Alt-BEAM Archive

Message #09026



To: beam@sgiblab.sgi.com
From: Dave Hrynkiw dave@solarbotics.com
Date: Tue, 11 Jan 2000 00:47:40 -0700
Subject: [alt-beam] Re: parts source


At 08:25 PM 1/10/00 , Bumper314@aol.com wrote:
>In a message dated 1/10/00 7:25:51 PM Mountain Standard Time,
>dave@solarbotics.com writes:
>
> > Flat sides mean that they went cheap on the magnets. They won't have as
> > good performance as fully cylindrical motors (assuming same magnets). As
> > for soldering on flats vs. cylinders, I'd take better performance anyday
> > for the extra effort.
>
>Well I'm sure you have seen the inside of one of those namiki's...now thats a
>small magnet. Although i doubt the proformance can be argued here.

Argued how? We've played with these truncated-type motors before, and
destroyed a few just soldering to them. The adhesive they used to mount the
magnets loosened under the heat and they jammed hard against the armature.

I didn't actually remove the magnets and do side-by-side comparisons, but I
have removed the namiki magnets - they're as strong as any other
neodymium-style magnet I've ever seen (and I've seen a few).

Regards,
Dave
---------------------------------------------------------------
"Um, no - that's H,R,Y,N,K,I,W. No, not K,I,U,U, K,I,_W_. Yes,
that's right. Yes, I know it looks like "HOCKYRINK." Yup, only
2 vowels. Pronounciation? _SMITH_".
http://www.solarbotics.com



9027 Tue, 11 Jan 2000 01:24:23 -0700 [alt-beam] Re: parts source beam@sgiblab.sgi.com Dave Hrynkiw At 09:39 PM 1/10/00 , Bob Shannon wrote:
>Sorry Dave,
>
>I have to strongly disagree. Many motors have much higher efficiencies than
>pager motors, but also have flat sides. Motors such as the Mabucci FF-K10WA
>for example.

Gotta compare apples to apples. A coreless DC motor like a Namiki pager
will outperform a cored "flat-sided" motor, given similar dimensions.

But I'm not familiar with the FF-K10WA, but from what you said a while back
on the list (giving the URL:
http://www.mabuchi-motor.co.jp/mot/motor1/ff-k10wa.html), these are NOT
pager motors.

And from the stats on the FF-K10WA, it peaks at 25% efficiency. The
Namiki's peak at 38% efficiency.

>Flat motors simply cannot have the same magnets as cylindrical motors, so the
>argument you make is flawed. A better brush can more than compenstate for a
>using different magnets.

Yes, better brushes can help, but like I said, I was trying to compare
apples to apples.

Regards,
Dave
---------------------------------------------------------------
"Um, no - that's H,R,Y,N,K,I,W. No, not K,I,U,U, K,I,_W_. Yes,
that's right. Yes, I know it looks like "HOCKYRINK." Yup, only
2 vowels. Pronounciation? _SMITH_".
http://www.solarbotics.com



9028 Sat, 8 Jan 2000 19:02:52 +0800 Re: Just Another Newbie Mike Kulesza
> the only other thing
> >is to scavenge motors from busted pagers (juest ring up your local pager
> >company and ask politely).
>
>
> Last time i called up a few pager repair shops they didnt know what i was
> talking about when i said "pager motors." I went through the prcess of
> explaining to them that they are the little thingies that make your pager
> vibrate - theyre still clueless!!!
> ______________________________________________________
>


9029 Tue, 11 Jan 2000 12:09:29 +0100 [alt-beam] 16DOF BIPEDS (!) "Thomas Pilgaard" In reply to Kyle's request on the MIT bipeds here's the link

http://www.ai.mit.edu/projects/leglab/robots/robots.html

Especially, have a look at Troody - a 16DOF selfcontained Sinornithoides
dinosaur. Currently when turned on it is capable of getting on its feet a=
nd
keep it's balance. There's even a quicktime of it. It is so sweet!

Enjoy

Thomas




> -----Oprindelig meddelelse-----
> Fra: owner-beam@sgiblab.sgi.com [mailto:owner-beam@sgiblab.sgi.com]P=E5
> vegne af Senior
> Sendt: 10. januar 2000 16:20
> Til: beam@sgiblab.sgi.com
> Emne: Re: SV: BIPEDS Was: Pressure Sensors
>
>
> Yes, those guys are great. There's three of them I think. A combination
> of those and Honda's P3 would be the 'perfect' walker in my opinion.
> Yes, please do post the URL.
> Kyle
>
> Thomas Pilgaard wrote:
> > However, have you guys seen that MIT robot that keeps it balance
> > dynamically? It has two straight legs, no kneejoints, no feet
> or whatever.
> > It walks in a pogo-stick style manner which means it gives a
> jump each time
> > one stick touches the ground. It is not capable of standing
> still since it
> > lacks an area on which to stand. It can - however - somersault and st=
ill
> > keep it's balance afterwards. If you need an URL I'll see if I
> can find it
> > again.
> >
> > Cheers
> >
> > Thomas
>

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