EV Digest 7059
Topics covered in this issue include:
1) Re: What is the typical amperage draw of the field for a sepex motor?
by "Zeke Yewdall" <[EMAIL PROTECTED]>
2) ebay item no. 230154106495
by "Michael Mohlere" <[EMAIL PROTECTED]>
3) Digest mode issues, html and truncation
by Jeff Shanab <[EMAIL PROTECTED]>
4) Re: Capacitor recommendations, ripple current
by Lee Hart <[EMAIL PROTECTED]>
5) Re: What is the typical amperage draw of the field for a sepex motor?
by Lee Hart <[EMAIL PROTECTED]>
6) Re: Corded mower
by Lee Hart <[EMAIL PROTECTED]>
7) What EV to see in LA
by Lee Hart <[EMAIL PROTECTED]>
8) electric Sonex
by "gary" <[EMAIL PROTECTED]>
9) Re: What is the typical amperage draw of the field for a sepex motor?
by "Zeke Yewdall" <[EMAIL PROTECTED]>
10) Re: oversized motor?
by dale henderson <[EMAIL PROTECTED]>
11) Re: What EV to see in LA
by "Roy LeMeur" <[EMAIL PROTECTED]>
12) Re: What EV to see in LA
by "Joseph T. " <[EMAIL PROTECTED]>
13) RE: To Feed or Not To Feed (the troll) [was: RE:
by Mike Willmon <[EMAIL PROTECTED]>
14) Re: 11s in '07...Timing is Everything! (pt 2)
by "Roy LeMeur" <[EMAIL PROTECTED]>
15) RE: Looking for zilla speed sensor mount design/picutres for double
shaftADC motor
by Mike Willmon <[EMAIL PROTECTED]>
16) RE: individual chargers
by "David (Battery Boy) Hawkins" <[EMAIL PROTECTED]>
17) Re: ebay item no. 230154106495
by "Loni" <[EMAIL PROTECTED]>
18) Re: 11s in '07...Timing is Everything! (pt 2)
by Paul <[EMAIL PROTECTED]>
19) Re: FourthGen ''PB6' Pot Box
by <[EMAIL PROTECTED]>
20) Re: "Message truncated" problem - workaround for Mac users
by Doug Weathers <[EMAIL PROTECTED]>
21) Re: Series/Parallel switching (was Re: Karmann Ghia Design - System
voltage)
by "Joseph T. " <[EMAIL PROTECTED]>
22) Re: Karmann Ghia Design - System voltage
by Doug Weathers <[EMAIL PROTECTED]>
23) Re: Corded mower
by =?ISO-8859-1?Q?Jukka_J=E4rvinen?= <[EMAIL PROTECTED]>
24) Re: Series/Parallel switching (was Re: Karmann Ghia Design - System
voltage)
by "(-Phil-)" <[EMAIL PROTECTED]>
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Dunno what GE intended it to be used for. I bought it from a guy who
had bought in new in 1978 for use in an electric corvette (when I got
it, it came with a corvette clutch, and will bolt right to a chevy V8
transmission bell housing). That's about all I know about it....
Z
On 7/24/07, Rod Hower <[EMAIL PROTECTED]> wrote:
Zeke,
The reason we call a motor 'Sepex' is to show that it
has much lower winding resistance and can be operated
by the controller (The control changes PWM on the
field to keep appropriate current in the field in
relation to the armature). A sepex is designed to
never see full battery voltage and has the capability
to boost field strength to get regen at slower speeds.
A shunt motor like the one you seem to have will
operate the shunt field at full battery voltage and
will not have the advantages of a sepex motor (that is
boosting field voltage at lower speeds to allow
regen). A shunt motor like yours will not run-away as
long as the field has power, regardless of load
(unlike a series motor that will disassemble itself
with no load and high voltage)
What was the original application of this motor?
Looks like something GE would use in a mining car
(pulling coal from the bowels of earth?).
Rod
--- Zeke Yewdall <[EMAIL PROTECTED]> wrote:
> It's got two separate terminals for the field. And,
> I measured the
> resistance between them -- 6.8ohms. Which I guess
> would translate to
> only 14 amps at rated voltage (96 volts)
>
> The previous owner said he only used field control
> for it, in
> conjunction with the clutch. It seems like it would
> actually be
> pretty easy to do this -- use a low amperage PWM
> controller, with the
> pot-box reverse connected to give less voltage as
> you pressed down on
> the accelerator, in series with a 25ohm 100 watt
> resistor in order to
> insure that the field always had at least 1/4th of
> armature voltage.
> Since I might run a 120 or 144 volt pack, I could
> also put a series
> resistor to keep the field from ever getting full
> pack voltage.
> Though that would also limit the ability to operate
> at base RPM.
>
> Wonder if there's a way to hook some switches to the
> transmission,
> such that when you put in in gear, it energized the
> main contactor and
> spun the motor up with full field and armature
> voltages (too bad this
> truck doesn't have a neutral safety switch). The,
> as you pressed down
> on the accelerator (and let the clutch out) the
> field voltage would
> be reduced, and the motor RPM would increase. When
> driving, if the
> motor was turning faster than 1000rpm*armature
> voltage/field voltage,
> then you would get regen braking, and it was turning
> slowing that
> that, you would draw current to accelerate.
>
> Just sort of rambling and designing out loud at this
> point.... am I
> completely off base here?
>
> Z
>
>
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figured this might make a nice first conversion for someone depending on the
reserve price.
_________________________________________________________________
http://newlivehotmail.com
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I do think i may have at lease narrowed it down. Usually comes from apple-mail
this line when not removed seems to cut off the digest when found in my client.
I hve to hit view source and read it in mono font with headers mixed in
Other times I get the block and I have looked at the source and the
multipart/alternative with the boundry marker has benn properly removed.
I have edited a digest removing this line and it comes back.
Content-Type: text/plain; charset="US-ASCII"
Content-Transfer-Encoding: 7bit
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* ---REMAINDER OF MESSAGE TRUNCATED--- *
* This post contains a forbidden message format *
* (such as an attached file, a v-card, HTML formatting) *
* Lists at sjsu.edu only accept PLAIN TEXT *
* If your postings display this message your mail program *
* is not set to send PLAIN TEXT ONLY and needs adjusting *
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Dan Frederiksen wrote:
Thank you, Lee. That was the conclusion I was reaching too. Even the
much revered zilla2k with 1400 battery amps and only 26? caps must be
well under sufficient too.
It has "sufficient" capacitors, in that none that I know of have
exploded or otherwise expired.
Curtis controllers, on the other hand, have had capacitor failures. I
just fixed one with Nichicon caps. A quick test showed that most of them
were way out of spec on ESR.
> you say caps made for switch mode, do you know of any specific model
> that qualify?
I replaced the Nichicon PR(M) series parts with Panasonic EB series,
which have about 4 times the ripple current rating.
I came across a guy who had it on good authority that you can even get
away with using no caps on the battery side.
The less capacitance you have, the worse the battery ripple current, and
the higher the voltage spikes on the semiconductors get.
More battery ripple current causes extra heating in the batteries and
connecting wires, and lowers your battery's apparent amphour capacity
via the Peukert effect.
Extra voltage spikes requires higher voltage transistors and diode, and
if not high enough, they *die*!
So yes; you can "get by" with little or no capacitance. But the system
works worse and is less reliable.
If actually viable that would be an interesting simplification of the
controller making it almost ridiculously simple. right up my alley.
The older SCR controllers did this, in part because they didn't know any
better (didn't know that capacitors helped). Also, they typically used
SCRs with very high voltage ratings (like a 600v part in a 72v
controller). And, these controllers were often used with massive 1000
amphour forklift batteries that didn't mind the high peak currents.
I found that panasonic lyt caps had higher than typical ratings.
Panasonic has parts with reasonably good ratings at reasonably good
prices -- a good combination. You can get better parts, but they cost a
lot more. Or, you can get parts a lot worse for only a little less money.
--
"Excellence does not require perfection." -- Henry James
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart-at-earthlink.net
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Zeke Yewdall wrote:
It's got two separate terminals for the field. And, I measured the
resistance between them -- 6.8ohms. Which I guess would translate to
only 14 amps at rated voltage (96 volts)
That sounds about right for a sepex motor. Field power is on the order
of 2% of armature power. I think you said this was a 96v 22 horsepower
motor? That means armature power is around 22kw. 2% of 22kw is 440 watts
for the field. With a 6.8 ohm field, 440 watts is 57 volts at 7.67 amps.
This is an educated guess as to what the field could stand for (say) one
hour.
The full 96v into a 6.8 ohm field would be over 1350 watts, which would
burn it out in 5-10 minutes. So, it's unlikely to be a shunt motor,
which would have had a field wound to withstand full armature voltage
for an hour or more.
--
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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David Hankins wrote:
I'm thinking about converting my riding lawn mower to a corded
electric... I was thinking about using one of those cord reel setups.
farthest point is around 200'+ from the plug. I have almost an acre
under grass and It will get kind of dicey out on the edge where
about a 1/3 acre chunk has a dozen trees on it.
The main question that I have is: The current ICE motor on it is a
19HP Briggs. What HP electric motor do I need to replace that?
My ElecTrak electric riding garden tractor doesn't use anything close to
19 HP. Its power consumption is more like 50 amps at 36v, which is
around 1.9 horsepower. These tractors are considerably heavier (and
better built) than most riding lawn mowers.
David Hankins wrote:
> The problem with batteries is that it takes about 2.5 to 3 hours to
> do the lawn. I don't think I can get that many batteries onboard
> without overloading it.
This is probably true for a typical riding lawn mower, which might only
weigh 100-200 lbs. The ElecTrak is more like 700 lbs (most of it batteries).
1.9 horsepower is feasible to get through a 200' extension cord. You'd
want to use #10 wire, and operate on 240vac to minimize voltage drop
(1900w at 240v is 8 amps, which causes a 3.2v drop in a 200' #10 cord).
--
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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--- Begin Message ---
A friend of mine, Herb Johnson, is on vacation in Los Angeles. He knows
I'm an EV nut, and asked whether there were any he could see while in
this "hotbed of EV activity".
He's an engineer, computer junkie, and a "techie" at heart, so we may be
able to sway him to the EV cause. Does anyone have any suggestions I
could pass onto him?
--
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 ---
Since this list is "electric vehicles", this is not (too far) OT ;<} -
an electric airplane in progress ...
http://www.airventure.org/2007/news/070724_sonex.html
Gary Krysztopik
Z Wheelz, LLC
San Antonio, TX
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Thanks Lee. Yup, 220A is the total continuous rating, which is
21.2kW at 96 volts.
Man, I can't wait to get my donor vehicle here so I get start testing
everything in the car, instead of just sitting on the workbench (it's
in my friend's shop 400 miles away).
Zeke
On 7/24/07, Lee Hart <[EMAIL PROTECTED]> wrote:
Zeke Yewdall wrote:
> It's got two separate terminals for the field. And, I measured the
> resistance between them -- 6.8ohms. Which I guess would translate to
> only 14 amps at rated voltage (96 volts)
That sounds about right for a sepex motor. Field power is on the order
of 2% of armature power. I think you said this was a 96v 22 horsepower
motor? That means armature power is around 22kw. 2% of 22kw is 440 watts
for the field. With a 6.8 ohm field, 440 watts is 57 volts at 7.67 amps.
This is an educated guess as to what the field could stand for (say) one
hour.
The full 96v into a 6.8 ohm field would be over 1350 watts, which would
burn it out in 5-10 minutes. So, it's unlikely to be a shunt motor,
which would have had a field wound to withstand full armature voltage
for an hour or more.
--
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 ---
single speed harder and more expensive? i'm still in
the planning stages of a four wheeled vehicle but from
working on electric motorcycles i find single speed
easy while hooking up to an existing trany seems
harder? that gives me hope that an electric car is
not as hard as i'm making it out to be!
--- Jeremy Rutman <[EMAIL PROTECTED]>
wrote:
> Thanks for the answers guys it helps a lot.
> as for single speed reduction i would like it
> eventually.
> i'll skip the extra expense and time right now, if i
> finally get my
> ev on the road
> one day and find the extra time+cash I'll upgrade to
> singlespeed etc.
> i am a little worried about the high rpms of the
> motor [4000 nominal]
> when compared to gas motor,
> e.g. running at 60mph in 2nd gear, will the gearbox
> not become
> stressed by such high rpms?
>
> >From: "Peter VanDerWal" <[EMAIL PROTECTED]>
> >Well, it is a little bigger than is required...for
> moderate driving.
> >A fork lift motor won't be much smaller and you'd
> need a completely
> >different controller.
> >So, if the AC42 motor will fit, then I'd say go for
> it.
> >Actually, if you don't mind some extra work, this
> motor is large enough
> >that you can get away with a single speed reduction
> and skip the
> >transmission, clutch, etc. However, you'd need
> some custom parts to make
> >that work.
>
> >From: "Dale Ulan" <[EMAIL PROTECTED]>
> >AC42 should be plenty powerful. AC offers enough
> advantages,
> >especially if you have the motor and controller
> already.
> >I'd go with it, myself. I would not go with a DC
> brushed
> >motor (forklift motor) if I had a choice of an AC
> that
> >would fit (and at a reasonable price - or already
> owned).
> >Another option would be to try to trade for an AC24
> >which would be a nicer fit but would not go quite
> as
> >quickly.
> >With Solectria controllers, make sure you keep the
> batteries
> >and connections in good shape, and don't exceed the
> voltage
> >rating of the controller, even when in regeneration
> mode.
> >Some of the Solectria controllers were pretty
> sensitive.
> >-Dale
>
> >From: Jeff Major <[EMAIL PROTECTED]>
> >Motor "way too" big? My guess is no. You could
> >probably get by with less. Depends on your
> objectives
> >and system design. Not familiar with Suzuki Alto.
> >Just saw a picture of one on google. Looks like a
> >fairly small compact 4 door. Didn't see GVW.
> Direct
> >drive might need a bigger motor over 5 speed tranny
> to
> >get accel times decent.
>
> the original curb weight is 600kg
> i didnt understand the bit about bigger motor over 5
> speed
> transmission for direct drive?
>
> >150 kg for controller,
> >battery, etc doesn't sound like enough kWhrs to
> >overheat the motor. I've seen bigger motors in
> >smaller cars and smaller motors in bigger cars.
> >Jeff
>
>
>
>
> Jeremy Rutman
> Technion Physics Dep't
> Haifa 32000
> Israel
> 972 4 8293669
>
>
Albuquerque, NM
http://geocities.com/hendersonmotorcycles/blog.html
http://www.austinev.org/evalbum/1000
http://www.austinev.org/evalbum/1179
http://www.austinev.org/evalbum/1221
http://geocities.com/solarcookingman
____________________________________________________________________________________
Park yourself in front of a world of choices in alternative vehicles. Visit the
Yahoo! Auto Green Center.
http://autos.yahoo.com/green_center/
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Re: What EV to see in LA
Hi Lee
How about Reverend Gadget?
Left Coast Conversions.
http://www.reverendgadget.com/gpage1.html
~~~~~~
Roy LeMeur
_________________________________________________________________
http://liveearth.msn.com
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Tesla Motors will be at Pebble Beach (although it's far from LA) in
mid-August and PGE has a fleet of Rav4 EVs.
I don't know much about California, so I have no idea if the PGE fleet
of EVs are in LA. But what I do know is that it's hybrids galore in
California!!!
On 7/24/07, Roy LeMeur <[EMAIL PROTECTED]> wrote:
Re: What EV to see in LA
Hi Lee
How about Reverend Gadget?
Left Coast Conversions.
http://www.reverendgadget.com/gpage1.html
~~~~~~
Roy LeMeur
_________________________________________________________________
http://liveearth.msn.com
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No use getting in a fight with a pig, you'll only get dirty, and the pig likes
it :-O
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Fantastic story as you always do John.
This is what creates excitement in the world of EVs.
Don't ever stop.
The 10th Anniversary NEDRA Nationals are yet to arrive, 8/17 and 8/18 at
PIR.
Come one, come all.
The competitor list is continuing to grow.
The media interest is more than ever.
Be There!
Roy
_________________________________________________________________
http://newlivehotmail.com
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You can see mine for the CE shaft on a WarP9 here:
http://www.austinev.org/evalbum/756
or here:
http://home.gci.net/~saintbernard/DSCF3519.JPG
http://home.gci.net/~saintbernard/DSCF3524.JPG
http://home.gci.net/~saintbernard/DSCF3525.JPG
Mike,
Anchorage, Ak
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
> Behalf Of Paul Wallace
> Sent: Tuesday, July 24, 2007 1:09 PM
> To: ev@listproc.sjsu.edu
> Subject: Looking for zilla speed sensor mount design/picutres for double
> shaftADC motor
>
>
> I've got a new zilla 1k ehv with the stock motor speed sensor. I need
> to mount the speed sensor on an ADC 9" double shaft motor. I'm sure
> that someone has already built a bracket to mount the stock sensor at
> the free end of the tail shaft. If you have pictures and/or dwgs and
> measurements of such a bracket, please drop me a line.
>
> Paul Wallace
> /91 Chevy S10 full of almost dead SAFT nicads
>
>
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David and All,
I have been running 16 Soneil model 1212SR chargers on-board the RX-7 for
six years, and have had no failures from vibration. I believe they were
designed for on-board wheelchair use. What model are you using?
BB
>From: "David Sherritze" <[EMAIL PROTECTED]>
>Date: Fri, 20 Jul 2007 19:55:28 -0500
>
>I used Soneils on a string of six - 12 volt batteries.
>
>I never had to disconnect the string.
>
>The problem I had is they were mounted on board the vehicle and could not
>stand the vibration and kept failing.
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Yeah, uh, thanks for encouraging everyone to bid against me...
----- Original Message -----
From: "Michael Mohlere" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>; <ev@listproc.sjsu.edu>
Sent: Tuesday, July 24, 2007 7:19 PM
Subject: ebay item no. 230154106495
figured this might make a nice first conversion for someone depending on
the reserve price.
_________________________________________________________________
http://newlivehotmail.com
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I'm really pleased to get part 2, better a little late than never!
I'm looking forward to your take on the Wayland Invitational III. I
was only there for Saturday the 14th. To bad you had to resort to
dragging the work truck after that 11.466 run :-)
This seems like a good time to point out that EV racing in the
Pacific North West is not over yet! The NEDRA Nationals will be at
PIR August 17th and 18th. I'm making plans to be there.
See Ya,
Paul "neon" Gooch
On Jul 24, 2007, at 7:26 AM, John Wayland wrote:
The above title now seems at odds, as I finally get this part 2
post out. The timing for it sucks. By now, everyone knows that
another EVent has come and gone (Wayland Invitational III) and I
should be writing about 'it' instead. Oh well...chalk it up to
being over-the-top busy the past three weeks, chalk it up to just
being plain wrung-out from all the ups and downs of putting on a
major racing EVent, chalk it up to being worn-down from weeks of
constant media attention more fitting of a visiting Hollywood super
star than some Greek geek playing around with his electric car. On
the other hand, to fully appreciate the July 13th & 14th weekend's
track numbers you really need to know the build-up to the Wayland
Invitational III, which our racing from June 29th was very much
part of.
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I have one in The Skunk, 700 mi and no problems.
respectfully,
John
http://www.austinev.org/evalbum/751
----- Original Message -----
From: "Martin Winlow" <[EMAIL PROTECTED]>
To: "[EMAIL PROTECTED] Sjsu. Edu" <ev@listproc.sjsu.edu>
Sent: Tuesday, July 24, 2007 7:19 AM
Subject: FourthGen ''PB6' Pot Box
Hi, All,
Has anyone tried the above (available on Ebay auction # 150143859148)?
Half
the cost (in the UK at least) of a real PB6.
Regards, MW
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On Jul 23, 2007, at 12:03 PM, Roger Stockton wrote:
I'm pretty sure John is a staunch Mac user, and so he may have a mail
client that behaves differently (probably correctly ;^), and so
displays
the truncation messages instead of the original text portion.
If John is using Apple Mail, he can hit Command-Option-P to display the
text version of the "truncated" messages (assuming there is a text
version, which doesn't always happen). Dennis Berube's posts in this
thread display the text with no problem.
The mouse version is View > Message > Plain Text Alternative.
The rest of you using Apple Mail are also welcome to try this :)
P.S. I'm using Apple Mail 1.3.11, which is part of Mac OS X 10.3.
Other versions may behave differently.
--
Doug Weathers
Las Cruces, NM, USA
http://www.gdunge.com/
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Yes, it does help alot! After careful reading and re-reading, I now understand.
But I still have one pesky little question. You say,
"If we wait until the current drops to 1,000 amps (which happens at a much
higher RPM). Then each motor is seeing 120V @ 1,000 amps, 120 KW
If we continue to accelerate, then the current will fall below 1,000 amps
and our power will drop."
Why would the Zilla's output current drop if your accelerating? How
could you accelerate if current is dropping without voltage
increasing?
O 7/24/07, Peter VanDerWal <[EMAIL PROTECTED]> wrote:
> "Under these
> conditions, the motors see more voltage and more
> current in seriese mode than in parallel mode."
>
> I must be missing something here. You're saying that the Zilla gives
> more voltage and current in series than in parralel. Since voltage
> times current is power, you're basically saying that the Zilla is more
> powerful in series than in parralel mode. Does the Zilla limit overall
> power in parralel mode compared to series?
No. At low RPMS the 'zilla delivers more power in series. At high RPMS,
the zilla delivers more power in parallel.
The point where is switches from one to the other is when the current
drops below 1,000 amps in series mode.
The 'zilla 2k protects itself. It won't send more than 2,000 amps to the
motors. It does this by reducing the output voltage to the point where
only 2,000 amps flows.
Once the motor RPMs climb to the point where they won't draw 2,000 amps
even at full pack voltage, then the controller no longer limits current
and doesn't reduce the voltage. Now the only thing limiting current is
the back EMF from the motor and that depends on RPM, more RPM = less
current.
Let's say we have a 240V pack. The controller will come out of current
limit when the series motors are seeing 240V and drawing 2,000 amps. As
the RPMs increase the current will fall. Basically each motor sees 120V
and 2,000 amps. That's 240 kw per motor.
If we switch to parallel at this point, then the controller will go BACK
into current limit. Now remember at this RPM 120V equals 2,000 amps on
each motor. The 'zilla can ONLY put out 2,000 amps TOTAL. In parallel
that means 1,000 amps per motor.
Now the 'zilla can't send 120V to the motors because they would each try
to draw 2,000 amps for a total of 4,000 amps. In order to only allow each
motor to draw 1,000 amps, the output voltage has to drop to 60V. So now
each motor sees 60V.
60V x 1,000 amps = 60kw per motor.
By switching too soon we have reduce our power to only 25%
If we wait until the current drops to 1,000 amps (which happens at a much
higher RPM). Then each motor is seeing 120V @ 1,000 amps, 120 KW
If we continue to accelerate, then the current will fall below 1,000 amps
and our power will drop.
Switching to parallel now will put the controller back in current limit,
2,000 amps across two motors, the output voltage from the controller will
drop to 120V and increase as the motors RPM climbs (it has to increase to
keep the current at 1,000 amps), until the voltage across the parallel
motors reachs 240 volts. Since the current is held at 1,000 amps, our
power level INCREASES as the voltage climbs until it reachs 240 kw per
motor (240V * 1,000Amps)
So if we keep them in series our power would continue to drop from 120kw.
By switching to parallel the power starts at 120kw and INCREASES until it
reachs 240 kw, per motor.
Switch to soon and we loose power until we can accelerate to the point
where we should have switched.
Does that help?
>
> On 7/24/07, Steven Ciciora <[EMAIL PROTECTED]> wrote:
>> I know I don't explain this very well, 'cause I've
>> confused many a person... so, note that my previous
>> example was why the zilla doesn't shift before the
>> series current drops to the the value of half the
>> current limit in parallel mode. If the zilla shifted
>> sooner, then in parallel mode, the motor current would
>> be _limited_ to 2000 amps total, or 1,000 amps per
>> motor, by the zilla's 2,000 amp overall limit. The
>> way the zilla limits motor current is by reducing the
>> motor voltage. Under these conditions, in series
>> mode, the zilla doesn't have to limit current, so it
>> doesn't have to back off on voltage. Under these
>> conditions, the motors see more voltage and more
>> current in seriese mode than in parallel mode.
>>
>> Did that help clear up anything, or just confuse
>> things more?
>>
>> Steven Ciciora
>>
>> --- "Joseph T. " <[EMAIL PROTECTED]> wrote:
>>
>> > "You would be better off in series (where they are
>> > drawing more than
>> > 1,000 amps)."
>> >
>> > As I understand, as you accelerate and reach higher
>> > and higher speeds,
>> > more rpm is required and less torque is needed. The
>> > way to achieve
>> > higher rpm with an electric motor is with more
>> > volts. Therefore,
>> > you're better off with each motor getting less than
>> > 1,000 amps because
>> > that way they are getting more voltage, and
>> > producing more rpm, and
>> > therefore reaching higher speeds. Am I wrong?
>> >
>> > On 7/24/07, Steven Ciciora
>> > <[EMAIL PROTECTED]> wrote:
>> > > One small detail that could be inserted after
>> > "...the
>> > > current will decrease as motor rpm continues to
>> > > increase." The zilla waits for the current to
>> > > decrease to half of the parallel current limit
>> > that is
>> > > programmed into the zilla. For example, when
>> > racing a
>> > > Z2K, it is likely that the current limit in
>> > parallel
>> > > mode is 2,000 amps. So the zilla waits until the
>> > > motors are only drawing 1,000 amps in series
>> > before
>> > > shifting. If the zilla shifted sooner than this,
>> > they
>> > > would be drawing more than 1,000 amps (each) in
>> > > series. Since the zilla 2K can only put out 2,000
>> > > motor amps total, each motor can only see 1,000
>> > amps
>> > > each when in parallel mode. You would be better
>> > off in
>> > > series (where they are drawing more than 1,000
>> > amps).
>> > >
>> > > - Steven Ciciora
>> > >
>> > > --- "Joseph T. " <[EMAIL PROTECTED]> wrote:
>> > >
>> > > > Series/Parallel switching motors is great!
>> > > >
>> > > > Bill Dube gives an excellent explanation on his
>> > > > website:
>> > > >
>> > > > "The Zilla Controller has the ability to operate
>> > a
>> > > > series/parallel
>> > > > motor contactor automatically. The motors are
>> > > > initially configured in
>> > > > series. Thus, the full controller output current
>> > > > travels through both
>> > > > motors. This gives maximum starting torque. As
>> > the
>> > > > motors spin up, the
>> > > > voltage across each of them increases. When that
>> > > > voltage matches the
>> > > > battery voltage, the current will decrease as
>> > motor
>> > > > rpm continues to
>> > > > increase. The Zilla will then switch the motors
>> > into
>> > > > parallel
>> > > > connection. This will double to voltage
>> > available to
>> > > > each motor, but
>> > > > will divide the current. The motors can turn
>> > much
>> > > > faster, but with
>> > > > half the torque. It result is just like shifting
>> > a
>> > > > transmission from
>> > > > low to high."
>> > > >
>> > > >
>> > >
>> > >
>> > >
>> > >
>> > >
>> >
>>
____________________________________________________________________________________
>> > > Looking for a deal? Find great prices on flights
>> > and hotels with Yahoo! FareChase.
>> > > http://farechase.yahoo.com/
>> > >
>> > >
>> >
>> >
>>
>>
>>
>>
>>
____________________________________________________________________________________
>> Sick sense of humor? Visit Yahoo! TV's
>> Comedy with an Edge to see what's on, when.
>> http://tv.yahoo.com/collections/222
>>
>>
>
>
--
If you send email to me, or the EVDL, that has > 4 lines of legalistic
junk at the end; then you are specifically authorizing me to do whatever I
wish with the message. By posting the message you agree that your long
legalistic signature is void.
--- End Message ---
--- Begin Message ---
On Jul 24, 2007, at 5:48 PM, Peter VanDerWal wrote:
The only other thing to
remove is the gas tank which weighs 20lbs? not counting fuel.
When I count the fuel, I get about 57 pounds of gasoline. Anyone like
to verify? (Tank size 9.2 gallons, I think.)
You can remove a lot of sound-deadening and fireproofing material from
around the engine compartment, under the back seats, etc. Your new
motor won't be nearly as loud as the old one. Sorry I didn't weight it
before I threw it out. It was pretty heavy, though. Your Ghia may
have already had this stuff removed.
As far as my Ghia design goes, I'm putting eight Orbitals where the gas
tank used to be, and eight more behind the rear seat. I needed to put
in air shocks to handle the extra weight directly over the suspension,
but I'm just barely under GVWR. This puts the system voltage at 192v.
nominal.
My motor is an 8 inch ADC, adapter from Electro Automotive.
<http://www.electroauto.com> Fantastic quality, long delivery time.
You might be able to fit a 9 inch motor with this adapter, but you'll
need to modify the sheet metal of the engine deck. A clutchless
adapter might be short enough to shoehorn in a 9 inch without
modifications. There's also the WaRP 9 Impulse motor, which is 9
inches in diameter but only as long as an ADC 8 inch. It should fit
fine.
Speaking of modifying sheet metal, I fully enclosed the bottom of the
engine compartment to keep out water and debris. I have an older Ghia
trunk lid that has a drip tray fully covering the vents (from when the
Ghia engines were smaller and cooler). This should keep the engine
compartment dry enough to mount the Zilla and PFC-20 back there.
Cooling might be an issue.
Charger is a Manzanita Micro PFC-20 with regulators. Bad
documentation, good support, great product.
Still saving up for the Zilla controller :) Kind of hard now that I'm
a starving student again.
I'm worried about the brakes. I have read that you can replace the
rear drums with the larger rear drums from the Type III fastback. Of
course there are also disc brake kits for the rear.
I have a couple of Vicor MegaMods that I'm going to try to turn into a
DC/DC converter. If it doesn't work out, I'll probably buy one of
Victor's Brusa units. I want the car to be reliable.
Heater from Canadian EV. I plan to get one of their prewired
electrical boxes too.
I'm also kind of wondering how to cool this car in the southern New
Mexico heat. First things first, though - getting it running is the
big deal.
There is a small section devoted to this project on my website. Well,
websites, actually.
I originally was hosting my own blog on a server at home. It has lots
of text (conversion journal) but very few pictures. Good writeups of
the first year or so. It's archived here:
<http://www.gdunge.com/cgi-bin/blosxom.cgi>.
Then I tried migrating to a RapidWeaver blog hosted at .Mac. Too much
work to maintain, but there's still a photo album up at
<http://homepage.mac.com/annaparadox/dougw/pictures/ghiapictures/
index.html>.
Now I'm trying to migrate the two older sites to the new one.
<http://www.gdunge.com> Almost no EV content as yet.
Later,
Doug
--
Doug Weathers
Las Cruces, NM, USA
http://www.gdunge.com/
--- End Message ---
--- Begin Message ---
I was involved in development of this EV mowler. And it operates 8 hours
on batteries.
http://www.actioneco.com/
So I would say it IS doable with batteries too..
-Jukka
David Hankins kirjoitti:
The problem with batteries is that it takes about 2.5 to 3 hours to do the
lawn. I don't think I can get that many batteries onboard without
overloading it.
David
-----Original Message-----
From: Zeke Yewdall [mailto:[EMAIL PROTECTED]
Sent: Sunday, June 10, 2007 8:50 PM
To: ev@listproc.sjsu.edu
Subject: Re: Corded mower
You are looking at at least a 5 or 7 HP electric motor I'd bet. That
means 240vac, 40A circuit or more -- not a regular extension cord. If
you use a regular AC induction motor, it also tends to overheat under
voltage drop -- so a 200 foot cord is bad news.
I'd highly recommend doing a battery electric instead of corded
electric for something like this. It'll be easier, and likely cheaper
too.
Z
On 6/8/07, David Hankins <[EMAIL PROTECTED]> wrote:
I'm thinking about converting my riding lawn mower to a corded electric.
I have some ideas to deal with the cord. I was thinking about using one of
those cord reel setups. We'll have to see how it holds up reeling under
load. Or maybe a coiled cord affair with a mast on the mower and elevated
attach point on the house. The farthest point is around 200'+ from the
plug.
I have almost an acre under grass and It will get kind of dicey out on the
edge where about a 1/3 acre chunk has a dozen trees on it.
The main question that I have is: The current ICE motor on it is a 19HP
Briggs. What HP electric motor do I need to replace that?
Thanks
David
--- End Message ---
--- Begin Message ---
At a stall the motor will suck maximum current. As the torque generated by
these amps accelerates the car, the motor will increase speed, thus dropping
amps.
-Phil
----- Original Message -----
From: "Joseph T. " <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Tuesday, July 24, 2007 11:05 PM
Subject: Re: Series/Parallel switching (was Re: Karmann Ghia Design - System
voltage)
Yes, it does help alot! After careful reading and re-reading, I now
understand.
But I still have one pesky little question. You say,
"If we wait until the current drops to 1,000 amps (which happens at a much
higher RPM). Then each motor is seeing 120V @ 1,000 amps, 120 KW
If we continue to accelerate, then the current will fall below 1,000 amps
and our power will drop."
Why would the Zilla's output current drop if your accelerating? How
could you accelerate if current is dropping without voltage
increasing?
O 7/24/07, Peter VanDerWal <[EMAIL PROTECTED]> wrote:
> "Under these
> conditions, the motors see more voltage and more
> current in seriese mode than in parallel mode."
>
> I must be missing something here. You're saying that the Zilla gives
> more voltage and current in series than in parralel. Since voltage
> times current is power, you're basically saying that the Zilla is more
> powerful in series than in parralel mode. Does the Zilla limit overall
> power in parralel mode compared to series?
No. At low RPMS the 'zilla delivers more power in series. At high RPMS,
the zilla delivers more power in parallel.
The point where is switches from one to the other is when the current
drops below 1,000 amps in series mode.
The 'zilla 2k protects itself. It won't send more than 2,000 amps to the
motors. It does this by reducing the output voltage to the point where
only 2,000 amps flows.
Once the motor RPMs climb to the point where they won't draw 2,000 amps
even at full pack voltage, then the controller no longer limits current
and doesn't reduce the voltage. Now the only thing limiting current is
the back EMF from the motor and that depends on RPM, more RPM = less
current.
Let's say we have a 240V pack. The controller will come out of current
limit when the series motors are seeing 240V and drawing 2,000 amps. As
the RPMs increase the current will fall. Basically each motor sees 120V
and 2,000 amps. That's 240 kw per motor.
If we switch to parallel at this point, then the controller will go BACK
into current limit. Now remember at this RPM 120V equals 2,000 amps on
each motor. The 'zilla can ONLY put out 2,000 amps TOTAL. In parallel
that means 1,000 amps per motor.
Now the 'zilla can't send 120V to the motors because they would each try
to draw 2,000 amps for a total of 4,000 amps. In order to only allow
each
motor to draw 1,000 amps, the output voltage has to drop to 60V. So now
each motor sees 60V.
60V x 1,000 amps = 60kw per motor.
By switching too soon we have reduce our power to only 25%
If we wait until the current drops to 1,000 amps (which happens at a much
higher RPM). Then each motor is seeing 120V @ 1,000 amps, 120 KW
If we continue to accelerate, then the current will fall below 1,000 amps
and our power will drop.
Switching to parallel now will put the controller back in current limit,
2,000 amps across two motors, the output voltage from the controller will
drop to 120V and increase as the motors RPM climbs (it has to increase to
keep the current at 1,000 amps), until the voltage across the parallel
motors reachs 240 volts. Since the current is held at 1,000 amps, our
power level INCREASES as the voltage climbs until it reachs 240 kw per
motor (240V * 1,000Amps)
So if we keep them in series our power would continue to drop from 120kw.
By switching to parallel the power starts at 120kw and INCREASES until it
reachs 240 kw, per motor.
Switch to soon and we loose power until we can accelerate to the point
where we should have switched.
Does that help?
>
> On 7/24/07, Steven Ciciora <[EMAIL PROTECTED]> wrote:
>> I know I don't explain this very well, 'cause I've
>> confused many a person... so, note that my previous
>> example was why the zilla doesn't shift before the
>> series current drops to the the value of half the
>> current limit in parallel mode. If the zilla shifted
>> sooner, then in parallel mode, the motor current would
>> be _limited_ to 2000 amps total, or 1,000 amps per
>> motor, by the zilla's 2,000 amp overall limit. The
>> way the zilla limits motor current is by reducing the
>> motor voltage. Under these conditions, in series
>> mode, the zilla doesn't have to limit current, so it
>> doesn't have to back off on voltage. Under these
>> conditions, the motors see more voltage and more
>> current in seriese mode than in parallel mode.
>>
>> Did that help clear up anything, or just confuse
>> things more?
>>
>> Steven Ciciora
>>
>> --- "Joseph T. " <[EMAIL PROTECTED]> wrote:
>>
>> > "You would be better off in series (where they are
>> > drawing more than
>> > 1,000 amps)."
>> >
>> > As I understand, as you accelerate and reach higher
>> > and higher speeds,
>> > more rpm is required and less torque is needed. The
>> > way to achieve
>> > higher rpm with an electric motor is with more
>> > volts. Therefore,
>> > you're better off with each motor getting less than
>> > 1,000 amps because
>> > that way they are getting more voltage, and
>> > producing more rpm, and
>> > therefore reaching higher speeds. Am I wrong?
>> >
>> > On 7/24/07, Steven Ciciora
>> > <[EMAIL PROTECTED]> wrote:
>> > > One small detail that could be inserted after
>> > "...the
>> > > current will decrease as motor rpm continues to
>> > > increase." The zilla waits for the current to
>> > > decrease to half of the parallel current limit
>> > that is
>> > > programmed into the zilla. For example, when
>> > racing a
>> > > Z2K, it is likely that the current limit in
>> > parallel
>> > > mode is 2,000 amps. So the zilla waits until the
>> > > motors are only drawing 1,000 amps in series
>> > before
>> > > shifting. If the zilla shifted sooner than this,
>> > they
>> > > would be drawing more than 1,000 amps (each) in
>> > > series. Since the zilla 2K can only put out 2,000
>> > > motor amps total, each motor can only see 1,000
>> > amps
>> > > each when in parallel mode. You would be better
>> > off in
>> > > series (where they are drawing more than 1,000
>> > amps).
>> > >
>> > > - Steven Ciciora
>> > >
>> > > --- "Joseph T. " <[EMAIL PROTECTED]> wrote:
>> > >
>> > > > Series/Parallel switching motors is great!
>> > > >
>> > > > Bill Dube gives an excellent explanation on his
>> > > > website:
>> > > >
>> > > > "The Zilla Controller has the ability to operate
>> > a
>> > > > series/parallel
>> > > > motor contactor automatically. The motors are
>> > > > initially configured in
>> > > > series. Thus, the full controller output current
>> > > > travels through both
>> > > > motors. This gives maximum starting torque. As
>> > the
>> > > > motors spin up, the
>> > > > voltage across each of them increases. When that
>> > > > voltage matches the
>> > > > battery voltage, the current will decrease as
>> > motor
>> > > > rpm continues to
>> > > > increase. The Zilla will then switch the motors
>> > into
>> > > > parallel
>> > > > connection. This will double to voltage
>> > available to
>> > > > each motor, but
>> > > > will divide the current. The motors can turn
>> > much
>> > > > faster, but with
>> > > > half the torque. It result is just like shifting
>> > a
>> > > > transmission from
>> > > > low to high."
>> > > >
>> > > >
>> > >
>> > >
>> > >
>> > >
>> > >
>> >
>>
____________________________________________________________________________________
>> > > Looking for a deal? Find great prices on flights
>> > and hotels with Yahoo! FareChase.
>> > > http://farechase.yahoo.com/
>> > >
>> > >
>> >
>> >
>>
>>
>>
>>
>>
____________________________________________________________________________________
>> Sick sense of humor? Visit Yahoo! TV's
>> Comedy with an Edge to see what's on, when.
>> http://tv.yahoo.com/collections/222
>>
>>
>
>
--
If you send email to me, or the EVDL, that has > 4 lines of legalistic
junk at the end; then you are specifically authorizing me to do whatever
I
wish with the message. By posting the message you agree that your long
legalistic signature is void.
--- End Message ---
