EV Digest 6615
Topics covered in this issue include:
1) Re: Motor problems
by Jeff Shanab <[EMAIL PROTECTED]>
2) Welding A123's
by Jeff Shanab <[EMAIL PROTECTED]>
3) Best of luck to the Killacycle crew
by Jim Husted <[EMAIL PROTECTED]>
4) Killacycle friday race update
by Jim Husted <[EMAIL PROTECTED]>
5) Re: Best of luck to the Killacycle crew
by "Roderick Wilde" <[EMAIL PROTECTED]>
6) Re: Slightly lower cost A123's
by Jack Murray <[EMAIL PROTECTED]>
7) Re: Best of luck to the Killacycle crew
by Jim Husted <[EMAIL PROTECTED]>
8) Re: May C&D Article on White Zombie
by Jim Husted <[EMAIL PROTECTED]>
9) Re: practical grounding (RE: Quick PFC20 question)
by "David Roden" <[EMAIL PROTECTED]>
10) Arc Flash & Ark Blast Warning !!!!!
by [EMAIL PROTECTED]
11) The winds of change seem about the same
by bruce parmenter <[EMAIL PROTECTED]>
12) RE: Arc Flash & Ark Blast Warning !!!!!
by Cor van de Water <[EMAIL PROTECTED]>
13) Re: Slightly lower cost A123's
by "Philippe Borges" <[EMAIL PROTECTED]>
14) RE: Advanced brushes
by Mike Willmon <[EMAIL PROTECTED]>
15) Re: Motor temp
by "Andrew Kane" <[EMAIL PROTECTED]>
--- Begin Message ---
Shipping tricks
When I went to ship my motor to Jim, I took it apart and put it in
two seperate boxes. This kept them under a certain weight and the total
shipping price was cut in half.
Then I happened to work where they did a lot of shipping and were on a
route so I had our shipping department ship it for me. This was almost
1/2 the price, again, of Useing UPS as a person off the street.
Fresno, ca to somewhere (Corvalis?) oregon for < $50.
--- End Message ---
--- Begin Message ---
These are probably Questions for Bill Dube....
1) If I was welding up A123 cells into a pack, How many amps can a
single tab take and how much can be passed thru 4 1/8 diameter weld
spots anyway? (I say if cause I still don't have money saved up for the
Welder I want)
2) I want to weld the tabs to a bar first that interconnects 12 cells in
parallel. If this bar is nickel plated, will it help or hurt the weld
process?
--- End Message ---
--- Begin Message ---
Hey Bill, all
Just wanted to wish you luck and say I'll be rooting
for you and the gang this weekend. Don't forget to
pack the spare motor now 8^P
Looking forward to the reports and some video not
ending with plasma!
BTW after zorching motors you're not supossed to build
a bigger battery 8^o
Mother Hen mode full on!
Cya
Jim Husted
Hi-Torque Electric
____________________________________________________________________________________
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--- End Message ---
--- Begin Message ---
Hey all
Steve just called me to let me know the motors are
doing good 8^) Unfortunantly He was beaking up alot
so I only got pieces. Although the motors are well
the Zilla's not engaging the series parallel shift.
Steve was upbeat though saying they saw the best 60'
times they have EVer run 8^)
I believe he said they clocked 115 MPH at the 1/8th
and 119 on the 1/4 8^( He was trying to get me the
stats but he broke up to much for me to quote
anything. After my recent "Tim" report I'll leave the
real facts to them 8^) Just thought I'd share what I
do know. Anyway it's seems some of you out there
aren't thinking "happy thoughts" so you better get
with the program or I'll beat the happy thoughts out
of you 8^o
Here's hoping the guys can work the bugs out as it
seems that the changes made show serious promise!
Best of luck guys
Thanks for the call
Cya
Jim Husted
Hi-Torque Electric
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--- Begin Message ---
Jim, You are on to something here, if you are going to use a bigger battery
then use a bigger motor. Very simple logic. I actually never understood why
Bill chose the 6.7" over the 8". Personal preference I guess. I would never
divulge what motors I would put in an ideal drag bike with A123s but I will
tell you one thing it would not be 6.7"s. There is not enough distance to
prevent high voltage arcing from many points in that tiny little brush box.
Heck, I've blown molten holes of aluminum right through the end of a nine
inch brush end bell from high voltage arcing. The volts the motor "sees"
times the amps the motor "sees" is the horsepower. We are not talking major
science project here. We are talking nuts and bolts amp sucking. Yes the
horsepower they have is in the batteries but if you can not deliver that to
the ground because you chose tiny inexpensive motors then you will find the
limit of those tiny motors and I think they are getting very close to that
limit. Just my opinion of course. Hey, what do I know.
Roderick
PS: All in all I wish the crew luck and hope they blow away their old
record!
----- Original Message -----
From: "Jim Husted" <[EMAIL PROTECTED]>
To: "EVDL" <ev@listproc.sjsu.edu>
Sent: Friday, March 30, 2007 7:21 PM
Subject: Best of luck to the Killacycle crew
Hey Bill, all
Just wanted to wish you luck and say I'll be rooting
for you and the gang this weekend. Don't forget to
pack the spare motor now 8^P
Looking forward to the reports and some video not
ending with plasma!
BTW after zorching motors you're not supossed to build
a bigger battery 8^o
Mother Hen mode full on!
Cya
Jim Husted
Hi-Torque Electric
____________________________________________________________________________________
We won't tell. Get more on shows you hate to love
(and love to hate): Yahoo! TV's Guilty Pleasures list.
http://tv.yahoo.com/collections/265
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--- Begin Message ---
..
What if they made the cases so they could be threaded together? Then
have threaded "bus bars" to hook parallel rows together with?
I don't think I'm giving away any Intellect Battery secrets to tell you
that this is what they are doing for me with the NiMH D-cell blocks,
they have threaded studs welded to the end-cells of the welded columns,
which currently are 10-cell (12v) stacks. And yes, the columns then use
busbars to build 120v block. How they weld the columns together IS one
of their secrets.
Should have some pics soon of the pack in the hybrid.
Jack
--- End Message ---
--- Begin Message ---
Hey Rod, all
--- Roderick Wilde <[EMAIL PROTECTED]> wrote:
> Jim, You are on to something here, if you are going
> to use a bigger battery
> then use a bigger motor. Very simple logic.
Well actually I was leaning toward Bill not wanting to
be outdone by Wayland's recent motor zorch 8^o
> I actually never understood why
> Bill chose the 6.7" over the 8". Personal preference
> I guess.
Knowing what motor for what job is the trick now isn't
it. Just looking at the Tiny and Might "Tim" motors I
did for Shawn and Matt they were both 4" Prestolite
motors. Mighty did the 1/8th much faster than poor
Tiny. Shawns son did take 1st in the scooter cross
using Tiny though this year 8^)
Anyway I'd say size may be deceptive as far as racing
goes to an extent.
> I would never
> divulge what motors I would put in an ideal drag
> bike with A123s but...
Ohhh you could tell ol Uncle Jim 8^) I got my lick
and stick Rod tatoo on 8^P
> I will
> tell you one thing it would not be 6.7"s. There is
> not enough distance to
> prevent high voltage arcing from many points in that
> tiny little brush box.
Well I can tell you this... It'd been a whole heck of
a lot easier to have crammed in half inch copper leads
into an 8".
> Heck, I've blown molten holes of aluminum right
> through the end of a nine
> inch brush end bell from high voltage arcing. The
> volts the motor "sees"
> times the amps the motor "sees" is the horsepower.
I've seen your carnage! first hand! I bow to your
opulance, LMAO. As far as the arcing goes has anyone
plotted the volts to motor comparing WZ's to
Killacycle's. This would be some nice data to get.
I'm hoping that by protecting the springs with Nomex
they stay crisp and not crispy 8^) Being all the
failures have been on the spring side of the holder if
the gaurds don't work then reversing the springs to
the other side of the holder will be my next attempt
or advise. I believe that at least for a CCWDE
rotation the springs are located on the wrong side.
Not that a flashover is good but if you don't have a
major blowout like you describe the damage is really
not that bad. The armature barely gets hurt as it
spreads the arcing to all the bars and only at the
edge where the brushes don't really ride. What this
means is that you guys stay on the track, get that
next run in and hit those goals that were intended.
I guess that's my goal 8^)
> We are not talking major
> science project here. We are talking nuts and bolts
> amp sucking. Yes the
> horsepower they have is in the batteries but if you
> can not deliver that to
> the ground because you chose tiny inexpensive motors
> then you will find the
> limit of those tiny motors and I think they are
> getting very close to that
> limit. Just my opinion of course. Hey, what do I
> know.
Hey I'm the motor guy and this type of question is
almost a non stop thought proccess. BTW they may have
been cheap tiny motors but I got them pretty armored
up and ready to fight a good fight. As someone who
gets a peak at a wide field of view on those racing DC
motors there are individual damages and needs when
compared. Even when talking about the same motor
there are still apple to watermelon examples to be
seen. I guess knowing what needs protecting is part
of the motor choosing game.
Just some thoughts I had on this.
Hopefully they get the Zilla programed and they don't
find it's somehow some motor trick so they don't have
to shift, cause that's when the bad stuff happens,
They're saying "you want us to do WHAT"? LMAO!
Like all racers and fans alike lots of luck going your
way!
Had fun
Cya
Jim Husted
Hi-Torque Electric
____________________________________________________________________________________
Now that's room service! Choose from over 150,000 hotels
in 45,000 destinations on Yahoo! Travel to find your fit.
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--- End Message ---
--- Begin Message ---
Hey Paul
--- "Paul G." <[EMAIL PROTECTED]> wrote:
> You know, a closed mouth gather no feet! Please
> don't quit talking
> though, I'm always looking for a chance to feed you
> feet LMAO.
>
> More seriously, we need your wisdom too :-)
That's pretty funny 8^P I think from now on though
I'll be keeping to posting about motor pics as I'm
pretty sure I'm safe there 8^) I'm usually really
good at those finding Waldo books to <sigh>
No need to worry, I'm not going anywhere no matter how
big a fool I might make myself look sometime in the
future (I have done much better than this before)8^o
I'm surprised I didn't see more "how many motor guys
does it take to find Tim" jokes though, hehe
The funny thing is I've had it up on the computer the
whole time showing EVeryone I know!
I mean come on this is a pretty neat thing for me, not
every day I've had my name in something this big.
Then again it doesn't take much to get me excited!
Anyway still no copies in Redmond 8^( I guess it
serves me right for living in the boonies.
Hey John you get copies yet in Portland? Buy me fifty
copys and I'll square up with you on it, at least save
some for me 8^) Stores we'll be telling me sorry no
Redmond deliveries due to a Wayland delivery, hehehe.
Cya
Jim Husted
Hi-Torque Electric
____________________________________________________________________________________
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--- Begin Message ---
On 30 Mar 2007 at 15:27, Rich Rudman wrote:
> Warnings.. you really need a ground close to your EV.. having the ground rod
> too far away , can give you a Ground lift effect if and when there is a need.
> The point is you need a ground at the EV site. Not 300 yards away.
I hope you don't mean grounding >only< to a local ground rod. In order to
properly clear gross ground faults by opening the breaker or fuse, the
safety ground >must< go back to the same electrical panel where the circuit
originates. Grounding solely to a local ground rod is not safe and will not
protect you from electrical shock. The main panel ground rod's function is
to sink lightning and other induced currents, NOT to provide personnel
protection.
If you mean adding and bonding a supplemental ground system at the point of
consumption, that's OK (as far as I know). It would be similar to what's
done with hot tubs and spas. I hope someone will correct me if I'm wrong
about this.
> I think the rules are 50 ft from a out door recepticle. It's not far.
Can you cite chapter and verse on this? I can find nothing in the code
requiring or even suggesting a ground 50 feet from an outdoor receptacle.
Or is it the hot tub / spa bonding rule you're thinking of?
David Roden - Akron, Ohio, USA
EV List Administrator
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--- Begin Message ---
I hope anyone who has a pack voltage over 120 volts or is thinking of adding
batteries that will increase their existing voltage to exceed 120 volts is
aware of an extreme danger of an arc flash explosion. It seems common
knowledge about using gloves, face shields, and one hand behind your back.
Yesterday I had my first and hope last flash arc experience. It was such an
astounding event I Google to learn more about what happened. Words do not
even come close to describing it. It was about as loud as a large m-60
firecracker, blinding bright, and a very very hot expanding explosion.
If copper is in the arc the expansion rate is 40,000 to 1 when the arc
vaporizes copper. With vaporized copper you have for an instant a path that is
transferring an unbelievable amount of power into heat. Clothing that is made
of
a polyester blend is not something you want on.
I cannot say how strongly I recommend you at least read what I found below
searching Google on "Arc Flash". Although this is mostly about electricians I
can assure you the danger from a pack of batteries is very real. You may not
receive an electrical shock but you will be exposed to an unbelievable
amount of heat.
Don
The cause of the short normally burns away during the initial flash and the
arc fault is then sustained by the establishment of a highly-conductive
plasma. The plasma will conduct as much energy as is available and is only
limited
by the impedance of the arc. This massive energy discharge burns the bus
bars, vaporizing the copper and thus causing an explosive volumetric increase,
the arc blast, conservatively estimated, as an expansion of 40,000 to 1. This
fiery explosion devastates everything in its path, creating deadly shrapnel
as it dissipates.
Based on available statistics, it's expected that the explosive energy
released during an arc blast will send more than 2,000 North American
electrical
workers to burn centers each year. The sad thing is that most of these workers
will not have been properly warned of the magnitude of the hazard — if
they're warned at all.
Although arc blast injuries are not as frequent as other electrical
injuries, their severity makes the costs to human life and to industry as a
whole
much, much greater.
Arc Flash is a short circuit that flashes from one exposed live conductor to
another, or to ground. The resulting ionized air creates electrically
conductive superheated plasma that can reach temperatures of 5000°F and above.
The
explosion takes less than one second and produces a brilliant flash, intense
heat, and a pressure blast equivalent to several sticks of dynamite.
Consider...
an electrical arc may reach a temperature in excess of the surface of the
sun. This causes vaporization of copper in the arc zone. Its expansion,
combined with that of the superheated of surrounding air, creates a deadly
plasma
mixture that is explosively blasted from the fault zone, with heavy concussive
forces imposed on nearby personnel.
What is Arc Flash?
Electrical workers are exposed to a number of hazards whenever they work
live, including electrical shock. But arc flash is another hazard that can
cause
serious injury or death - even if an employee doesn't come into direct
contact with an energized conductor.
What is Arc Flash?
Arc flash is a short circuit through air that flashes over from one exposed
live conductor to another conductor or to ground. Arc flash incidents are
common and costly, and the frequency of reported accidents is increasing. This
is why arc flash has become a very hot topic within OSHA and the safety
industry overall
What Causes Arc Flash?
Arc flashes can be caused in a variety of ways:
Just coming close to a high-amp source with a conductive object can cause
the electricity to flash over.
Dropping a tool or otherwise creating a spark can ignite an arc flash.
Equipment failure due to use of substandard parts, improper installation, or
even normal wear and tear.
Breaks or gaps in insulation.
Dust, corrosion or other impurities on the surface of the conductor.
How Common Is Arc Flash?
In the past, if someone suffered burns in an electrical accident, people
thought the burns were caused by the electrical shock passing through the
body.
Electrical shocks can cause burns. But what research has shown is that most
burns from electrical accidents actually come from arc flash.
The majority of hospital admissions due to electrical accidents are from arc
flash burns, not from electrical shocks. (Taken from NFPA 70E-2004
standard) Of the approximately 350 persons killed in the work place by
electricity
last year, roughly 50% were related to arch flash.
A report compiled by Capelli-Schellpfeffer, Inc., estimates that five to 10
arc flash explosions happen in the USA every day, resulting in 1 to 2 deaths
per day.
That figure only in takes into account incidents where victims were sent to
special burn centers. The number does not include cases sent to regular
hospitals or clinics, nor unreported cases or near misses.
What Kind of Injuries Can Arch Flash Cause?
What is the impact of these accidents and what types of injuries can they
cause? Injuries from arc flash accidents tend to be very severe, and result
from two types of hazards: arc flash and arc blast.
Arc Flash: Electric arcs produce intense heat, and can heat the air to
temperatures as high as 35,000 degrees Fahrenheit. This is 4 times the
surface
temperature of the sun. Fatal burns can occur when the victim is several feet
from the arc. Serious burns are not uncommon even at a distance of 10 feet.
Arc flash can cause the following injuries:
Skin burns by direct heat exposure
Metal is vaporized at this temperature. Droplets of molten metal can be
propelled over great distances, causing serious burns or igniting clothing.
High-intensity flash can also cause damage to eyesight.
Arc Blast: a high-energy arcing fault can produce a considerable pressure
wave and sound blast. The intense heat from arc causes the sudden expansion
of air, resulting in a blast.
************************************** See what's free at http://www.aol.com.
--- End Message ---
--- Begin Message ---
[Editor's Notes, IMHO:
As some know, I sieve through the newswires I pay for to know
what the media is putting out for public consumption. Though I
mainly POST Electric and a few hybrid newswire items to the EVDL,
I also read items that are h2fcv, h2 ICE, bio-fuel (aka: ethanol,
WVO, bio-diesel, etc.), solar, and more.
As I have POSTed in the past the newswires are now including a
larger amount of bio-fuel use in some hybrid pieces & that I plan
to POST a few of these that have an 'EVDL focus' with the intent
of informing you of what I find without implying I am promoting
the discussion non-EVDL allowed topics. OT POSTs should not be
POSTed on the EVDL.
As some know, news sources tout themselves as 'all the news fit
to print' like some writer went out and did the research to
create the news piece. Most of the time that is far from the
truth. Most news pieces are a re-write of what is provided by
companies (regurgitated company PR). The companies are getting
the media to do their selling for them by doing most of the
writer's work (writers just copy from the PR-copy).
Since some of these same companies also have contributed large
sums of money to these media outlets in the form of advertising,
they can sway a media outlet to put out news pieces that have
their views (verses the truth the public would see if they
provided all of the facts). These opinionated or colored news
pieces are not something new, but have become more the
bread-n-butter main-stay of media outlets (business as usual -
all the news that is fit to profit by).
I POST newswire items not to promote these colored views, but to
let you, the public, know they are out there. I try to POST both
the pro & con pieces so all can see what is going on in the
media.
Most of the public has no idea that what they know they really
have been told to think. So many times at EVents or shows when
the public comes up and speaks their views it is like they are
repeating a highly read news item (the public read it, and now
repeat it as their view; not unlike a parrot).
I hope that my POSTing these newswire pieces makes other EVangels
aware of what the public has been told so they make help get the
truth out when talking to the public.
But the balancing of my POSTs (pro & con) is my doing. The
amount of pro vs. con, company-PR to truth news pieces is not
actually represented by my POSTs. You would have to also
constantly sieve though all these newswires to know what kind of
@#$#%^! junk is being put out for public consumption.
One current trend I am seeing is a higher amount of negative
hybrid pieces (like: they are not worth it, automakers whining
they won't make enough profit, hybrids are dangerous, etc.). This
reminds me of the 1990's when even before production EVs were
available for the public to lease, a larger amount of news items
were negative / against EVs.
As several pro EV writers found out, automaker-and-oil
companies were paying for these negative news pieces, bad EV
press on radio talk shows, and con EV magazine articles. All
at the same time taking Fed. money for production EV R&D.
This makes me wonder if the same counter forces (con hybrids /
phEVs) aren't paying the media outlets to reduce hybrid
interest, and continue the flow of h2fcv funding. Like
working to keep the new up-n-coming h2 addiction rolling
while reducing the public's interest in the interim lower
profit hybrids (men and women might be from Mars and Venus,
but sometimes I thing automakers are from Mercury).
Another current trend is a larger amount of h2fcv news items.
These are not the trolling-for-dollar$ PR pieces of the past
that only sought investors. Mostly the h2fcv news pieces have
both touting-the-future, and the current high proto-typing
costs. I have not found negative h2fcv pieces that state where
the h2 that is used at the h2 pumps is actually derived from,
etc. They tend to have pie-in-the-sky wording (not unlike
sugar-less, low-carb, fat-free fat).
News item trends will change again as more h2fcvs are being put
on roads as city or company fleet vehicles (it is happening
right now). If not already, I foresee production h2fcvs vs.
EVS & phEVs fighting over funding. Thus again there will be a
war of good PR vs. bad news pieces to sway public opinion.
Currently production EVs and nEVs are not getting the bashing in
the media like in the 1990's. No negative EV news pieces about:
not enough electricity to charge all the EVs, dangerous
battery toxins, hazardous high voltages, etc. (except
now they state Tesla's 250 mile range is not enough).
I hope my work has been beneficial to you all and now I have
brought an awareness of newswire trends I am currently seeing.]
Bruce {EVangel} Parmenter
' ____
~/__|o\__
'@----- @'---(=
. http://geocities.com/brucedp/
. EV List Editor & AFV newswires
. (originator of the above ASCII art)
===== Undo Petroleum Everywhere
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--- End Message ---
--- Begin Message ---
While I won't deny the fact that you had a very scary experience
and I hope you and your EV are unharmed, the problem you are
describing occurs with electrical installations that are a wee
bit heftier than our average EV's battery pack.
We really need to create an all-out short circuit to make a
current of 2,000 or maybe even 3,000 flow, the problems with
the deadly arc-blast occur on lines that are over 480V and
several tens of kA, as outlined in Ferraz-Shawmut papers at
http://www.ferrazshawmut.com/arcflash/getting_help/articles_whitepapers.cfm
So, yes - batteries can kill and plasma's can certainly occur.
Getting electrocuted and getting (hot) acid on you are certainly
one of the less desirable side-effects of wrenching on EVs.
But they usually are preventable.
Use enough isolation and common sense when working around HV;
use a mid-pack fuse to prevent plasma's, even though this is
more to protect the batteries and equipment than to avoid
arc blasts, because the ones we make are really babies....
Cor van de Water
Systems Architect
Proxim Wireless Corporation http://www.proxim.com
Email: [EMAIL PROTECTED] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [EMAIL PROTECTED]
Tel: +1 408 542 5225 VoIP: +31 20 3987567 FWD# 25925
Fax: +1 408 731 3675 eFAX: +31-87-784-1130
Second Life: www.secondlife.com/?u=3b42cb3f4ae249319edb487991c30acb
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of [EMAIL PROTECTED]
Sent: Saturday, March 31, 2007 12:12 AM
To: ev@listproc.sjsu.edu
Subject: Arc Flash & Ark Blast Warning !!!!!
I hope anyone who has a pack voltage over 120 volts or is thinking of
adding batteries that will increase their existing voltage to exceed 120
volts is aware of an extreme danger of an arc flash explosion. It seems
common knowledge about using gloves, face shields, and one hand behind your
back.
Yesterday I had my first and hope last flash arc experience. It was such an
astounding event I Google to learn more about what happened. Words do not
even come close to describing it. It was about as loud as a large m-60
firecracker, blinding bright, and a very very hot expanding explosion.
If copper is in the arc the expansion rate is 40,000 to 1 when the arc
vaporizes copper. With vaporized copper you have for an instant a path that
is transferring an unbelievable amount of power into heat. Clothing that is
made of a polyester blend is not something you want on.
I cannot say how strongly I recommend you at least read what I found below
searching Google on "Arc Flash". Although this is mostly about electricians
I can assure you the danger from a pack of batteries is very real. You may
not receive an electrical shock but you will be exposed to an unbelievable
amount of heat.
Don
The cause of the short normally burns away during the initial flash and the
arc fault is then sustained by the establishment of a highly-conductive
plasma. The plasma will conduct as much energy as is available and is only
limited
by the impedance of the arc. This massive energy discharge burns the bus
bars, vaporizing the copper and thus causing an explosive volumetric
increase,
the arc blast, conservatively estimated, as an expansion of 40,000 to 1.
This
fiery explosion devastates everything in its path, creating deadly shrapnel
as it dissipates.
Based on available statistics, it's expected that the explosive energy
released during an arc blast will send more than 2,000 North American
electrical
workers to burn centers each year. The sad thing is that most of these
workers
will not have been properly warned of the magnitude of the hazard — if
they're warned at all.
Although arc blast injuries are not as frequent as other electrical
injuries, their severity makes the costs to human life and to industry as a
whole
much, much greater.
Arc Flash is a short circuit that flashes from one exposed live conductor
to
another, or to ground. The resulting ionized air creates electrically
conductive superheated plasma that can reach temperatures of 5000°F and
above. The
explosion takes less than one second and produces a brilliant flash,
intense
heat, and a pressure blast equivalent to several sticks of dynamite.
Consider...
an electrical arc may reach a temperature in excess of the surface of the
sun. This causes vaporization of copper in the arc zone. Its expansion,
combined with that of the superheated of surrounding air, creates a deadly
plasma
mixture that is explosively blasted from the fault zone, with heavy
concussive
forces imposed on nearby personnel.
What is Arc Flash?
Electrical workers are exposed to a number of hazards whenever they work
live, including electrical shock. But arc flash is another hazard that can
cause
serious injury or death - even if an employee doesn't come into direct
contact with an energized conductor.
What is Arc Flash?
Arc flash is a short circuit through air that flashes over from one exposed
live conductor to another conductor or to ground. Arc flash incidents are
common and costly, and the frequency of reported accidents is increasing.
This
is why arc flash has become a very hot topic within OSHA and the safety
industry overall
What Causes Arc Flash?
Arc flashes can be caused in a variety of ways:
Just coming close to a high-amp source with a conductive object can cause
the electricity to flash over.
Dropping a tool or otherwise creating a spark can ignite an arc flash.
Equipment failure due to use of substandard parts, improper installation,
or
even normal wear and tear.
Breaks or gaps in insulation.
Dust, corrosion or other impurities on the surface of the conductor.
How Common Is Arc Flash?
In the past, if someone suffered burns in an electrical accident, people
thought the burns were caused by the electrical shock passing through the
body.
Electrical shocks can cause burns. But what research has shown is that
most
burns from electrical accidents actually come from arc flash.
The majority of hospital admissions due to electrical accidents are from
arc
flash burns, not from electrical shocks. (Taken from NFPA 70E-2004
standard) Of the approximately 350 persons killed in the work place by
electricity
last year, roughly 50% were related to arch flash.
A report compiled by Capelli-Schellpfeffer, Inc., estimates that five to 10
arc flash explosions happen in the USA every day, resulting in 1 to 2 deaths
per day.
That figure only in takes into account incidents where victims were sent to
special burn centers. The number does not include cases sent to regular
hospitals or clinics, nor unreported cases or near misses.
What Kind of Injuries Can Arch Flash Cause?
What is the impact of these accidents and what types of injuries can they
cause? Injuries from arc flash accidents tend to be very severe, and result
from two types of hazards: arc flash and arc blast.
Arc Flash: Electric arcs produce intense heat, and can heat the air to
temperatures as high as 35,000 degrees Fahrenheit. This is 4 times the
surface
temperature of the sun. Fatal burns can occur when the victim is several
feet
from the arc. Serious burns are not uncommon even at a distance of 10
feet.
Arc flash can cause the following injuries:
Skin burns by direct heat exposure
Metal is vaporized at this temperature. Droplets of molten metal can be
propelled over great distances, causing serious burns or igniting clothing.
High-intensity flash can also cause damage to eyesight.
Arc Blast: a high-energy arcing fault can produce a considerable pressure
wave and sound blast. The intense heat from arc causes the sudden
expansion
of air, resulting in a blast.
************************************** See what's free at
http://www.aol.com.
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--- Begin Message ---
welding or soldering eternal question.
Soldering is not a problem and in fact give better conducting joint (more
contact area)
Problem is you have too use right tools, material and skill or you will heat
the cell and short is life !
I made a battery pack out of 18650.
it's a fast technic (1 second operation/cell) and takes me probably same
time (maybe it's even faster) as i would with a battery spot welder.
this said i aggree than secrets are on the connections ;^)
Lithium is the way to go, i received yesterday a beautiful lipoly cell
assembly for 3.7V/105AH which is 4,2kg and 25cm*15cm*6cm size, only 125Wh/kg
compared to 18650 but this one is really "bolt and play" an so could be a
rEVolution for us.
if i'm autorized to, i will give test results here.
Cordialement,
Philippe
Et si le pot d'échappement sortait du volant, quel carburant choisiriez-vous
?
http://vehiculeselectriques.free.fr
Forum de discussion sur les véhicules électriques
http://vehiculeselectriques.free.fr/Forum/index.php
----- Original Message -----
From: <[EMAIL PROTECTED]>
To: <ev@listproc.sjsu.edu>
Sent: Saturday, March 31, 2007 12:28 AM
Subject: Re: Slightly lower cost A123's
Ryan> See the price here for the four pack:
Ryan> http://www.a123racing.com/html/rcdevkits.html
Ryan> And then here for the same(different price):
Ryan> http://www.maxamps.com/products.php?cat=62
Someone else pointed out that these require welding or soldering which is
expensive, infeasible or both, depending what connection technology you're
dealing with and your access to fancy schmancy welding gear. They aren't
dual tab batteries as are contained in the more expensive kit on the A123
site.
--
Skip Montanaro - [EMAIL PROTECTED] - http://www.webfast.com/~skip/
"The hippies and the hipsters did some great stuff in the sixties,
but the geeks pulled their weight too." -- Billy Bragg
--- End Message ---
--- Begin Message ---
Hey Jim,
I'm not 100% on this either but I'll give it a go. If I understand the
"Neutral Plane Shifting" as you describe, it results from
the magnetic field set up on one side of an armature coil. This is simply the
field you get when you pass a current through a
straight piece of wire. On one side of the arm coil the magnetic field
subtracts from the Pole field. On the other side of the
arm coil it adds to the opposing pole field. This net shift in the magnetic
field from one opposing pole to the other shifts the
*Neutral* point on the commutator. So if the brushes are in the normal
unloaded neutral position but the neutral position
actually changes, then whenever the next advancing coil comes up for
commutation, it may still have some magnetic field associated
with it. Once the brushes hit the comm bar you have a field that wants to
drive a current in the same direction as the newly
applied voltage. As you imply, at low voltages this is not nearly a problem.
With larger voltages and large currents flowing this
can cause the much discussed Plasmaboy events.
Another problem which I definitely have to have someone else elaborate on is
the field weakening you'll see in a saturated core.
If the core is saturated, one side of the arm coil will actually decrease the
flux on that side, but the opposing arm coil cannot
add to an already saturated pole field. This leads to a point where no more
amount of current will be able to increase the torque
delivered from a motor. (although wouldn't it prevent any further shifting of
the neutral plane??) (and could there be a point
where additional current would actually decrease the amount of torque a motor
could make?)(and might that point be well beyond the
current carrying capacity of the coils themselves?) I guess more questions
than answers here ;-P
One thing I might bring up though is that amount of neutral plane shift is not
determined by the voltage. Its determined by the
amount of current flowing through the armature coils. The voltage on the motor
is not low during low RPM because of anything the
motor does. The controllers we use will hit their current limit and Pulse
Width Modulate a lower voltage on a slow turning motor.
As the RPM's rise, if the voltage were kept the same the current would taper
off. But because the controllers job is to keep the
current up it will increase the duty cycle of the PWM. This is what you see as
an increasing voltage with RPM. If you dump a
pack onto a motor straight through a big ass contactor (BAC) the voltage
developed across the motor terminals WILL be that of a
(very miserable) battery pack. As the RPM's rise the current will taper off,
but the voltage on the motor terminals will still
be that of the pack.
I probably mangled this one too. But maybe someone else can elaborate further.
Mike,
Anchorage, Ak.
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
> Behalf Of Jim Husted
> Sent: Thursday, March 29, 2007 3:17 AM
> To: ev@listproc.sjsu.edu
> Subject: Re: Advanced brushes
>
>
> Hey Tim
>
> To be honest this is something that I'm not 100% on
> myself but let me see if I can explain it as I see it.
>
> The brushes sit on the comm which polorizes the
> armature coils. These react with the field coils to
> produce rotation. When the motor is being run under
> OEM loads and voltages a nuetral setting alignes the
> brushes with the field magnetics. As voltage
> increases the field magnetics warp out of line. Now
> the brushes are not lined up and arcing begins as
> RPM's and voltage increase.
>
> Although advancing the brushes brings the armature
> coils back in line with the field coils for when it's
> warped there is a trade off. Nuetral is better for
> starting off, so if the brushes are advanced they are
> "starting up" unlined but line up once the field's
> magnetics warp over. This causes a drop in startup
> torque and increase in current draw but increases
> performance and reduces arcing and flashover as the
> brushes become lined up with the warped coils.
>
> This is why I'm so eager to get data on some of my
> ajustable brush rings. Marko loves his set "way"
> advanced while Jeff Shanab would prefer a little less.
> In a perfect world I'd love to see a little servo
> motor being able to time it kind of like an ICE engine
> is timed on the fly.
>
> Alas, I've never seen it close up and in real time.
> John and Tim tried to get me to climb into the hood
> area while they race but I decided to pass on that
> invite 8^P I do know that Otmar has some old video of
> when he tortured some ADC motors but they're probably
> still packed in some box from the move 8^(
>
> Anyway I hope this helps. I'd actually love a "big
> brains" view on this myself 8^)
>
> Cya
> Jim Husted
> Hi-Torque Electric
>
>
>
>
>
> ____________________________________________________________________________________
> The fish are biting.
> Get more visitors on your site using Yahoo! Search Marketing.
> http://searchmarketing.yahoo.com/arp/sponsoredsearch_v2.php
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>
--- End Message ---
--- Begin Message ---
Well, I'm just another lurker newbie with nothing solid to contribute,
but as long as I'm giving props to Mr. Wayland and Mr. Husted, I may as well
cheer for you too: this is exactly the kind of post I *love* to see and I'll
be very interested to peruse the data when they become available. Mr.
Massey, you too are THE MAN!
On 3/30/07, Jim Husted <[EMAIL PROTECTED]> wrote:
Hey James
ADC just tapes it against the side of a coil. Unless
you've got a field burning MKZ type motor the coils
really aren't a good place to put them. Being most
people don't even use them I've been yanking them out
and sealing the hole that the wires come out of.
The brushes / holders are gonna be the hot area
(although I'll be watching for your updates on what
they find) so this would be my area to connect to.
The two Green meanie motors that Shawn listed on Ebay
had the temp sensors attached to the holders for a
faster relay of heat being generated vs.the OEM coil
mounted area.
Now I don't like "brush mounted" anything! First off
it can impeded the brush tention and flow through the
holder if the wires are thick, or snag, ect. There is
also he danger of melting the insulation from it do to
overheating and has the ability to short out especialy
if they are on two opposite holders. Another bummer
area of this type of mounting is when the brushes wear
out you have to redo it to the replacement set.
Even in the lift world they used to drill out the
brush and insert a wire into it at a determined
length. When the brush wore down it would rub off the
wires insulation when it contacts the comm and light a
brushwear light. They no longer do it that way and
instead use an insulated tab that the spring contacts
when the brushes wear down. I guess in general I
don't like anything that can carry juice to come out
of the motor.
As far as how to attach a temp sensor to a holder
(where I think it'd be best to place one) it depends
on each motor type, there will not be a one answer
solve all on this. Silver soldering a tang that you
could mount to is my best guess solve all. In reusing
an OEM ADC type silver soldering a piece of copper
refigerator tube to it and then cementing it into it
would be a good option as well. It's another Devil's
in the details kind of thing.
At least you have a some new goodies to play with on
the motor now 8^)
Anyway that's my take on this.
Hope it helps
Cya
Jim Husted
Hi-Torque Electric
--- James Massey <[EMAIL PROTECTED]> wrote:
> At 08:25 PM 29/03/07 -0500, Ryan wrote:
> >If we use this gauge:
> >
>
>http://www.autometer.com/cat_gaugedetail.aspx?gid=2565
> >
> >And if this is the temp sender for it, how do we
> best mount it into
> >the motor for best results?
>
> G'day Ryan, and All
>
> This doesn't answer your question, but that sender
> looks like being really
> not appropriate for an EV motor.
>
> As for best position, an a couple of months I should
> be able to answer that
> - and Jim Husted will probably be re-wrapping fields
> to install thermocouples!
>
> I've been "volunteered" to supply the local
> (national) Australian Maritime
> College with a DC motor and control system. They
> have a 'model' boat about
> 25' long that they take out on the river. It
> currently has a 12hp ICE in it
> but they want to use an electric for various
> reasons.
>
> The motor I believe to be a GE, but its' original
> lable is missing - two
> rivets remain. It has "48" stamped on it, 48 volts
> is a reasonable
> assesment, and a serial number. It currently is a
> dual-series field
> (high/low) fully series motor that only goes one
> way. By the time I am done
> with it I intend it to be reversing with the fields
> able to be operated
> series or divided for high/low with low being the
> old high connections.
>
> I'll be prepping the motor over the next week or so,
> and installing
> somewhere around 12 (or more) thermocouples in
> various locations so they
> can map temperature rise in various locations, and
> asses the positions for
> optimal positioning to protect the motor. They will
> be looking at motor
> efficiency as well as air blowing rates and a bunch
> of other "academic"
> parameters. They even intend looking at inbound air
> temp vs outbound air
> temp against volume to calculate the energy increase
> from the waste heat of
> the motor (not sure how they intend to accurately
> measure the air
> mass-flow, though!). They plan on Dyno testing the
> motor so that they can
> pick an optimal propellor for it.
>
> I'll be supplying them with a GE SCR controller that
> they will be able to
> play with smoothing the battery current, and
> probably loaning them a Curtis
> to compare later once they have a dataset of
> performance for the SCR
> controller.
>
> The motor has a female spline, I know that it is a
> problem and there are
> various means to do the job, but I took the
> difficult :^) decision of
> handing them the spline stub and saying "there is
> your spline, adapt that".
> They are intending to drive straight off the end of
> the motor with a box to
> duct out the cooling air, so they can put a carrier
> bearing on the other
> side of the box, before the propellor shaft adaptor.
>
> The thermocouple positions will probably be:
> 1,2) Isolated in two 90 degrees apart brush holders,
> or if I can do it with
> good electrical isolation with good thermal bond in
> the brushes themselves.
> 3,4,5,6,7) in a group around the end of one field 3)
> againt the field pole,
> 4) against the body tube, 5) under the wrap on the
> face closest to the
> brush, 6) under the wrap on the face closest the
> rotor and 7) central to
> the winding.
> 8,9,10,11,12) half-way down the field in the same
> configuration.
>
> I am thinking of putting four in the airflow one
> between each field so to
> see how the air temperatures vary around the motor
> (to compare airflow
> effectiveness of one blower port vs two or more).
> Another may go into a
> pole shoe.
>
> Does anyone know where a typical ADC etc thermal
> switch is positioned? If
> it is somewhere other than one of the locations
> mentioned, I'll put one
> there as well.
>
> As always, comments welcome
>
> Regards
>
> [Technik] James
>
>
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