Electronical ( actually, electromagnetical) Question :-)

[Rich Grise]

Yeah, I know there's no such word - I made them up, trying to
be clever. Ha, ha.

Anyway, I'm about to embark on a STFW for a pie-wound solenoid,
with taps and probably pole pieces. Yeah, I got LEM on the mind.

Application: Desk Drawer opener/closer/damper.

Motivation: Everything I need in my desk drawer always slides
to the back. I figure it's because of that whump when the drawer
seats closed. Even when I really try not to slam it! So I closed
it really, really slowly, and it's got a tit at the end that
the roller rolls over to thump it closed. Well, I could lose
that easily enough - I live in a machine shop. (actually, I live
in the Winnebago in the machine shop's parking lot, but you get
the idea. So, I'm thinking dashpot to damp the damn thing, and
realize that rather than trying to dick around with dashpot
settings, (i.e. adjusting the set screw for bleed rate), I could
control some kind of force thing, that can exert a specified
amount of force to result in a well-defined deceleration rate,
such that s, v, and a all reach 0 simultaneously.

Cool, huh?

And, to me, anyway, the obvious choice is some form of LIM.
I could even have it control the opening part. I could find
or clooge some kind of accelerometer, to find out what to
limit the, lessee, is there a single word for "rate of onset
of acceleration?" Maybe that's not that important - or I
guess it'd be hard to achieve anything other than n/0.

So, any recommendations before I commit?

btw, I just now sketched up what first sprang to mind for the
LIM core:
http://home.earthlink.net/~entheos_engineering/images/Solenoid.gif

Thanks!
Rich

 

[John Larkin]

Yeah, I know there's no such word - I made them up, trying to
be clever. Ha, ha.

Anyway, I'm about to embark on a STFW for a pie-wound solenoid,
with taps and probably pole pieces. Yeah, I got LEM on the mind.

Application: Desk Drawer opener/closer/damper.

Motivation: Everything I need in my desk drawer always slides
to the back. I figure it's because of that whump when the drawer
seats closed. Even when I really try not to slam it! So I closed
it really, really slowly, and it's got a tit at the end that
the roller rolls over to thump it closed. Well, I could lose
that easily enough - I live in a machine shop. (actually, I live
in the Winnebago in the machine shop's parking lot, but you get
the idea. So, I'm thinking dashpot to damp the damn thing, and
realize that rather than trying to dick around with dashpot
settings, (i.e. adjusting the set screw for bleed rate), I could
control some kind of force thing, that can exert a specified
amount of force to result in a well-defined deceleration rate,
such that s, v, and a all reach 0 simultaneously.

Cool, huh?

And, to me, anyway, the obvious choice is some form of LIM.
I could even have it control the opening part. I could find
or clooge some kind of accelerometer, to find out what to
limit the, lessee, is there a single word for "rate of onset
of acceleration?" Maybe that's not that important - or I
guess it'd be hard to achieve anything other than n/0.

So, any recommendations before I commit?

btw, I just now sketched up what first sprang to mind for the
LIM core:
http://home.earthlink.net/~entheos_engineering/images/Solenoid.gif

Thanks!
Rich

If you had enough supermagnets and maybe a hunk of copper pipe or
something, you could make a passive eddy-current damper, but it would
soak up all the paper clips in the drawer.

John

 

[Tim Wescott]

If you had enough supermagnets and maybe a hunk of copper pipe or
something, you could make a passive eddy-current damper, but it would
soak up all the paper clips in the drawer.

John

I was going to suggest that, but I hadn't thought of the paper clip problem.

Even so, changing to all brass and plastic paper clips may be less
expensive than making an active system.

Perhaps you could make a really big CD door opener? Just think, though
"I'm sorry Mr. Auditor, I can't get into my desk drawers because it's
not plugged in..."

 

[Tim Wescott]

Yeah, I know there's no such word - I made them up, trying to
be clever. Ha, ha.

Anyway, I'm about to embark on a STFW for a pie-wound solenoid,
with taps and probably pole pieces. Yeah, I got LEM on the mind.

Application: Desk Drawer opener/closer/damper.

Motivation: Everything I need in my desk drawer always slides
to the back. I figure it's because of that whump when the drawer
seats closed. Even when I really try not to slam it! So I closed
it really, really slowly, and it's got a tit at the end that
the roller rolls over to thump it closed. Well, I could lose
that easily enough - I live in a machine shop. (actually, I live
in the Winnebago in the machine shop's parking lot, but you get
the idea. So, I'm thinking dashpot to damp the damn thing, and
realize that rather than trying to dick around with dashpot
settings, (i.e. adjusting the set screw for bleed rate), I could
control some kind of force thing, that can exert a specified
amount of force to result in a well-defined deceleration rate,
such that s, v, and a all reach 0 simultaneously.

Cool, huh?

And, to me, anyway, the obvious choice is some form of LIM.
I could even have it control the opening part. I could find
or clooge some kind of accelerometer, to find out what to
limit the, lessee, is there a single word for "rate of onset
of acceleration?" Maybe that's not that important - or I
guess it'd be hard to achieve anything other than n/0.

So, any recommendations before I commit?

btw, I just now sketched up what first sprang to mind for the
LIM core:
http://home.earthlink.net/~entheos_engineering/images/Solenoid.gif

Thanks!
Rich

The rate of change if acceleration is called "jerk", probably because
when you're a passenger in a stick shift car and the driver drops the
clutch you say "wow, what a jerk!".

 

[John Larkin]

I was going to suggest that, but I hadn't thought of the paper clip problem.

Even so, changing to all brass and plastic paper clips may be less
expensive than making an active system.

Perhaps you could make a really big CD door opener? Just think, though
"I'm sorry Mr. Auditor, I can't get into my desk drawers because it's
not plugged in..."

Hey, how about buying one of those little plastic drawer organizers,
or maybe machining one from a solid block of Delrin?

John

 

[Active8]

Hey, how about buying one of those little plastic drawer organizers,
or maybe machining one from a solid block of Delrin?

John

Is Delrin that white plastic that they use on CNC vacuum tables to
line up the work piece?

 

[mook johnson]

Home depot has some dampers used for cabinet doors on higher end homes. Its
like little shock absorbers that catch the door right before it closes and
gently eases it closed.

This might be a first order solution..

 

[Paul Burke]

Yeah, I know there's no such word - I made them up, trying to
be clever. Ha, ha.

I used to have much discussion with the kids over words like these. Why
do some words end -ical (e.g. grammatical), while others end -ic
(magnetic?)? It was important, because we were always looking for new
characters for the Tickles - Nuclear Pa Tickle, Martha Ma Tickle, Anna
Lyt Tickle, Thea Rhett Tickle, etc. etc.- so that I could be dragooned
into making up stories about them.

Paul Burke

 

[Roy McCammon]

Yeah, I know there's no such word - I made them up, trying to
be clever. Ha, ha.

Anyway, I'm about to embark on a STFW for a pie-wound solenoid,
with taps and probably pole pieces. Yeah, I got LEM on the mind.

Application: Desk Drawer opener/closer/damper.

Motivation: Everything I need in my desk drawer always slides
to the back.

Raise the back of the desk to that it tilts forward.

 

[Paul Hovnanian P.E.]

[snip]

If you had enough supermagnets and maybe a hunk of copper pipe or
something, you could make a passive eddy-current damper, but it would
soak up all the paper clips in the drawer.

Any floppy disks with important data in the drawer?

 

[Rich Grise]

[snip]

If you had enough supermagnets and maybe a hunk of copper pipe or
something, you could make a passive eddy-current damper, but it would
soak up all the paper clips in the drawer.

Any floppy disks with important data in the drawer?

I was kinda idly wondering - would lining the drawer with mu metal
help?

Thanks,
Rich

 

[Paul Hovnanian P.E.]

[snip]

If you had enough supermagnets and maybe a hunk of copper pipe or
something, you could make a passive eddy-current damper, but it would
soak up all the paper clips in the drawer.

Any floppy disks with important data in the drawer?

I was kinda idly wondering - would lining the drawer with mu metal
help?

With enough shielding and other hardware attached, that drawer is going
to become too heavy to open by hand. Why not just attach a suitable
drive system and ramp the speed up/down smoothly with a control loop?

 

[Rich Grise]

John Larkin wrote:

[snip]

If you had enough supermagnets and maybe a hunk of copper pipe or
something, you could make a passive eddy-current damper, but it would
soak up all the paper clips in the drawer.

Any floppy disks with important data in the drawer?

I was kinda idly wondering - would lining the drawer with mu metal
help?

With enough shielding and other hardware attached, that drawer is going
to become too heavy to open by hand. Why not just attach a suitable
drive system and ramp the speed up/down smoothly with a control loop?

I do have an accumulation of motors in my growing junk box - I even
have a "matched pair" of one of each from two retired Epson dot-matrix
printers. And when I retired my 6x86, I also retired the LS-120 drive,
which should have some nifty motors - the eject mech isn't as cool as
a CD, but the price is right!

Thanks everybody!
Rich

 

[Dave Cole]

Yeah, I know there's no such word - I made them up, trying to
be clever. Ha, ha.

Anyway, I'm about to embark on a STFW for a pie-wound solenoid,
with taps and probably pole pieces. Yeah, I got LEM on the mind.

Application: Desk Drawer opener/closer/damper.

Motivation: Everything I need in my desk drawer always slides
to the back. I figure it's because of that whump when the drawer
seats closed. Even when I really try not to slam it! So I closed
it really, really slowly, and it's got a tit at the end that
the roller rolls over to thump it closed. Well, I could lose
that easily enough - I live in a machine shop. (actually, I live
in the Winnebago in the machine shop's parking lot, but you get
the idea. So, I'm thinking dashpot to damp the damn thing, and
realize that rather than trying to dick around with dashpot
settings, (i.e. adjusting the set screw for bleed rate), I could
control some kind of force thing, that can exert a specified
amount of force to result in a well-defined deceleration rate,
such that s, v, and a all reach 0 simultaneously.

Cool, huh?

And, to me, anyway, the obvious choice is some form of LIM.
I could even have it control the opening part. I could find
or clooge some kind of accelerometer, to find out what to
limit the, lessee, is there a single word for "rate of onset
of acceleration?"

I was told they call the derivative of acceleration "Jerk"
HTH
DC

 

[Terry Given]

I was told they call the derivative of acceleration "Jerk"
HTH
DC

indeed it is. and I wonder, every time I go to the supermarket, why jerk
control is not in common usage (IIRC smooth motion requires continuous 2nd
derivative of velocity)

cheers
Terry