# [EVDL] Doubling up on Breakers



## EVDL List (Jul 27, 2007)

Sure John you can do this and it will work fine for what you are 
thinking, but what it will also do is make you have to leave the breaker 
on while charging.
If you were to have two half pack chargers then this won't be a problem. 
But if you want to charge the whole pack in bulk you can't split it 
while charging.

I think I have the same breakers in my truck as you mention, I put one 
on the pack positive and one on pack minus, physically located together 
with the handles ganged.

Mike




> John G. Lussmyer wrote:
> 
> > I have a pair of 300A, 160VDC breakers.
> > My pack is going to be in the 240-288V range.
> ...


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## EVDL List (Jul 27, 2007)

Hello John,

Even though you have two or more circuit breakers in series, they may not 
exactly trip all at once. One breaker acts like a conductor of a wire going 
to the breaker that may trip first.

The breaker that trips first still has a higher voltage across it at that 
point in time.

As a test, turn on one breaker and turn off the other and you will read the 
full battery voltage across the turn off breaker.

Even if you use a tie handle between the breakers, there will be a small 
delay between the two. In time, the breaker when turning off under a short 
may not stop the arcing because of the clearances.

The breakers will work if you turn them off while not under load. My 600 
amp 500 volt industrial DC contactors look like new after 30 years, but when 
I had to open one under full 300 amp battery load one time, I had to 
re-surface the contacts that time.

Roland


----- Original Message ----- 
From: "John G. Lussmyer" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Thursday, April 02, 2009 11:02 AM
Subject: [EVDL] Doubling up on Breakers


> I have a pair of 300A, 160VDC breakers.
> My pack is going to be in the 240-288V range.
> So I'm planning on putting the breakers in series, and mechanically
> coupling their handles (just like ever 240VAC breaker in the house).
>
> One thing I was thinking about, do they have to be directly in series?
> Or could I put one mid-pack, and one at the end of the pack.
> This would nicely cut the pack in half if either breaker ever popped.
>
> -- 
> --
> John G. Lussmyer mailto:[email protected]
> Electric Vehicle Battery Monitoring Systems, http://www.CasaDelGato.com
>
>
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## EVDL List (Jul 27, 2007)

> Roland Wiench wrote:
> > Even though you have two or more circuit breakers in series, they may not
> > exactly trip all at once. One breaker acts like a conductor of a wire going
> > to the breaker that may trip first.
> ...


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## EVDL List (Jul 27, 2007)

> [email protected] wrote:
> > Sure John you can do this and it will work fine for what you are
> > thinking, but what it will also do is make you have to leave the breaker
> > on while charging.
> ...


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## EVDL List (Jul 27, 2007)

I don't have two main contactors. Plus my main contactor that I do have 
is in the front, the batteries are in the back. So to keep one side of 
high potential from running up into the motor compartment all the time I 
turn off the breakers all the time. The charger feeds through fuses 
directly to the pack bypassing the breakers. If you were to have dual 
main contactors and left the breakers on then you could split the pack 
with one of them subject to the insulation issue Jeff brings up.

Mike




> John G. Lussmyer wrote:
> 
> > [email protected] wrote:
> >> Sure John you can do this and it will work fine for what you are
> ...


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## EVDL List (Jul 27, 2007)

> John G. Lussmyer wrote:
> > I have a pair of 300A, 160VDC breakers.
> > My pack is going to be in the 240-288V range.
> > So I'm planning on putting the breakers in series, and mechanically
> ...


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## EVDL List (Jul 27, 2007)

Hold on a minute. I just checked some breakers I had sitting around. 
The single and dual breakers have an interrupt 240V AC. They don't 
put two 120V rated breakers together to make a 240V breaker. I think 
you making a mistake putting two 160 V rated ones together. Whichever 
one breaks first is going to see the full voltage arc across it. Even 
if their handles are tied together one is going to break a millisecond 
before the other.




> [email protected] wrote:
> 
> > I don't have two main contactors. Plus my main contactor that I do
> > have
> ...


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## EVDL List (Jul 27, 2007)

The delay may not even be that long if the handles are hard ganged. Yes 
the first one may set up an arc the instant it is tripped but it won't 
last for more than the time it takes for its mate to start opening. 
I've done multiple 0-60 mph runs at 1000 amps in my truck (breakers are 
313 trip amps) before they got hot enough to trip. And they trip. And 
they reset, and they have done it several times. Its better than 
replacing $40 fuses. I cannot get inside to see the contacts, it may 
be one gets more wear than the other, but I don't think it would be much 
of a difference.

Mike




> Roger Heuckeroth wrote:
> 
> > Hold on a minute. I just checked some breakers I had sitting around.
> > The single and dual breakers have an interrupt 240V AC. They don't
> ...


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## EVDL List (Jul 27, 2007)

> Roland Wiench wrote:
> > Even though you have two or more circuit breakers in series, they may
> > not exactly trip all at once... The breaker that trips first still
> > has a higher voltage across it at that point in time.
> ...


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## EVDL List (Jul 27, 2007)

> Roger Heuckeroth wrote:
> > Hold on a minute. I just checked some breakers I had sitting around.
> > The single and dual breakers have an interrupt 240V AC. They don't
> > put two 120V rated breakers together to make a 240V breaker.
> ...


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## EVDL List (Jul 27, 2007)

Take special care with Airpax breakers. Their trip handles are somewhat 
brittle and don't need a lot of encouragement to snap off. At least 
they're dirt cheap! I have 3 of them ganged together on my (small) pickup.

-Adrian



> Lee Hart wrote:
> 
> > Just be sure to tie their handles together, so they both turn on/off at
> > once.
> ...


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## EVDL List (Jul 27, 2007)

Is there a repair for this?



> Adrian DeLeon <[email protected]> wrote:
> 
> > Take special care with Airpax breakers. Their trip handles are somewhat
> > brittle and don't need a lot of encouragement to snap off. At least
> ...


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## EVDL List (Jul 27, 2007)

> Lee Hart wrote:
> 
> > Roger Heuckeroth wrote:
> >> Hold on a minute. I just checked some breakers I had sitting around.
> ...


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## EVDL List (Jul 27, 2007)

> Roger Heuckeroth wrote:
> > I just called my brother. He is a senior engineer a GE Global Power
> > Projects. His response was that he wouldn't even dream about doing
> > such a thing with AC or DC... that was a disaster and a law suit
> ...


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## EVDL List (Jul 27, 2007)

> Roger Heuckeroth wrote:
> > He works with really, big breakers and fuses. Its all about the
> > extinguishing the arc. The higher the voltage the more arc, and with
> > DC the arc is harder to extinguish than with AC. Circuit breakers use
> ...


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## EVDL List (Jul 27, 2007)

> Roger Heuckeroth wrote:
> 
> > I just called my brother. He is a senior engineer a GE
> > Global Power Projects. His response was that he wouldn't
> ...


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## EVDL List (Jul 27, 2007)

> John G. Lussmyer wrote:
> 
> > Roger Heuckeroth wrote:
> >> I just called my brother. He is a senior engineer a GE Global Power
> ...


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## EVDL List (Jul 27, 2007)

> Roger Stockton wrote:
> 
> > Roger Heuckeroth wrote:
> >
> ...


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## EVDL List (Jul 27, 2007)

Looking in my Square D book, these circuit breakers are only common trip 
type using only one handle where you series the internal poles of one 
breaker.

Not recommended to do this type of wiring with separate breakers or several 
breakers with a tie handle.

I have found that the tie handle type breaker when trip, may only trip one 
breaker and leave the other one close. This does not matter much if the 
breaker is rated for the line voltage.

I had one electrician come back to the shop with his face and hand all 
black, because he though the power was off to that circuit.

Roland


----- Original Message ----- 
From: "Roger Stockton" <[email protected]>
To: "'Electric Vehicle Discussion List'" <[email protected]>
Sent: Friday, April 03, 2009 8:25 AM
Subject: Re: [EVDL] Doubling up on Breakers




> > Roger Heuckeroth wrote:
> >
> > > I just called my brother. He is a senior engineer a GE
> > > Global Power Projects. His response was that he wouldn't
> ...


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## EVDL List (Jul 27, 2007)

No idea. I thought about drilling a hole in the remaining stub and 
threading a long bolt into it. That would make it useable as a single 
breaker. I sure wouldn't gang them together this way.

I bought mine as a pack of 6 for $180 on eBay. Can't complain about the 
price...

-Adrian



> m gol wrote:
> 
> > Is there a repair for this?
> >
> ...


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## EVDL List (Jul 27, 2007)

> Roger Heuckeroth wrote:
> > Maybe John could tell us the exact brand and model of breaker he plans
> > on using, and then we could look into the specifics of that particular
> > breaker.
> ...


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## EVDL List (Jul 27, 2007)

> Roger Heuckeroth wrote:
> 
> > Ah, but KA, LA, and MA families all carry a 600V Maximum
> > rating. See page 18:
> ...


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## EVDL List (Jul 27, 2007)

> John G. Lussmyer wrote:
> 
> > Roger Heuckeroth wrote:
> >> Maybe John could tell us the exact brand and model of breaker he
> ...


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## EVDL List (Jul 27, 2007)

> Roger Stockton wrote:
> 
> >> You can't automatically take what one manufacturer
> >> says about their product and apply it to another.
> ...


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## EVDL List (Jul 27, 2007)

I don't see anything in the ADC or Warfield literature about using their 
motors for highway capable transportation.
I didn't come across any literature on gear couplings that specifically 
listed ganging electric motors together for EV's as an "approved" 
application either.
Same with the rubber shock mounts that I'm using in my motor mounts.

The point is that the "Engineer", whoever it is desiging the vehicle, 
has to look at the manufacturer specifications and "recommended" 
applications, look at other component uses and applications and make 
judgements based on if the component will safely perform the job outside 
the scope of the products intended purpose. I wouldn't put my PE stamp 
on a design to use the two 160V DC Airpax breakers in series to break 
192V DC pack, but I do it on my own car because I believe it is safe 
enough to do so. I wouldn't do it if I were building cars to sell. In 
all likelihood if you have to look for components that are rated and 
accepted for EV use and meet all the name plate values and 
specifications that are reasonable to meet the "accepted" minimum safety 
standards of the component, then you will be buying $600 G.E. breakers 
and $1000 couplers and $10,000 drive motors.....and you can't make a 
business case to do this.

If you gang the handles on these particular 160v Airpax breakers they 
will break 1000 amps after about 30 seconds or so. And the spring is 
stong enough to trip both of them. I use a pair of these breakers on 
each pack in the Pinto as well. Although each pack only puts out 750 
amps and the pack resting voltage is 380V, with any amount of current 
the pack voltage drops below the 320V "combined" rating of my set up. 
380V at no current, no problem. 200V at 750 amps, no problem. They 
work and I trust them. I use my own judgement. Anyone who would do 
this themselves should use theirs too.

The first thing I learned when I became an engineer is don't listen to 
an engineer that says it can't be done. It was an engineer that said we 
will never be able to break the sound barrier, it was an engineer that 
said we would never make it to the moon (among others who said the same 
thing), it was an engineer that told John Wayland that it was 
impossible to make an electric vehicle do a 13 second 1/4 
mile..........and the list goes on. In all fairness to engineers 
though, it was probably an engineer that came up with Nike's slogan, 
"Just Do it".

Mike





> Roger Heuckeroth wrote:
> 
> > On Apr 3, 2009, at 2:53 PM, John G. Lussmyer wrote:
> >
> ...


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