Re: capacitor

Les,

I completely agree with everything you say.

The fun part of designing is to find the "sweet spot" where the
design is adequate to the task but not greatly in excess of what is
needed. Philosophically it just feels "better" when it's neither over
or under engineered. It's kind of like poetry; no spare words.

I love math much more now than when I took it every single quarter at
OSU. Funny how things taste better when they are not force-fed.

Mariss

--- In CAD_CAM_EDM_DRO@y..., "Les Watts" <leswatts@r...> wrote:
> Mariss,
>
> Yes this energy approximation neglects motor and wire
> resistance, magnetic losses,cap ESR, etc. It certainly does
> not consider time, being an energy solution. It is pessimistic,
> but it is very very safe. Please understand- I am an aerospace
engineer! It
> will result in a larger capacitor than is needed but not a totally
> unreasonable value, particularly
> considering that we may be talking about 20 year old
> electrolytics from joe's electronic surplus shop.
> (disclaimer: I do not use old or used electrolytics in any
> project and neither will anyone else that has had a 10,000 uf
> 250v one blow up in their face as I have ;^) )
>
> Being so conservative I also go for 2.5x working voltage
> safety factor on my simple unregulated supplies.
> I just had the power company float my neutral and you can guess how
many
> fuses I blew on 120v stuff. I still have a scope to fix. No caps
popped
> though!
>
> The supply overvoltage condition during regeneration that Jon and I
mention
> Is something discussed by my amplifier maker
> and I follow their recommendations...except for buying
> their expensive shunt regenerative energy dissipators.
> I just derate supply voltage by 10 % for ac line conditions
> and a few more volts for 1/2C(v+vr)^2 and I know I am
> going to be good to go. Sound ok?
>
> In my case I decelerate 1000+ kg effective mass at up to
> .5g very worst case so it can be a whopping violent stop.
> Certainly detonation category rather than burning dynamite
> slowly in a fire. (disclaimer again: Don't do that!!!! ;^) )
> Normally it is much much less.
>
>
> In any event You are the servo amp maker and we are users.
> I plan on using your amps in later projects, perhaps for clients.
> God knows how you can sell them for such a low price.
> I defer to your knowledge on the subject and would like to
> hear more of your thoughts. I would like very much to see a detailed
> analysis if it is not too esoteric for the group charter.
> (guess it is)
>
> We love math!!
>
> Les
>
>
> Leslie Watts
> L M Watts Furniture
> Tiger, Georgia USA
> http://www.rabun.net/~leswatts/wattsfurniturewp.html
> engineering page:
> http://www.rabun.net/~leswatts/shop.html
>
> ----- Original Message -----
> From: "mariss92705" <mariss92705@y...>
> To: <CAD_CAM_EDM_DRO@y...>
> Sent: Wednesday, March 20, 2002 11:32 AM
> Subject: [CAD_CAM_EDM_DRO] Re: capacitor