# 400V/500A curcuit breaker



## electroauto.ru (Oct 11, 2009)

Hello,

I'm looking for 400V/500A curcuit breaker for my EV project.
Looks like this part is not common in EV conversions...

What can you recommend?

Regards,
Oleg


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## major (Apr 4, 2008)

electroauto.ru said:


> I'm looking for 400V/500A curcuit breaker for my EV project.
> Looks like this part is not common in EV conversions...
> 
> What can you recommend?


Hi Oleg,

Use a fuse. DC circuit breakers of that rating are hard to come by, and if you do find one, it will likely be very large, heavy and expensive.

Regards,

major


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## dtbaker (Jan 5, 2008)

there is a big difference between AC rating and DC.... This one is supposed to work for controller systems up to 800a max:
http://store.kta-ev.com/Circuit_Breakers_Fuses_Safety_Switches/Airpax_250Amps.aspx

in your main traction pack use a fuse, a keyed contactor, an inertial switch on the contactor (for accidents), AND a circuit breaker with a manual pull wire so you can 'kill' the circuit from the drivers seat!


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## brainzel (Jun 15, 2009)

Not really a switch, but a circuit breaker up to 630A is my "Jean Müller LTL3-1/9" http://e-vw.blogspot.com/2009/10/sachspende-von-jean-muller.html

Can anyone tell me, why there is such a different in specification?
"Airpax Circuit Breaker *250-400A*/160V"
"for controller systems *up to 800 amps*"
Is this only a AC to DC multiplication-factor? I thought, it was about 1.4 times?
Or is this a continuous / peak rating?


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## electricmini (Oct 21, 2008)

brainzel said:


> Can anyone tell me, why there is such a different in specification?
> "Airpax Circuit Breaker *250-400A*/160V"
> "for controller systems *up to 800 amps*"
> Is this only a AC to DC multiplication-factor? I thought, it was about 1.4 times?
> Or is this a continuous / peak rating?


It's to do with the continuous rating of the breaker
(won't trip if the current stays at 400A or less for a 400A breaker**)
( **note breakers to USA standards are rated differently from ones built to EU/UK standards)

If you have an 800A controller, you probably won't be drawing 800A for
long enough time to trip a 400A breaker (this depends on the current/time curve of the breaker, they are available with different delay curves to suit some applications)

HTH

Richard (electricmini)

P.S. Did you get those RM4 fluid heaters in the end? If you still have a spare I'd be interested in it - I'm having trouble with my homemade fluid heater system...


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## Gummitwist (May 20, 2009)

Hello Oleg,

take a look at this http://www.schaltbau-gmbh.com/CMXS/Detail_647.html

Schaltbau has an office in Moscow, for further information contact www.schaltbau.ru

Regards


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