Driver to drive?

[Jan Panteltje]

On a sunny day (Sun, 29 Dec 2013 13:32:27 +0200) it happened
upsidedown@downunder.com wrote in
<8b00c9poj6njm2l81cblo66dp74uj1k2he@4ax.com>:

Variacs are usually auto transformers and auto transformers work best
when the output is +/-30 % from the input (70 - 130 %) voltage. Trying
to get out only 5 % of the input voltage may cause some problems to
the autotransformer. If there are some advanced protection mechanism
on the variac, this might be triggered at such low setting, even if it
might OK around the input voltage.

Exactly,
and auto transformers have no mains isolation.
It could just be he has the + or - of the bridge output somewhere connected to
[test]equipment that is is on mains ground via a 3 core cable.
A scope will do.

That would be a very basic mistake, and should always be checked before even applying power.

 

On Sun, 29 Dec 2013 13:32:27 +0200, upsidedown@downunder.com wrote:

3. Not that it matters, but we use a 230V/50Hz mains supply with the
installation capable of handling 15A of current. (The variac fuse would
blow somewhere around 10V AC output with no load connected to the output.)

Variacs are usually auto transformers and auto transformers work best
when the output is +/-30 % from the input (70 - 130 %) voltage. Trying
to get out only 5 % of the input voltage may cause some problems to
the autotransformer. If there are some advanced protection mechanism
on the variac, this might be triggered at such low setting, even if it
might OK around the input voltage.

To understand why auto transformers are attractive with small up/down
voltage conversion (say +/- 10 % to +/- 30 %) , one should remember
that in an ordinary transformer, all the power is transferred through
the iron core, while in an auto transformer, only the power related to
the voltage _difference_ goes through the iron core, in this case only
10 % to 30 %.

You can think about the auto transformer as an ordinary transformer
with the primary connected to the input voltage and secondary with 10
to 30 % of the input voltage. connect the secondary in series with the
input voltage and you get 10-30 % boost (in phase) or 10-30 % drop
(connect in antiphase). Only a small amount of the power goes through
the iron core.

Trying to run an auto transformer (variac) at only 5 % of input,
practically all power flows through the iron core of the transformer,
might cause saturation and similar problems.

 

[Jim Thompson]

On Sat, 28 Dec 2013 21:16:57 -0800, Robert Baer
<robertbaer@localnet.com> wrote:

Fred Abse wrote:
On Thu, 26 Dec 2013 21:41:14 -0800, Robert Baer wrote:

Bill Sloman wrote:
On 27/12/2013 8:51 AM, Robert Baer wrote:
Take the TDK datasheet for their C4532X5R1C226M230KA.
It bloats the scree (easy fix, just "-" a few times).
BUT it is too big to print on ONE sheet of paper.
HOW can one get it to fit?

Select "fit to paper" at printing?

Absolutely NO such thing in GsView!

There certainly is in GSview 4.9.

And every older version I've had.

Screenshot of the dialog box posted to a.b.s.e.

Alternatively, you can "print", to a file, using the pswrite device,
which should give you a pdf 1.4 (Acrobat 5) file, then print from Acrobat.
That actually puts a 1.4 wrapper around the later format. Useful for
people who don't want to install the latest, bloated, Acrobat.

OK; i have tried everything.
One: I have GsView ver 5.0 and GhostScript ver 9.10; both the most
recent versions (Win32-bit) i can find and they are written for each other.
Two: That dialog box exists nowhere in GsView; there certainly is no
"fit to page" function in GsView.
Three: If i set GsView to Landscape mode first, then Convert with
pdfwrite at 300DPI (not the default 600DPI that i had been using), then
and only then do i get a document that shows everything (one page).

So, i ask again, where, oh where did that come from?

From wonderland >:-} GSview ver 4.9...

<http://www.analog-innovations.com/SED/GSviewTest.png>

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

Liberalism: A haunting fear that someone, somewhere, may be happy.

(Twisted Quotation from H.L. Mencken)

 

[Jim Thompson]

On Sat, 28 Dec 2013 20:30:31 -0800 (PST),
bloggs.fredbloggs.fred@gmail.com wrote:

They also claim "In addition to the Saville payout, the county already has had to fork over more than $43 million in lawsuit settlements and expenses to the families of jail-abuse victims during Arpaio's tenure as sheriff."

The county is getting ripped off big time by that joke. The elections have to be rigged.

Sadly, you only reading one side of the story. Joe is the most
popular politician in Arizona, because he kicks ass.

Ruthless at times? Yes, indeed! But the crime rate is wa-a-ay down,
and the illegals (*) are scared shitless >:-}

(*) A hefty portion of the crime source. Remember, this is ARIZONA,
on the border, drug traffic like crazy, and Obama and
dumber-than-she-is-ugly Napolitano ignore the problem... they consider
illegals as good Democrat voters. So Joe gets in their face and
arrests illegals.

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[Jim Thompson]

On Sat, 28 Dec 2013 20:54:32 -0800 (PST),
bloggs.fredbloggs.fred@gmail.com wrote:

On Saturday, December 28, 2013 4:35:14 PM UTC-5, Jim Thompson wrote:


As for the James Saville case... "four years in jail awaiting trial"

has a smell about it that someone other than the sheriff's department

was involved... sheriffs don't determine detention while awaiting

trial... Judges do.

The pre-trial detention lasted for four years because the suspect was indicted, no warrant required, and Arpaio's office was sandbagging the delivery of critical investigational and evidentiary reports needed by the prosecution and the defense.

Bullshit. You're making stuff up.

Here's more info on that useless narcissist who needs to be kicked in the trash where he belongs:

"Controversy and criticism
To several organizations such as the ACLU and Amnesty International, Arpaio’s actions may be based less on a desire to serve the public and to lower crime, but more on demagoguery and grandstanding that does not serve the public welfare. Amnesty International issued a report critical of the treatment of inmates in Maricopa County facilities. The family members of inmates who have died in jail custody have filed lawsuits against the sheriff’s office. The lawsuits have cost Maricopa County more than $43 million in settlement claims during Arpaio’s tenure.
From 2004 through November 2007, Arpaio was the target of 2,150 lawsuits in U.S. District Court and hundreds more in Maricopa County courts; 50 times as many prison-conditions lawsuits as the New York, Los Angeles, Chicago, and Houston jail systems combined.
Arpaio is named in a class-action lawsuit, Hart v. Arpaio, brought by Phoenix attorney Debra Hill and the American Civil Liberties Union on behalf of jail inmates. The lawsuit centers on the treatment of pretrial detainees, who are legally innocent until proven guilty. The lawsuit claims that Arpaio is violating the constitutional rights of those detainees. The trial in the lawsuit began on August 12, 2008.
By mid-2007, more than $50 million in claims had been filed against the sheriff’s office and Maricopa County.
In her book on prison policy The Use of Force by Detention Officers, Arizona State University criminal justice professor Marie L. Griffin reported on a 1998 study commissioned by Arpaio to examine recidivism rates based on conditions of confinement. Comparing recidivism rates under Arpaio to those under his predecessor, the study found “there was no significant difference in recidivism observed between those offenders released in 1989-1990 and those released in 1994-1995.”

Source?

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[Fred Abse]

On Sun, 29 Dec 2013 00:04:42 -0600, John Fields wrote:

On Fri, 27 Dec 2013 11:09:11 +0530, "Anand P. Paralkar"
anand.paralkar@gnospammale.com> wrote:

Hi everyone,

I am trying to build a relatively high voltage-high current DC source.
The scheme is simple and uses no regulation (therefore no feedback
control). The scheme is as follows:

Utility mains supply => Variac => Three full wave rectifier bridges in
parallel => Huge capacitor bank => Load.

Variac: something similar to this one:
http://orgchem.colorado.edu/Technique/Equipment/Communityequip/Variac.html

Bridge: KBPC3510

Capacitor bank: 6800uF, 400V

I could not find a full wave bridge rectifier with a sufficiently high
current rating and therefore, I thought of paralleling three that were
readily available.

I start (slowly) increasing the output AC voltage of variac so as to
increase the DC supply to the load. However, the variac fuse blows-up at
around 10V AC output!

Paralleling three bridges may not be the most elegant way to build a
high-current DC source, but I do not understand what could cause the fuse
in the variac to blow-up. (Please note, everything works fine with a
single bridge rectifier. This ofcourse limits the amount of load current
I can draw out from the source.)

Thank you for your help and greetings for festive season. Wish everyone
a new year full of good health and prosperity!

Regards,
Anand

---
Here's what you'll have with the 240V VARIAC cranked to 100% and ideal
diodes:

<LTspice listing snipped.>

For reality's sake, you need some series resistance in the source.

Why hide V1 parameters?

--
"Design is the reverse of analysis"
(R.D. Middlebrook)

 

[Fred Abse]

On Sun, 29 Dec 2013 15:08:53 +0530, Anand P. Paralkar wrote:

On 27-12-2013 11:09, Anand P. Paralkar wrote:
Hi everyone,

I am trying to build a relatively high voltage-high current DC source.
The scheme is simple and uses no regulation (therefore no feedback
control). The scheme is as follows:

Utility mains supply => Variac => Three full wave rectifier bridges in
parallel => Huge capacitor bank => Load.

Variac: something similar to this one:
http://orgchem.colorado.edu/Technique/Equipment/Communityequip/Variac.html

Bridge: KBPC3510

Capacitor bank: 6800uF, 400V

I could not find a full wave bridge rectifier with a sufficiently high
current rating and therefore, I thought of paralleling three that were
readily available.

I start (slowly) increasing the output AC voltage of variac so as to
increase the DC supply to the load. However, the variac fuse blows-up at
around 10V AC output!

Paralleling three bridges may not be the most elegant way to build a
high-current DC source, but I do not understand what could cause the
fuse in the variac to blow-up. (Please note, everything works fine with
a single bridge rectifier. This ofcourse limits the amount of load
current I can draw out from the source.)

Thank you for your help and greetings for festive season. Wish everyone
a new year full of good health and prosperity!

Regards,
Anand


Thank you everyone for your replies. My replies to some of the posts:

1. I did check each one of the bridges and the capacitors for faulty
devices, incorrect polarity, short circuits and open. Didn't find
anything there. Also, the three bridges are identical.

2. I would doubt that inrush current is an issue here. Each time that I
ran this experiment, I was careful enough to increase the variac output
voltage very slowly. (Ofcourse, connecting an uncharged capacitor bank to
full output voltage of the variac would surely trip the circuit breakers
on the utility mains line.)

3. Not that it matters, but we use a 230V/50Hz mains supply with the
installation capable of handling 15A of current. (The variac fuse would
blow somewhere around 10V AC output with no load connected to the output.)

4. I am not sure, but I get a feeling that some of us reading this post
have "registered" this as "bridge blowing-up". No, it is the variac fuse
that blows-up. Infact, there was no heating on any of the bridge (or
capacitors for that matter).

I didn't know about the balancing resistor scheme. As already indicated,
it may not be the solution for this problem, but, thanks for the idea,
simple way of controlling current hogging.

I guess, monitoring the variac current with a clamp meter (or may be even
an oscilloscope may be a good idea).

You still haven't told us what the variac fuse is rated at.

--
"Design is the reverse of analysis"
(R.D. Middlebrook)

 

[RobertMacy]

On Sat, 28 Dec 2013 14:35:14 -0700, Jim Thompson
<To-Email-Use-The-Envelope-Icon@on-my-web-site.com> wrote:

...snip....

To hold someone more than a few hours take a warrant. Sheriffs don't
issue warrants, Judges do. Detaining someone for questioning, then
quickly releasing doesn't count as false arrest.
..snip...
Interestingly, I've lived right here in Arizona (always in the Phoenix
area) for 51 years... and I don't recall the case even making the
news... TV or newspapers (I don't count New Times as a newspaper).

...snip...

I've seen paperwork from the Sheriff's Dept [Arizona] NOT get through the
system to the judge for 9+ months due to an 'oversight' on someone's part.
Albeit, a person could be detained that long without a judge even being
involved.

I wouldn't count on the relevance of 'making the news' here. Examples,
glancing through local coverage trying to obtain news, all I saw were
people doing stupid crimes, justifications for harsh police actions, a lot
of interviews of bystanders and neighbors stating their 'feelings' about
some incident, a box of puppies [yes, a box of puppies], a whole segment
on 'how to shop'; with the best/worst of all,...all the newspeople were
dancing and chattering at the same time with the image turned upside down
demonstrating what I have no idea and further don't care. It's all crap.

In defense, the absolutely BEST news coverage I've ever seen locally was
when the events were unfolding and there was no time to sanitize, nor
homogenize, the news into standard blather. However, when the unfolding
did slow down enough for the station to get ahead, they actually rescinded
some statments [which from viewing the footage were correct so why
rescind?] and then came the 'sound/video bites' justifying the brutal
actions, followed by, you guessed it, almost a box of warm puppies.

 

[Fred Abse]

On Sun, 29 Dec 2013 16:14:27 +0200, upsidedown wrote:

To understand why auto transformers are attractive with small up/down
voltage conversion (say +/- 10 % to +/- 30 %) , one should remember that
in an ordinary transformer, all the power is transferred through the iron
core, while in an auto transformer, only the power related to the voltage
_difference_ goes through the iron core, in this case only 10 % to 30 %.

Huh?
In *any* transformer, all the primary current goes through the primary,
and all the secondary current through the secondary. The secondary amp
turns oppose the primary amp turns, resulting (in a perfect transformer
having no leakage inductance) in zero net amp turns hence zero flux.
Connecting windings in series makes no difference.

You can think about the auto transformer as an ordinary transformer with
the primary connected to the input voltage and secondary with 10 to 30 %
of the input voltage. connect the secondary in series with the input
voltage and you get 10-30 % boost (in phase) or 10-30 % drop (connect in
antiphase). Only a small amount of the power goes through the iron core.

Where does the rest go?

Trying to run an auto transformer (variac) at only 5 % of input,
practically all power flows through the iron core of the transformer,
might cause saturation and similar problems.

You cannot saturate a transformer core with secondary amp turns. Even a
shorted secondary won't do it.
Saturation occurs where the magnetizing inductance (inductance of primary
with open secondary) allows enough current to flow to saturate the core.
That's why big current transformers, such as use in distribution equipment
buzz like hell if the secondary is O/C. That's a good danger warning.

COTS transformers are generally designed to run as close to saturation as
possible, at rated voltage and frequency, to economize on iron.

--
"Design is the reverse of analysis"
(R.D. Middlebrook)

 

[Jim Thompson]

On Sun, 29 Dec 2013 09:02:25 -0700, RobertMacy
<robert.a.macy@gmail.com> wrote:

On Sat, 28 Dec 2013 14:35:14 -0700, Jim Thompson
To-Email-Use-The-Envelope-Icon@on-my-web-site.com> wrote:

...snip....

To hold someone more than a few hours take a warrant. Sheriffs don't
issue warrants, Judges do. Detaining someone for questioning, then
quickly releasing doesn't count as false arrest.
..snip...
Interestingly, I've lived right here in Arizona (always in the Phoenix
area) for 51 years... and I don't recall the case even making the
news... TV or newspapers (I don't count New Times as a newspaper).

...snip...

I've seen paperwork from the Sheriff's Dept [Arizona] NOT get through the
system to the judge for 9+ months due to an 'oversight' on someone's part.
Albeit, a person could be detained that long without a judge even being
involved.

How can that be? He would have been assigned a public defender at
arraignment. Maybe the public defender dropped the ball?

I wouldn't count on the relevance of 'making the news' here. Examples,
glancing through local coverage trying to obtain news, all I saw were
people doing stupid crimes, justifications for harsh police actions, a lot
of interviews of bystanders and neighbors stating their 'feelings' about
some incident, a box of puppies [yes, a box of puppies], a whole segment
on 'how to shop'; with the best/worst of all,...all the newspeople were
dancing and chattering at the same time with the image turned upside down
demonstrating what I have no idea and further don't care. It's all crap.

In defense, the absolutely BEST news coverage I've ever seen locally was
when the events were unfolding and there was no time to sanitize, nor
homogenize, the news into standard blather. However, when the unfolding
did slow down enough for the station to get ahead, they actually rescinded
some statments [which from viewing the footage were correct so why
rescind?] and then came the 'sound/video bites' justifying the brutal
actions, followed by, you guessed it, almost a box of warm puppies.

I no longer live in Sheriff Joe's jurisdiction, I now live in Sheriff
Paul's...

<http://tinyurl.com/lukq649>

Another "noisy" sheriff >:-}

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[Fred Abse]

On Sun, 29 Dec 2013 09:02:25 -0700, RobertMacy wrote:

NOT get through the
system to the judge for 9+ months due to an 'oversight' on someone's part.
Albeit, a person could be detained that long without a judge even being
involved.

Without his lawyer invoking habeas corpus?

--
"Design is the reverse of analysis"
(R.D. Middlebrook)

 

[John Fields]

On Sun, 29 Dec 2013 07:08:51 -0800, Fred Abse
<excretatauris@invalid.invalid> wrote:

On Sun, 29 Dec 2013 00:04:42 -0600, John Fields wrote:

Here's what you'll have with the 240V VARIAC cranked to 100% and ideal
diodes:


LTspice listing snipped.

For reality's sake, you need some series resistance in the source.

---
That's left as an exercise for the interested/curious.
---

>Why hide V1 parameters?

---
Why not?

I prefer a less busy schematic and the data's a couple of clicks
away for anyone who's interested.

 

[Jim Thompson]

On Sun, 29 Dec 2013 08:11:20 -0800, Fred Abse
<excretatauris@invalid.invalid> wrote:

On Sun, 29 Dec 2013 09:02:25 -0700, RobertMacy wrote:

I've seen paperwork from the Sheriff's Dept [Arizona] NOT get through the
system to the judge for 9+ months due to an 'oversight' on someone's part.
Albeit, a person could be detained that long without a judge even being
involved.

Without his lawyer invoking habeas corpus?

I suspect Robert is misconscrewing (perhaps on purpose , comparing
"papers served" on the public by deputies, against "writs" delivered
by courier to/from judges.

My son-in-law will be sworn in as a presiding judge on the 4th...

<http://www.analog-innovations.com/SED/Inauguration.jpg>

I'll ask him what he knows of that case... and how come the (supposed)
4-year delay.

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

On Sun, 29 Dec 2013 08:04:59 -0800, Fred Abse
<excretatauris@invalid.invalid> wrote:

On Sun, 29 Dec 2013 16:14:27 +0200, upsidedown wrote:

To understand why auto transformers are attractive with small up/down
voltage conversion (say +/- 10 % to +/- 30 %) , one should remember that
in an ordinary transformer, all the power is transferred through the iron
core, while in an auto transformer, only the power related to the voltage
_difference_ goes through the iron core, in this case only 10 % to 30 %.

Huh?
In *any* transformer, all the primary current goes through the primary,
and all the secondary current through the secondary. The secondary amp
turns oppose the primary amp turns, resulting (in a perfect transformer
having no leakage inductance) in zero net amp turns hence zero flux.
Connecting windings in series makes no difference.

True for ordinary transformers with separate primary and secondary
windings.

You can think about the auto transformer as an ordinary transformer with
the primary connected to the input voltage and secondary with 10 to 30 %
of the input voltage. connect the secondary in series with the input
voltage and you get 10-30 % boost (in phase) or 10-30 % drop (connect in
antiphase). Only a small amount of the power goes through the iron core.

Where does the rest go?

It goes through the galvanic connection.

Trying to run an auto transformer (variac) at only 5 % of input,
practically all power flows through the iron core of the transformer,
might cause saturation and similar problems.

You cannot saturate a transformer core with secondary amp turns. Even a
shorted secondary won't do it.
Saturation occurs where the magnetizing inductance (inductance of primary
with open secondary) allows enough current to flow to saturate the core.
That's why big current transformers, such as use in distribution equipment
buzz like hell if the secondary is O/C. That's a good danger warning.

COTS transformers are generally designed to run as close to saturation as
possible, at rated voltage and frequency, to economize on iron.

Depending on the variac setting, you can run hundreds of kW at 1:1
setting (limited only by the contact ratings), at 90 .. 110 % we are
talking about 10 % of the nominal power goes through the core, the
rest goes through the galvanic connection.

At 5 %, most goes through the core. possibly 1/20 of the nominal power
can be transferred through the iron core.

 

On Sun, 29 Dec 2013 09:08:29 -0700, Jim Thompson
<To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:

On Sun, 29 Dec 2013 09:02:25 -0700, RobertMacy
robert.a.macy@gmail.com> wrote:

On Sat, 28 Dec 2013 14:35:14 -0700, Jim Thompson
To-Email-Use-The-Envelope-Icon@on-my-web-site.com> wrote:

...snip....

To hold someone more than a few hours take a warrant. Sheriffs don't
issue warrants, Judges do. Detaining someone for questioning, then
quickly releasing doesn't count as false arrest.
..snip...
Interestingly, I've lived right here in Arizona (always in the Phoenix
area) for 51 years... and I don't recall the case even making the
news... TV or newspapers (I don't count New Times as a newspaper).

...snip...

I've seen paperwork from the Sheriff's Dept [Arizona] NOT get through the
system to the judge for 9+ months due to an 'oversight' on someone's part.
Albeit, a person could be detained that long without a judge even being
involved.

How can that be? He would have been assigned a public defender at
arraignment. Maybe the public defender dropped the ball?

A judge isn't involved in the arraignment?

I wouldn't count on the relevance of 'making the news' here. Examples,
glancing through local coverage trying to obtain news, all I saw were
people doing stupid crimes, justifications for harsh police actions, a lot
of interviews of bystanders and neighbors stating their 'feelings' about
some incident, a box of puppies [yes, a box of puppies], a whole segment
on 'how to shop'; with the best/worst of all,...all the newspeople were
dancing and chattering at the same time with the image turned upside down
demonstrating what I have no idea and further don't care. It's all crap.

In defense, the absolutely BEST news coverage I've ever seen locally was
when the events were unfolding and there was no time to sanitize, nor
homogenize, the news into standard blather. However, when the unfolding
did slow down enough for the station to get ahead, they actually rescinded
some statments [which from viewing the footage were correct so why
rescind?] and then came the 'sound/video bites' justifying the brutal
actions, followed by, you guessed it, almost a box of warm puppies.

I no longer live in Sheriff Joe's jurisdiction, I now live in Sheriff
Paul's...

http://tinyurl.com/lukq649

Another "noisy" sheriff >:-}

I like the ones in Colorado who've told the legislature to pound sand
(re: enforcing the absurd new gun laws).

 

[Fred Abse]

On Sun, 29 Dec 2013 18:28:44 +0200, upsidedown wrote:

On Sun, 29 Dec 2013 08:04:59 -0800, Fred Abse
excretatauris@invalid.invalid> wrote:

On Sun, 29 Dec 2013 16:14:27 +0200, upsidedown wrote:

To understand why auto transformers are attractive with small up/down
voltage conversion (say +/- 10 % to +/- 30 %) , one should remember
that in an ordinary transformer, all the power is transferred through
the iron core, while in an auto transformer, only the power related to
the voltage _difference_ goes through the iron core, in this case only
10 % to 30 %.

Huh?
In *any* transformer, all the primary current goes through the primary,
and all the secondary current through the secondary. The secondary amp
turns oppose the primary amp turns, resulting (in a perfect transformer
having no leakage inductance) in zero net amp turns hence zero flux.
Connecting windings in series makes no difference.

True for ordinary transformers with separate primary and secondary
windings.

You can think about the auto transformer as an ordinary transformer
with the primary connected to the input voltage and secondary with 10
to 30 % of the input voltage. connect the secondary in series with the
input voltage and you get 10-30 % boost (in phase) or 10-30 % drop
(connect in antiphase). Only a small amount of the power goes through
the iron core.

Where does the rest go?

It goes through the galvanic connection.

If, by that, you mean two inductors in series, how do you square that
with; voltage ratio=turns ratio, inductance ratio=turns ratio squared?

Trying to run an auto transformer (variac) at only 5 % of input,
practically all power flows through the iron core of the transformer,
might cause saturation and similar problems.

You cannot saturate a transformer core with secondary amp turns. Even a
shorted secondary won't do it.
Saturation occurs where the magnetizing inductance (inductance of
primary with open secondary) allows enough current to flow to saturate
the core. That's why big current transformers, such as use in
distribution equipment buzz like hell if the secondary is O/C. That's a
good danger warning.

COTS transformers are generally designed to run as close to saturation
as possible, at rated voltage and frequency, to economize on iron.

Depending on the variac setting, you can run hundreds of kW at 1:1
setting (limited only by the contact ratings), at 90 .. 110 % we are
talking about 10 % of the nominal power goes through the core, the rest
goes through the galvanic connection.

At 5 %, most goes through the core. possibly 1/20 of the nominal power
can be transferred through the iron core.

That's just plain wrong.

--
"Design is the reverse of analysis"
(R.D. Middlebrook)

 

[RobertMacy]

On Sun, 29 Dec 2013 09:08:29 -0700, Jim Thompson
<To-Email-Use-The-Envelope-Icon@on-my-web-site.com> wrote:

...snip...
How can that be? He would have been assigned a public defender at
arraignment. Maybe the public defender dropped the ball?

I attributed it to the mediocrity of the defense attorney's capability AND
their desire to not make waves in order to move 'up' in someone else's
eyes. After all the Defendant they work with usually once and the system
they work with everyday.

 

[Jim Thompson]

On Sun, 29 Dec 2013 11:30:12 -0500, krw@attt.bizz wrote:

On Sun, 29 Dec 2013 09:08:29 -0700, Jim Thompson
To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:

On Sun, 29 Dec 2013 09:02:25 -0700, RobertMacy
robert.a.macy@gmail.com> wrote:

On Sat, 28 Dec 2013 14:35:14 -0700, Jim Thompson
To-Email-Use-The-Envelope-Icon@on-my-web-site.com> wrote:

...snip....

To hold someone more than a few hours take a warrant. Sheriffs don't
issue warrants, Judges do. Detaining someone for questioning, then
quickly releasing doesn't count as false arrest.
..snip...
Interestingly, I've lived right here in Arizona (always in the Phoenix
area) for 51 years... and I don't recall the case even making the
news... TV or newspapers (I don't count New Times as a newspaper).

...snip...

I've seen paperwork from the Sheriff's Dept [Arizona] NOT get through the
system to the judge for 9+ months due to an 'oversight' on someone's part.
Albeit, a person could be detained that long without a judge even being
involved.

How can that be? He would have been assigned a public defender at
arraignment. Maybe the public defender dropped the ball?

A judge isn't involved in the arraignment?

Yes. But initial arraignment is (IIRC) a 48-hour hold until your own
lawyer or public defender files for a bail hearing or a writ of habeas
corpus.

I wouldn't count on the relevance of 'making the news' here. Examples,
glancing through local coverage trying to obtain news, all I saw were
people doing stupid crimes, justifications for harsh police actions, a lot
of interviews of bystanders and neighbors stating their 'feelings' about
some incident, a box of puppies [yes, a box of puppies], a whole segment
on 'how to shop'; with the best/worst of all,...all the newspeople were
dancing and chattering at the same time with the image turned upside down
demonstrating what I have no idea and further don't care. It's all crap.

In defense, the absolutely BEST news coverage I've ever seen locally was
when the events were unfolding and there was no time to sanitize, nor
homogenize, the news into standard blather. However, when the unfolding
did slow down enough for the station to get ahead, they actually rescinded
some statments [which from viewing the footage were correct so why
rescind?] and then came the 'sound/video bites' justifying the brutal
actions, followed by, you guessed it, almost a box of warm puppies.

I no longer live in Sheriff Joe's jurisdiction, I now live in Sheriff
Paul's...

http://tinyurl.com/lukq649

Another "noisy" sheriff >:-}

I like the ones in Colorado who've told the legislature to pound sand
(re: enforcing the absurd new gun laws).

Sheriff Paul Babeu is like that as well. He sticks it right in the
nose of the Feds. Of course they bounce right back with an ad hominem
attack outing Babeu as gay. Such a country we've come to :-(

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[RobertMacy]

On Sun, 29 Dec 2013 09:11:20 -0700, Fred Abse
<excretatauris@invalid.invalid> wrote:

On Sun, 29 Dec 2013 09:02:25 -0700, RobertMacy wrote:

I've seen paperwork from the Sheriff's Dept [Arizona] NOT get through
the
system to the judge for 9+ months due to an 'oversight' on someone's
part.
Albeit, a person could be detained that long without a judge even being
involved.

Without his lawyer invoking habeas corpus?

the example I mentioned the defense attorney didn't 'notice', just assumed
the case was moving through the system.

 

On Sun, 29 Dec 2013 09:44:25 -0700, Jim Thompson
<To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:

On Sun, 29 Dec 2013 11:30:12 -0500, krw@attt.bizz wrote:

On Sun, 29 Dec 2013 09:08:29 -0700, Jim Thompson
To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:

On Sun, 29 Dec 2013 09:02:25 -0700, RobertMacy
robert.a.macy@gmail.com> wrote:

On Sat, 28 Dec 2013 14:35:14 -0700, Jim Thompson
To-Email-Use-The-Envelope-Icon@on-my-web-site.com> wrote:

...snip....

To hold someone more than a few hours take a warrant. Sheriffs don't
issue warrants, Judges do. Detaining someone for questioning, then
quickly releasing doesn't count as false arrest.
..snip...
Interestingly, I've lived right here in Arizona (always in the Phoenix
area) for 51 years... and I don't recall the case even making the
news... TV or newspapers (I don't count New Times as a newspaper).

...snip...

I've seen paperwork from the Sheriff's Dept [Arizona] NOT get through the
system to the judge for 9+ months due to an 'oversight' on someone's part.
Albeit, a person could be detained that long without a judge even being
involved.

How can that be? He would have been assigned a public defender at
arraignment. Maybe the public defender dropped the ball?

A judge isn't involved in the arraignment?

Yes. But initial arraignment is (IIRC) a 48-hour hold until your own
lawyer or public defender files for a bail hearing or a writ of habeas
corpus.

Sure but 48hrs <> 9+ months

I wouldn't count on the relevance of 'making the news' here. Examples,
glancing through local coverage trying to obtain news, all I saw were
people doing stupid crimes, justifications for harsh police actions, a lot
of interviews of bystanders and neighbors stating their 'feelings' about
some incident, a box of puppies [yes, a box of puppies], a whole segment
on 'how to shop'; with the best/worst of all,...all the newspeople were
dancing and chattering at the same time with the image turned upside down
demonstrating what I have no idea and further don't care. It's all crap.

In defense, the absolutely BEST news coverage I've ever seen locally was
when the events were unfolding and there was no time to sanitize, nor
homogenize, the news into standard blather. However, when the unfolding
did slow down enough for the station to get ahead, they actually rescinded
some statments [which from viewing the footage were correct so why
rescind?] and then came the 'sound/video bites' justifying the brutal
actions, followed by, you guessed it, almost a box of warm puppies.

I no longer live in Sheriff Joe's jurisdiction, I now live in Sheriff
Paul's...

http://tinyurl.com/lukq649

Another "noisy" sheriff >:-}

I like the ones in Colorado who've told the legislature to pound sand
(re: enforcing the absurd new gun laws).

Sheriff Paul Babeu is like that as well. He sticks it right in the
nose of the Feds. Of course they bounce right back with an ad hominem
attack outing Babeu as gay. Such a country we've come to :-(

The left is homophobic? Lefties are bigots? Who wudda thunk.