EV Digest 3383
Topics covered in this issue include:
1) Motor break in
by "Diana Trevino" <[EMAIL PROTECTED]>
2) Re: GP at PIR?
by Jessica & Donald Jansen & Crabtree <[EMAIL PROTECTED]>
3) RE: Motor properties
by "Myles Twete" <[EMAIL PROTECTED]>
4) OT: Jet Electrica for sale/ SoCal
by "Scott Davis" <[EMAIL PROTECTED]>
5) Re: Long term storage of Nicads
by "Semb" <[EMAIL PROTECTED]>
6) Re: Motor properties
by Rich Rudman <[EMAIL PROTECTED]>
7) EV Album Hits 500 Entries!
by Mike Chancey <[EMAIL PROTECTED]>
8) Motor construction
by [EMAIL PROTECTED]
9) BLDC on my sons go-cart
by Rod Hower <[EMAIL PROTECTED]>
10) Stern Magazine at Woodburn 2003
by "Roy LeMeur" <[EMAIL PROTECTED]>
11) Re: Long term storage of Nicads
by Seth <[EMAIL PROTECTED]>
12) Re: Motor properties
by "garry" <[EMAIL PROTECTED]>
13) Re: Motor properties
by "Tom Shay" <[EMAIL PROTECTED]>
14) Re: Surge Protection
by "Peter Eckhoff" <[EMAIL PROTECTED]>
15) BLDC go cart pics
by Rod Hower <[EMAIL PROTECTED]>
16) Re: Long term storage of Nicads
by Ralph Merwin <[EMAIL PROTECTED]>
17) RE: Motor properties
by "Myles Twete" <[EMAIL PROTECTED]>
18) Motortech1
by Rich Rudman <[EMAIL PROTECTED]>
19) Re: BLDC go cart pics
by John Wayland <[EMAIL PROTECTED]>
20) Re: Motor properties
by Rich Rudman <[EMAIL PROTECTED]>
21) Re: Motor properties
by Rich Rudman <[EMAIL PROTECTED]>
22) Re: Motor properties
by Peter VanDerWal <[EMAIL PROTECTED]>
23) Re: Long term storage of Nicads
by "David Roden" <[EMAIL PROTECTED]>
24) Re: BLDC on my sons go-cart
by "Joe Smalley" <[EMAIL PROTECTED]>
25) Re: Motor properties
by Rich Rudman <[EMAIL PROTECTED]>
26) Re: BLDC go cart pics
by "David Roden" <[EMAIL PROTECTED]>
27) Re: Motor properties, &newdata
by Rich Rudman <[EMAIL PROTECTED]>
28) Re: Motor properties
by "Joe Smalley" <[EMAIL PROTECTED]>
29) Re: Surge Protection
by "Jon \"Sheer\" Pullen" <[EMAIL PROTECTED]>
30) Re: Gas prices make electric sound pretty good!
by Michael Hurley <[EMAIL PROTECTED]>
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* LP8.2: HTML/Attachments detected, removed from message *
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we found out last week that the track opening has been delayed until
late march.
F.T.
Lightning Ryan wrote:
> So when does the track open on sunday?
> What's the ETA for Gone Postal?
>
> L8r
> Ryan
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--- Begin Message ---
Joe-
> The back EMF is 228 milliohms per 1000 RPM
Your units for backEMF are wrong.
I think you meant 2.28 VOLTS/1000RPM...?
My AC4-4002 (just sold) had measured approx. 6.83 volts/kRPM.
Also, for those who don't know, Kt (newton-meter/amps) == Kb (
volts/rad/sec).
Measure one, you have the other.
> Amps per Foot pound = 6.87
Mine measured .045 ft-lb/A, or, 22.22 amps/ft-lb.
This 3.23:1 diff looks near consistent with the near 3:1 diff between our Kb
measurements.
-Myles Twete, Portland, Or.
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Hello all
As I have a newer AC powered S10, here is a shameless plug to sell my old EV, a 1980
Jet Electrica 007. I live in the Orange County area outside of LA, am willing to
assist with shipping within the US as long as you arrange the carrier.
Current specifications are as follows:
-GE 23hp series DC motor
-Curtis PMC25 controller (2kHz switching, 400A maximum)
-20 US-145 6v deep cycle batteries, 3 months old (delivered Nov 03).
-Sevcon DC-DC converter
-Rewired with 2/0 cable throughout the traction pack
-Goodyear Invicta GLR low rolling resistance tires
-K&W BC20 charger
-All factory manuals, documentation for car, charger and controller
-California Carpool lane stickers and LA charging sticker
-Max speed on level ground ~75mph
-Range 74 miles, as the batteries are still being broken in I've done a maximum of 60
miles at a stretch.
Specs and pictures all on the web page listed below:
http://www.davisengineering.net/Jet.html
Thanks
Scott
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--- Begin Message ---
Thanks for the info. I didn't think of the battery as a module made up of
single cells when I mentioned shorting the module. Will there be any
degradation of the module when stored in this condition? Can they be stored
for a "infinite" time, say 5-10 years?
Thanks
----- Original Message -----
From: "David Roden" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Sunday, February 29, 2004 12:49 AM
Subject: Re: Long term storage of Nicads
> On 28 Feb 2004 at 11:57, Semb wrote:
>
> > I have several STM 5-100 Nicad's which I'm planning to store in a cold
> > (10�C), dry basement for a couple of years. Some advice of how to store
them
> > (charged/uncharged/shorted) are much appreciated !
>
> Store them uncharged. DO NOT short these modules as you would a single
> cell, because that will lead to reversal of individual cells within the
> module.
>
> No periodic maintenance is needed.
>
>
>
>
--- End Message ---
--- Begin Message ---
Myles Twete wrote:
>
> Joe-
>
> > The back EMF is 228 milliohms per 1000 RPM
>
> Your units for backEMF are wrong.
> I think you meant 2.28 VOLTS/1000RPM...?
>
> My AC4-4002 (just sold) had measured approx. 6.83 volts/kRPM.
>
> Also, for those who don't know, Kt (newton-meter/amps) == Kb (
> volts/rad/sec).
> Measure one, you have the other.
>
> > Amps per Foot pound = 6.87
>
> Mine measured .045 ft-lb/A, or, 22.22 amps/ft-lb.
> This 3.23:1 diff looks near consistent with the near 3:1 diff between our Kb
> measurements.
>
> -Myles Twete, Portland, Or.
By the way Myles you do know that you both have the same motors, that
came from Wayland??
What We, Joe, Dave Cloud, and I are trying to do is predict a winner
motor from a looser, and then add real test data to back this up.
The Dyno will answer these questions for real quite soon.
I do belive that Joe meant 228 ohms per 1000 rpm as a measure of how
the motor is building back EMF. Since back EMF is the limiting factor in
doing high RPM high torque Racing motors, We need to get a handle on it
and how it is generated and how to minimizes it and still get some real
torque.
Dave Cloud tends to search for really low voltage motors, that pull big
amps, All and good, but if you go too low you get all RPM and no torque.
So testing at 12 volts and no loads is a good start, but the really fun
data points are under HEAVY loads and medium rpms. The torque does not
increase linearly with amps, as Otmar's G-dyno torques clearly show. So
low amp and high rpms, may be hiding what the motors really do on Big
amps.
Hey I gotta time the GPs new AvDC... it's rather well broken in, I am
amazed at how well the brush sanding and hours of spining are doing. I
have never seen such a well groomed brush set. This just has to be done
to everything that I own!!!
Myles, remember that the first brush shots of the 4002 had less than
%50 of the brush in contact with the comm. If you have one please grind
in the brushes, so we don't accululate Bad motor data, from flat
Graphite!
--
Rich Rudman
Manzanita Micro
www.manzanitamicro.com
1-360-297-7383,Cell 1-360-620-6266
--- End Message ---
--- Begin Message ---
Hi folks,
It has been a long long road, and about a bizzillion key strokes, but today
I just added entry number 500 to the EV Photo Album. I just went over the
statistics, and I was surprised to find the Album currently contains 621
pages of HTML and 6476 images. This includes:
345 street use cars and trucks
28 motorcycles
32 bicycles
37 scooters
13 racers and dragsters
8 boats
15 tractors and mowers
3 ATVs
6 go-karts
5 hybrids
10 miniature cars
8 utility vehicles
2 pusher trailers
9 unclassifiable "things"
Yes, this does add up to more than 500, some fall into two classes and are
getting counted twice. (For instance racing motorcycles) I don't think it
is worth breaking this all down completely just for this report.
At this point, I guess it is time for me to really start thinking about
moving to a more advanced method for all this. There is now an awful lot
of data points for folks wishing to do a bit of analysis. I better find a
way to move this into a dynamic format working from a database. I just
want to make sure we don't leave anyone behind, so what ever it is must be
supported by older browsers and WebTV.
Anyway, that is where things stand, and since almost all of you have all
contributed to this I wanted you all to know. And for those who talk about
your EVs but don't submit any pictures, do you really think we believe
you? :^)
Thanks,
Mike Chancey,
'88 Civic EV
'95 Solectria Force (almost there)
Kansas City, Missouri
EV List Photo Album at: http://evalbum.com
My Electric Car at: http://www.geocities.com/electric_honda
Mid-America EAA chapter at: http://maeaa.org
Join the EV List at: http://www.madkatz.com/ev/evlist.html
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Came across this link:
http://www.phact.org/e/skeptic/biss.htm
Tells a little inside info on construction of electric motors.
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--- Begin Message ---
Last night and this morning I finished installing
a motor and control on my sons go cart.
The motor on my daughters was rated at 1700 RPM at
24V. My sons is rated at 3400 RPM at 24V but has a
50% higher gear ratio.
I also only have 3 12V batteries (for now) on his
cart.
This thing is actually scary, it goes about 40MPH
and doesn't bog down to much on the hills. If I
had some hawkers I could pull the hills even faster
(the fully charged batteries were dropping to 28V
loaded on the hill).
I wouldn't let my son drive it, to dangerous for now.
Time to get a 1500 RPM motor.
Rod
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--- Begin Message ---
Has anyone heard when the article on the NEDRA Nationals 2003 is supposed to
be out?
I know that many on this list went above and beyond the call of duty to
assist the producer and cameraman for Stern.
Six months now, just curious...
Plus, they took a bunch of pics of me cleaning the White Zombie with Windex
and paper towels, still hoping to see those :D
Roy LeMeur Olympia, WA
Updated!
My Electric Vehicle Pages:
http://www.angelfire.com/ca4/renewables/evpage.html
Informative Electric Vehicle Links:
http://www.angelfire.com/ca4/renewables/evlinks.html
_________________________________________________________________
Dream of owning a home? Find out how in the First-time Home Buying Guide.
http://special.msn.com/home/firsthome.armx
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--- Begin Message ---
The 20 year old single cell flooded NiCads I bought make nameplate
amp-hours... They aren't saft, they are GE. But I suspect Saft will do
the same. They were stored shorted. But they are cells, not modules.
Seth
On Feb 29, 2004, at 1:48 PM, Semb wrote:
Thanks for the info. I didn't think of the battery as a module made up
of
single cells when I mentioned shorting the module. Will there be any
degradation of the module when stored in this condition? Can they be
stored
for a "infinite" time, say 5-10 years?
Thanks
----- Original Message -----
From: "David Roden" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Sunday, February 29, 2004 12:49 AM
Subject: Re: Long term storage of Nicads
On 28 Feb 2004 at 11:57, Semb wrote:
I have several STM 5-100 Nicad's which I'm planning to store in a
cold
(10�C), dry basement for a couple of years. Some advice of how to
store
them
(charged/uncharged/shorted) are much appreciated !
Store them uncharged. DO NOT short these modules as you would a
single
cell, because that will lead to reversal of individual cells within
the
module.
No periodic maintenance is needed.
--- End Message ---
--- Begin Message ---
Hi Folks,
Rich said "
The Dyno will answer these questions for real quite soon.
I do belive that Joe meant 228 ohms per 1000 rpm as a measure of how
the motor is building back EMF. Since back EMF is the limiting factor in
doing high RPM high torque Racing motors, We need to get a handle on it
and how it is generated and how to minimizes it and still get some real
torque.
"
So I guess this is where I remind people that some time ago I pointed out
the value of reducing and even eliminating bemf.
I have found a way to completely eliminate the induced voltage or current in
a motor without stopping it from running, this as you might imagine is a
huge benefit to the performance of a motor, I can equally show you how to
eliminate the bemf from the motor completely and once you comprehend this
you should be able to rewire your motors to work in this manner, of course
this makes me wonder why they aren't build like this in the first place :).
If you want to really understand what im saying try spinning a motor and
then join the power wires of this motor together and see how hard it is to
spin and you will see that there is much loss to bemf even at low speeds, I
can make the motor run and allow you to join the wires with little or no
resistance when you turn it with the wires joined.
I have done this successfully with dc permanent magnet motors so if you are
using ac then it might take some figuring to make it work with your motor
but I suspect you will find it will be worth the effort.
I will not post further on this after last time, unless asked, I do not want
to rekindle the argument, I can do it and will be happy to help you
understand how you can do it, if you wish.
Garry Stanley
Cable.net.nz
--- End Message ---
--- Begin Message ---
----- Original Message -----
From: "garry" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Sunday, February 29, 2004 3:01 PM
Subject: Re: Motor properties
I don't remember what you said before about reducing or eliminating
back EMF and possibly some others don't either. Will you tell us again?
Tom Shay
> So I guess this is where I remind people that some time ago I pointed out
> the value of reducing and even eliminating bemf.
>
> I have found a way to completely eliminate the induced voltage or current
in
> a motor without stopping it from running, this as you might imagine is a
> huge benefit to the performance of a motor, I can equally show you how to
> eliminate the bemf from the motor completely and once you comprehend this
> you should be able to rewire your motors to work in this manner, of course
> this makes me wonder why they aren't build like this in the first place
:).
>
> If you want to really understand what im saying try spinning a motor and
> then join the power wires of this motor together and see how hard it is to
> spin and you will see that there is much loss to bemf even at low speeds,
I
> can make the motor run and allow you to join the wires with little or no
> resistance when you turn it with the wires joined.
>
> I have done this successfully with dc permanent magnet motors so if you
are
> using ac then it might take some figuring to make it work with your motor
> but I suspect you will find it will be worth the effort.
>
> I will not post further on this after last time, unless asked, I do not
want
> to rekindle the argument, I can do it and will be happy to help you
> understand how you can do it, if you wish.
>
> Garry Stanley
>
> Cable.net.nz
>
>
--- End Message ---
--- Begin Message ---
Did you make the extension cord yourself or did you buy it somewhere?
----- Original Message -----
From: "Jon "Sheer" Pullen" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Saturday, February 28, 2004 16:33 PM
Subject: Re: Surge Protection
> > Are voltage spikes, transient surges, etc. a problem with chargers and
> other EV related equipment? If so, what sort of surge protection do you
all
> use to > protect your equipment?
>
>
> Yes! When you turn on two PFC-20s togeather, expect voltage spikes and
> brownouts on every outlet in the house...
>
> Oh! You meant do voltage spikes _damage_ chargers?
>
> Well, yes and no.
>
> Most dumb and semi-smart [bad boy and light dimmer style] chargers will
take
> a fair amount of abuse in the noisy-power department. Switching chargers
> like the PFC-20s are a titch more fragile - it's a good idea to put some
big
> MOVs on their input, especially if you're going to run them on 'dirty'
power
> like a genset. [Rich doesn't approve of doing this in-box so I have a
> special extension cord - a 50A 220V power strip, if you will - which has a
> bunch of MOVs in it.
>
> I think the Brusa chargers already have transient supression built into
> them.
>
> In general, if your charger has a microprocessor, clean power can't hurt.
>
> S.
--- End Message ---
--- Begin Message ---
http://www.qsl.net/w8rnh/gocart/gocart.html
I took a few pics of the kids go carts.
Definately not a Wayland instillation, but these
are merely testbeds for my prototype control.
David Roden stopped by tonight and dropped off an
Elec Trak plow blade. I think he liked the
performance of this setup but agreed that it's not
a setup that kids should be using (excluding myself).
Hopefully in the next month I'll get the aluminum
housing for the controls and I'll crank up the current
limit 2x. This should be interesting. I'm not the
risk taker I was 15 years ago, and the current setup
is kind of scary. It should be interesting with twice
the current limit. I'm also building a control for a
72Volt pack, this should really be fun.
--- End Message ---
--- Begin Message ---
The SAFT spec says the STM modules may be stored for any period of time
at any state of charge. I'd make sure the water connections are covered
to keep the bugs and dust out, and cover the terminal posts. When you
want to put them back in service, you will need to run the INIT cycle
and then water them.
Ralph
Semb writes:
>
> Thanks for the info. I didn't think of the battery as a module made up of
> single cells when I mentioned shorting the module. Will there be any
> degradation of the module when stored in this condition? Can they be stored
> for a "infinite" time, say 5-10 years?
>
> Thanks
>
>
>
> ----- Original Message -----
> From: "David Roden" <[EMAIL PROTECTED]>
> To: <[EMAIL PROTECTED]>
> Sent: Sunday, February 29, 2004 12:49 AM
> Subject: Re: Long term storage of Nicads
>
>
> > On 28 Feb 2004 at 11:57, Semb wrote:
> >
> > > I have several STM 5-100 Nicad's which I'm planning to store in a cold
> > > (10�C), dry basement for a couple of years. Some advice of how to store
> them
> > > (charged/uncharged/shorted) are much appreciated !
> >
> > Store them uncharged. DO NOT short these modules as you would a single
> > cell, because that will lead to reversal of individual cells within the
> > module.
> >
> > No periodic maintenance is needed.
> >
> >
> >
> >
>
--- End Message ---
--- Begin Message ---
Thanks Rich-
> I do belive that Joe meant 228 ohms per 1000 rpm as a measure of how
> the motor is building back EMF.
So what do you call this "measure" of the motor?
Is this a new type of measure or did I miss something back in 1981 in my
early servo motor days?
I think you guys need to explain it more. Unless you're saying that the
Back EMF is a nonlinear combination of the motor current and a linearly
increasing resistance with RPM, I haven't a clue what you are talking about.
I'm not saying it isn't real, it's just that Back EMF is commonly known to
be a constant for electric motors and is expressed in terms of VOLTS/SPEED.
So to have a Back EMF expression of 228 ohms/1000RPM, I read this as there
would be ZERO back EMF
if the motor current is ZERO, regardless of the RPM. I.E., Vbemf = Im *
Rbemf ; where Rbemf = Kbemf * Wm ; and Kbemf = 228ohms/1000RPM, or
whatever, it doesn't matter, since Zero * anything = Zero. You're also
saying that BackEMF resistance itself increases with RPM---something totally
new to me---does this happen due to the high currents in an EV motor?
So I'm confused.
As I said earlier, motor theory says that Kt = Kb if the units are right.
So, we can try to "get a handle" on BackEMF, but if we mean by that that we
want to get rid of it, we're also reducing Kt in the process. Maybe that's
OK, maybe not. If high current is acceptable, sure, a low Kt works, but not
for every situation.
AS for eliminating BackEMF, go for it Garry. May the force be with you. I
once foolishly paid $10 to personally watch Bruce DePalma display his
"N-machine" free energy ZERO-BackEMF device only to be given a dog and pony
show. No theory. No detail measurements. Nothing but a freaking
drillmotor spinning a copper disk sandwiched between speaker magnets. Sure,
it generated a whopping 30mv when spun up, but there was nothing else to
show squat for loading.
Remember, the lower the Kt, the lower the Kb. I.E. a HIGH CURRENT device
like a Homopolar motor with a VERY LOW Kt, a correspondingly VERY LOW Kb
will be expected. So it's incumbent on those claiming the ridiculous ZERO
BackEMF to accordingly properly instrument the setup. How sensitive does
such a setup need to be? EASY! Surely you'd know your Kt, right? That
would be Torque/current. Once you have this number in N-m/Amp, you now
have the EXPECTED BackEMF in Volts/Rad/sec.
-MT
--- End Message ---
--- Begin Message ---
Ok Motor tech data: If not into motors delete now!
Advanced DC Motor XP-1965 Stock 9 incher with Tach sensor.
FB4001 with tach sensor= XP-1965
13 field turns
49 commutator Bars
0.080 air gap total(.040 shoe to armature)
Lapped arc into brushes.
Ran for 5 hours, brushes look almost perfect.
Static timed to 13.0 Deg advance Brush rigging is 1.024 ahead of the
Actual nuetral point measured on the outside of the case circumfrence.
The Nuetral hole set(center set of holes) is about about 5 Deg
advanced.
Running data:
38 AMPS
14.40V at inverter( one large voltage regulated DC supply)
2397 RPM(Thanks Otmar for the encoder pinouts and sensor data!)
14.047 volts at terminals
147 mV across fields.
13.900 volts across armature.
Load:
Free spin with fan installed:
--
Rich Rudman
Manzanita Micro
www.manzanitamicro.com
1-360-297-7383,Cell 1-360-620-6266
--- End Message ---
--- Begin Message ---
Hello to All,
Rod Hower wrote:
> http://www.qsl.net/w8rnh/gocart/gocart.html
>
> I took a few pics of the kids go carts.
> Definately not a Wayland instillation, but these
> are merely testbeds for my prototype control.
Wow, looks like a lot of motor for such a light cart...bet it really accelerates!
It may not be a Wayland Install, but we have identical, blue C.H. air compressors.
I do see room for a subwoofer and an amplifier or two :-)
See Ya....John Wayland
--- End Message ---
--- Begin Message ---
garry wrote:
>
> Hi Folks,
>
> Rich said "
>
> The Dyno will answer these questions for real quite soon.
> I do belive that Joe meant 228 ohms per 1000 rpm as a measure of how
> the motor is building back EMF. Since back EMF is the limiting factor in
> doing high RPM high torque Racing motors, We need to get a handle on it
> and how it is generated and how to minimizes it and still get some real
> torque.
> "
> So I guess this is where I remind people that some time ago I pointed out
> the value of reducing and even eliminating bemf.
>
> I have found a way to completely eliminate the induced voltage or current in
> a motor without stopping it from running, this as you might imagine is a
> huge benefit to the performance of a motor, I can equally show you how to
> eliminate the bemf from the motor completely and once you comprehend this
> you should be able to rewire your motors to work in this manner, of course
> this makes me wonder why they aren't build like this in the first place :).
>
> If you want to really understand what im saying try spinning a motor and
> then join the power wires of this motor together and see how hard it is to
> spin and you will see that there is much loss to bemf even at low speeds, I
> can make the motor run and allow you to join the wires with little or no
> resistance when you turn it with the wires joined.
>
> I have done this successfully with dc permanent magnet motors so if you are
> using ac then it might take some figuring to make it work with your motor
> but I suspect you will find it will be worth the effort.
>
> I will not post further on this after last time, unless asked, I do not want
> to rekindle the argument, I can do it and will be happy to help you
> understand how you can do it, if you wish.
>
> Garry Stanley
>
> Cable.net.nz
funny... I remember....
Ok I have series wound motors, they rotate... they have BEMF..... any
sugestions???
Oh yea I want massive amounts of torque... so.... I still need a real
field, and I need all the iron I can get to sustain the forces.
If you wish you can take this off the list, and do direct e-mail.
I would love to have you show me how to rewite the fundimental laws of
rotating electrical machines. I am all ears.
If you can't do this in a standard Ev type motor, then don't waste my
time, I have rubber to burn and Drive trains to mangle.
--
Rich Rudman
Manzanita Micro
www.manzanitamicro.com
1-360-297-7383,Cell 1-360-620-6266
--- End Message ---
--- Begin Message ---
Myles Twete wrote:
>
> Thanks Rich-
>
> > I do belive that Joe meant 228 ohms per 1000 rpm as a measure of how
> > the motor is building back EMF.
>
> So what do you call this "measure" of the motor?
> Is this a new type of measure or did I miss something back in 1981 in my
> early servo motor days?
> I think you guys need to explain it more. Unless you're saying that the
> Back EMF is a nonlinear combination of the motor current and a linearly
> increasing resistance with RPM, I haven't a clue what you are talking about.
> I'm not saying it isn't real, it's just that Back EMF is commonly known to
> be a constant for electric motors and is expressed in terms of VOLTS/SPEED.
>
> So to have a Back EMF expression of 228 ohms/1000RPM, I read this as there
> would be ZERO back EMF
> if the motor current is ZERO, regardless of the RPM. I.E., Vbemf = Im *
> Rbemf ; where Rbemf = Kbemf * Wm ; and Kbemf = 228ohms/1000RPM, or
> whatever, it doesn't matter, since Zero * anything = Zero. You're also
> saying that BackEMF resistance itself increases with RPM---something totally
> new to me---does this happen due to the high currents in an EV motor?
>
> So I'm confused.
> As I said earlier, motor theory says that Kt = Kb if the units are right.
> So, we can try to "get a handle" on BackEMF, but if we mean by that that we
> want to get rid of it, we're also reducing Kt in the process. Maybe that's
> OK, maybe not. If high current is acceptable, sure, a low Kt works, but not
> for every situation.
>
I am going to skip the Zero BMF stuff since it doesn't apply to me....
Ok you have a pile of Brushed series wound motors, that looks a lot
like Dave Clouds garage.....Which one works, which one doesn't??That cut
the pile in half!.
Now which one is good for racing, Electrathons, Hydroplanes, and
homebuilt dragsters.... Now the piles are mangable. You have a DVM, and
clip on amp meter, and a good RPM tuned ear.
Which ones are worth taking farther???
TBC, gotta get the Teenager to the Winslow ferry dock.
--
Rich Rudman
Manzanita Micro
www.manzanitamicro.com
1-360-297-7383,Cell 1-360-620-6266
--- End Message ---
--- Begin Message ---
On Sun, 2004-02-29 at 21:44, Rich Rudman wrote:
> garry wrote:
> >
> > Hi Folks,
> >
> > Rich said "
> >
> > The Dyno will answer these questions for real quite soon.
> > I do belive that Joe meant 228 ohms per 1000 rpm as a measure of how
> > the motor is building back EMF. Since back EMF is the limiting factor in
> > doing high RPM high torque Racing motors, We need to get a handle on it
> > and how it is generated and how to minimizes it and still get some real
> > torque.
> > "
> > So I guess this is where I remind people that some time ago I pointed out
> > the value of reducing and even eliminating bemf.
> >
> > I have found a way to completely eliminate the induced voltage or current in
> > a motor without stopping it from running, this as you might imagine is a
> > huge benefit to the performance of a motor, I can equally show you how to
> > eliminate the bemf from the motor completely and once you comprehend this
> > you should be able to rewire your motors to work in this manner, of course
> > this makes me wonder why they aren't build like this in the first place :).
> >
> > If you want to really understand what im saying try spinning a motor and
> > then join the power wires of this motor together and see how hard it is to
> > spin and you will see that there is much loss to bemf even at low speeds, I
> > can make the motor run and allow you to join the wires with little or no
> > resistance when you turn it with the wires joined.
> >
> > I have done this successfully with dc permanent magnet motors so if you are
> > using ac then it might take some figuring to make it work with your motor
> > but I suspect you will find it will be worth the effort.
> >
> > I will not post further on this after last time, unless asked, I do not want
> > to rekindle the argument, I can do it and will be happy to help you
> > understand how you can do it, if you wish.
> >
> > Garry Stanley
> >
> > Cable.net.nz
>
> funny... I remember....
> Ok I have series wound motors, they rotate... they have BEMF..... any
> sugestions???
> Oh yea I want massive amounts of torque... so.... I still need a real
> field, and I need all the iron I can get to sustain the forces.
>
> If you wish you can take this off the list, and do direct e-mail.
> I would love to have you show me how to rewite the fundimental laws of
> rotating electrical machines. I am all ears.
Don't forget to ask for proof that his "motors" have high efficiency.
Proof should be from REAL test equipment and not estimates based on
readings taken with a calibrated fingertip.
It's ridiculously easy to build motors with very low back emf, you just
have to build motors with lousy efficiency.
--
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
The problem with the world is stupidity. Not saying there should be a
capital punishment for stupidity, but why don't we just take the
safety labels off of everything and let the problem solve itself?
--- End Message ---
--- Begin Message ---
On 29 Feb 2004 at 19:48, Semb wrote:
> Will there be any
> degradation of the module when stored in this condition? Can they be stored
> for a "infinite" time, say 5-10 years?
As far as I know, there's no significant degradation over any arbitrary time
period. The fact that the individual cells can't be stored shorted may be
something of a disadvantage, but they will self-discharge to zero (or close)
eventually anyway.
I wouldn't be concerned about storing them for 4-5 years.
They won't freeze, so temperature isn't an issue.
--- End Message ---
--- Begin Message ---
Why not put an RPM limit in the software?
Joe Smalley
Rural Kitsap County WA
Fiesta 48 volts
NEDRA 48 volt street conversion record holder
[EMAIL PROTECTED]
----- Original Message -----
From: "Rod Hower" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Sunday, February 29, 2004 12:05 PM
Subject: BLDC on my sons go-cart
> Last night and this morning I finished installing
> a motor and control on my sons go cart.
> The motor on my daughters was rated at 1700 RPM at
> 24V. My sons is rated at 3400 RPM at 24V but has a
> 50% higher gear ratio.
> I also only have 3 12V batteries (for now) on his
> cart.
> This thing is actually scary, it goes about 40MPH
> and doesn't bog down to much on the hills. If I
> had some hawkers I could pull the hills even faster
> (the fully charged batteries were dropping to 28V
> loaded on the hill).
> I wouldn't let my son drive it, to dangerous for now.
> Time to get a 1500 RPM motor.
> Rod
>
--- End Message ---
--- Begin Message ---
Peter VanDerWal wrote:
>
> It's ridiculously easy to build motors with very low back emf, you just
> have to build motors with lousy efficiency.
>
> --
Yea we need enough torque to beable to measure it with a 1000 ftlbs
sensor.
No back EMF I wonder if the sensor would notice.
Rich Rudman
Manzanita Micro
www.manzanitamicro.com
1-360-297-7383,Cell 1-360-620-6266
--- End Message ---
--- Begin Message ---
He didn't let me ride it, but I did watch Rod bum around a bit on the cart.
It's pretty quick, even up the hills. Down the hills ... well, he was
really flying. I wasn't so sure he was going to be able to stop, but he did
OK. It makes a really interesting sound, mostly from just the chain drive.
If I squinted my eyes just right, I could almost sort of see a 13 year old
version of John Wayland riding there. <g>
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switch to digest mode? See http://www.evdl.org/help/
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David Roden - Akron, Ohio, USA
1991 Solectria Force 144vac
1991 Ford Escort Green/EV 128vdc
1970 GE Elec-trak E15 36vdc
1974 Avco New Idea rider 36vdc
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
MPG of Ford's most fuel-efficient 2003 car: 36
MPG of Ford's 1912 Model T: 35
-- Harper's Index, Sept. 2003
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--- End Message ---
--- Begin Message ---
Myles Twete wrote:
>
> Thanks Rich-
>
> > I do belive that Joe meant 228 ohms per 1000 rpm as a measure of how
> > the motor is building back EMF.
>
> So what do you call this "measure" of the motor?
> Is this a new type of measure or did I miss something back in 1981 in my
> early servo motor days?
> I think you guys need to explain it more. Unless you're saying that the
> Back EMF is a nonlinear combination of the motor current and a linearly
> increasing resistance with RPM, I haven't a clue what you are talking about.
> I'm not saying it isn't real, it's just that Back EMF is commonly known to
> be a constant for electric motors and is expressed in terms of VOLTS/SPEED.
>
> -MT
Ok some more thought... If we don't know the V/f ratio. We have to
beable to find it, and then do some calculations with it.
On the better known Ev motors, of course we can look it up. On some
unknown Pretolite, that has not been made for awhile, that a bit harder.
So we are talking about measuring enough points to GET the volts to
speed ratio, Or the V/f ratio if we are talking about AC or BLDC drives.
Data: The GP's new 9 incher.
As of this evening,
RPM=469
Amps =151.2
Motor voltage = 11.17 volts
Armature volts= 10.65
Field volts 0.520
Total power in 1699.45 watts.
Load not properly timed. Load is still a 8 incher.
75.6 amps
10.24 volts
Total power out 774.14 watts. Input to put put is %45.
this is NOT a
very good transfer of energy. I will drop the load motor's brush rigging
in the retarded hole position. I will play with the system to find the
most optimal for power transfer.
Did you all know that you can get your brushes to arc even without a
load on the Armature..???? if the field is excited and the brushes are
REALLY way off???
It makes a mess of the mirror finish on the commutator.... I did this to
MY motor... not Rod's or Dave's.... 30 Deg of advance while you are
playing generator instead of motor.... NOT a good thing.
Got amps and volts times 2
Got RPM
NEED torque!!!
Gulp Swallow! we need a locked rotor amps.....and volts, and the split
of the arm to field while doing this.
--
Rich Rudman
Manzanita Micro
www.manzanitamicro.com
1-360-297-7383,Cell 1-360-620-6266
--- End Message ---
--- Begin Message ---
Yes, Back EMF is the product of motor current and a linearly increasing
resistance with RPM multiplied by a motor constant. I don't know the names
and that is where I need some help.
Yes, you are confused. You are using PM (or shunt) motor theory with series
motors. Your theory applies to fixed field motors. Not series motors where
the field strength varies with motor current.
Joe Smalley
Rural Kitsap County WA
Fiesta 48 volts
NEDRA 48 volt street conversion record holder
[EMAIL PROTECTED]
----- Original Message -----
From: "Myles Twete" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Sunday, February 29, 2004 8:08 PM
Subject: RE: Motor properties
> So what do you call this "measure" of the motor?
> Is this a new type of measure or did I miss something back in 1981 in my
> early servo motor days?
> I think you guys need to explain it more. Unless you're saying that the
> Back EMF is a nonlinear combination of the motor current and a linearly
> increasing resistance with RPM, I haven't a clue what you are talking
about.
> I'm not saying it isn't real, it's just that Back EMF is commonly known to
> be a constant for electric motors and is expressed in terms of
VOLTS/SPEED.
>
> So to have a Back EMF expression of 228 ohms/1000RPM, I read this as there
> would be ZERO back EMF
> if the motor current is ZERO, regardless of the RPM. I.E., Vbemf = Im *
> Rbemf ; where Rbemf = Kbemf * Wm ; and Kbemf = 228ohms/1000RPM, or
> whatever, it doesn't matter, since Zero * anything = Zero. You're also
> saying that BackEMF resistance itself increases with RPM---something
totally
> new to me---does this happen due to the high currents in an EV motor?
>
> So I'm confused.
> As I said earlier, motor theory says that Kt = Kb if the units are right.
> So, we can try to "get a handle" on BackEMF, but if we mean by that that
we
> want to get rid of it, we're also reducing Kt in the process. Maybe
that's
> OK, maybe not. If high current is acceptable, sure, a low Kt works, but
not
> for every situation.
>
> AS for eliminating BackEMF, go for it Garry. May the force be with you.
I
> once foolishly paid $10 to personally watch Bruce DePalma display his
> "N-machine" free energy ZERO-BackEMF device only to be given a dog and
pony
> show. No theory. No detail measurements. Nothing but a freaking
> drillmotor spinning a copper disk sandwiched between speaker magnets.
Sure,
> it generated a whopping 30mv when spun up, but there was nothing else to
> show squat for loading.
> Remember, the lower the Kt, the lower the Kb. I.E. a HIGH CURRENT device
> like a Homopolar motor with a VERY LOW Kt, a correspondingly VERY LOW Kb
> will be expected. So it's incumbent on those claiming the ridiculous ZERO
> BackEMF to accordingly properly instrument the setup. How sensitive does
> such a setup need to be? EASY! Surely you'd know your Kt, right? That
> would be Torque/current. Once you have this number in N-m/Amp, you now
> have the EXPECTED BackEMF in Volts/Rad/sec.
>
> -MT
>
--- End Message ---
--- Begin Message ---
Made it myself. It's just a outlet box with a 50A plug that matches my
genset, and 2 20A outlets that match the plugs I've placed on the chargers,
with a bunch o' MOVs in the appropriate places. Nothing high tech.
S.
----- Original Message -----
From: "Peter Eckhoff" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Sunday, February 29, 2004 5:48 PM
Subject: Re: Surge Protection
>
> Did you make the extension cord yourself or did you buy it somewhere?
>
> ----- Original Message -----
> From: "Jon "Sheer" Pullen" <[EMAIL PROTECTED]>
> To: <[EMAIL PROTECTED]>
> Sent: Saturday, February 28, 2004 16:33 PM
> Subject: Re: Surge Protection
>
>
> > > Are voltage spikes, transient surges, etc. a problem with chargers and
> > other EV related equipment? If so, what sort of surge protection do you
> all
> > use to > protect your equipment?
> >
> >
> > Yes! When you turn on two PFC-20s togeather, expect voltage spikes and
> > brownouts on every outlet in the house...
> >
> > Oh! You meant do voltage spikes _damage_ chargers?
> >
> > Well, yes and no.
> >
> > Most dumb and semi-smart [bad boy and light dimmer style] chargers will
> take
> > a fair amount of abuse in the noisy-power department. Switching chargers
> > like the PFC-20s are a titch more fragile - it's a good idea to put some
> big
> > MOVs on their input, especially if you're going to run them on 'dirty'
> power
> > like a genset. [Rich doesn't approve of doing this in-box so I have a
> > special extension cord - a 50A 220V power strip, if you will - which has
a
> > bunch of MOVs in it.
> >
> > I think the Brusa chargers already have transient supression built into
> > them.
> >
> > In general, if your charger has a microprocessor, clean power can't
hurt.
> >
> > S.
>
>
--- End Message ---
--- Begin Message ---
At 10:08 PM -0600 on 2/26/04, Michael Hurley wrote:
At 12:16 PM +0000 on 2/26/04, John Lawton wrote:
Well imagine in the UK where petrol (gas) is
$5.30 per US gallon (at 1.8 USD to the UKP).
Try $5.46, assuming �2.95 per gallon. Current
exchange rate is about $1.86 to �1, as of 4pm
GMT, Feb. 27, 2004.
I forgot something important here when I was
figuring this last time. The Imperial gallon is
larger than US gallon (about 1.2 UK to 1 US).
This means the UK pice is more like 6.55 per
gallon here. Ouch.
--
Auf wiedersehen!
______________________________________________________
"..Um..Something strange happened to me this morning."
"Was it a dream where you see yourself standing in sort
of Sun God robes on a pyramid with a thousand naked
women screaming and throwing little pickles at you?"
"..No."
"Why am I the only person that has that dream?"
-Real Genius
--- End Message ---
