Alt-BEAM Archive
Message #07234
To: beam@sgiblab.sgi.com
From: JVernonM@aol.com [mailto:JVernonM@aol.com]
Date: Mon, 1 Nov 1999 09:12:36 +0100
Subject: Re: aquabot
In a message dated 10/30/99 6:57:46 AM Eastern Daylight Time,
gpowell@engr.uvic.ca writes:
Hi Greg,
Aquabots aye? You know I love 'em.
> I recently came upon a page with a vertically diving bot. I really liked
the
> idea. The person proposed to put it in a long glass tube filled with
water
> in his living room as a piece of work to admire. I liked that idea too
:).
That would be Bram. That was the first working Aquabot that I ever saw as
well.
> propose to build one and I propose to build one in an inverted test tube.
> The solar panel (perhaps some of the very small 0.5 volt, 3mA cells in
> series) will be in the top where it will charge under a lamp or sunshine
at
> the surface of the water level. The cap will be below it with a solar
> engine, probably a 1381 type and the pager motor will have a shaft
extending
> out the bottom test tube plug with a propeller. I intend to use metal
> washers of equal diameter to the test tube to achieve just above neutral
> bouancy. I want to make it in as small a test tube possible so that I can
> put it in a large graduated cylinder on my desk as an active ornament.
OK, here's some things to keep in mind. Make the beast slightly more buoyant
than you think you need. I have found that over time the Aquabots become
slightly heavier when constantly submerged in water. This is not water
encroachment into the bot or motor.
[Snip some very good explainations]
Just for the record.
Materials like nylon will absorbe water like a sponge in time. Nylon is used
in propellershaft liners of ships because of this behavior. The nylon will
soak up water and will grow in size a little. Providing a bit of lubricant
and coolling.
Bram
7235 Mon, 01 Nov 1999 00:25:09 PST [alt-beam] magnets beam@sgiblab.sgi.com "Timothy Flytcher" Jim, I was being sarcastic... I never said any thing about heat. I don't
think heat really has much to do with it. I think that it is the surrounding
environment. Any magnet once magnetized will hold a field as long as it is
insolated but once it is in close contact with other ferrous objects and/or
magnetic fields it will transfer some of its field... thous loosing some
strength... In a motor that would be the armature... stationary or not.
if stationary then the initial burst of energy must overcome a magnetized
armature.. I think of it like an out of balance wheel being rolled down a
slight hill. The more amps the steeper the hill...
Timothy...
>I "smoked" my astro 25 a month or 2 ago.
Bummer! sorry to hear about your loss :(
>bigger problems then the magnets :)
> > >A magnet does not loose any strenght from age.
> >
> > Ok Bob... do you know at what temperature they start to degrade???
______________________________________________________
7236 Mon, 1 Nov 1999 09:20:51 +0100 Re: aquabot beam@sgiblab.sgi.com Greg Powell [mailto:gpowell@engr.uvic.ca]
What if I put distilled water in the graduated cylinder and a thin layer of
oil on the top. Thus no bacteria and no evaporation or contamination, yet
light still gets in.
Greg
7237 Mon, 1 Nov 1999 09:40:32 +0100 Re: aquabot beam@sgiblab.sgi.com Ripter01@aol.com [mailto:Ripter01@aol.com]
In a message dated 10/31/99 4:50:55 AM US Eastern Standard Time,
flytch@hotmail.com writes:
> but I know that a lava lamps fluid is flammable (don't ask) it's just
> sealed...
The fluid in lava lamps is just water, the blobs are just wax, the lamp just
heats the wax and then the wax cools and so on. Sorry that this is off the
subject.
Ta-Ta
7238 Mon, 01 Nov 1999 08:33:26 -0500 [alt-beam] Re: magnets beam@sgiblab.sgi.com Bob Shannon Timothy Flytcher wrote:
> Jim, I was being sarcastic... I never said any thing about heat. I don't
> think heat really has much to do with it. I think that it is the surrounding
> environment. Any magnet once magnetized will hold a field as long as it is
> insolated but once it is in close contact with other ferrous objects and/or
> magnetic fields it will transfer some of its field... thous loosing some
> strength... In a motor that would be the armature... stationary or not.
> if stationary then the initial burst of energy must overcome a magnetized
> armature.. I think of it like an out of balance wheel being rolled down a
> slight hill. The more amps the steeper the hill...
> Timothy...
Sorry, this is wrong.
Most powerful magets come with 'keepers' that close the path of magnetic
flux, to protect the magnet when stored.
A magnet stuck to the front of your refrigerator does not loose any strenght
in the process of sticking there, for months or years.
PM motors will loose efficiency if the armature becomes magnetized, which
happens much quicker if the motor overheats, and then cools again (this is how
many mangets are made in the first place).
Home