From: David C Brown <dcb.home@gmail.com>
To: Microcontroller discussion list - Public. <piclist@mit.edu>
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Date: Sun, 19 Jan 2020 09:33:29 -0800
Subject: Re: [EE] Magnetic lock
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They are DC
__________________________________________
David C Brown
43 Bings Road
Whaley Bridge
High Peak                           Phone: 01663 733236
Derbyshire                eMail: dcb.home@gmail.com
SK23 7ND          web: www.bings-knowle.co.uk/dcb
<http://www.jb.man.ac.uk/~dcb>



*Sent from my etch-a-sketch*


On Sun, 19 Jan 2020 at 16:25, Sean Breheny <shb7@cornell.edu> wrote:

> If the electromagnet uses AC then it will indeed draw less current when i=
t
> is closed against the piece of metal it attracts. This is because there i=
s
> no longer an air gap in the magnetic circuit so the inductance is higher.
>
> On Sat, Jan 18, 2020, 8:43 PM mike brown <mike@n5qmg.com wrote:
>
> > In my experience, the electromagnet appears to draw less current when
> > latched to the metal plate.  This is an unscientific observation based
> upon
> > the temperature of the magnet increasing when not latched to the steel
> > plate.  Amazing that they can generate such a strong holding force usin=
g
> > three watts of power as long as the two parts perfectly mate to each
> other.
> >
> > On Sat, Jan 18, 2020, 19:07 Bob Blick <bobblick@outlook.com> wrote:
> >
> > > Admin message to Allen, since his email address seems to reject direc=
t
> > > email.
> > >
> > > Hi Allen,
> > > Please, when you reply to a piclist post, insure that the subject lin=
e
> > > topic tag is not preceded by your own email system's bracketing syste=
m,
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> > > interferes with our archiving system, and also with users that rely o=
n
> > the
> > > topic tag to sort their piclist emails.
> > > Thanks.
> > > Bob
> > >
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