Your pet peeve, technical or otherwise.

[CatalinaWOW]

How do you use a mercury arc rectifier to turn DC into AC? I didn't realize that was possible.

Either way it was not practical for small scale stuff. It would make no sense to use DC transmission into residential neighborhoods with converters to turn it into AC and step it down for each group of houses.

It would make no sense to convert the existing installed base.   Starting from scratch with today's components it might make a lot of sense.  No capacitive or inductive loss.  No power factor issues.  Simplified grid sync. 

[Circlotron]

The inverters used thyratrons or ignitions.

Ignitrons
Not being pedantic, just fixing the word so those unfamiliar with this olde timey tech can look it up.

[TimFox]

Oops!  I typed "ignitron" but Microsoft didn't recognize the word.  I remember a comic strip where the office workers were not allowed to have games on their company computers, so they goofed off by entering their names into spell-check to see what came out.

[Labrat101]

Quote from: Circlotron on Today at 04:44:14 am>Quote from: TimFox on Yesterday at 09:30:10 pm

The inverters used thyratrons or ignitions.

Ignitrons
Not being pedantic, just fixing the word so those unfamiliar with this olde timey tech can look it up.


Ignitrons are ignitor-fired mercury pool rectifiers with very high peak and average current handling capability. Low frequency ignitrons were the backbone of the welder control and electroplating industries for years. These low-cost devices are still in use today in large motor speed controls and many welder panels around the world.
 Just A cool home garage project 

[themadhippy]

office workers were not allowed to have games on their company computers

so instead  microsoft hid them as easter eggs within excel and word

[radar_macgyver]

It would make no sense to convert the existing installed base.   Starting from scratch with today's components it might make a lot of sense.  No capacitive or inductive loss.  No power factor issues.  Simplified grid sync.

It would require very expensive breakers that can deal with the arcs produced when interrupting a DC current. HVDC links (point-to-point) get around this by shutting off the rectifier, this won't work for a one-to-many distribution.

[Labrat101]

Quote from: radar_macgyver on Today at 05:41:07 pm>Quote from: CatalinaWOW on Yesterday at 10:09:07 pm

It would make no sense to convert the existing installed base.   Starting from scratch with today's components it might make a lot of sense.  No capacitive or inductive loss.  No power factor issues.  Simplified grid sync.

It would require very expensive breakers that can deal with the arcs produced when interrupting a DC current. HVDC links (point-to-point) get around this by shutting off the rectifier, this won't work for a one-to-many distribution.

These are still in production and shutting the arc off is simple . without a contactor .
 https://www.relltubes.com/products/High-Energy-Transfer-Products/Ignitron.html
 

[srb1954]

I said “Mercury-vapor tubes”.  The inverters used thyratrons or ignitions.  Mercury-vapor rectifiers do not use arcs.

There are mercury arc rectifiers that certainly do seem to contain arcs when operating.

I have seen a demonstration mercury arc rectifier operating. It looked like a glass octopus with a large bulbous head about 800mm high in total. From each of the arms lightning bolts appeared to travel in a jagged arc to a spot on the surface of the mercury pool. The spot where the arcs terminated seemed to dance around randomly on the surface of the pool.

The whole assembly was enclosed in a explosion containment box made of a a thick, very dark tint plastic to filter out the prodigious UV emissions from the arcs.

[TimFox]

There is some confusion in nomenclature.
Mercury-arc rectifiers indeed have arcs into a pool of liquid mercury.
The mercury-vapor rectifiers to which I referred (e.g. 872 and 866) have hot cathodes emitting electrons, and the mercury ions inhibit space charge, allowing a much lower anode-cathode voltage when forward biased.  The 872A could withstand 10 kV reverse voltage, with only 10 V forward drop at several amperes forward conduction (much lower than a high-vacuum rectifier).

[mag_therm]

Mercury Arc DC to AC inverters were in use probably before WW2.
They used 3 phase half wave (triple anode, 1 cathode, grid controlled)
glass bulb  mercury arc devices.

Probably used by rail-road and heavy industry eg steel rolling mill etc.

I have a reference here:
Robert Wells: "Static Power Converters" published 1962

[Circlotron]

Oops!  I typed "ignitron" but Microsoft didn't recognize the word.  I remember a comic strip where the office workers were not allowed to have games on their company computers, so they goofed off by entering their names into spell-check to see what came out.

That’s like MS Word 97. You would type in the name of former Australian prime minister Paul Keating and it would substitute the word “cheating”. 

[TimFox]

In a different arc discussion here, I referred to the “Poulsen arc” (later known as the “Federal arc”), and spell-check changed it to “Poulenc”.  When typing this, it did it again, but I was ready for it.  At least it was a high-class cultural error, instead of, say, “poultry”.

[NiHaoMike]

That’s like MS Word 97. You would type in the name of former Australian prime minister Paul Keating and it would substitute the word “cheating”. 

On some old version of OS X, entering "bill gates" into the terminal gives the response "kill gates?".

[Siwastaja]

Saying "LDO" when you definitely mean "linear regulator".

[DimitriP]

Entering a conversation with:
"I'm a noob"
"I'm new to all this"
"All this is new to me"
"I just got this xyz and I know nothing"

and last but not least ....
"I'm a new ham"

Or "a ham radio license is "a license to learn" "

[SilverSolder]

Entering a conversation with:
"I'm a noob"
"I'm new to all this"
"All this is new to me"
"I just got this xyz and I know nothing"

and last but not least ....
"I'm a new ham"

Or "a ham radio license is "a license to learn" "

I don't know, it seems kind of useful to state up front what your level of experience is?   

E.g. if someone starts the conversation "I have used oscilloscopes for years, but this measurement is driving me crazy..." you might respond differently than if someone says "I'm a complete n00b and this is my first 'scope, how would you...."

No?

[E-Design]

Entering a conversation with:
"I'm a noob"
"I'm new to all this"
"All this is new to me"
"I just got this xyz and I know nothing"

and last but not least ....
"I'm a new ham"

Or "a ham radio license is "a license to learn" "

I don't know, it seems kind of useful to state up front what your level of experience is?   

E.g. if someone starts the conversation "I have used oscilloscopes for years, but this measurement is driving me crazy..." you might respond differently than if someone says "I'm a complete n00b and this is my first 'scope, how would you...."

No?

Agreed.. level of experience can be useful in creating responses. So a free pass this time. But dont use the word n00b. Makes you sound like a b00b.

Speaking of scopes.. how about this GEM of a thread starter
"Help a woman choose here first oscilloscope" - like being a woman has ANYTHING to do with it. geez, geat real.

[Ed.Kloonk]

They are better off making sandwiches.

[james_s]

Entering a conversation with:
"I'm a noob"
"I'm new to all this"
"All this is new to me"
"I just got this xyz and I know nothing"

and last but not least ....
"I'm a new ham"

Or "a ham radio license is "a license to learn" "

I don't know, it seems kind of useful to state up front what your level of experience is?   

E.g. if someone starts the conversation "I have used oscilloscopes for years, but this measurement is driving me crazy..." you might respond differently than if someone says "I'm a complete n00b and this is my first 'scope, how would you...."

No?

I find it useful. It saves me from trying to explain Ohms law to an experienced EE, or making the assumption that someone already knows such basics and jumping straight to more complicated things.

[Bud]

"I am designing thing X but I have no clue how to do it".

Really?

You are "designing" ?

[DimitriP]

"I am designing thing X but I have no clue how to do it".

Really?

You are "designing" ?

You forgot to add "noob" in the sentence    

[SilverSolder]

Entering a conversation with:
"I'm a noob"
"I'm new to all this"
"All this is new to me"
"I just got this xyz and I know nothing"

and last but not least ....
"I'm a new ham"

Or "a ham radio license is "a license to learn" "

I don't know, it seems kind of useful to state up front what your level of experience is?   

E.g. if someone starts the conversation "I have used oscilloscopes for years, but this measurement is driving me crazy..." you might respond differently than if someone says "I'm a complete n00b and this is my first 'scope, how would you...."

No?

Agreed.. level of experience can be useful in creating responses. So a free pass this time. But dont use the word n00b. Makes you sound like a b00b.

Speaking of scopes.. how about this GEM of a thread starter
"Help a woman choose here first oscilloscope" - like being a woman has ANYTHING to do with it. geez, geat real.

Sure it has something to do with it...  like attracting hundreds of men to help her!  Probably the best framing of a question ever!   

[Labrat101]

Entering a conversation with:
"I'm a noob"
"I'm new to all this"
"All this is new to me"
"I just got this xyz and I know nothing"

and last but not least ....
"I'm a new ham"

Or "a ham radio license is "a license to learn" "

I don't know, it seems kind of useful to state up front what your level of experience is?   

E.g. if someone starts the conversation "I have used oscilloscopes for years, but this measurement is driving me crazy..." you might respond differently than if someone says "I'm a complete n00b and this is my first 'scope, how would you...."

No?

Agreed.. level of experience can be useful in creating responses. So a free pass this time. But dont use the word n00b. Makes you sound like a b00b.

Speaking of scopes.. how about this GEM of a thread starter
"Help a woman choose here first oscilloscope" - like being a woman has ANYTHING to do with it. geez, geat real.

Sure it has something to do with it...  like attracting hundreds of men to help her!  Probably the best framing of a question ever!   

That has really got to me that Post   
    Its like putting the sweets near the checkout  . 

[HobGoblyn]

Nothing at all against charity and helping those in need,

BUT

I’ve had a bad week, we’ve also got the pandemic, I want to switch off from reality for a couple of hours, have a few beers and watch a comedy on the COMEDY channel and hopefully make myself laugh.

There was about 10 different charities advertising during that film, everything from children going blind to crippled donkeys. I’ve got all the sympathy in the world for their plight, but lately in the UK the charity tv adds are in overload. Imo I should be able to turn on the Comedy channel without seeing this sort of thing every 15 mins.

Hope no one misinterprets what I’m saying 

[Labrat101]

I know how you feel .
Charity for the Dogs Cats , Donkey etc & children OK They need .

        And
     Then the next Advert is a Donkey advertising Mouth Wash