EV Digest 3381
Topics covered in this issue include:
1) Re: Float charging a pack overnight?
by Chris Zach <[EMAIL PROTECTED]>
2) Re: new question was AC induction vs BLDC
by Rod Hower <[EMAIL PROTECTED]>
3) Kids Go carts
by Rod Hower <[EMAIL PROTECTED]>
4) Dynasty shed battery mystery solved...
by Chris Zach <[EMAIL PROTECTED]>
5) Re: Voltage to motor
by Lee Hart <[EMAIL PROTECTED]>
6) Re: new question was AC induction vs BLDC
by Lee Hart <[EMAIL PROTECTED]>
7) Re: The EMW goes for a test ride
by Reverend Gadget <[EMAIL PROTECTED]>
8) Re: new question was AC induction vs BLDC
by Seth <[EMAIL PROTECTED]>
9) OT -testing
by JCT <[EMAIL PROTECTED]>
10) Re: OT Re: Playing with a Basic Stamp
by Doug Weathers <[EMAIL PROTECTED]>
11) Re: new question was AC induction vs BLDC
by Seth <[EMAIL PROTECTED]>
12) powerwheels forensics!
by David Brandt <[EMAIL PROTECTED]>
13) Re: OT Re: Playing with a Basic Stamp- Lego stuff
by Rod Hower <[EMAIL PROTECTED]>
14) Re: new question was AC induction vs BLDC
by Rod Hower <[EMAIL PROTECTED]>
15) Re: fun with powerwheels 2...
by Lee Hart <[EMAIL PROTECTED]>
16) Re: Power steering question - can't find a manual Echo
by John Wayland <[EMAIL PROTECTED]>
17) Re: OT Metro knowledgeable HELP!
by "Mark Thomasson" <[EMAIL PROTECTED]>
18) Re: Float charging a pack overnight?
by Lee Hart <[EMAIL PROTECTED]>
19) Re: new question was AC induction vs BLDC
by Lee Hart <[EMAIL PROTECTED]>
20) Re: Dynasty shed battery mystery solved...
by "Joe Smalley" <[EMAIL PROTECTED]>
21) Re: AC induction vs BLDC
by "[EMAIL PROTECTED]" <[EMAIL PROTECTED]>
22) Rewinding a charger transformer - strange turns.
by James Massey <[EMAIL PROTECTED]>
23) Re: Rewinding a charger transformer - strange turns.
by "David Chapman" <[EMAIL PROTECTED]>
--- Begin Message ---
Oh, I've read them all. The IUI charge recommends a cool down of one
hour followed by a CV float trickle charge.
Before I re-program the MC I was wondering what other people thought.
Chris
Alex Karahalios wrote:
The Hawker manual says that the battery life expectancy for CV float
charging at 13.5V-13.8V is 10 years. But you really need to read the
various application manuals which recommend a variety of charging
regiments.
Alex Karahalios
On Feb 27, 2004, at 5:13 PM, Chris Zach wrote:
The Hawker manuals say to float charge a pack every once in awhile;
does anyone see any danger in doing this? I'm thinking of
reporgramming the MagneCharger on the prizm to apply a steady 13.7
volts per battery CV charge on the pack for eight hours. What is the
risks?
--- End Message ---
--- Begin Message ---
I certainly don't claim to be a motor expert,
my expertice is power electronics. I'm wondering
why Toyota and Honda chose the BLDC (AKA synchronous
AC motor) for their hybrid vehicles? If AC induction
is more efficient and powerfull than BLDC, why would
these auto companies choose BLDC?
Rod
--- Victor Tikhonov <[EMAIL PROTECTED]> wrote:
> Reverend Gadget wrote:
>
> > 3 phase synchronous AC motors vs AC induction,
> which
> > do you think would give the best performance and
> > efficiency. I'll throw price out the window...
> >
> > Gadget
> >
>
> Synchronous PM motors are slightly more efficient
> because no energy lost to slip. But the difference
> is small and overall efficiency for either one
> is high, say 97% vs 94%. Synchronous PM motors
> cannot develop as much torque as induction ones
> because mag field of PM is fixed while in the
> induction
> machine is externally controlled.
>
> So, in my opinion, if you want the most efficient
> vehicle with moderate performance, synchronous PM
> motor is way to do it. If performance is the top
> priority, use induction machine.
>
> --
> Victor
> '91 ACRX - something different
>
--- End Message ---
--- Begin Message ---
I hooked up my new 100 Amp BLDC control to my
daughters go cart tonight and took it for a spin.
I weigh 170 lbs and the go cart actually accomodates
my 6'1" height. It ran very well and didn't trip on
overcurrent like my 20AMP BLDC control. Much more
testing this weekend when my 7 year old son gets to
tear up the yard (Wife and 10 year old daughter are
going to
a national cheerleading compition, so it's a good
bonding weekend with the son). This is field testing
at its best!. My kids will be hard core EV drivers
before they ever get a drivers license!.
Rod
--- End Message ---
--- Begin Message ---
Well, I took a small screwdriver and a hammer to the tops of that dead
Dynasty 12-370 battery in the shed. Under the ratings sticker are a pair
of sealed cap-strips. I removed them with gentle prying via screwdriver
and hammer (Chris wears safety glasses and the like). Took them off and
peered inside the battery
Dry as a bone.
Totally dry. The tops of the plates had a thin sheet of what looked like
crud on them. My guess is sulphuric acid without water or something.
That's what I would hear rattle.
So I tried filling the ports with distilled water. Just enough to cover
the plates and a bit took almost half a gallon of water. I could hear
little hissings as I filled the cells.
Put it on charge; it's not drawing any current yet. We'll see in an
hour; I'll leave the caps on but loose overnight and see what happens.
I also took the caps off an *old* sealed battery. I think what I saw in
there was the battery interconnects; destroyed by the concentrated acid.
Not sure, but that would explain one mystery: Why batteries fail in
quantum 2 volt amounts. Perhaps the cell dries out, the concentrated
sulphuric acid remains cause the interconnects to fail and the debris
shorts a cell. Or the dried out cell simply becomes a conductor,
shorting itself out.
We shall see. Interesting though; next step is to take it's good sister
apart and see if it is dry. I might just want to "water" these sealed
batteries; any idea how much water they should get?
Chris
--- End Message ---
--- Begin Message ---
From: "Jack Knopf" <[EMAIL PROTECTED]>
>> How much CAN one go over the name plate voltage on a ADC motor?
Joe Smalley wrote:
> I have seen triple the rated voltage on several motors.
> I have been advised that I can put 96 volts on my 24 Volt
> starter/generator and it should live.
I agree with Joe, for the special cases mentioned (*some* Advanced DC
motors, and the *particular* type of starter/generator Joe has. But do
not take these as general-case answers for motors in general.
Advanced DC tends to under-rate their motors, simply because they don't
have the equipment to test them at higher voltages. But they are *built*
like higher-voltage motors. They have many commutator bars, so there are
many inter-bar gaps between brushes. Each inter-bar gap can stand 30v,
and you have 5-10 such gaps between brushes (depending on the motor), so
they can survive 150-300v under the right conditions.
ADC motors do not have interpoles or compensating windings, so the
optimum brush location to minimize arcing moves with current. If you
apply high voltage AND high current simultaneously, an arc starts
between the bars the brush just opened, and it CONTINUES because the
voltage is high enough to maintain it. The commutator rotates, striking
arcs between each successive pair of bars. You can quickly have a 'ring
of fire' all the way around the commutator! The motor is going to die,
very very soon!
Another problem is that at high voltage and low current, rpm has to be
high. The motor is jeopardized from the high rpm.
Finally, the terminal screws, brush mounting, and windings don't really
have enough insulation for high voltages. Some depend on just the air
gaps, others on the insulation on the wire. Plus, you can get brush
dust, water, and other contaminants on things that reduce the breakdown
voltage until something arcs over.
All these problems can be dealt with to varying degrees. You can set the
controller's current limit down to prevent high current. You can shift
the brush position, to optimize commutation when you need it the most.
And, you can handle all the 'little' mechanical problems, like balancing
and banding the armature, and adding supplemental insulation wherever
there is a chance for a breakdown.
Joe's starter/generator is I believe one of the old aircraft surplus
types. These are perhaps the most technologically advanced DC brush
machines ever made. They have special high-class insulation, interpoles,
compensating windings, precision balanced and banded armatures, and
every other trick in the book. They too will survive at high voltages;
moreover, they can still handle substantial current at several times
rated voltage because the extra windings keep commutation from shifting.
Most of these tricks seem to be a 'lost art'; not being applied by any
motor manufacturer any more. You can apply them yourself (with some
difficulty), but don't assume any modern off-the-shelf motor will let
you 'push' it to such extremes.
--
"Never doubt that a small group of committed people can change the
world. Indeed, it's the only thing that ever has!" -- Margaret Meade
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
Seth wrote:
> Yeah, what Oat said. (And Lee and Rod...) As for the application, I
> assume you want a powerful motor. If that is the case, then induction
> will win for efficiency, but you will be splitting hairs.
I think you've got it. Induction is more efficient at light load, so it
will win over PM synchronous ("brushless DC") if you must have a motor
whose peak power is *much* larger than the power needed for cruising.
But if you can size the motor for the cruising power you need (and force
it to run inefficiently when high power is needed), then the PM motor
will win because its peak efficiency is higher.
The same is true for brushed DC motors. PM motors have higher peak
efficiency, but lower light-load efficiency.
> BLDC will do more peak power per pound, and induction will be much
> more flexible due to field weakening.
This is more a consequence of controller limitations than motor
limitations. If you really drive the field hard, the wound-field motor
will outperform the PM field.
> Induction can win due in a drag race to the area under the curve
> with a lower peak power for this reason, IMO. **ESPECIALLY** if
> you go transmissionless.
Boy, this one really gets complicated. Everything hinges on what
assumptions you make. I don't think you can clearly say what kind of
motor will win in a drag race. At present, all the records are held by
series DC brushed motors.
> Yes you can field weaken a BLDC/PM Synchronous motor. 100+kW ones are
> very rare and the amount of field weakening is nothing like that you
> can get on induction, where you can quadruple base speed.
Obviously you are ignoring the megawatt-sized wound-field synchronous
motors used in power plants, ships, etc. :-)
--
"Never doubt that a small group of committed people can change the
world. Indeed, it's the only thing that ever has!" -- Margaret Meade
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
--- Lawrence Rhodes <[EMAIL PROTECTED]> wrote:
> >From my experience at 48v and a top speed of 40
> with the Lectra I would
> imagine that 72v should be capable of 60 mph with
> good hill climbing with only one gear.
How right you are! that sucker easily goes 60 but I
have to finish off the electrical to find out just how
fast. (it has an electronic speedo) It easily takes
off in fifth gear on flat streets, but it's a rocket
in second. I wouldn't want to pull any long hills in
top gear so I'm happy having the gearbox. my future
driveway is about 1/4 of a mile of 25% grade after
several miles of 10% or better grade so I think gears
are the ticket for my application. now begins the job
of building a nice aluminum fairing and buttoning up
the package, however I will be leaving a window into
the batteries and cables.
> I'm not sure what the
> Reverend's pack weighs but I sure do want to know.
My pack weighs 276 lbs and the bike feels about the
same as it did with the ICE and a full tank of dino
juice
Gadget
=====
visit my website at www.reverendgadget.com
--- End Message ---
--- Begin Message ---
Power density, for one reason. The other is that they are small motors
run hard so they are run more optimally that a large motor replacing
the entire engine. When that is done, the part load efficiency hit
becomes more of the issue. But I suspect the first part and not having
to cool a rotor is a big issue.
Sort of a packaging/system engineer's answer to a motor question.
Seth
P.S. I would consider you a motor expert...
On Feb 27, 2004, at 8:45 PM, Rod Hower wrote:
I certainly don't claim to be a motor expert,
my expertice is power electronics. I'm wondering
why Toyota and Honda chose the BLDC (AKA synchronous
AC motor) for their hybrid vehicles? If AC induction
is more efficient and powerfull than BLDC, why would
these auto companies choose BLDC?
Rod
--- Victor Tikhonov <[EMAIL PROTECTED]> wrote:
Reverend Gadget wrote:
3 phase synchronous AC motors vs AC induction,
which
do you think would give the best performance and
efficiency. I'll throw price out the window...
Gadget
Synchronous PM motors are slightly more efficient
because no energy lost to slip. But the difference
is small and overall efficiency for either one
is high, say 97% vs 94%. Synchronous PM motors
cannot develop as much torque as induction ones
because mag field of PM is fixed while in the
induction
machine is externally controlled.
So, in my opinion, if you want the most efficient
vehicle with moderate performance, synchronous PM
motor is way to do it. If performance is the top
priority, use induction machine.
--
Victor
'91 ACRX - something different
--- End Message ---
--- Begin Message ---
1-2-3
--- End Message ---
--- Begin Message ---
On Friday, February 27, 2004, at 11:02 AM, Lee Hart wrote:
Aaron Birenboim wrote:
Definately take a look at those little Leggo Robotics kits.
Very k00l.
You're probably thinking of the Lego Mindstorms kits. The official
name is the Robotics Invention System. They contain a Hitachi H8
microcontroller.
They've been discontinued.
Nope - still for sale on the Lego web site.
http://shop.lego.com/product.asp?p=KB565 .
They can also be had at Pitsco, along with a large variety of Lego (and
non-Lego) parts.
http://www.pldstore.com/
And Robot Books carries them, along with lots of other goodies.
http://www.robotbooks.com/
Besides, the programs allowed for the
'bricks' was rather severely limited by the software that ran on the
PC.
Plus it was only for Windows, which kept it out of my hands for a few
years. However, when I got VirtualPC working with it, I was impressed
with how simple and accessible the programming environment was. Great
for kids.
However, several groups have 'hacked' the brick's micro, and wrote
their
own development system to support it.
Oh yes indeed. There's also a copious body of work on adding hardware
(sensors, actuators, etc).
Try some web searches on "Lego Mindstorms" to see what I mean. Amazon
lists 31 books with "Lego Mindstorms" in the title.
Here's a cool site that shows a great educational use for the
Mindstorms system.
http://www.planetary.org/rrrr/index.html
--
"Never doubt that a small group of committed people can change the
world. Indeed, it's the only thing that ever has!" -- Margaret Meade
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
Disclaimer: I don't work for Lego, but I wish I did.
--
Doug Weathers
Bend, OR, USA
http://learn-something.homedns.org:8100/weblog/
--- End Message ---
--- Begin Message ---
Ok, I was referring to field weakening permanent magnet 3 phase AC
synchronous machines. Specifically in the 5-200kW size you might see in
a ground vehicle. Heard of teething issues secondhand...
I respectfully suggest that most AC drives (synchronousPM or induction)
shouldn't drive motors so hard as to saturate them to the point of
having great difficulty maintaining current control as the inductance
drops. Ok, technically a function of the inverter hardware. The other
side effect is that an induction rotor incinerates (first!) because it
has losses that are many times higher than the PM machine. Or so I keep
hearing. No I haven't done an aplle to apple comparison. And yes you
can run an induction rotor hotter than PM. But how much hotter? I don't
know.
The drag records are held by series wound motors. Which have a power
delivery curve not unlike AC induction with a monster inverter. I
strongly suspect that these records could be broken with the right AC
induction hardware. That hardware is slowly coming down in price. IGBTs
keep getting a bit better every year. Especially the higher voltage
stuff. Imagine a 600V battery pack at 400A and a motor that pulls at
inverter current limit most of the way to the motor's mechanical
redline. I think it is a matter of time. And not that much time. After
all, how much would 56 x 16 Ah hawkers sag under a 400A load?
"... this message may contain forward looking statements..."
Seth
On Feb 27, 2004, at 8:14 PM, Lee Hart wrote:
Seth wrote:
Yeah, what Oat said. (And Lee and Rod...) As for the application, I
assume you want a powerful motor. If that is the case, then induction
will win for efficiency, but you will be splitting hairs.
I think you've got it. Induction is more efficient at light load, so it
will win over PM synchronous ("brushless DC") if you must have a motor
whose peak power is *much* larger than the power needed for cruising.
But if you can size the motor for the cruising power you need (and
force
it to run inefficiently when high power is needed), then the PM motor
will win because its peak efficiency is higher.
The same is true for brushed DC motors. PM motors have higher peak
efficiency, but lower light-load efficiency.
BLDC will do more peak power per pound, and induction will be much
more flexible due to field weakening.
This is more a consequence of controller limitations than motor
limitations. If you really drive the field hard, the wound-field motor
will outperform the PM field.
Induction can win due in a drag race to the area under the curve
with a lower peak power for this reason, IMO. **ESPECIALLY** if
you go transmissionless.
Boy, this one really gets complicated. Everything hinges on what
assumptions you make. I don't think you can clearly say what kind of
motor will win in a drag race. At present, all the records are held by
series DC brushed motors.
Yes you can field weaken a BLDC/PM Synchronous motor. 100+kW ones are
very rare and the amount of field weakening is nothing like that you
can get on induction, where you can quadruple base speed.
Obviously you are ignoring the megawatt-sized wound-field synchronous
motors used in power plants, ships, etc. :-)
--
"Never doubt that a small group of committed people can change the
world. Indeed, it's the only thing that ever has!" -- Margaret Meade
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
Well, when I got home, I got the REST of the story...both kids were in
the car at the time, and they hit something, likely a rock sticking out
of the ground, since they had run the car into the flowerbed while
arguing...
Anyway, I disassembled the gearboxes and found out what happened.
Chris, you are right about cost, but in this case it was apparently
cheaper still to make every unit using the same or similar components.
These gearboxes (and even the motors) are identical to those on the 12V
4-wheeler unit, except for one thing.
The 12V 4-wheeler I have uses a metal gear that is press fit or brazed
to the motor's "D" shaft. The Countach uses a small metal yoke with a
hole to match the "D" shaft to transfer torque to a plastic gear. all
the gears were in fine shape, but there is enough clearance between the
motor face and the yoke/gear assembly that a good bump can jar the yoke
up off of the gear, at which point it spins freely.
I think the problem is solved by adding several no. 6 washers as
spacers between the motor face and the yoke, so it can't separate from
the gear. Unfortunately I only had enough for one side:-) Tomorrow
I'll make a parts run and see how this turns out. The fun continues!
Interestingly, these gearboxes were sealed well, and the grease in
these was in excellent condition.
By the way, I had higher voltage and therefore speed, but I believe the
current (and therefore torque) was the same at speed, although it would
have pulsed higher at startup.
=====
David Brandt, P.E.
918-342-1252 (hm)
918-401-5689 (wk)
__________________________________
Do you Yahoo!?
Get better spam protection with Yahoo! Mail.
http://antispam.yahoo.com/tools
--- End Message ---
--- Begin Message ---
I bought a Lego Spybotics robot for my son.
this is pretty cool, you program a 'route'
and the robot follows this with your IR remote
command. The PC interface is too difficult for
my 6 year old, but with help the entire process
is very rewarding and interesting for my son.
I commend Lego for their efforts in educating
kids with interesting science projects.
This 'micro EV' project is a good introduction
to EV's for my kids.
Rod
--- Doug Weathers <[EMAIL PROTECTED]> wrote:
>
> On Friday, February 27, 2004, at 11:02 AM, Lee Hart
> wrote:
>
> > Aaron Birenboim wrote:
> >>
> >> Definately take a look at those little Leggo
> Robotics kits.
> >> Very k00l.
>
> You're probably thinking of the Lego Mindstorms
> kits. The official
> name is the Robotics Invention System. They contain
> a Hitachi H8
> microcontroller.
>
> > They've been discontinued.
>
> Nope - still for sale on the Lego web site.
>
> http://shop.lego.com/product.asp?p=KB565 .
>
> They can also be had at Pitsco, along with a large
> variety of Lego (and
> non-Lego) parts.
>
> http://www.pldstore.com/
>
> And Robot Books carries them, along with lots of
> other goodies.
>
> http://www.robotbooks.com/
>
> > Besides, the programs allowed for the
> > 'bricks' was rather severely limited by the
> software that ran on the
> > PC.
>
> Plus it was only for Windows, which kept it out of
> my hands for a few
> years. However, when I got VirtualPC working with
> it, I was impressed
> with how simple and accessible the programming
> environment was. Great
> for kids.
>
> > However, several groups have 'hacked' the brick's
> micro, and wrote
> > their
> > own development system to support it.
>
> Oh yes indeed. There's also a copious body of work
> on adding hardware
> (sensors, actuators, etc).
>
> Try some web searches on "Lego Mindstorms" to see
> what I mean. Amazon
> lists 31 books with "Lego Mindstorms" in the title.
>
> Here's a cool site that shows a great educational
> use for the
> Mindstorms system.
>
> http://www.planetary.org/rrrr/index.html
>
> > --
> > "Never doubt that a small group of committed
> people can change the
> > world. Indeed, it's the only thing that ever has!"
> -- Margaret Meade
> > --
> > Lee A. Hart 814 8th Ave N Sartell MN 56377
> leeahart_at_earthlink.net
> >
> >
>
> Disclaimer: I don't work for Lego, but I wish I did.
> --
> Doug Weathers
> Bend, OR, USA
> http://learn-something.homedns.org:8100/weblog/
>
--- End Message ---
--- Begin Message ---
A neodynium iron cobalt BLDC motor can
operate at very high temps without a problem.
We run these motors in 100C environments on
transportation pumps without a problem.
Electric Louie is hoping to run a BLDC in a
dragster at several hundred KWatts. I think he
needs a control however (which Bob Gruenwald at
Electric motor sports can provide with the appropriate
software).
In the mean time I plan on working on a high power
BLDC control for Louie's scooters.
Rod.
--- Seth <[EMAIL PROTECTED]> wrote:
> Ok, I was referring to field weakening permanent
> magnet 3 phase AC
> synchronous machines. Specifically in the 5-200kW
> size you might see in
> a ground vehicle. Heard of teething issues
> secondhand...
>
> I respectfully suggest that most AC drives
> (synchronousPM or induction)
> shouldn't drive motors so hard as to saturate them
> to the point of
> having great difficulty maintaining current control
> as the inductance
> drops. Ok, technically a function of the inverter
> hardware. The other
> side effect is that an induction rotor incinerates
> (first!) because it
> has losses that are many times higher than the PM
> machine. Or so I keep
> hearing. No I haven't done an aplle to apple
> comparison. And yes you
> can run an induction rotor hotter than PM. But how
> much hotter? I don't
> know.
>
> The drag records are held by series wound motors.
> Which have a power
> delivery curve not unlike AC induction with a
> monster inverter. I
> strongly suspect that these records could be broken
> with the right AC
> induction hardware. That hardware is slowly coming
> down in price. IGBTs
> keep getting a bit better every year. Especially the
> higher voltage
> stuff. Imagine a 600V battery pack at 400A and a
> motor that pulls at
> inverter current limit most of the way to the
> motor's mechanical
> redline. I think it is a matter of time. And not
> that much time. After
> all, how much would 56 x 16 Ah hawkers sag under a
> 400A load?
>
> "... this message may contain forward looking
> statements..."
>
> Seth
>
>
> On Feb 27, 2004, at 8:14 PM, Lee Hart wrote:
>
> > Seth wrote:
> >> Yeah, what Oat said. (And Lee and Rod...) As for
> the application, I
> >> assume you want a powerful motor. If that is the
> case, then induction
> >> will win for efficiency, but you will be
> splitting hairs.
> >
> > I think you've got it. Induction is more efficient
> at light load, so it
> > will win over PM synchronous ("brushless DC") if
> you must have a motor
> > whose peak power is *much* larger than the power
> needed for cruising.
> > But if you can size the motor for the cruising
> power you need (and
> > force
> > it to run inefficiently when high power is
> needed), then the PM motor
> > will win because its peak efficiency is higher.
> >
> > The same is true for brushed DC motors. PM motors
> have higher peak
> > efficiency, but lower light-load efficiency.
> >
> >> BLDC will do more peak power per pound, and
> induction will be much
> >> more flexible due to field weakening.
> >
> > This is more a consequence of controller
> limitations than motor
> > limitations. If you really drive the field hard,
> the wound-field motor
> > will outperform the PM field.
> >
> >> Induction can win due in a drag race to the area
> under the curve
> >> with a lower peak power for this reason, IMO.
> **ESPECIALLY** if
> >> you go transmissionless.
> >
> > Boy, this one really gets complicated. Everything
> hinges on what
> > assumptions you make. I don't think you can
> clearly say what kind of
> > motor will win in a drag race. At present, all the
> records are held by
> > series DC brushed motors.
> >
> >> Yes you can field weaken a BLDC/PM Synchronous
> motor. 100+kW ones are
> >> very rare and the amount of field weakening is
> nothing like that you
> >> can get on induction, where you can quadruple
> base speed.
> >
> > Obviously you are ignoring the megawatt-sized
> wound-field synchronous
> > motors used in power plants, ships, etc. :-)
> > --
> > "Never doubt that a small group of committed
> people can change the
> > world. Indeed, it's the only thing that ever has!"
> -- Margaret Meade
> > --
> > Lee A. Hart 814 8th Ave N Sartell MN 56377
> leeahart_at_earthlink.net
> >
>
--- End Message ---
--- Begin Message ---
>> Where do you find power wheels for less than $5?? I can't
>> seem to find any for less than $50.
David Brandt wrote:
> At our local thrift shop. Usually, you can just pop in a new
> battery and go. On one I had to do some rewiring, but that wasn't
> any big deal.
Or at any spring garage sale. They generally got it for Christmas, ran
the battery down, left it in the garage until it froze, and the sell it
cheap when it won't work in the spring.
--
"Never doubt that a small group of committed people can change the
world. Indeed, it's the only thing that ever has!" -- Margaret Meade
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
Hello to All,
Mark Farver wrote:
> Hate to nitpick, but the MR2's with 12v power steering pumps were the
> 2nd generation cars. (And John has seen both and probably knows better)
>
Oops. Yes, Mark's right, it was the 2nd gen. car that had the nifty pump, not the 1st
gen....thanks for the correction. I guess I should have waited for the morning fog to
clear
before typing!
See Ya......John Wayland
--- End Message ---
--- Begin Message ---
The last time I had a charging problem (it's been a while) the voltage
regulator was a separate box in the engine compartment. If that's gone out,
the alternator will not charge. If you have a separate voltage regulator,
there will be an extra pair of wires plugged into the alternator.
Did you check voltages with the engine running when there should be a load
on the alternator? With no current load through the connections, a high
resistance connection will not show up with just a voltage check.
This one is obvious, but make sure the belt is tight enough to spin the
alternator.
Good mystery. Let me know what you find. Mark T.
----- Original Message -----
From: "Paul G" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Friday, February 27, 2004 4:48 PM
Subject: OT Metro knowledgeable HELP!
> Sorry for the OT post, but I know there are Metro owners here, and
> people with converted Geo Metros that have disassembled the stuff
> under the hood.
>
> It will not charge its 12v battery. The alternator tests out good on
> the computerized machine at my local NAPA (alternator make and model
> specific test). They have tested it twice 'cause its the most
> expensive alternator at over $200 rebuilt. The battery was replaced
> with a new one, still the problem persists. I have looked for any
> voltage drop between the alternator output and the battery positive
> post (to rule out wiring I think) and they read the same voltage to
> the 0.01 volt. But this voltage is WAY to low, generally just over 13
> volts, and drops if you turn on the headlights.
>
> Since others have worked these vehicles over with a short stick I was
> wondering if there could be something wrong in the circuit that the 2
> small wires go to. The dash ALT warning light does work and goes off
> when its started. *Any* ideas?
>
> thanx,
> Neon
>
--- End Message ---
--- Begin Message ---
Chris Zach wrote:
> Question: Last night I decided to float charge the dead Hawker on the
> charger at 14 volts overnight. Today after leaving it off charge all
> day it reads a nice 13.0 volts and has no problem with the load
> tester (500 CCA as opposed to <300 before with a "full charge")
14 volts is NOT a float voltage -- it is an equalization voltage (and a
low one at that).
It 'came back' because it had at least one cell that was at a much lower
state of charge than the rest. You forced it to charge even though the
rest of the cells were full by applying the overvoltage.
However, I would guess you aren't done yet. Only one night at 14v won't
fully equalize it. The current at 14v probably fell to well under 1 amp.
8 hours at 1 amp is only 8 amphours. What I would do is apply at least
15v but thru a resistor to limit the current to less than an amp until
the current stops falling and starts rising again.
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
Rod Hower wrote:
> I certainly don't claim to be a motor expert,
> my expertice is power electronics. I'm wondering
> why Toyota and Honda chose the BLDC (AKA synchronous
> AC motor) for their hybrid vehicles? If AC induction
> is more efficient and powerful than BLDC, why would
> these auto companies choose BLDC?
My guess is that these cars mainly operate their electric motors near
full power. As an electric 'turbocharger' for example. They spend so
little time operating at light load that it doesn't matter if they are
less efficient there.
--
"Never doubt that a small group of committed people can change the
world. Indeed, it's the only thing that ever has!" -- Margaret Meade
--
Lee A. Hart 814 8th Ave N Sartell MN 56377 leeahart_at_earthlink.net
--- End Message ---
--- Begin Message ---
I put 10 cc of water in each cell of a Concorde AGM. That was how much it
took to go from dry looking to shiny and no free liquid.
The capacity went from 48 AHr to 78 AHr on the next full cycle.
Joe Smalley
Rural Kitsap County WA
Fiesta 48 volts
NEDRA 48 volt street conversion record holder
[EMAIL PROTECTED]
----- Original Message -----
From: "Chris Zach" <[EMAIL PROTECTED]>
To: "Electric Vehicle Discussion List" <[EMAIL PROTECTED]>
Sent: Friday, February 27, 2004 5:57 PM
Subject: Dynasty shed battery mystery solved...
> Well, I took a small screwdriver and a hammer to the tops of that dead
> Dynasty 12-370 battery in the shed. Under the ratings sticker are a pair
> of sealed cap-strips. I removed them with gentle prying via screwdriver
> and hammer (Chris wears safety glasses and the like). Took them off and
> peered inside the battery
>
> Dry as a bone.
>
> Totally dry. The tops of the plates had a thin sheet of what looked like
> crud on them. My guess is sulphuric acid without water or something.
> That's what I would hear rattle.
>
> So I tried filling the ports with distilled water. Just enough to cover
> the plates and a bit took almost half a gallon of water. I could hear
> little hissings as I filled the cells.
>
> Put it on charge; it's not drawing any current yet. We'll see in an
> hour; I'll leave the caps on but loose overnight and see what happens.
>
> I also took the caps off an *old* sealed battery. I think what I saw in
> there was the battery interconnects; destroyed by the concentrated acid.
> Not sure, but that would explain one mystery: Why batteries fail in
> quantum 2 volt amounts. Perhaps the cell dries out, the concentrated
> sulphuric acid remains cause the interconnects to fail and the debris
> shorts a cell. Or the dried out cell simply becomes a conductor,
> shorting itself out.
>
> We shall see. Interesting though; next step is to take it's good sister
> apart and see if it is dry. I might just want to "water" these sealed
> batteries; any idea how much water they should get?
>
> Chris
>
--- End Message ---
--- Begin Message ---
....it's kind of like calling a motor with three
wires that 'has' to be fed with AC in order to spin, a brushless DC!
"DC" motors really run on AC, once you get inside. ALL motors are
AC inside.
The "Brushless" DC term is just easier to say than
"Electronically-Commutated DC". The original BLDC motors were really just
that, DC motors with an electronic commutator. The waveform on a DC motor
armature winding was nearly identical to that fed to the BLDC motor
armature winding by the electronics. In most cases, it still is.
You can feed a BLDC motor a sine wave if you like. The controller
is an AC controller, but the motor is still a BLDC motor. The motor hasn't
changed even though the controller has. You can feed a BLDC trapezoidal
waveform into an induction motor if you like. The induction motor might get
a little warm, but it will run if the voltage and frequency are something
within reason.
_ /| Bill "Wisenheimer" Dube'
\'o.O' <[EMAIL PROTECTED]>
=(___)=
U
Check out the bike -> http://www.KillaCycle.com
--- End Message ---
--- Begin Message ---
Hi All
Well, with batteries on the way, it is time to sort out my charger. I
pulled apart a very old 72V 3600VA (rated input 240V 15A) charger
transformer in order to get it rewound to be multi-tapped output to charge
96V, 120V or 144V (contingency for as my pack ages).
The transformer is 'I' laminates, of two different lengths, lapped up to
form a single-loop core, as follows:
_____________
| | |
| |_________|
| | | | The laminates are 65mm wide
| | | | the laminate stack is 92mm thick
| | | |
| | | | the laminates are laid in pairs,
|___|_____| | pairs alternate direction to overlap.
| | |
|_________|___|
There are no gaps or odd windings to limit the current capacity of the
transformer, I assume that the limit on the charging current is either by
turns per volt, or purely that the taps are selected to set the current
when matched to the battery. The charger originally had a 2-step rate
control PCB (charge to 90V on high rate, switch taps, charge to 87V at
lower rate, run on for [X] time). I am going to use battery monitors,
perhaps Rudman Regs, and charge at bulk rate until the first regulator
comes on, then switch to equalise rate until all regs are on. Then perhaps
turn the regs off and use current interrupt to perform a conditioning
charge every tenth or so charge (I'll be using Exide Orbital deep cycle).
The transformer design is that the primary is wound on first, half on each
side of the core, with the secondary on top, half on each side....well not
quite half, which is part of what I am seeking advice on. One end of the
primary has fine taps, the other coarse taps. The voltages stated are as
measured at the time of the test (the 240VAC is normally high here, so the
electricity supply company gets to sell more power).
Primary Secondary
VAC
0V ----, ||| ,------0V
(6t) ||| @
6.5 ---@ ||| @
(6t) ||| @
12.8 ---@ ||| @
(6t) ||| @
19.3 ---@ ||| @
(6t) ||| @
25.7 ---@ ||| @ 47 turns
(6t) ||| @
32.2 ---@ ||| @
(6t) ||| @
38.6 ---@ ||| @
(79t) ||| @
cross ,-' ||| '--, cross link
link '-, ||| ,--' between halves
(76t) ||| @
216.6 --@ ||| @
(15t) ||| @ 46 turns
232.7 --@ ||| @
(15t) ||| @
248.7 --' ||| '---100.8V
Apart from adding some additional fine taps to the primary, I'm going to
have the secondary wound with taps that are in ratio of the existing number
of turns to give me 96V, 120V and 144V.
First question, since the taps are to allow me to reconnect to reduce pack
volts by removing 12V modules (as the pack gets old), should I allow for
108 and 132V as well?
Second question, how many turns? (since the secondary has odd counts each
side (I was expecting to find the same number of secondary turns on each
half). Should I maintain the offset ratio of secondary turns? (is that what
limits the current?)
What I am planning is as follows: Since for 72V this had 93 turns, there is
a turns to pack voltage ratio that is 93:72, or 1.291667.
Which extrapolates to:
96V = 124 turns, (62 per side, or should it be 61 and 63?)
108V = 139.5 turns, (140 turns, 70/70 or 71/69?)
120V = 155 turns, (77 and 78?)
132V = 170.5 turns, (171 turns, 85 and 86 turns?)
144V = 186 turns (should it be 93 per side, or 92 and 94?).
The primary was wound in approximately 3.5mm OD wire, which if I haven't
stuffed up and remembered the wrong formula for area gives around 9.5mm2.
This is is capable according to my cable sizing guide of around 50 Amps,
although the input rating of the charger is only 15A. Assuming that it was
deliberately over sized (due to its age), what size wire should I specify
to the winding shop?
The secondary was wound in flat aluminium strap, as wide as the coils (note
I didn't say as wide as the former, since it doesn't have one yet). The
local winders will not have flat strap, so they are likely to want to use
round or rectangular wire. Since this is nominally a 3.6kVa transformer,
the nominal output current at 96V (lowest tap, sizing wire to suit) is
37.5A, although the peak currents will be higher. So part two of what size
wire, how many mm2 should they use on the output? (if you know the size in
gauge, AWG or SWG, I should be able to find a conversion to mm2, but please
specify the standard you are using).
I am going to make new formers for them to wind on to using insulation
panel for the ends, and PCB fibreglass sheet (with the copper removed) as
the inside box, epoxy resin glued together.
Any and all comments welcome.
Thanks
James Massey
Launceston, Tasmania, Australia.
'78 Daihatsu 1300kg tray truck under conversion.
--- End Message ---
--- Begin Message ---
Isnt it going to be kind of expensive to rewind this transformer? Seems like
with a little hunting you could find a Fair Radio charger and go from there.
Thats what it sounds kinda like you are building and they run off 220. Or
what about a good sized Variac? David Chapman.
----- Original Message -----
From: "James Massey" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Saturday, February 28, 2004 1:26 AM
Subject: Rewinding a charger transformer - strange turns.
> Hi All
>
> Well, with batteries on the way, it is time to sort out my charger. I
> pulled apart a very old 72V 3600VA (rated input 240V 15A) charger
> transformer in order to get it rewound to be multi-tapped output to charge
> 96V, 120V or 144V (contingency for as my pack ages).
>
> The transformer is 'I' laminates, of two different lengths, lapped up to
> form a single-loop core, as follows:
> _____________
> | | |
> | |_________|
> | | | | The laminates are 65mm wide
> | | | | the laminate stack is 92mm thick
> | | | |
> | | | | the laminates are laid in pairs,
> |___|_____| | pairs alternate direction to overlap.
> | | |
> |_________|___|
>
> There are no gaps or odd windings to limit the current capacity of the
> transformer, I assume that the limit on the charging current is either by
> turns per volt, or purely that the taps are selected to set the current
> when matched to the battery. The charger originally had a 2-step rate
> control PCB (charge to 90V on high rate, switch taps, charge to 87V at
> lower rate, run on for [X] time). I am going to use battery monitors,
> perhaps Rudman Regs, and charge at bulk rate until the first regulator
> comes on, then switch to equalise rate until all regs are on. Then perhaps
> turn the regs off and use current interrupt to perform a conditioning
> charge every tenth or so charge (I'll be using Exide Orbital deep cycle).
>
> The transformer design is that the primary is wound on first, half on each
> side of the core, with the secondary on top, half on each side....well not
> quite half, which is part of what I am seeking advice on. One end of the
> primary has fine taps, the other coarse taps. The voltages stated are as
> measured at the time of the test (the 240VAC is normally high here, so the
> electricity supply company gets to sell more power).
>
> Primary Secondary
> VAC
> 0V ----, ||| ,------0V
> (6t) ||| @
> 6.5 ---@ ||| @
> (6t) ||| @
> 12.8 ---@ ||| @
> (6t) ||| @
> 19.3 ---@ ||| @
> (6t) ||| @
> 25.7 ---@ ||| @ 47 turns
> (6t) ||| @
> 32.2 ---@ ||| @
> (6t) ||| @
> 38.6 ---@ ||| @
> (79t) ||| @
> cross ,-' ||| '--, cross link
> link '-, ||| ,--' between halves
> (76t) ||| @
> 216.6 --@ ||| @
> (15t) ||| @ 46 turns
> 232.7 --@ ||| @
> (15t) ||| @
> 248.7 --' ||| '---100.8V
>
> Apart from adding some additional fine taps to the primary, I'm going to
> have the secondary wound with taps that are in ratio of the existing
number
> of turns to give me 96V, 120V and 144V.
>
> First question, since the taps are to allow me to reconnect to reduce pack
> volts by removing 12V modules (as the pack gets old), should I allow for
> 108 and 132V as well?
>
> Second question, how many turns? (since the secondary has odd counts each
> side (I was expecting to find the same number of secondary turns on each
> half). Should I maintain the offset ratio of secondary turns? (is that
what
> limits the current?)
>
> What I am planning is as follows: Since for 72V this had 93 turns, there
is
> a turns to pack voltage ratio that is 93:72, or 1.291667.
>
> Which extrapolates to:
> 96V = 124 turns, (62 per side, or should it be 61 and 63?)
> 108V = 139.5 turns, (140 turns, 70/70 or 71/69?)
> 120V = 155 turns, (77 and 78?)
> 132V = 170.5 turns, (171 turns, 85 and 86 turns?)
> 144V = 186 turns (should it be 93 per side, or 92 and 94?).
>
> The primary was wound in approximately 3.5mm OD wire, which if I haven't
> stuffed up and remembered the wrong formula for area gives around 9.5mm2.
> This is is capable according to my cable sizing guide of around 50 Amps,
> although the input rating of the charger is only 15A. Assuming that it was
> deliberately over sized (due to its age), what size wire should I specify
> to the winding shop?
>
> The secondary was wound in flat aluminium strap, as wide as the coils
(note
> I didn't say as wide as the former, since it doesn't have one yet). The
> local winders will not have flat strap, so they are likely to want to use
> round or rectangular wire. Since this is nominally a 3.6kVa transformer,
> the nominal output current at 96V (lowest tap, sizing wire to suit) is
> 37.5A, although the peak currents will be higher. So part two of what size
> wire, how many mm2 should they use on the output? (if you know the size in
> gauge, AWG or SWG, I should be able to find a conversion to mm2, but
please
> specify the standard you are using).
>
> I am going to make new formers for them to wind on to using insulation
> panel for the ends, and PCB fibreglass sheet (with the copper removed) as
> the inside box, epoxy resin glued together.
>
> Any and all comments welcome.
>
> Thanks
>
> James Massey
>
> Launceston, Tasmania, Australia.
> '78 Daihatsu 1300kg tray truck under conversion.
>
--- End Message ---
