Re: Braking

["Thomas J Webster" <ford1929@frontiernet.net>]

Or you could build a load box, like what they do to exersize diesel
locomotives? Tom
----- Original Message -----
From: "Bryan Andersen" <bryan@visi.com>
To: <ev@listproc.sjsu.edu>
Sent: Tuesday, January 29, 2002 12:23 AM
Subject: Re: Braking


> A possibility I just thought of:
>
> Why not incorporate a electrical heat dump into the car.  Size
> it for the maximum amount of regen braking you can dump into
> your batteries.  If the batteries are full, then dump the excess
> energy into the electrical heat dump.  This way "regen" braking
> is consistent and one can simplify the regen / mechanical braking
> distribution.
>
> A suitable heat dump could be quite similar to an electric heater.
> Basically some resistive heating elements with a fan blowing over
> them.  Locomotives have been using this method for years.  Note,
> you will not want this in your passenger compartment.  One stop
> with it fully engaged and you will understand.  Multiple heating
> elements each switched separately can provide simple control of
> the energy dumped through it.  An issue is how many kilowatts one
> can easily dump in a small area.
>
> As an example, a 2200W 240VAC finned strip heater has an active
> finned length of 19" with 2" x 1.375" fins and an overall length
> of 23.25".  Smaller and larger sizes are available.  I chose this
> size as a single $3 IGBT can switch it easily.  Even placing them
> two deep in an array one ends up with a rather significant sized
> box if one wanted to dump 200A.  The overall box would end up about
> 24" long, 16" wide, and 4" deep + whatever one needs for fans, say
> an additional 3".  Maybe not quite practical, but an idea.  The
> maximum temperature of the elements is 600F.  If one had suitable
> air flow one could easily go deeper than the two deep I used.
> Going 4 deep gives a box size of 24"L x 8"W x 11" deep.
>
> Anyways it's an idea.
>
> --
> |  Bryan Andersen   |   bryan@visi.com   |   http://www.nerdvest.com   |
> | Buzzwords are like annoying little flies that deserve to be swatted. |
> |      "Linux, the OS Microsoft doesn't want you to know about.".      |
> |   -Bryan Andersen                                                    |
>
>