I wonder what the FCC has to say about the EMI generated by not isolating?
On 9/18/08, Peter Gabrielsson <peter.xxx@xxx.xxx> wrote:
> Oh dear.
>
> Well, it strikes me that he provides no reasoning as to why a center
> grounded system with the protection he mentions would provide better
> protection than an insulated battery pack. He counters none of the arguments
> made by people on this list. He just states that it is safer, tears down a
> straw man argument, attacks DC motor people, etc.
>
> This is probably a waste of my time but, more comments below
>
>
> [quote] Ian Hooper <xxx@xxx.xxx.au> wrote:
>
>
> > Sorry to dig up an old thread, but I shared everyone's comments
> > regarding isolation with our EV safety committee, and here's the
> > response from main proponent for non-isolated traction circuits. (He
> > has a habit of fighting hard for his beliefs!) I welcome any further
> > comment:
> >
> > ----------
> >
> > Floating battery systems with one module of 200 or 300V without even
> > the offering of leakage detection are so old school and give the owner
> > a false sense of safety.
>
>
>
> Isolated battery packs does not prevent leakage detection.
>
>
>
> >
> > They go against Australian and European electrical standards that
> > require protective earth and supply neutral connected to earth.
>
>
>
> All high voltage EV standards I'm aware of calls for isolated battery pack.
> Can he provide us with what specific standard he's referring to?
>
>
>
> >
> > They will also give EVs a bad reputation with the public as people get
> > electrocuted.
> >
>
>
> Care to provide an example of people having been electrocuted by an EV
> because of its isolated battery pack?
>
>
>
> >
> > Centre grounded systems with breakup contactors to 72V or less and
> > fuses at each battery pack location with automatic crash sensor
> > activated contactor dropout and effectively insulated wiring, motor
> > and terminals offer the best safety practice for the future of EVs.
> >
>
>
> All of those things are good measure commonly used in EVs, except, the
> center ground for reasons already discussed.
>
>
>
>
> >
> > OK, the wet DC motor people may not like the home truths.
>
>
> ad hominem
>
>
> >
> >
> > You can post that on any forum you like and I will be interested to
> > hear any informed and justified argument to the contrary.
> > Reasons such as "we have always done it that way" and "that would mean
> > I need to make my motor waterproof" don't wash.
> >
>
>
> strawman
>
>
>
> >
> > Tell Bill Dube that the regulation does not have to require that the
> > traction system is not isolated, however it must not require that IT
> > BE isolated as there are better, more reliable and more predicatable
> > ways to make the system safe and these should be allowed, even
> > encouraged for the future safety of EVs.
> >
> > I am talking EV conversions.
> >
> > Commercial EV manufacturers will go their own way and have to meet
> > their own standards. If ADRs set higher standards then manufacturers
> > will have to meet them.
> >
>
>
> Commercial EV manufacturers follow SAE standards j1772, j1773,j2344,j2289.
>
>
>
>
> >
> > ----------
> >
> > Ian Hooper
> > --
> > "Never doubt that the work of a small group of thoughtful, committed
> > citizens can change the world." - Margaret Mead
> > http://www.zeva.com.au
> >
> > On 08/09/2008, at 2:52 PM, Ian Hooper wrote:
> >
> > > Hi all,
> > >
> > > I'm part of a group currently working towards updating the national
> > > regulations for road-legal electric vehicles in Australia, and the
> > > group's opinion is currently divided on the subject of whether the
> > > power circuit should be isolated from the vehicle body.. So I'm hoping
> > > to get some *technical* reasons for and against this from any experts
> > > in the field!
> > >
> > > Some people believe it should be isolated, because then you can't get
> > > a shock from touching any one point in the power circuit and the
> > > vehicle itself.
> > >
> > > Others believe they should have a common ground so the potentials are
> > > known, and so that there is a predictable voltage potential across the
> > > insulation in the motor (i.e between the motor windings and the motor
> > > housing).
> > >
> > > I'm of the opinion that the power circuit should be isolated but
> > > perhaps with a ground leakage detector between the power circuit and
> > > the vehicle body, so you actually know if there is a ground fault in
> > > the circuit.
> > >
> > > Thoughts?
> > >
> > > Ian Hooper
> > > --
> > > "Never doubt that the work of a small group of thoughtful, committed
> > > citizens can change the world." - Margaret Mead
> > > http://www.zeva.com.au
> > >
> > > _______________________________________________
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> > >
> >
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> >
>
>
>
> --
> www.electric-lemon.com
>
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Re: [EVDL] Isolation of the power circuit - reasons for and against?
Linear Mode
