tell you if it has retained its original accuracy, which if
it is poor, doesn't help much.
This may seem like FUD (Fear, Uncertainty & Doubt), but IMO a cheap
uncalibrated DMM is worse than none, and maybe more expensive.
Seth
On Mar 1, 2005, at 1:58 PM, Don Cameron wrote:
Victor - great idea. I will get one and use it as a reference.
thanks
Don
Victoria, BC, Canada
See the New Beetle EV Conversion Web Site at
www.cameronsoftware.com/ev/
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Victor Tikhonov
Sent: March 1, 2005 10:28 AM
To: ev@listproc.sjsu.edu
Subject: Re: Accuracy of voltmeters, revisited
Don,
Two (or all three) voltmeters are out of calibration then.
The way to check your meters it is to measure voltage on a band-gap
voltage
reference you can ger from digikey or others.
Say, 10V is convenient value. For example, you can use:
0.05% accurate: LT1236ACN8-10 or AD587KN both $6.14 0.1% accurate:
ADR01AR
%2.93 or LM4040 - $2.39
You can check all your meters against it.
Use spec's temp (usually room 25'C) when you do this.
That above is valid for pure DC measurements though.
When you measure voltage while on charge, results will vary because of
the
waveform (not pure DC). Unless you use the scope to see what you're
measuring or you know what the voltmeter error is, it will be a guess.
Knowing the error exactly is near impossible since the load changes the
duration of voltage pulses present on top of DC voltage, and that
skews the
measurements for different voltmeters to different degrees.
Victor
Don Cameron wrote:
Good question. I have three DVMs, I measured the same battery with
each:
Radio Shack: 12.78
Meterman: 12.82
OTC: 12.7
I thought maybe the leads have an effect, so I tried each with each
other leads and get the same results. I wonder, what can be used as
an accurate voltage reference?
Victoria, BC, Canada
See the New Beetle EV Conversion Web Site at
www.cameronsoftware.com/ev/
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
On Behalf Of Bob Bath
Sent: February 28, 2005 6:11 PM
To: ev@listproc.sjsu.edu
Subject: Accuracy of voltmeters, revisited
In setting up my charger, either I trust that the e-meter is accurate,
(shows 186V) or the Gardner-Bender voltmeter is accurate (shows 179V).
I suppose this has to do with ripples in the DC, that is, that the
voltmeter is spending more time seeing 179V, and the E-meter is seeing
the 186V at the points it is sampling?
=====
'92 Honda Civic sedan, 144V
____
__/__|__\ __
=D-------/ - - \
'O'-----'O'-'
Would you still drive your car if the tailpipe came out of the
steering wheel? Are you saving any gas for your kids?
__________________________________
Do you Yahoo!?
Yahoo! Sports - Sign up for Fantasy Baseball.
http://baseball.fantasysports.yahoo.com/
--- End Message ---
--- Begin Message ---
I've read several times in various places that the brushes in a DC
motor can last up to "80,000 miles". If I had a ~348 volt vehicle
with a 9" Advanced DC motor in it, that I drove hard nearly every day
and also raced it at the local 1/4 mile track often, would this motor
not consume brushes on a regular basis? Would it need new brushes
every two weeks or every month?
I was looking at the 4WS24 motor; I like how it red lines at nearly 10,000 rpm:
http://www.metricmind.com/motor.htm
Will this motor produce take off torque comparable to a DC motor?
If this motor was connected to a stout 5 speed transmission in a rear
wheel drive vehicle at 348 volts, could it run 100 in the 1/4?
Are the AC controllers; because of their seemingly low amps, what are
holding back AC motors from being "really fast"? (excluding their
relatively high price)
I want to build an impressively fast, street able EV. I just worry
with the 9" motor setup at "max voltage", that the car will be stuck
in the 13's. I mean, that's pretty good and all and nothing to sneeze
at, but for me, a lot of the fun is making it faster and faster. I
could always put a controller bypass on it, and even couple another
motor onto it. But then how fast would it be and then, how to make it
faster?
With the AC because of it's higher voltage potential(650v?), and also
it's high rpm, it right now has some mystique too it..
Can AC "run the number"?
--- End Message ---
--- Begin Message ---
> Tim Clevenger wrote:
> I would probably drill through the shifter and install an on/off
> button, similar to what Honda used to do with their Overdrive
> on/off switches on the side of their automatic shifters.
Another option might be to get a either a ball or T handle shifter
that has a button built into it:
T handle:
http://www.jegs.com/photos/5301530003.jpg
http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=1893&prmenbr=361
Ball:
Button on top:
http://www.jegs.com/photos/5301630049.jpg
Button on the side:
http://www.jegs.com/photos/5301630051.jpg
http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=1921&prmenbr=361
--- End Message ---
--- Begin Message ---
Dave Cloud is one of only 16 people in the Roger Hedlund 100 MPH Club and he
did it with relatively high voltage (192) and very low bucks. Note: He did
not do this on 72 volts. I do not think Dave is a lunatic but I will go
ahead and print this and wait for a year to see an 8 second, 72 volt car.
Horsepower is still watts and watts is volts times amps. Let's see, to make
a 600,000 watt car you divide by 72. That is over 8000 amps. Show me the
batteries. Drag racing is still horsepower per pound. You can only build a
car so light before you are pushing safety limits. Rich, please pass on to
Dave.
Roderick Wilde
"Suck Amps EV Racing"
www.suckamps.com
----- Original Message -----
From: "Rich Rudman" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Tuesday, March 01, 2005 10:16 AM
Subject: re: Dave Cloud's Rules ideas.
Rich:
Would you please post this for me on the EV Discussion List?
Thanks. Dave
02/27/05
My name is Dave Cloud (not Steve/Dave Cloud). My brother and I are
not connected at the brain and never have been. We are not in business
together and don't always have the same opinions.
I have never proposed a NEDRA rule change that would benefit only me
as Rich Madman posted (although he later apologized to me on the phone).
I have discussed my ideas with Rich and others about class divisions
based on voltage. I believe the potential quarter mile time difference
between a 72V system and a 360V setup is less than 0.5 seconds. I realize
that this is a controversial point of view, but I expect to prove it at the
racetrack. Obviously, if this were the case, I hope we would all be in
agreement that 10 separate divisions within a 0.5 second difference would
be ridiculous.
I have pondered the idea of classes divided based on battery weight
(never wattage). I believe it would have more validity than voltage and
would be much easier to verify. [A cheater could more easily move a wire
than hide a battery.]
If I were to propose a new way to separate class divisions, it would
be based on money, a standard claimer system used in many forms of racing.
What makes a vehicle go faster is more money, not more voltage. Dragster
class might have something like 6 divisions: $5K, $10K, $20K, $50, $100K,
Unclaimable. For example, it you entered your vehicle in the $10K
category, you would have to sell it at the end of the event for that price.
The vehicle would have to be in the same condition and have the same
contents (less driver & driver's gear) as when it crossed the quarter mile
light.
Records would be rewarded in each division based on low ET. If
someone had a better ET than in any division above, they would be awarded
that record also. I believe claimer divisions would have several benefits.
The concern that someone with unlimited funding could sweep all the records
would be eliminated since they would not put their expensive vehicle at risk
in a lower $$ class.
I believe competition would be tighter than voltage classes since
vehicle built with similar funding are more likely to have similar
performance. Looking at past performance NEDRA records, it is true that
generally the higher voltage vehicles are faster. However, these same
vehicles also are much more expensive.
Claimer classes would also result in more competitors. More
spectators would come to the races with the idea of possibly claiming a
vehicle so then the original owner would have to build a new one. This
would help the development of low cost EV's in general.
If you think voltage by itself is still a good way to define class
divisions, why not let low voltage record holders with better ET's than the
higher voltage in the same class have the higher record also? This change
would probably benefit me greatly, but I believe it is the most fair and
logical approach which treats everyone equally.
It has been suggested that a 20 second minimum ET be enforced.
This sounds like a good idea to me, but we should also let all voltage
classes including the 96V and under run the full quarter mile under this
limitation if they so choose.
If any of you NEDRA members (Rich, Otmar, Lee, Bill, Dennis) think
this post was written by a lunatic, please print this, save for one year and
then read again.
This message has been approved by Dave Cloud.
--------------------------------------------------------------------------------
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--- Begin Message ---
Just thought I would ask, when everyone is speaking about motor efficiency
are they using ratings at the motor's peak efficiency or its average
efficiency through the rpm band.
--- End Message ---
--- Begin Message ---
One thing to remember. If you self calibrate, you get what you pay
for. Assuming that there is zero offset error and the error is only
in the slope, and then calibrating, then measuring a voltage 18X as
high (180V pack on charge) may work. Or it may not.
Calibration of a modest DMM shouldn't be more than $40. Of course it
will only tell you if it has retained its original accuracy, which
if it is poor, doesn't help much.
This may seem like FUD (Fear, Uncertainty & Doubt), but IMO a cheap
uncalibrated DMM is worse than none, and maybe more expensive.
Seth
How about if everyone brings their DMMs to the next EAA meetings?
That way the high quality ones can be references while everyone
measures the same DC pack at the same time.
I have two high quality meters that have out of date calibration
papers. One is a Fluke 89 IV ($350) and the other is a TEK THS720P
Scope ($3000). I just hooked them up to a 180V supply and they are
within 0.2V at 181V. I'd say they are pretty trustworthy.
If anyone in this area (Shallow Alto, Kalifornia) wants to check
their meter against mine they are welcome to come over for a
comparison.
--
-Otmar-
http://www.CafeElectric.com/ Home of the Zilla.
http://www.evcl.com/914 My electric 914
--- End Message ---
--- Begin Message ---
Correction: Dave is actually is in the 100 MPH twice. the other dragster was
running 168 volts. Nine of the cars in the 100 MPH Club are rail dragsters.
Roderick Wilde
"Suck Amps EV Racing"
www.suckamps.com
----- Original Message -----
From: "Rich Rudman" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Tuesday, March 01, 2005 10:16 AM
Subject: re: Dave Cloud's Rules ideas.
Rich:
Would you please post this for me on the EV Discussion List?
Thanks. Dave
02/27/05
My name is Dave Cloud (not Steve/Dave Cloud). My brother and I are
not connected at the brain and never have been. We are not in business
together and don't always have the same opinions.
I have never proposed a NEDRA rule change that would benefit only me
as Rich Madman posted (although he later apologized to me on the phone).
I have discussed my ideas with Rich and others about class divisions
based on voltage. I believe the potential quarter mile time difference
between a 72V system and a 360V setup is less than 0.5 seconds. I realize
that this is a controversial point of view, but I expect to prove it at the
racetrack. Obviously, if this were the case, I hope we would all be in
agreement that 10 separate divisions within a 0.5 second difference would
be ridiculous.
I have pondered the idea of classes divided based on battery weight
(never wattage). I believe it would have more validity than voltage and
would be much easier to verify. [A cheater could more easily move a wire
than hide a battery.]
If I were to propose a new way to separate class divisions, it would
be based on money, a standard claimer system used in many forms of racing.
What makes a vehicle go faster is more money, not more voltage. Dragster
class might have something like 6 divisions: $5K, $10K, $20K, $50, $100K,
Unclaimable. For example, it you entered your vehicle in the $10K
category, you would have to sell it at the end of the event for that price.
The vehicle would have to be in the same condition and have the same
contents (less driver & driver's gear) as when it crossed the quarter mile
light.
Records would be rewarded in each division based on low ET. If
someone had a better ET than in any division above, they would be awarded
that record also. I believe claimer divisions would have several benefits.
The concern that someone with unlimited funding could sweep all the records
would be eliminated since they would not put their expensive vehicle at risk
in a lower $$ class.
I believe competition would be tighter than voltage classes since
vehicle built with similar funding are more likely to have similar
performance. Looking at past performance NEDRA records, it is true that
generally the higher voltage vehicles are faster. However, these same
vehicles also are much more expensive.
Claimer classes would also result in more competitors. More
spectators would come to the races with the idea of possibly claiming a
vehicle so then the original owner would have to build a new one. This
would help the development of low cost EV's in general.
If you think voltage by itself is still a good way to define class
divisions, why not let low voltage record holders with better ET's than the
higher voltage in the same class have the higher record also? This change
would probably benefit me greatly, but I believe it is the most fair and
logical approach which treats everyone equally.
It has been suggested that a 20 second minimum ET be enforced.
This sounds like a good idea to me, but we should also let all voltage
classes including the 96V and under run the full quarter mile under this
limitation if they so choose.
If any of you NEDRA members (Rich, Otmar, Lee, Bill, Dennis) think
this post was written by a lunatic, please print this, save for one year and
then read again.
This message has been approved by Dave Cloud.
--------------------------------------------------------------------------------
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Checked by AVG Anti-Virus.
Version: 7.0.300 / Virus Database: 266.5.7 - Release Date: 3/1/2005
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--- End Message ---
--- Begin Message ---
>> At continuous driving speeds, series hybrids will NEVER exceed
>> the mileage you could get by directly connecting the ICE to the
>> wheels (first law of thermodynamics), in fact the second law of
>> thermodynamics states that you won't even match it.
Not true. Consider the Toyota Prius. If you drive at a constant 30 mph,
you only need a few horsepower. The ICE won't burn much gasoline, but it
isn't very efficient at this low power level. You get a fuel economy of
something like 50 mpg.
But with the hybrid system, the ICE cycles on and off. When off, the car
runs on purely electric power and consumes zero gasoline. When on, it
runs at a more efficient higher-hp level to both drive the car and
recharge the batteries. Now you get more like 60 mpg average.
The key to making this work is that the efficiency of the ICE when
operating at higher HP has to be enough greater than that at lower HP to
compensate for the losses in the electric drive system.
--
If you would not be forgotten
When your body's dead and rotten
Then write of great deeds worth the reading
Or do the great deeds worth repeating
-- Ben Franklin, Poor Richard's Almanac
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
OK Lee...
Schottkys can only be gotten up to about 60 volts, The voltage spikes ring
higher than that while boosting.
Good fets usually have good body diodes or are co-packed with better
diodes..
Yup... unless you can't use Schottkys then fets are your only choice.
I predicted a full Fet bridge was going to be better. Switching the top
allows you to reduce rectification losses. A ON fet is a LOT lower than
even a Schottky.
They staid with diodes on the top side. ...I think. We had long arguments
about what was doable and what was right and cost effective. Yea to do
topside sync rect they needed encoders,
Not cheap and easy. Doing this with BEMF sensing and a DSP... Would...
allow for cheap commutation control.
Then again they didn't want to use a expensive Micro, they used a MicroChip
of some sort.
So... there are ways to suck Trons from small sources... elegantly...
----- Original Message -----
From: "Lee Hart" <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Tuesday, March 01, 2005 10:43 AM
Subject: Re: Question: Max efficiency charging with 3 phase alternator
> Rich Rudman wrote:
> > The best in the Buisness are PM windturbine power sections.
> > They use FETs and Diodes. The top of the 3 phase bridge is Diodes,
> > Low voltage, low conduction losses. Ultra fast soft recovery.
>
> Who cares if they are fast or soft recovery? We're only dealing with low
> audio frequencies. I would think they would choose the diodes based on
> forward voltage drop (probably schottkys).
>
> > The bottoms are FETS that can be PWMed. This allows normal
> > rectification when there is enough windblowing.
>
> Presumably by using the MOSFET's body diode? This is a high-drop diode.
>
> > When there is not sufficient wind for conduction into the Batteries,
> > but there is voltage, they switch the bottoms Fets as a boost
> > converter.
>
> Clever.
>
> > Fet can be better than a diode, if switched properly.
>
> True, but if they are using ~1v drop body diode and non-schottkys, there
> goes efficiency.
> --
> If you would not be forgotten
> When your body's dead and rotten
> Then write of great deeds worth the reading
> Or do the great deeds worth repeating
> -- Ben Franklin, Poor Richard's Almanac
> --
> Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
>
--- End Message ---
--- Begin Message ---
Peter VanDerWal wrote:
Lee Hart wrote:
>> Who cares if [the upper 3 diodes] are fast or soft recovery?
>> We're only dealing with low audio frequencies. I would think
>> they would choose the diodes based on forward voltage drop
>> (probably schottkys).
Peter VanDerWal wrote:
> They are probably using fast diodes as much as freewheeling diodes
> as well as rectifiers.
But if this is a normal laminated iron cored alternator, it can't switch
at speeds out of the audio range. You don't need fast or soft-recovery
diodes for this. In fact, it works against you, because such diodes
sacrifice forward voltage drop to get speed.
Schottkys are already plenty fast enough, and have the low forward
voltage drop needed in this application.
>>> The bottoms are FETS that can be PWMed. This allows normal
>>> rectification when there is enough windblowing.
>> Presumably by using the MOSFET's body diode? This is a high-drop
>> diode.
> I don't think that's what he meant, I think he meant they were doing
> synchronous rectification (sort of).
You could synchronously switch the MOSFETs to reduce the forward drop as
compared to the body diodes. But I got the impression Rich was saying
they were PWMing the MOSFETs to *short* the alternator's windings (when
the diodes would not have been conducting), so as to use the winding
inductance as a "free" inductor for a boost converter. This works, but
is a "cheap and easy" trick to raise the output when the wind isn't
blowing fast enough, rather than something you do for high efficiency
when you *do* have enough wind.
--
If you would not be forgotten
When your body's dead and rotten
Then write of great deeds worth the reading
Or do the great deeds worth repeating
-- Ben Franklin, Poor Richard's Almanac
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
