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various OTs

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  various OTs John Larkin <jjlarkin@highland_snip_technology.com> - 2018-10-12 12:50 -0700
    Re: various OTs George Herold <gherold@teachspin.com> - 2018-10-12 13:04 -0700
      Re: various OTs John Larkin <jjlarkin@highland_snip_technology.com> - 2018-10-12 13:48 -0700
        Re: various OTs George Herold <gherold@teachspin.com> - 2018-10-12 17:46 -0700
    Re: various OTs dplatt@coop.radagast.org (Dave Platt) - 2018-10-12 14:53 -0700
      Re: various OTs John Larkin <jjlarkin@highland_snip_technology.com> - 2018-10-12 15:30 -0700
        Re: various OTs Martin Brown <'''newspam'''@nezumi.demon.co.uk> - 2018-10-13 10:13 +0100
          Re: various OTs John Larkin <jjlarkin@highlandtechnology.com> - 2018-10-13 09:33 -0700
            Re: various OTs Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2018-10-13 14:15 -0400
            Re: various OTs Martin Brown <'''newspam'''@nezumi.demon.co.uk> - 2018-10-15 10:09 +0100
              Re: various OTs John Larkin <jjlarkin@highlandtechnology.com> - 2018-10-15 06:50 -0700
      Re: various OTs Clive Arthur <cliveta@nowaytoday.co.uk> - 2018-10-13 10:37 +0100
        Re: various OTs DecadentLinuxUserNumeroUno@decadence.org - 2018-10-13 10:01 +0000
          Re: various OTs John Larkin <jjlarkin@highland_snip_technology.com> - 2018-10-13 11:08 -0700
        Re: various OTs John Larkin <jjlarkin@highlandtechnology.com> - 2018-10-13 09:55 -0700
        Re: various OTs MikeP <mjp993@googlemail.com> - 2018-10-16 03:22 +0000
      Re: various OTs Robert Baer <robertbaer@localnet.com> - 2018-10-13 22:39 -0700
        Re: various OTs Sjouke Burry <burrynulnulfour@ppllaanneett.nnll> - 2018-10-14 21:43 +0200
          Re: various OTs Robert Baer <robertbaer@localnet.com> - 2018-10-15 19:46 -0700
    Re: various OTs DecadentLinuxUserNumeroUno@decadence.org - 2018-10-12 23:55 +0000
      Re: various OTs Lasse Langwadt Christensen <langwadt@fonz.dk> - 2018-10-12 16:58 -0700
      Re: various OTs bill.sloman@ieee.org - 2018-10-12 17:52 -0700
      Re: various OTs speff <spehro@gmail.com> - 2018-10-18 06:53 -0700
        Re: various OTs John Larkin <jjlarkin@highlandtechnology.com> - 2018-10-18 06:59 -0700
          Re: various OTs tabbypurr@gmail.com - 2018-10-18 14:10 -0700
            Re: various OTs "Tim Williams" <tiwill@seventransistorlabs.com> - 2018-10-18 17:49 -0500
          Re: various OTs Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2018-10-18 21:04 -0400
            Re: various OTs Steve Wilson <no@spam.com> - 2018-10-19 01:34 +0000
              Re: various OTs <698839253X6D445TD@nospam.org> - 2018-10-19 07:11 +0000
    Re: various OTs "Tim Williams" <tiwill@seventransistorlabs.com> - 2018-10-12 19:10 -0500
      Re: various OTs Lasse Langwadt Christensen <langwadt@fonz.dk> - 2018-10-13 06:22 -0700
        Re: various OTs Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2018-10-13 14:16 -0400
          Re: various OTs John Larkin <jjlarkin@highlandtechnology.com> - 2018-10-13 17:19 -0700
      Re: various OTs whit3rd <whit3rd@gmail.com> - 2018-10-13 12:24 -0700
        Re: various OTs Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2018-10-13 17:30 -0400
          Re: various OTs Jasen Betts <jasen@xnet.co.nz> - 2018-10-14 20:13 +0000
            Re: various OTs John Larkin <jjlarkin@highland_snip_technology.com> - 2018-10-14 13:59 -0700
              Re: various OTs Steve Wilson <no@spam.com> - 2018-10-14 23:58 +0000
                Re: various OTs Steve Wilson <no@spam.com> - 2018-10-15 01:05 +0000
                  Re: various OTs Jasen Betts <jasen@xnet.co.nz> - 2018-10-15 05:57 +0000
                    Re: various OTs DecadentLinuxUserNumeroUno@decadence.org - 2018-10-15 11:09 +0000
                Re: various OTs <698839253X6D445TD@nospam.org> - 2018-10-15 07:23 +0000
        Re: various OTs "Tim Williams" <tiwill@seventransistorlabs.com> - 2018-10-13 21:39 -0500
    Re: various OTs bitrex <user@example.net> - 2018-10-13 00:08 -0400
    Re: various OTs <698839253X6D445TD@nospam.org> - 2018-10-13 06:59 +0000
      Re: various OTs John Larkin <jjlarkin@highland_snip_technology.com> - 2018-10-13 12:08 -0700
    Re: various OTs <698839253X6D445TD@nospam.org> - 2018-10-13 07:27 +0000
      Re: various OTs speff <spehro@gmail.com> - 2018-10-18 06:55 -0700
    Re: various OTs Winfield Hill <hill@rowland.harvard.edu> - 2018-10-13 07:32 -0700
      Re: various OTs John Larkin <jjlarkin@highland_snip_technology.com> - 2018-10-13 12:17 -0700
    Re: various OTs Joseph Gwinn <joegwinn@comcast.net> - 2018-10-15 08:37 -0400
      Re: various OTs Martin Brown <'''newspam'''@nezumi.demon.co.uk> - 2018-10-15 13:58 +0100
        Re: various OTs Tom Gardner <spamjunk@blueyonder.co.uk> - 2018-10-15 14:34 +0100
        Re: various OTs Clifford Heath <no.spam@please.net> - 2018-10-16 10:26 +1100
      Re: various OTs Clive Arthur <cliveta@nowaytoday.co.uk> - 2018-10-16 10:46 +0100
        Re: various OTs tabbypurr@gmail.com - 2018-10-16 08:46 -0700
          Re: various OTs Clive Arthur <cliveta@nowaytoday.co.uk> - 2018-10-16 19:53 +0100
            Re: various OTs tabbypurr@gmail.com - 2018-10-17 05:56 -0700

Page 3 of 3 — ← Prev page 1 2 [3]

#519350

Jasen Betts <jasen@xnet.co.nz> wrote in
news:pq1a8t$40d$5@gonzo.alcatraz: 

> On 2018-10-15, Steve Wilson <no@spam.com> wrote:
>> Steve Wilson <no@spam.com> wrote:
>>
>> There is nothing to replace the Hubble. 
> 
> Apart from those two that NRO decided not to launch,
> 
> https://en.wikipedia.org/wiki/2012
_National_Reconnaissance_Office_space
> _telescope_donation_to_NASA 
> 
> Dunno how they'd launch 'em though.
> 

The JWST will replace it, but will not have the same speed of 
maneuverability due to its larger size.

  It is worth it to invest in a way to do a repair on it without our 
shuttle program.  I wonder how big each gyro axis unit is.  For a mass 
the size of the HST, They are likely pretty big.  Remember the huge IBM 
hard drives?

  Anyway, short of getting up there pretty soon, it will fall hopelessly 
out of any serviceable orbit.  I suppose they could boost it one more 
time to some higher orbit to give more time to get to it to service it.

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#519332

Steve Wilson wrote
>John Larkin <jjlarkin@highland_snip_technology.com> wrote:
>
>> It's tough to get stuff to work in space. Probably even tougher to
>> figure out what went wrong.
> 
>As I understand, gyros use sealed gas bearings and very thin conductors to 
>drive the motors. Here's some more information (old)
>
>https://forum.nasaspaceflight.com/index.php?action=dlattach;topic=
>32804.0;attach=542152
>
>Apparently the new mems gyros would be more reliable:
>
>https://www.siliconsensing.com/technology/mems-gyroscopes/
>
>Apparently some models are super-sensitive and require recalibration due to 
>changes in G due to the moon's gravity.

Ha, I ran a test with the MEMS with a very precisely controlled temperature
to see if I could see correlation with the moon phases...
Published that in some related group few years ago.
The idea was to replace GPS with an inertia based system.
Did not get to see the effect of the moon, but noted daily variations
very likely due to chip expansion and board expansion caused by minuscule temperature changes.
concluded that I needed a better oven.
Then somebody at some university repeated it with a better oven.
It is out there can search for the graph, lemme see
 http://panteltje.com/pub/xgc.gif

The spike is where I opened the box to check some switches...
At least when those sats fail I know where to pick up...

Its fun. so many things to get into...

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#519217

"whit3rd" <whit3rd@gmail.com> wrote in message 
news:3b61ba6c-2db5-4080-9144-c080861a5432@googlegroups.com...
>Metal
> should hold up well.   If ZrO turns to Zr, though, it's gonna lose the
> smooth surface.

ZrO's binding energy is higher than that of Fe.

You might as well consider transmutation of Fe or Zr due to high energy 
spallation, too, but you'll only be that much further down in the noise.  Or 
Wigner energy.  Bulk effects are an extremely small priority.  It would have 
to be in orbit for a very long time indeed.

I don't know that asteroids have these problems after billions of years. 
And common minerals, like olivine, aren't as stable as zirconia.

Photoemission is the only mechanism with a plausible risk factor -- showers 
of charged particles exiting a surface, multiplied by the energy of the 
impacting particle.

There should be ions in there, too, but again, that's a bulk effect manifest 
at the surface.  Sure, it'll roughen the surface, atomically.  The surface 
is already microscopically rough.  Drops in the bucket.

I'd worry much more about chemical breakdown of the grease.  If it's carbon 
or silicone based, expect fragmentation and cross-linking.  If it can be dry 
(graphite, MoS2 or PTFE?), that helps, but a purely dry lubricant would only 
stay in place by van der Waals forces.

Material composition is critical inside a fission reactor, say.  But that's 
not an environment that humans can sit in for years with mainly just an 
elevated cancer risk.  That's an environment that liquifies biological 
tissue in -- minutes, hours, days?
http://www.srl.caltech.edu/ACE/ASC/DATA/bibliography/ICRC2005/usa-mewaldt-RA-abs1-sh35-oral.pdf
This says space is ~Sv/yr equivalent, which is kind of scary actually, to 
the point that I wonder if long-duration astronauts are growing anything 
interesting yet.  But it's not something you're likely to die of, during a 
mission.

And that's in the mSv for casual (days-long) missions, comparable to a PET 
scan, or CT of the more sensitive areas, so as long as you don't make a 
habit of, say, space tourism, it's not going to affect your long-term risk.

Tim

-- 
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Design
Website: https://www.seventransistorlabs.com/ 

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#519123

On 10/12/2018 03:50 PM, John Larkin wrote:
> 
> https://wattsupwiththat.com/2018/10/12/another-space-telescope-shuts-down-one-week-after-hubble/
> 
> Gyros, reaction wheels, seem to be a chronic problem in satellites. I
> have a friend who designs cubesats, and he says that the gyros are the
> most expensive and unreliable parts. They should be redundant, or
> redesigned, or something.

Hall thrusters/plasma pulse thrusters (can be?) more efficient, fewer 
moving parts

<https://en.wikipedia.org/wiki/Hall-effect_thruster>

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#519136

John Larkin wrote
>https://wattsupwiththat.com/2018/10/12/another-space-telescope-shuts-down-one-week-after-hubble/

Now they retired the shuttle no way to send a repair crew up there...

The Russian mission to the ISS also failed, crew made an emergency landing and is safe.

Statistics...



>Gyros, reaction wheels, seem to be a chronic problem in satellites. I
>have a friend who designs cubesats, and he says that the gyros are the
>most expensive and unreliable parts. They should be redundant, or
>redesigned, or something.
>
>===========
>
>Another friend, a Fellow of a giant areospace conglomerate, tells me
>that they have a new CEO. The old one was big on outsourcing, and they
>did stuff like using contract programmers in India, and things went to
>hell. They will be hiring 8000 engineers in the next few years, so
>they can start learning how to do stuff again.

Software made elsewhere, hardware made elsewhere, that leaves the US with nothing...
Can the trend be reversed? I think not in the short run.

The empire is over the hill, and as all empires before it, will vanish.
Climate change will accelerate things. large migration, population changes..

A reality show host closing the borders for trade will cause the US dollar to
be replaced by some other currency, Chinese, European..
Starting an other war will not work as the 'enemy' has as many nukes as US,
even if you could get people to fight, they won't, they will sit down in protest,
unity lost.
Mr Xi will be visiting my country soon, and Dutch Chinese relations are the best ever now.

The markets took a big hit recently, US people lost a lot of money..
The high tech you need, the factories you need, the workers you need
are not there.
And you will not be able to buy those with a dollar that is no longer accepted.
The expertise is not there, the milking of the taxpayer for military nonsense projects like for example the F35
has made a farce of US defense.
Alienating your allies with tariffs and a gun to their head to sell your inferior weapons, creating wars to sell your weapons.
some other power will do that has the resources now.
Breaking promises, stepping gout of international treaties, claiming to be a capitalist state and being against free trade
at the same time, not a good thing.
Evolution, things change, stars are born and stars die.

Success with finding 8000 engineers with any experience.
Where would they have gained experience? 
Everything is made in China.


>This is a cool part:
>
>http://www.ti.com/product/lmg1020


Yes, nano nano, higher switching frequencies, short wave is already 100% polluted, next GPS goes out due to interference of switchers,
next .. chips emit light.... mm satellite TV interference
better stop here.
Does not sound all that optimistic now does it ;-)

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#519176

On Sat, 13 Oct 2018 06:59:26 GMT, <698839253X6D445TD@nospam.org>
wrote:

>John Larkin wrote
>>https://wattsupwiththat.com/2018/10/12/another-space-telescope-shuts-down-one-week-after-hubble/
>
>Now they retired the shuttle no way to send a repair crew up there...
>
>The Russian mission to the ISS also failed, crew made an emergency landing and is safe.
>
>Statistics...

ISS will probably be abandoned soon, certainly if we kill another
crew. It wasted around a trillion dollars to basically demonstrate
that space is too hostile for humans.





>
>
>
>>Gyros, reaction wheels, seem to be a chronic problem in satellites. I
>>have a friend who designs cubesats, and he says that the gyros are the
>>most expensive and unreliable parts. They should be redundant, or
>>redesigned, or something.
>>
>>===========
>>
>>Another friend, a Fellow of a giant areospace conglomerate, tells me
>>that they have a new CEO. The old one was big on outsourcing, and they
>>did stuff like using contract programmers in India, and things went to
>>hell. They will be hiring 8000 engineers in the next few years, so
>>they can start learning how to do stuff again.
>
>Software made elsewhere, hardware made elsewhere, that leaves the US with nothing...
>Can the trend be reversed? I think not in the short run.

The outsourcing trend turned out to be mostly bad business. D's tax
and tariff changes also encourage doing things here in the USA.

I don't see a lot of engineering innovation happening in China or
India or even much in Europe. 


>
>The empire is over the hill, and as all empires before it, will vanish.
>Climate change will accelerate things. large migration, population changes..

Doubt it.


>
>A reality show host closing the borders for trade will cause the US dollar to
>be replaced by some other currency, Chinese, European..
>Starting an other war will not work as the 'enemy' has as many nukes as US,
>even if you could get people to fight, they won't, they will sit down in protest,
>unity lost.
>Mr Xi will be visiting my country soon, and Dutch Chinese relations are the best ever now.
>
>The markets took a big hit recently, US people lost a lot of money..

Stock markets are emotion-driven and noisy. That started with spice
ships and tulip bulbs. Nothing new there. The long-term outlook for
sensible investments has been good.


>The high tech you need, the factories you need, the workers you need
>are not there.
>And you will not be able to buy those with a dollar that is no longer accepted.
>The expertise is not there, the milking of the taxpayer for military nonsense projects like for example the F35
>has made a farce of US defense.
>Alienating your allies with tariffs and a gun to their head to sell your inferior weapons, creating wars to sell your weapons.
>some other power will do that has the resources now.
>Breaking promises, stepping gout of international treaties, claiming to be a capitalist state and being against free trade
>at the same time, not a good thing.
>Evolution, things change, stars are born and stars die.
>
>Success with finding 8000 engineers with any experience.
>Where would they have gained experience? 

Some from schools, some poached from competitors, some imported, some
developed on site. They will do it. It's a cool place to work for.

I'm hoping they will stay with their core competances and continue to
outsource electronics. Big aerospace companies (and national labs, and
others) used to have in-house electronic design groups, but haven't
replaced them as they retired.


>Everything is made in China.
>
>
>>This is a cool part:
>>
>>http://www.ti.com/product/lmg1020
>
>
>Yes, nano nano, higher switching frequencies, short wave is already 100% polluted, next GPS goes out due to interference of switchers,
>next .. chips emit light.... mm satellite TV interference
>better stop here.
>Does not sound all that optimistic now does it ;-)

No, you don't sound cheerful.



-- 

John Larkin         Highland Technology, Inc
picosecond timing   precision measurement 

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

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#519139

PS
Huawei to invest 1 billion yuan in fostering AI specialists:
 http://chinaplus.cri.cn/news/china/9/20181013/195106.html

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#519743

On Saturday, 13 October 2018 15:27:45 UTC+8, 69883925...@nospam.org  wrote:
> PS
> Huawei to invest 1 billion yuan in fostering AI specialists:
>  http://chinaplus.cri.cn/news/china/9/20181013/195106.html

I sat through a (moderately) technical presentation by one of the Huawei engineers last week. Very impressive company. 

--sp 

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#519160

John Larkin wrote...
>
> This is a cool part:
> http://www.ti.com/product/lmg1020

 0.4mm dot spacing, awkk!


-- 
 Thanks,
    - Win

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#519178

On 13 Oct 2018 07:32:28 -0700, Winfield Hill
<hill@rowland.harvard.edu> wrote:

>John Larkin wrote...
>>
>> This is a cool part:
>> http://www.ti.com/product/lmg1020
>
> 0.4mm dot spacing, awkk!

That's within reasonable PCB design rules. What's scary will be heat
sinking the thing.

It's obviously intended to drive the EPC GaN fets (fig 15) which took
us getting some used to too.


-- 

John Larkin         Highland Technology, Inc
picosecond timing   precision measurement 

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

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#519369

On Oct 12, 2018, John Larkin wrote
(in article<r2u1sddojvr815ukjlm0qhsr5bpa2fbe6s@4ax.com>):

>
> <https://wattsupwiththat.com/2018/10/12/another-space-telescope-shuts-down-one-
> week-after-hubble/>
>
> Gyros, reaction wheels, seem to be a chronic problem in satellites. I
> have a friend who designs cubesats, and he says that the gyros are the
> most expensive and unreliable parts. They should be redundant, or
> redesigned, or something.

I recently read that the root cause of gyro and reaction-wheel failures in 
space had been uncovered: Electric currents passing through the balls in ball 
bearings were destroying the bearings, causing premature failure (compared to 
testing on the ground).

I has been known for a century of electric motor experience that electric 
currents passing through bearings is a bad idea. (Commutators are not 
bearings.)

This was a big mystery - nobody could figure out what was different between 
space and ground, and nobody could imagine where such currents could be 
coming from. It turns out to be space weather and the solar wind, by a 
mechanism I have not studied and so cannot explain.

The solution was to use ball bearings with ceramic balls, so no current can 
flow. Such bearings are catalog items, and have been for some time. It’s 
just that nobody thought it necessary to pay the added cost.

.
>
> ===========
>
> Another friend, a Fellow of a giant areospace conglomerate, tells me
> that they have a new CEO. The old one was big on outsourcing, and they
> did stuff like using contract programmers in India, and things went to
> hell. They will be hiring 8000 engineers in the next few years, so
> they can start learning how to do stuff again.

My immediate question is why anyone was surprised. Today’s programmers are 
typically innocent of any hardware knowledge or instinct, and have no idea 
how the system they are working on actually works.

Joe Gwinn

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#519373

On 15/10/2018 13:37, Joseph Gwinn wrote:
> On Oct 12, 2018, John Larkin wrote
> (in article<r2u1sddojvr815ukjlm0qhsr5bpa2fbe6s@4ax.com>):
> 
>> Another friend, a Fellow of a giant areospace conglomerate, tells me
>> that they have a new CEO. The old one was big on outsourcing, and they
>> did stuff like using contract programmers in India, and things went to
>> hell. They will be hiring 8000 engineers in the next few years, so
>> they can start learning how to do stuff again.
> 
> My immediate question is why anyone was surprised. Today’s programmers are
> typically innocent of any hardware knowledge or instinct, and have no idea
> how the system they are working on actually works.

OTOH I think it may be more an example of "you get what you pay for".

India also has a handful of organisations capable of writing six sigma 
quality code to the standard expected on manned space programs.

When you outsource stuff you had better get the specification right 
first time and choose the correct partners to work with. Otherwise you 
can get back something at the end which does exactly what you asked for 
rather than what you thought you had asked for. Seen it happen...

Cultural assumptions about ambiguities may be different and any loose 
ends have a nasty habit of causing serious trouble in software specs.

-- 
Regards,
Martin Brown

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#519376

On 15/10/18 13:58, Martin Brown wrote:
> On 15/10/2018 13:37, Joseph Gwinn wrote:
>> On Oct 12, 2018, John Larkin wrote
>> (in article<r2u1sddojvr815ukjlm0qhsr5bpa2fbe6s@4ax.com>):
>>
>>> Another friend, a Fellow of a giant areospace conglomerate, tells me
>>> that they have a new CEO. The old one was big on outsourcing, and they
>>> did stuff like using contract programmers in India, and things went to
>>> hell. They will be hiring 8000 engineers in the next few years, so
>>> they can start learning how to do stuff again.
>>
>> My immediate question is why anyone was surprised. Today’s programmers are
>> typically innocent of any hardware knowledge or instinct, and have no idea
>> how the system they are working on actually works.
> 
> OTOH I think it may be more an example of "you get what you pay for".
> 
> India also has a handful of organisations capable of writing six sigma quality 
> code to the standard expected on manned space programs.
> 
> When you outsource stuff you had better get the specification right first time 
> and choose the correct partners to work with. Otherwise you can get back 
> something at the end which does exactly what you asked for rather than what you 
> thought you had asked for. Seen it happen...
> 
> Cultural assumptions about ambiguities may be different and any loose ends have 
> a nasty habit of causing serious trouble in software specs.

I have been warned by an Indian project manager working
in Bangalore that the Indian culture explicitly believes
that miracles happen.

Couple that with other factors common to many cultures,
and optimistic underbidding is certain to happen.

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#519420

On 15/10/18 23:58, Martin Brown wrote:
> When you outsource stuff you had better get the specification right 
> first time and choose the correct partners to work with. Otherwise you 
> can get back something at the end which does exactly what you asked for 
> rather than what you thought you had asked for. Seen it happen...

Natural language can be a killer. ESA uses English to
specify the ICDs (Interface Control Documents), but the
language usage is highly structured according to a 500+
page standards document which dictates the structure,
sentence construction, glossary and interpretation.
Each ICD defines the entire monitoring and control
interface between a satellite module and the central
computing, and is the primary artefact to specify
the supply contract.

I have worked with the main author of this standard
on software which is now capable of *generating* the
structured English from the logical model (more below).

> Cultural assumptions about ambiguities may be different and any loose 
> ends have a nasty habit of causing serious trouble in software specs.

Every ESA mission in the last decade, and decreasingly
so for a decade before that, applied the discipline of
Fact-Based Modeling <http://factbasedmodeling.org>
in creating these logical models. FBM is a first-order
logic, so all the logical proof theory of Russell and
Whitehead applies to ensuring semantic consistency.
This has avoided the re-occurrence of expensive
in-flight failures which had occurred a couple of
times earlier (despite extensive ground testing),
which were blamed on the use of industry standard
techniques including UML and XML. These have no
complete basis in mathematical logic, and so they
sometimes allow multiple interpretations. Such core
failures could not be fixed by updating the software
in-flight.

My "Constellation Query Language" is one implementation
of an FBM language that conforms to the draft Exchange
Schema, see <http://dataconstellation.com/ActiveFacts/>.
Some might be interested in the fact that CQL is itself
a controlled natural language (English, with incomplete
implementations for French, German, Italian, Spanish
and Mandarin). It allows use of *open vocabulary* in
sentences that conform to particular linguistic
structures which map unambiguously to the underlying
logic. The sentence structures and open vocabulary
are designed to facilitate correct interpretation by
anyone fluent in that natural language, whether or not
they are already familiar with the technology being
defined. That means they can understand the model, and
perhaps detect errors or omissions in the intended
behaviour.

What remains now is the further promulgation of *other*
tools that comply with the new model exchange standard,
so that the supply contracts can start to migrate to
using the models themselves, not just the generated
English.

Clifford Heath.

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#519453

On 15/10/2018 13:37, Joseph Gwinn wrote:

<snipped>
> 
> I has been known for a century of electric motor experience that electric
> currents passing through bearings is a bad idea. (Commutators are not
> bearings.)

There is an exception...

http://www.electricstuff.co.uk/bbmotor.html#article

Cheers
-- 
Clive

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#519492

On Tuesday, 16 October 2018 10:46:55 UTC+1, Clive Arthur  wrote:
> On 15/10/2018 13:37, Joseph Gwinn wrote:
> 
> <snipped>
> > 
> > I has been known for a century of electric motor experience that electric
> > currents passing through bearings is a bad idea. (Commutators are not
> > bearings.)
> 
> There is an exception...
> 
> http://www.electricstuff.co.uk/bbmotor.html#article
> 
> Cheers

I don't think that is an exception. AFAIK no-one uses those commercially because of their obvious flaws.


NT

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#519507

On 16/10/2018 16:46, tabbypurr@gmail.com wrote:
> On Tuesday, 16 October 2018 10:46:55 UTC+1, Clive Arthur  wrote:
>> On 15/10/2018 13:37, Joseph Gwinn wrote:
>>
>> <snipped>
>>>
>>> I has been known for a century of electric motor experience that electric
>>> currents passing through bearings is a bad idea. (Commutators are not
>>> bearings.)
>>
>> There is an exception...
>>
>> http://www.electricstuff.co.uk/bbmotor.html#article
>>
>> Cheers
> 
> I don't think that is an exception. AFAIK no-one uses those commercially because of their obvious flaws.
> 
> 
> NT
> 

Yes, it was intended to be a humorous comment, m'lud.

However, when this first appeared in Wireless World (how I miss those 
well-crafted circuit diagrams!) it did give rise to all sorts of 
crackpot theories involving magnetic fields.

Of course, it's all just a load of expanding balls.

Cheers
-- 
Clive

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#519616

On Tuesday, 16 October 2018 19:54:07 UTC+1, Clive Arthur  wrote:
> On 16/10/2018 16:46, tabbypurr wrote:
> > On Tuesday, 16 October 2018 10:46:55 UTC+1, Clive Arthur  wrote:
> >> On 15/10/2018 13:37, Joseph Gwinn wrote:
> >>
> >> <snipped>
> >>>
> >>> I has been known for a century of electric motor experience that electric
> >>> currents passing through bearings is a bad idea. (Commutators are not
> >>> bearings.)
> >>
> >> There is an exception...
> >>
> >> http://www.electricstuff.co.uk/bbmotor.html#article
> >>
> >> Cheers
> > 
> > I don't think that is an exception. AFAIK no-one uses those commercially because of their obvious flaws.
> > 
> > 
> > NT
> > 
> 
> Yes, it was intended to be a humorous comment, m'lud.
> 
> However, when this first appeared in Wireless World (how I miss those 
> well-crafted circuit diagrams!) it did give rise to all sorts of 
> crackpot theories involving magnetic fields.
> 
> Of course, it's all just a load of expanding balls.
> 
> Cheers

it gets in a spin because its balls swell up.


NT

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