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Discussion Starter · #1 ·
Hi Folk's

Generally combining functionality and not using a modular approach is
historically a bad idea. Look at the 1945 Philco-Ford TV's and RCA Victors
where they combined the radio, TV and phonograph with a common power supply.
The result was each "component" had a 4X MTBF (since they shared a lot of
components that got used when you were using any part of the system).

We went through the same hysterical (I mean historical :) exercise at GE-Ev
for marketing porposes (it does initially sell things) combining a DC-Dc
converter with a battery charger and then combining the charger with the
motor speed control. Due to the poor reliability of combining things, they
were seperated out later conventionally. Combining things works for
marketeers but not in reality, generally headed for a fall when you do. See
my EV charger patent 6,218,812 www.uspto.gov

BTW I saw one of those yellow ribbons today on a big SUV that instead of
saying "Support the Troops" was "Support My Gastank". Now there's someone
who's honest.

Have a renewable energy day,
Mark in Roanoke, VA

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Discussion Starter · #2 ·
Mark Hanson wrote:
> combining functionality and not using a modular approach is a bad idea.
> We went through the same hysterical (I mean historical :) exercise at
> GE-EV... Due to the poor reliability of combining things, they were
> separated out later conventionally.

I agree. It only works when the functions being combined are very
closely related and share many parts.

A controller and a DC/DC have almost nothing in common. You won't save
any money or parts by combining them. It's more likely that you will
create problems, such as lowered reliability, more expensive repair and
replacement cost, and weird limitations (can't get the big controller
with the small DC/DC, etc.)

No, combining things *does* make sense when the functions are closely
related, or can share many parts. For example, you might combine a DC/DC
with a battery charger, because the two functions are similar (converts
one DC voltage into another isolated DC voltage) and they are used at
different times (a charger while parked, and a DC/DC while driving).

> BTW I saw one of those yellow ribbons today on a big SUV that instead
> of saying "Support the Troops" was "Support My Gastank". Now there's
> someone who's honest.

Thanks for my laugh of the day, Mark! :)

--
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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Discussion Starter · #3 ·
Combining functionality can make sense under certain circumstances.
If, for example, the cost of producing the seperate parts drops to the
point where you can save money by making one combined part and
exconomicaly toss it if it fails.
I used to be against computer motherboards that included all of the common
interfaces (FDD, HDD, Serial, etc.)
But now, the integrated motherboards are so cheap, it doesn't matter if
one part fails.

So I can see, eventually, combining motor controller logic and DC-DC, with
the power stage on a separate card. After all the logic is going to need
a DC-DC anyway.
But this only makes sense if the volume is high enough that there is a
significant cst savings to combining them and the replacement cost of the
card is cheap enough to make tossing it economical.
I.e. it has to cost less to replace than to repair.

At any rate, we are no where near the volume for this to make sense and I
don't see us getting there in the forseable future.

> Hi Folk's
>
> Generally combining functionality and not using a modular approach is
> historically a bad idea. Look at the 1945 Philco-Ford TV's and RCA
> Victors
> where they combined the radio, TV and phonograph with a common power
> supply.
> The result was each "component" had a 4X MTBF (since they shared a lot
> of
> components that got used when you were using any part of the system).
>
> We went through the same hysterical (I mean historical :) exercise at
> GE-Ev
> for marketing porposes (it does initially sell things) combining a DC-Dc
> converter with a battery charger and then combining the charger with the
> motor speed control. Due to the poor reliability of combining things,
> they
> were seperated out later conventionally. Combining things works for
> marketeers but not in reality, generally headed for a fall when you do.
> See
> my EV charger patent 6,218,812 www.uspto.gov
>
> BTW I saw one of those yellow ribbons today on a big SUV that instead of
> saying "Support the Troops" was "Support My Gastank". Now there's someone
> who's honest.
>
> Have a renewable energy day,
> Mark in Roanoke, VA
>
> _________________________________________________________________
> Test your celebrity IQ. Play Red Carpet Reveal and earn great prizes!
> http://club.live.com/red_carpet_reveal.aspx?icid=3Dredcarpet_hotmailtextl=
ink2
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev


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