kill switch

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kill switch

CHARLIEP
Some of you may remember, I suggested useing carbon rod placed in the area of you'r choice.
  attach an insulated cable that you can pull or stomp on to break rod and current.
  I built and tested it, I hooked up my old buzz box, had the cables smoking then broke rod with an old golf club.
  There was little flash or smoke ,but the welder was no longer buzzing. no collateral damage any where. Charlie P
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Re: kill switch

Matt Lacey
Hi Charles,

Sounds like you tested that break method with a welder.
What voltage was it running at?

The two things that reduce breaking capacity (in A) are voltage and
inductance.

A traction pack has a fair bit of voltage, and the motor supplies a fair bit
of inductance.

If your test was shorting out a welder, at low voltage, that would be the
best case breaking scenario, but not necessarily relevant to EV use.

It is always good to test though :)

Matt

-----Original Message-----
From: [hidden email] [mailto:[hidden email]] On Behalf
Of charles price
Sent: Sunday, 7 March 2010 7:09 AM
To: [hidden email]
Subject: [EVDL] kill switch

Some of you may remember, I suggested useing carbon rod placed in the area
of you'r choice.
  attach an insulated cable that you can pull or stomp on to break rod and
current.
  I built and tested it, I hooked up my old buzz box, had the cables smoking
then broke rod with an old golf club.
  There was little flash or smoke ,but the welder was no longer buzzing. no
collateral damage any where. Charlie P
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Re: kill switch

Lee Hart
In reply to this post by CHARLIEP
charles price wrote:
> Some of you may remember, I suggested useing carbon rod placed in the area of you'r choice.
>   attach an insulated cable that you can pull or stomp on to break rod and current.
>   I built and tested it, I hooked up my old buzz box, had the cables smoking then broke rod with an old golf club.
>   There was little flash or smoke ,but the welder was no longer buzzing. no collateral damage any where. Charlie P

That's an interesting approach. It's cheap, it conducts electricity
(though not great), and it breaks easily.

If one wanted to go this way, I'd be more inclined to have a pair of
real contacts, with a big spring pulling them apart, but then something
easily breakable like glass holding the spring back. Break the glass,
and the spring pulls the contacts far apart.

Again, testing would be required to be sure it works.

--
Lee A. Hart | Ring the bells that still can ring
814 8th Ave N | Forget the perfect offering
Sartell MN 56377 | There is a crack in everything
leeahart earthlink.net | That's how the light gets in -- Leonard Cohen

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Re: kill switch

Jeff Shanab
In reply to this post by CHARLIEP
If I am understanding this correctly it is using carbon as a high
resistance short?

I wonder if we run over to harbor freight and disassemble the 500A
carbon pile tester it there would be a way to keep it from conducting
and have some kind of cam lock to enguage it.

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=91129

I have one of these and used it to put 300A draws on each battery in my
pack at two charge levels to guage battery health,
The meters are cheap and one good bump and they can be damaged and the
threaded rod** is toast which actually works out better. Just push.
But it gets hot! and you must let it cool

Anyway @$69 maybe a good source for carbon and holders for a crowbar. I
got mine when they were on sale for 39.99. happens occasionally.

** very soft metal very fine pitch stripped off  before 24 batteries
were tested. If you want this to last, lube it before use with soap or
something.


> charles price wrote:
>> Some of you may remember, I suggested useing carbon rod placed in the
>> area of you'r choice.
>>   attach an insulated cable that you can pull or stomp on to break
>> rod and current.   I built and tested it, I hooked up my old buzz
>> box, had the cables smoking then broke rod with an old golf club.  
>> There was little flash or smoke ,but the welder was no longer
>> buzzing. no collateral damage any where. Charlie P
>
> That's an interesting approach. It's cheap, it conducts electricity
> (though not great), and it breaks easily.
>
> If one wanted to go this way, I'd be more inclined to have a pair of
> real contacts, with a big spring pulling them apart, but then
> something easily breakable like glass holding the spring back. Break
> the glass, and the spring pulls the contacts far apart.
>
> Again, testing would be required to be sure it works.
>
> --
> Lee A. Hart        | Ring the bells that still can ring
> 814 8th Ave N        | Forget the perfect offering
> Sartell MN 56377    | There is a crack in everything
> leeahart earthlink.net    | That's how the light gets in -- Leonard Cohen
>
>
>
> ------------------------------------------------------------------------

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Re: kill switch

David Dymaxion
I have a Harbor Freight load tester. We tip it back at 45 degrees, and blow air from the air compressor at the base during a test, and also blow a fan on the clamps and battery terminals. My son would have the pile glowing hot for 10 to 15 minutes at 200 Amps this way for his science project. Once he forgot the cooling air, though, and cooked it. I have run it up to 400 Amps for shorter tests (~40 seconds), but couldn't get the resistance low enough for more Amps than about 400.

It's only a single data point, but mine would have needed more pressure than the knob could provide to be a crowbar circuit.



________________________________
From: Jeff Shanab <[hidden email]>
To: [hidden email]
Sent: Sun, March 7, 2010 2:05:38 PM
Subject: Re: [EVDL] kill switch

If I am understanding this correctly it is using carbon as a high
resistance short?

I wonder if we run over to harbor freight and disassemble the 500A
carbon pile tester it there would be a way to keep it from conducting
and have some kind of cam lock to enguage it.

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=91129

I have one of these and used it to put 300A draws on each battery in my
pack at two charge levels to guage battery health,
The meters are cheap and one good bump and they can be damaged and the
threaded rod** is toast which actually works out better. Just push.
But it gets hot! and you must let it cool

Anyway @$69 maybe a good source for carbon and holders for a crowbar. I
got mine when they were on sale for 39.99. happens occasionally.

** very soft metal very fine pitch stripped off  before 24 batteries
were tested. If you want this to last, lube it before use with soap or
something.


> charles price wrote:
>> Some of you may remember, I suggested useing carbon rod placed in the
>> area of you'r choice.
>>   attach an insulated cable that you can pull or stomp on to break
>> rod and current.   I built and tested it, I hooked up my old buzz
>> box, had the cables smoking then broke rod with an old golf club.  
>> There was little flash or smoke ,but the welder was no longer
>> buzzing. no collateral damage any where. Charlie P
>
> That's an interesting approach. It's cheap, it conducts electricity
> (though not great), and it breaks easily.
>
> If one wanted to go this way, I'd be more inclined to have a pair of
> real contacts, with a big spring pulling them apart, but then
> something easily breakable like glass holding the spring back. Break
> the glass, and the spring pulls the contacts far apart.
>
> Again, testing would be required to be sure it works.
>
> --
> Lee A. Hart        | Ring the bells that still can ring
> 814 8th Ave N        | Forget the perfect offering
> Sartell MN 56377    | There is a crack in everything
> leeahart earthlink.net    | That's how the light gets in -- Leonard Cohen
>
>
>
> ------------------------------------------------------------------------

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Re: kill switch

Dennis Miles
Gentlemen, your are missing it.
     The carbon rod originally referred to was a BIG  piece of over one half
inch diameter carbon rod several inches long securely mounted in series with
the main pack negative lead. and unlike other conductors, carbon is brittle
so it can be broken, yeah, smashed. into pieces thereby breaking the
electrical conductor reliably even better than a fuse or contactor if you
can hit it with a hammer or the equivalent,

 Not as a Crowbar, which would cause an equivalent to a short and blow ckt.
breakers or fuses..Crowbars are normally only used as protection of the
"Last resort" to prevent damage to the load and "Chuck" the supply, short it
dead out and kill it, blow the fuse, the rectifiers, the interconnect wiring
 and anything else but save the load from over voltage and current. That is
a Crowbar.

We need to get reasonable and decide upon a reliable disconnect which will
fail safe (No power to motor) in case of control system failure of any sort
so we don"t "Toyota" our EV. so far best I have heard of has several
requirements:
* First  Direct mechanical action is mandated in some jurisdictions so
include that.
* Second, Quick opening , so a jerk, or spring propelled contact opener.
* Third Robust enough for two times pack voltage and max pack current
because it is an
        inductive load.
 OK, I think that was most of the important points. (I hope I didn't leave
yours out but no omissions were intended. We just have been going at this so
long a summary was needed. IMHO.)

Hey, where can I buy a mechanical contact opener with 2,000 Amp. capability
and 400 V. DC minimum rating, that releases a hold on latch with a cable
release like a "Choke release" and will cost less than I paid for the
"Glider?"

Regards,

Dennis Miles


+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

On Mon, Mar 8, 2010 at 12:08 PM, David Dymaxion <[hidden email]>wrote:

> I have a Harbor Freight load tester. We tip it back at 45 degrees, and blow
> air from the air compressor at the base during a test, and also blow a fan
> on the clamps and battery terminals. My son would have the pile glowing hot
> for 10 to 15 minutes at 200 Amps this way for his science project. Once he
> forgot the cooling air, though, and cooked it. I have run it up to 400 Amps
> for shorter tests (~40 seconds), but couldn't get the resistance low enough
> for more Amps than about 400.
>
> It's only a single data point, but mine would have needed more pressure
> than the knob could provide to be a crowbar circuit.
>
>
>
> ________________________________
> From: Jeff Shanab <[hidden email]>
> To: [hidden email]
> Sent: Sun, March 7, 2010 2:05:38 PM
> Subject: Re: [EVDL] kill switch
>
> If I am understanding this correctly it is using carbon as a high
> resistance short?
>
> I wonder if we run over to harbor freight and disassemble the 500A
> carbon pile tester it there would be a way to keep it from conducting
> and have some kind of cam lock to enguage it.
>
> http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=91129
>
> I have one of these and used it to put 300A draws on each battery in my
> pack at two charge levels to guage battery health,
> The meters are cheap and one good bump and they can be damaged and the
> threaded rod** is toast which actually works out better. Just push.
> But it gets hot! and you must let it cool
>
> Anyway @$69 maybe a good source for carbon and holders for a crowbar. I
> got mine when they were on sale for 39.99. happens occasionally.
>
> ** very soft metal very fine pitch stripped off  before 24 batteries
> were tested. If you want this to last, lube it before use with soap or
> something.
>
>
> > charles price wrote:
> >> Some of you may remember, I suggested useing carbon rod placed in the
> >> area of you'r choice.
> >>   attach an insulated cable that you can pull or stomp on to break
> >> rod and current.   I built and tested it, I hooked up my old buzz
> >> box, had the cables smoking then broke rod with an old golf club.
> >> There was little flash or smoke ,but the welder was no longer
> >> buzzing. no collateral damage any where. Charlie P
> >
> > That's an interesting approach. It's cheap, it conducts electricity
> > (though not great), and it breaks easily.
> >
> > If one wanted to go this way, I'd be more inclined to have a pair of
> > real contacts, with a big spring pulling them apart, but then
> > something easily breakable like glass holding the spring back. Break
> > the glass, and the spring pulls the contacts far apart.
> >
> > Again, testing would be required to be sure it works.
> >
> > --
> > Lee A. Hart        | Ring the bells that still can ring
> > 814 8th Ave N        | Forget the perfect offering
> > Sartell MN 56377    | There is a crack in everything
> > leeahart earthlink.net    | That's how the light gets in -- Leonard
> Cohen
> >
> >.
>
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Re: kill switch

Seth Rothenberg
Here's one I am working on - maybe just need a lever
to reverse the direction of the force...

The retired Automatic Shifter on the floor...
(I have to check again, but I think) -
it pushes a steel cable out of its sheath
when pulled back (eg, to Drive or 1, 2, etc.)
So when it is in PARK, the cable is retracted
(I think, need to check again :-)


Ideally, it this lever is to be used at all,
I would like to use it as intuitively as possible,
i.e., make it part of the starting sequence....
which will take some thought - and/or change
to this cable.

Also I need to study how this shifter uses 12V
to release.   When 12V is absent, the shifter
doesn't move unless you over-ride it the lockout.

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