Alt-BEAM Archive
Message #07183
To: "'beam@sgiblab.sgi.com'" beam@sgiblab.sgi.com
From: Wilf Rigter Wilf.Rigter@powertech.bc.ca
Date: Sat, 30 Oct 1999 13:19:20 -0700
Subject: [alt-beam] Re: Time Capsules
Overdriving a the winding of a PM (or stepper) motor can demagnetize the
permanent magnets which could easily happen in the heat of a competition.
Afaik rare earth magnets in high quality PM motors are very stable and not
likely to demagnetize on their own when left on the shelf. After all there
are magnetic fields in native magnetite and other minerals that are a frozen
remnant of the earth's magnetic field of hundreds of millions of years ago
and can still be "read" in the geological record.
Wilf Rigter mailto:wilf.rigter@powertech.bc.ca
tel: (604)590-7493
fax: (604)590-3411
> -----Original Message-----
> From: Timothy Flytcher [SMTP:flytch@hotmail.com]
> Sent: Saturday, October 30, 1999 11:26 AM
> To: beam@sgiblab.sgi.com
> Subject: Re: [alt-beam] Re: Time Capsules
>
> >I have a 20 year old small electric DC motor and it still works
>
> > > what about the magnets in the motors??? would the motors still run
> after
> >...
> > > say 30 years???
>
> yes I too have some that old... but how efficient are they? I also have
> some
> that completely died after just a year or so (new still in package) I know
>
> my r/c friends magnetize there competition motors on a regular bases... I
> have seen gains of 10%-30% by dissembly of the motor and remagnetizing the
>
> magnets and demagnetizing the armature.
>
> Timothy...
>
> ______________________________________________________
>
7184 Sat, 30 Oct 1999 13:24:55 -0700 [alt-beam] Re: Micro Motors, Skitters, and BeetleBots beam@sgiblab.sgi.com Greg Powell what is the most efficient of solar engines?
Greg
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