Alt-BEAM Archive

Message #09594



To: beam@sgiblab.sgi.com
From: "Sathe Dilip" sathe_dilip@bah.com
Date: Fri, 28 Jan 2000 10:18:12 -0500
Subject: [alt-beam] Re: Incredible gear motors


I guess for a reading of torque at stall, this should be accurate
enough. If you want to measure the torque at a given speed, then that
will probably involve a pulley with a thread & some weights. Adjust the
weights till you get the required speed (at rated voltage). Then
knowing the pulley diameter, you should be able to calculate the torque.

I remember doing an experiment in college. IIRC you use a flat pulley
on the motor shaft & a friction belt that is anchored at one end to a
spring scale & loaded with some weights at the other. Then you run the
motor, adjust the weights till you get to the right speed. Then knowing
the reading on the spring scale, the weights, the pulley diameter, & the
coefficient of friction between the belt & the pulley you did the some
calculations to arrive at the torque. The last item (the COF) being
somewhat imperical, I am not sure if this method will work with our
small BEAM motors/gearmotors.

(PS: I tried to remember as to when I did the above expt. & realized it
was about 28 years back. MAy be there are simpler/better methods
available now. Man! I AM getting old :-)

Dilip
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Timothy Flytcher wrote:
>
> Ok I have a theoretical question for anybody/everybody... say I have a motor
> in my hand... how could/would I determine torque??? the only thing that
> comes to mind is a spring scale and a leaver arm... is this truly
> accurate??? is there a better way???
> Timothy...
> >I don't have a handy way to measure the torque. At 2.5v it is pretty easy
> >to stop the motor by hand, but at 5v it takes a fairly tight grip. Yes, I
> >know, not exactly rocket science.
>
> >>Just out of curiousity, what is the torque of these
> >>motors?
>
> ______________________________________________________
>


9595 Fri, 28 Jan 2000 10:54:55 -0500 [alt-beam] Re: Maximum electromagnetic kick beam@sgiblab.sgi.com "Sathe Dilip"

Justin wrote:
>

> Second question:
> Where do you get extremely powerful, incredibly light super magnets? :-)
> The strongest ones I've come across (I haven't looked very hard) are
> from cdrom drives (the EM fine-tuned reading lens for example) but these
> are strange shapes, and a source for nice wide flat/thin light STRONG
> magnets would be great. Cheap would also be nice :-)

Try the following page (You may also find the other stuff on this site
interesting)

http://www.scitoys.com/cgi-bin/shop.cgi/page=store.html/SID=2930911516

Dilip
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When everything's coming your way, you're in the wrong lane.
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9596 Fri, 28 Jan 00 09:55:45 +0600 [alt-beam] Re: Beam And IR light "beam@sgiblab.sgi.com" "Dan Larson" On Fri, 28 Jan 2000 09:55:37 -0500, Sathe Dilip wrote:

>
>A photo diode won't work for body heat. You need a Pyroelectric sensor
>for that & they are not cheap - unless you salvage one from one of those
>lamps/gadgets that use them.
>

Electronics Goldmine has one for $4.99 that can be hacked. They
even give you instructions on how to hack it. It runs off 9V and
includes an RF transmitter module.

I'll be ordering a few for my non-BEAM robots...

Dan




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