emergency disconnect

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emergency disconnect

CHARLIEP
Please consider this ,I believe carbon is a good electric conductor? but not very strong .  Place a carbon rod in a holder, with cables attached .In the center of this rod, place an insulated ring attached by cable to a handle in passenger compartment, a quick jerk or stomp on pedal or handle should break carbon into many pieces stopping current flow.
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Re: emergency disconnect

mark at evie-systems
Here's how Wayne implements a Quick Emergency Disconnect:

http://www.youtube.com/watch?v=PX5gdNQIWlw&feature=channel_page

Look at the beginning of the video, in the bottom right of the frame
you'll see the high current wire passing through a quick connect.  One
half of the quick connect is anchored to the car, and the other side has
a cable attached that goes in to the cabin.

Charlie P wrote:
> Please consider this ,I believe carbon is a good electric conductor? but not
> very strong .  Place a carbon rod in a holder, with cables attached .In the
> center of this rod, place an insulated ring attached by cable to a handle in
> passenger compartment, a quick jerk or stomp on pedal or handle should break
> carbon into many pieces stopping current flow.

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Re: emergency disconnect

Roland Wiench
In reply to this post by CHARLIEP
Hello Charlie,

Research the items it take to do this, and experiment.  Go to a welding
supply store and pick up two carbon rod holders that 2/0 cable can attach
to.  Install the carbon rod which you can get from the welding shop between
the two holders.

Apply a 50 amp load and break it to see how much arc and fire it will
develop. To enclose the arcing, you then will have to enclose the carbon rod
with a removable high temperature Pyrex tube with a guild tube fuse to it
for a insulated cable mechanism.

Try it again and see what happens. Now if you can get the cost of this
device below a quick disconnect made by Power Anderson or even some
contactors with a 2000 amp interrupting rating, then you may have something.

Roland


----- Original Message -----
From: "Charlie P" <[hidden email]>
To: <[hidden email]>
Sent: Saturday, July 18, 2009 7:48 AM
Subject: [EVDL] emergency disconnect


>
> Please consider this ,I believe carbon is a good electric conductor? but
> not
> very strong .  Place a carbon rod in a holder, with cables attached .In
> the
> center of this rod, place an insulated ring attached by cable to a handle
> in
> passenger compartment, a quick jerk or stomp on pedal or handle should
> break
> carbon into many pieces stopping current flow.
> --
> View this message in context:
> http://www.nabble.com/emergency-disconnect-tp24548611p24548611.html
> Sent from the Electric Vehicle Discussion List mailing list archive at
> Nabble.com.
>
> _______________________________________________
> General EVDL support: http://evdl.org/help/
> Usage guidelines: http://evdl.org/help/index.html#conv
> Archives: http://evdl.org/archive/
> Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev
>
>

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Re: emergency disconnect

Doug Weathers
In reply to this post by mark at evie-systems

On Jul 18, 2009, at 9:13 AM, mark at evie-systems wrote:

> Here's how Wayne implements a Quick Emergency Disconnect:
>
> http://www.youtube.com/watch?v=PX5gdNQIWlw&feature=channel_page
>
> Look at the beginning of the video, in the bottom right of the frame
> you'll see the high current wire passing through a quick connect.  One
> half of the quick connect is anchored to the car, and the other  
> side has
> a cable attached that goes in to the cabin.

I wonder if this has been tested under load?

Lee Hart tells us that Anderson Quick Connects are not supposed to be  
opened under load.  They might weld shut.

Neon John had a pedal in his CommutaCar that was above the main  
fuse.  When the pedal was stomped, it forced the fuse out of its  
clips.  He tested it; it worked.  I'd guess a panicked stomp would be  
stronger than an arm yank, and would better be able to overcome  
welding as the contacts slide past each other.

--
Doug Weathers          | "The Moon.  I've been there.  It's super!"
Las Cruces, NM, USA    |   - Astronaut Charles "Pete" Conrad
http://www.gdunge.com/ |

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Re: emergency disconnect

AMPhibian
I wonder about the Andersons as well.  I saw where KD mentioned the sliding contacts don't make a good high current disconnect.  I can picture how that might lead to welding.
John
Doug Weathers wrote

I wonder if this has been tested under load?

Lee Hart tells us that Anderson Quick Connects are not supposed to be  
opened under load.  They might weld shut.

Neon John had a pedal in his CommutaCar that was above the main  
fuse.  When the pedal was stomped, it forced the fuse out of its  
clips.  He tested it; it worked.  I'd guess a panicked stomp would be  
stronger than an arm yank, and would better be able to overcome  
welding as the contacts slide past each other.

--
Doug Weathers          | "The Moon.  I've been there.  It's super!"
Las Cruces, NM, USA    |   - Astronaut Charles "Pete" Conrad
http://www.gdunge.com/ |

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Re: emergency disconnect

Roland Wiench
As long as the Anderson disconnects are sliding and still making contact,
there will be no problem.  It's at the point where it breaks free.  Here is
where you have to jerk it hard to break the air gap distance to break the
arc.

Are high voltage open cutouts that are use on overhead exterior lines are
open with a jerk with no problem.  If you open it up slowly then there will
be a arc length up to 6 inches long for a 12,470 volts.  It will only be 7/8
of a inch if you open it up quickly.

Are low voltage disconnects at 480 volts are a spring loaded switch, where
the operator turns a lever, it BANG'S open. Its something like a ratchet
that is under spring tension and a lever releases the catch on the teeth of
the ratchet gear. If a person install a spring loaded mechanism like this on
a Anderson disconnect, it should work fine.

Some emergency brake release mechanism work like this.

Roland


----- Original Message -----
From: "AMPhibian" <[hidden email]>
To: <[hidden email]>
Sent: Sunday, July 19, 2009 8:17 AM
Subject: Re: [EVDL] emergency disconnect


>
> I wonder about the Andersons as well.  I saw where KD mentioned the
> sliding
> contacts don't make a good high current disconnect.  I can picture how
> that
> might lead to welding.
> John
>
> Doug Weathers wrote:
> >
> >
> >
> > I wonder if this has been tested under load?
> >
> > Lee Hart tells us that Anderson Quick Connects are not supposed to be
> > opened under load.  They might weld shut.
> >
> > Neon John had a pedal in his CommutaCar that was above the main
> > fuse.  When the pedal was stomped, it forced the fuse out of its
> > clips.  He tested it; it worked.  I'd guess a panicked stomp would be
> > stronger than an arm yank, and would better be able to overcome
> > welding as the contacts slide past each other.
> >
> > --
> > Doug Weathers          | "The Moon.  I've been there.  It's super!"
> > Las Cruces, NM, USA    |   - Astronaut Charles "Pete" Conrad
> > http://www.gdunge.com/ |
> >
> > _______________________________________________
> > General EVDL support: http://evdl.org/help/
> > Usage guidelines: http://evdl.org/help/index.html#conv
> > Archives: http://evdl.org/archive/
> > Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev
> >
> >
> >
>
> --
> View this message in context:
> http://www.nabble.com/emergency-disconnect-tp24548611p24557904.html
> Sent from the Electric Vehicle Discussion List mailing list archive at
> Nabble.com.
>
> _______________________________________________
> General EVDL support: http://evdl.org/help/
> Usage guidelines: http://evdl.org/help/index.html#conv
> Archives: http://evdl.org/archive/
> Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev
>
>

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Re: emergency disconnect

Lee Hart
In reply to this post by Doug Weathers
Doug Weathers wrote:

>> Here's how Wayne implements a Quick Emergency Disconnect:
>> http://www.youtube.com/watch?v=PX5gdNQIWlw&feature=channel_page
>> Look at the beginning of the video, in the bottom right of the frame
>> you'll see the high current wire passing through a quick connect.  One
>> half of the quick connect is anchored to the car, and the other  
>> side has a cable attached that goes in to the cabin.
>
> I wonder if this has been tested under load? Lee Hart tells us that
> Anderson Quick Connects are not supposed to be opened under load.
> They might weld shut.

When you unplug an Anderson connector, the contacts slide apart at
first. At high current, and if you pull slowly, there's time for the
contacts to weld together! For this to work under high fault current
conditions, you'd need an arrangement that pulls them apart *fast* and
with a *lot* of force. If it were me, I'd want to test it before I
relied on it.

> Neon John had a pedal in his CommutaCar that was above the main  
> fuse.  When the pedal was stomped, it forced the fuse out of its  
> clips.  He tested it; it worked.  I'd guess a panicked stomp would be  
> stronger than an arm yank, and would better be able to overcome  
> welding as the contacts slide past each other.

That sounds logical. Again, I'd like to test it to be sure it could
break your battery's short circuit current (which can easily be 1000 amps).

John Wayland uses a variation of this method in the White Zombie. It has
a large fuseholder in a closed box. The "fuse" has been replaced with a
copper bar. The cover of the box has a large handle on it. Grab that
handle and pull, and the "fuse" pops out of its holder to break the
circuit. He's used it under full power, and it successfully broke the
circuit.

Commercial emergency disconnects have a strong spring that pulls the
contacts apart, or a nonconductive blade that is forced between the
contacts to force them apart and break the arc.

Circuit breakers have a solenoid coil powered by the fault current to
pull the contacts apart. The higher the current, the greater the force,
so the faster the contacts pull apart.
--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in    --    Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net

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Re: emergency disconnect

Walter Guinon
 Late model BMWs use an explosive disconnect to  avoid short-circuiting  the high amperage starter circuit in an event of a collision. The battery safety terminal (BST) is actuated by the air bag control unit and uses a pyrotechnic charge to separate the starter cable from the battery in a crash.