Driver to drive?

[Hal Murray]

In article <iunpg5dhgph3qbetr1m2enmfvg2rnsumur@4ax.com>,
Geoff <geoff@invalid.invalid> writes:

On Tue, 24 Nov 2009 12:14:30 -0700, Jim Thompson
To-Email-Use-The-Envelope-Icon@My-Web-Site.com> wrote:

On Tue, 24 Nov 2009 13:07:36 -0600,
hal-usenet@ip-64-139-1-69.sjc.megapath.net (Hal Murray) wrote:

In article <4mnlg5d3uslb1j471rr9vohaaaolasvsbl@4ax.com>,
Jim Thompson <To-Email-Use-The-Envelope-Icon@My-Web-Site.com> writes:

I assume you'll agree that the Arctic is essentially neutral without
me having to pull out your finger nails ?

Is Greenland part of the Artic?


http://www.mnh.si.edu/arctic/html/resources_glossary.html

Arctic: The area lying above 66 ˝ degrees North latitude that includes
the Northern Lands and Arctic Ocean.

Looks like most of Greenland is above the Arctic circle:
http://www.geographicguide.net/america/greenland.htm


--
These are my opinions, not necessarily my employer's. I hate spam.

 

[Paul Keinanen]

On Wed, 25 Nov 2009 12:24:11 -0800, Rich Grise <richgrise@example.net>
wrote:

So, when the ice melts, the bedrock floats on the magma, which is pressed
down by the additional weight of the ocean, Greenland pops up, and sea
level stays the same. ;-)

In Greenland, the ice is up to 2 km above sea level and up to 1 km
below sea level, so a total of 3 km of ice in some places.

Even if the ice melted completely today, only the 2 km above sea level
will increase the ocean level. There will still be a 1 km deep lake in
the middle of Greenland, which does not initially affect the ocean
level. It will take more than 10000 years, before the bottom of the
lake will reach the sea level, emptying the lake water into the ocean.

Paul

 

[legg]

On Fri, 27 Nov 2009 12:35:26 -0800, D from BC
<myrealaddress@comic.com> wrote:

I'm using a fullpak TO220. (Plastic covered tab.)
It's case to sink capacitance is 12pF.
This capacitance is annoying in my smps design and has raised a few
questions..

1) Why do power mosfets have the drain connected to the tab?

Semiconductor fab limitations. Some are offered with an isolated tab,
but this is acheived at the cost of a physical isolation layer.

2) Can I get a mosfet with the source connected to the tab?

There are patented 'well' technologies that build the mosfet in an
isolated tub to ~ ground the substrate. Power Integrations use this in
their 'Top' switches. They are not sold as discrete devices.

3) What's a nice way to reduce case to sink capacitance yet have good
thermal conduction to an earth grounded heatsink? These 2 parameters
conflict.

You can increase the thickness of the isolator or try screening the
part from a quieter source-related node.

4) Maybe I can get less capacitance with metal tab + mica?

The distance criteria argues for aluminium or berylium oxide.

5) I've noticed that one of my junkbox switching supplies has a
heatsink on the power mosfet. The heatsink has no dc connection to
earth gnd (used ohm meter).
Is it typical in switching supplies for the power mosfet to be on an
electrically isolated heatsink?

If you don't have to ground it, it makes things simpler. It likely
does have a return, either directly or through a capacitor, to a
quieter source-related node in the circuit, for screening purposes.

RL

 

[Jamie]

D from BC wrote:

I'm using a fullpak TO220. (Plastic covered tab.)
It's case to sink capacitance is 12pF.
This capacitance is annoying in my smps design and has raised a few
questions..

1) Why do power mosfets have the drain connected to the tab?
2) Can I get a mosfet with the source connected to the tab?
3) What's a nice way to reduce case to sink capacitance yet have good
thermal conduction to an earth grounded heatsink? These 2 parameters
conflict.
4) Maybe I can get less capacitance with metal tab + mica?
5) I've noticed that one of my junkbox switching supplies has a
heatsink on the power mosfet. The heatsink has no dc connection to
earth gnd (used ohm meter).
Is it typical in switching supplies for the power mosfet to be on an
electrically isolated heatsink?

They make ceramic insulators. Used in R.F. for those type

of problems, alone with handling the heat of course!

An example here but not exactly what I was thinking of by may work.
http://www.futureelectronics.com/en/technologies/electromechanical/thermal-management/thermal-tapes/Pages/4383766-4171G.aspx?Language=en-CA
http://www1.futureelectronics.com/doc/AAVID%20THERMALLOY/4171G.pdf

 

[D from BC]

On Fri, 27 Nov 2009 17:04:12 -0500, Jamie
<jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote:

D from BC wrote:
I'm using a fullpak TO220. (Plastic covered tab.)
It's case to sink capacitance is 12pF.
This capacitance is annoying in my smps design and has raised a few
questions..

1) Why do power mosfets have the drain connected to the tab?
2) Can I get a mosfet with the source connected to the tab?
3) What's a nice way to reduce case to sink capacitance yet have good
thermal conduction to an earth grounded heatsink? These 2 parameters
conflict.
4) Maybe I can get less capacitance with metal tab + mica?
5) I've noticed that one of my junkbox switching supplies has a
heatsink on the power mosfet. The heatsink has no dc connection to
earth gnd (used ohm meter).
Is it typical in switching supplies for the power mosfet to be on an
electrically isolated heatsink?

They make ceramic insulators. Used in R.F. for those type
of problems, alone with handling the heat of course!

An example here but not exactly what I was thinking of by may work.
http://www.futureelectronics.com/en/technologies/electromechanical/thermal-management/thermal-tapes/Pages/4383766-4171G.aspx?Language=en-CA
http://www1.futureelectronics.com/doc/AAVID%20THERMALLOY/4171G.pdf

Thickness = 1.78mm

Assuming pure AL2O3 (sandpaper )

Al2O3 dielectric constant = 9.1
(air ~1,rubber~7)

A=TO220 area say 16mmx9.6mm
A~154mm^2

C=er*eo*A/d
C=9.1*8.854xE-12*((154mm^2/1.78mm)/1000)
C~7pF

If I switch from fullpack case to metal tab mosfet+ceramic insulator,
I'll get a case to heat sink capacitance of 7pF..
Or if I use the fullpak case, I'll get a case to heat sink capacitance
of C1C2/C1+C2 = 4.4pF
All's well if the mosfet temp is ok.

Interesting..

 

[ChrisQ]

Jon Kirwan wrote:

On Fri, 27 Nov 2009 14:15:47 -0700, Jim Thompson
To-Email-Use-The-Envelope-Icon@My-Web-Site.com> wrote:

I've got 2001 pick-em-up truck (Frontier) on which a door lock has
failed... can lock/unlock with the key, lock from the interior, but
not unlock.

I remember such a thing happening years ago on another vehicle... $4
part, $50 labor :-(

I can't figure out how you remove the interior door panel to get at
stuff :-(

Anyone with such experience?

Yes. But not on a Frontier. Try:

http://www.nissanhelp.com/diy/frontier/projects/2001_2004_nissan_frontier_door_panel_removal_procedure.htm

Jon

Most auto inner door panels i've seen are held in place with plastic pop
(barb/socket fasteners all round. They sometimes have one edge, say the
top edge, hooked under the metal in a narrow channel at the base of the
window.

The way to release them usually is to get fingers under the bottom edge
and tug sharply outwards to release one or two, then gently pull out the
others one by one. If the plastic is a bit old, the fastener barb end
sometimes breaks off, which is why you try to do one or two at a time
. Once you get that done (handles & arm rest off first, usually as
well), there is a polythene or some plastic sheet inside to seal the
water out and it needs to be peeled off before you can get at the door
frame internals, window winders etc...

Regards,

Chris

 

[John Larkin]

On Fri, 27 Nov 2009 16:17:26 -0500, legg <legg@nospam.magma.ca> wrote:

On Fri, 27 Nov 2009 12:35:26 -0800, D from BC
myrealaddress@comic.com> wrote:

I'm using a fullpak TO220. (Plastic covered tab.)
It's case to sink capacitance is 12pF.
This capacitance is annoying in my smps design and has raised a few
questions..

1) Why do power mosfets have the drain connected to the tab?

Semiconductor fab limitations. Some are offered with an isolated tab,
but this is acheived at the cost of a physical isolation layer.

2) Can I get a mosfet with the source connected to the tab?

There are patented 'well' technologies that build the mosfet in an
isolated tub to ~ ground the substrate. Power Integrations use this in
their 'Top' switches. They are not sold as discrete devices.

3) What's a nice way to reduce case to sink capacitance yet have good
thermal conduction to an earth grounded heatsink? These 2 parameters
conflict.

You can increase the thickness of the isolator or try screening the
part from a quieter source-related node.

4) Maybe I can get less capacitance with metal tab + mica?

The distance criteria argues for aluminium or berylium oxide.

The best ratio of thermal conductivity to dielectric constant
(ignoring diamond) is BeO. AlN is close.

5) I've noticed that one of my junkbox switching supplies has a
heatsink on the power mosfet. The heatsink has no dc connection to
earth gnd (used ohm meter).
Is it typical in switching supplies for the power mosfet to be on an
electrically isolated heatsink?

If you don't have to ground it, it makes things simpler. It likely
does have a return, either directly or through a capacitor, to a
quieter source-related node in the circuit, for screening purposes.

The best insulator is no insulator.

John

RL

 

[xray]

On Mon, 23 Nov 2009 18:31:36 -0700, Jim Thompson
<To-Email-Use-The-Envelope-Icon@My-Web-Site.com> wrote:

What an
annoying bastard.

...Jim Thompson

Reading the above all together is perfect. Indeed, YOU ARE an annoying
bastard.

Caught with no way to defend your deliberate biased scumbaggerism, after
several attempts to deflect, you now fall back to calling names.

You right-eous limp weenies are so predictable.

 

[David Lesher]

There's a long thread in m.t.r.a about the catenary network used on
Amtrak's NE Corridor and elsewhere. [See the ref's if you want to start
at the beginning..]

For historic [i.e. even older than Jim!] reasons, it's 11KV@25 Hz. over
much of the distance. Amtrak is awaiting money to make it all 25KV@60Hz,
and expects to do so about the time cold fusion power plants come on
line in Fedwick. Until then....

But someone points out it is really 50KV center-tapped. One leg is the
cat itself; the other a feeder in parallel. Periodically, a center-tapped
autotransformer mounted track-side goes feeder-rails-cat. Railroad folks
call this 2x25KV, I gather.

See a similar spec:
<http://indianrailways.gov.in/financecode/ACTraction-II-P-I/ACTractionIIPartICh11_data.htm>


The claimed advantages are:

a) less droop under load, no small matter when an Acela draws about 10 MW.

b) EMI cancellation since the feeder and parallel cat are out of phase.

c) You can tap up on the auto-formers further from a feed.

On a) I'm trying to model in my head why it is better than just
paralleling the feeder with the cat every few 100 meters. I can't see an
advantage.

b) I'm dubious on but will let go.

c) bothers me; if T{mile 0} is tapped at 25 0 25 [feeder rail cat], and T{mile2} is tapped so as to
provide more voltage there [25 0 26]; what happens at no load? I think the two transformers will
fight it out, heating the 2 miles of cat resistance and driving up the bill.

Insight welcome...


ps: Which Jim is the question...

 

[christofire]

"David Lesher" <wb8foz@panix.com> wrote in message
news:hfcsbi$2s5$1@reader1.panix.com...

There's a long thread in m.t.r.a about the catenary network used on
Amtrak's NE Corridor and elsewhere. [See the ref's if you want to start
at the beginning..]

For historic [i.e. even older than Jim!] reasons, it's 11KV@25 Hz. over
much of the distance. Amtrak is awaiting money to make it all 25KV@60Hz,
and expects to do so about the time cold fusion power plants come on
line in Fedwick. Until then....

But someone points out it is really 50KV center-tapped. One leg is the
cat itself; the other a feeder in parallel. Periodically, a center-tapped
autotransformer mounted track-side goes feeder-rails-cat. Railroad folks
call this 2x25KV, I gather.

See a similar spec:
http://indianrailways.gov.in/financecode/ACTraction-II-P-I/ACTractionIIPartICh11_data.htm


The claimed advantages are:

a) less droop under load, no small matter when an Acela draws about 10 MW.

b) EMI cancellation since the feeder and parallel cat are out of phase.

c) You can tap up on the auto-formers further from a feed.

On a) I'm trying to model in my head why it is better than just
paralleling the feeder with the cat every few 100 meters. I can't see an
advantage.

b) I'm dubious on but will let go.

c) bothers me; if T{mile 0} is tapped at 25 0 25 [feeder rail cat], and
T{mile2} is tapped so as to
provide more voltage there [25 0 26]; what happens at no load? I think the
two transformers will
fight it out, heating the 2 miles of cat resistance and driving up the
bill.

Insight welcome...


ps: Which Jim is the question...

Although it doesn't answer any of your questions directly, you might be
interested to read http://www.yorkemc.co.uk/research/railways/report.pdf
which discusses the EMC, or EMI as you put it in (b), aspects of overhead
electrification in some European systems. It explains that in the 'booster
transformer' system, the periodic lineside transformers act as common-mode
chokes which force the return current to flow in an elevated ancillary
conductor rather than the traction rails and the earth, and this reduces the
cross-sectional area of the current loop that can cause interference. See
Fig. 21. From the name of this system one might infer that the voltage at
the far end is increased by the action of the transformers, but this isn't
confirmed in this particular report.

Chris

 

[Paul Hovnanian P.E.]

Everyone stare at the spiral on the sky over Norway and chant, "AGW is
real. AGW is real...."

--
Paul Hovnanian mailtoaul@Hovnanian.com
------------------------------------------------------------------
I could get a new lease on life but I need the first and last month
in advance.

 

[Rich Grise]

Found on rec.crafts.metalworking, not crossposted because we all know what
happens when I do that!
----
On Thu, 10 Dec 2009 09:13:15 -0600, S. Caro wrote:

Cliff wrote:

http://www.google.com/hostednews/ap/article/ALeqM5j9MrjlmXzORMlHNvYfE9yAlgtiBwD9CGDL281
[
1,700 UK scientists back climate science (AP) - 3 hours ago

LONDON - Over 1,700 scientists in Britain have signed a statement
defending the evidence for human-made climate change in the wake of
hacked e-mails that emboldened climate skeptics. ....


Yea, but MY scientists are better than YOUR scientists.

--Over 31,000 U.S. scientists deny man-made global warming--

http://www.enterstageright.com/archive/articles/0508/0508gwpetition.htm
----

Cheers!
Rich

 

[Dirk Bruere at NeoPax]

Rich Grise wrote:

Found on rec.crafts.metalworking, not crossposted because we all know what
happens when I do that!
----
On Thu, 10 Dec 2009 09:13:15 -0600, S. Caro wrote:
Cliff wrote:

http://www.google.com/hostednews/ap/article/ALeqM5j9MrjlmXzORMlHNvYfE9yAlgtiBwD9CGDL281
[
1,700 UK scientists back climate science (AP) - 3 hours ago

LONDON - Over 1,700 scientists in Britain have signed a statement
defending the evidence for human-made climate change in the wake of
hacked e-mails that emboldened climate skeptics. ....

Yea, but MY scientists are better than YOUR scientists.

--Over 31,000 U.S. scientists deny man-made global warming--

http://www.enterstageright.com/archive/articles/0508/0508gwpetition.htm
----

Cheers!
Rich

And one anonymous scientist told a reporter that they felt they would
get no more work if they did not sign.

--
Dirk

http://www.transcendence.me.uk/ - Transcendence UK
http://www.theconsensus.org/ - A UK political party
http://www.blogtalkradio.com/onetribe - Occult Talk Show

 

[Jan Panteltje]

On a sunny day (Thu, 10 Dec 2009 14:52:21 -0700) it happened "Paul Hovnanian
P.E." <paul@hovnanian.com> wrote in <4B216D95.F54D538B@hovnanian.com>:

Everyone stare at the spiral on the sky over Norway and chant, "AGW is
real. AGW is real...."

--
Paul Hovnanian mailtoaul@Hovnanian.com
------------------------------------------------------------------
I could get a new lease on life but I need the first and last month
in advance.

It could be a new Russian weapon....
Black hole bomb.
?
Anonymous.

 

[Rich Grise]

On Thu, 10 Dec 2009 14:52:21 -0700, Paul Hovnanian P.E. wrote:

Everyone stare at the spiral on the sky over Norway and chant, "AGW is
real. AGW is real...."

It looked like a modified bat-signal to me. If you can find a pic of it,
look at the light beam coming up at about the 4:00 position. Somebody
took a searchlight and put a rotating mask over the front of it, and
projected it onto the clouds.

But they're blaming a failed Russin missile test. Would something like
that last that long?

Cheers!
Rich

 

[Jan Panteltje]

On a sunny day (Thu, 10 Dec 2009 14:55:53 -0800) it happened Rich Grise
<richgrise@example.net> wrote in <pan.2009.12.10.22.55.53.545184@example.net>:

On Thu, 10 Dec 2009 14:52:21 -0700, Paul Hovnanian P.E. wrote:

Everyone stare at the spiral on the sky over Norway and chant, "AGW is
real. AGW is real...."

It looked like a modified bat-signal to me. If you can find a pic of it,
look at the light beam coming up at about the 4:00 position. Somebody
took a searchlight and put a rotating mask over the front of it, and
projected it onto the clouds.

But they're blaming a failed Russin missile test. Would something like
that last that long?

Cheers!
Rich

It is a wormhole to an other universe were there is no global warming.

 

[Sylvia Else]

Rich Grise wrote:

Found on rec.crafts.metalworking, not crossposted because we all know what
happens when I do that!
----
On Thu, 10 Dec 2009 09:13:15 -0600, S. Caro wrote:
Cliff wrote:

http://www.google.com/hostednews/ap/article/ALeqM5j9MrjlmXzORMlHNvYfE9yAlgtiBwD9CGDL281
[
1,700 UK scientists back climate science (AP) - 3 hours ago

LONDON - Over 1,700 scientists in Britain have signed a statement
defending the evidence for human-made climate change in the wake of
hacked e-mails that emboldened climate skeptics. ....

Yea, but MY scientists are better than YOUR scientists.

--Over 31,000 U.S. scientists deny man-made global warming--

http://www.enterstageright.com/archive/articles/0508/0508gwpetition.htm
----

Cheers!
Rich

Is this a matter that's decided by a majority vote?

Sylvia.

 

[Bill Sloman]

On Dec 10, 11:36 pm, Rich Grise <richgr...@example.net> wrote:

Found on rec.crafts.metalworking, not crossposted because we all know what
happens when I do that!
----



On Thu, 10 Dec 2009 09:13:15 -0600, S. Caro wrote:
Cliff wrote:

http://www.google.com/hostednews/ap/article/ALeqM5j9MrjlmXzORMlHNvYfE....
[
1,700 UK scientists back climate science (AP) - 3 hours ago

LONDON - Over 1,700 scientists in Britain have signed a statement
defending the evidence for human-made climate change in the wake of
hacked e-mails that emboldened climate skeptics. ....

Yea, but MY scientists are better than YOUR scientists.

--Over 31,000 U.S. scientists deny man-made global warming--

http://www.enterstageright.com/archive/articles/0508/0508gwpetition.htm

They aren't actually. Less than 1% of your scientists had any
involvement in climatology. And most of them got sucked in by
Frederick Seitz in his capacity as a past president of the National
Academy of Science who was then a paid lackey of the denialist
propaganda machine.

Rich would like him - he was also active in the denial of the dangers
of smoking.

http://www.sourcewatch.org/index.php?title=Frederick_Seitz

--
Bill Sloman, Nijmegen

 

[Sylvia Else]

Bill Sloman wrote:

On Dec 11, 12:46 am, Sylvia Else <syl...@not.at.this.address> wrote:
Rich Grise wrote:
Found on rec.crafts.metalworking, not crossposted because we all know what
happens when I do that!
----
On Thu, 10 Dec 2009 09:13:15 -0600, S. Caro wrote:
Cliff wrote:
http://www.google.com/hostednews/ap/article/ALeqM5j9MrjlmXzORMlHNvYfE...
[
1,700 UK scientists back climate science (AP) - 3 hours ago
LONDON - Over 1,700 scientists in Britain have signed a statement
defending the evidence for human-made climate change in the wake of
hacked e-mails that emboldened climate skeptics. ....
Yea, but MY scientists are better than YOUR scientists.
--Over 31,000 U.S. scientists deny man-made global warming--
http://www.enterstageright.com/archive/articles/0508/0508gwpetition.htm
----
Cheers!
Rich
Is this a matter that's decided by a majority vote?

Sort of. The mindless majority will keep on burning fossil carbon and
the the earth will count the CO2 molecules and warm up appropriately.
Your grand-children will be able to read the outcome from their
thermometers, if their civilisation still retains the capacity to
build thermometers.

The question I was raising is whether the truth of anthropogenic global
warming (about which I'm expressing no view here) is to be determined by
a vote. That is not how scientific questions are usually decided.

Sylvia.

 

[Jan Panteltje]

On a sunny day (Fri, 11 Dec 2009 10:46:38 +1100) it happened Sylvia Else
<sylvia@not.at.this.address> wrote in
<009a168f$0$1478$c3e8da3@news.astraweb.com>:

Rich Grise wrote:
Found on rec.crafts.metalworking, not crossposted because we all know what
happens when I do that!
----
On Thu, 10 Dec 2009 09:13:15 -0600, S. Caro wrote:
Cliff wrote:

http://www.google.com/hostednews/ap/article/ALeqM5j9MrjlmXzORMlHNvYfE9yAlgtiBwD9CGDL281
[
1,700 UK scientists back climate science (AP) - 3 hours ago

LONDON - Over 1,700 scientists in Britain have signed a statement
defending the evidence for human-made climate change in the wake of
hacked e-mails that emboldened climate skeptics. ....

Yea, but MY scientists are better than YOUR scientists.

--Over 31,000 U.S. scientists deny man-made global warming--

http://www.enterstageright.com/archive/articles/0508/0508gwpetition.htm
----

Cheers!
Rich


Is this a matter that's decided by a majority vote?

Sylvia.

Yes, science works that way, you vote for the politicians,
they decide an agenda, and assign scientists to support that agenda.
And the agenda is set by what the Captains of Industry need at that moment,
usually more money.
Purely democratic, as you decide what products you buy from the captains of industry.
wait, lemme read this again, hey...
??
Oh well, it is 1 o'clock at night
Sorry.