Your pet peeve, technical or otherwise.

[Circlotron]

One thing that drives me nuts here in Canada is one of the habits TV news editors have when showing an interview.  The graphic tag line that shows who is being interviewed stays on the screen for about 1.7 seconds!  Who reads that fast?  And it doesn't matter how much, or little, text is there, it's impossible to read it all in that time.  That much time can elapse just with recognizing that its there and moving your eyes to begin reading it and then, poof! it's gone.  And if there is an unfamiliar acronym or lengthy multi-word descriptor, forget it!  

That reminds me of something that annoys me in shows/movies, when the editing cuts between cameras constantly and way too rapidly. My mind is still processing the detail in the scene and then it suddenly cuts to a different perspective, I find it quite jarring.

Kids CGI cartoon movies are often like that from start to finish.

[Sal Ammoniac]

I absolutely hate the recent trend for Hollywood movies to use shaky hand-held cameras. Gives me motion sickness just watching some of them.

[Ed.Kloonk]

"Are you sure you want to log out?"

 

[Labrat101]

I absolutely hate the recent trend for Hollywood movies to use shaky hand-held cameras. Gives me motion sickness just watching some of them.

Yes its beyond enoying . The camera men are ether Drunk or dogging bullets .
 From the other cheap scenes & Flash Backs   

 Quote from above.
  Are you sure you want to log out? 

     Not sure I will give it some thought ...
                         KK  eeee Y y Board E rr OOer

[Circlotron]

When people insist that with two engines of equal capacity [edit -> displacement, not capacity], the one with the longer stroke would produce greater torque, supposedly because of the greater leverage of the larger crank pin offset. What they fail to realise is what the longer stroke gains from greater crank leverage, it loses by smaller piston area.

 If you have 500psi pushing on 12 square inches of piston then you have 6000 lbs force pushing on a crank radius of say 3 inches = 5000x12x0.25 = 1500 lb/ft of torque. Then if you halve the piston area and double the stroke you have 500x6x0.5 = 1500 lb/ft again! As a first approximation, engine torque depends on capacity and volumetric efficiency, not stroke.

[james_s]

When people insist that with two engines of equal capacity, the one with the longer stroke would produce greater torque, supposedly because of the greater leverage of the larger crank pin offset. What they fail to realise is what the longer stroke gains from greater crank leverage, it loses by smaller piston area.

 If you have 500psi pushing on 12 square inches of piston then you have 6000 lbs force pushing on a crank radius of say 3 inches = 5000x12x0.25 = 1500 lb/ft of torque. Then if you halve the piston area and double the stroke you have 500x6x0.5 = 1500 lb/ft again! As a first approximation, engine torque depends on capacity and volumetric efficiency, not stroke.

Why are you assuming a longer stroke brings with it smaller piston area? Displacement, stroke and bore do not exist in isolation, they are all interactive. I don't do much engine tinkering these days but there are obviously advantages and disadvantages of different stroke and bore ratios. The belief may just be due to the fact that engines with a long stroke tend to be large displacement, relatively slow turning engines that produce a lot of torque because that is what they are optimized for, being low RPM.

[Cubdriver]

When people insist that with two engines of equal capacity, the one with the longer stroke would produce greater torque, supposedly because of the greater leverage of the larger crank pin offset. What they fail to realise is what the longer stroke gains from greater crank leverage, it loses by smaller piston area.

 If you have 500psi pushing on 12 square inches of piston then you have 6000 lbs force pushing on a crank radius of say 3 inches = 5000x12x0.25 = 1500 lb/ft of torque. Then if you halve the piston area and double the stroke you have 500x6x0.5 = 1500 lb/ft again! As a first approximation, engine torque depends on capacity and volumetric efficiency, not stroke.

Why are you assuming a longer stroke brings with it smaller piston area? Displacement, stroke and bore do not exist in isolation, they are all interactive. I don't do much engine tinkering these days but there are obviously advantages and disadvantages of different stroke and bore ratios. The belief may just be due to the fact that engines with a long stroke tend to be large displacement, relatively slow turning engines that produce a lot of torque because that is what they are optimized for, being low RPM.

I'm going with the assumption that when he said "engines of equal capacity" that he meant equal displacement.  Longer stroke with equal displacement would have to mean smaller bore.  As for the torque numbers, I have no input on that.

-Pat

[james_s]

I'm going with the assumption that when he said "engines of equal capacity" that he meant equal displacement.  Longer stroke with equal displacement would have to mean smaller bore.  As for the torque numbers, I have no input on that.

-Pat

Well yeah, you can't increase the stroke without decreasing the bore if you want to keep the same displacement. It does seem like longer stroke engines tend to have more torque but I suspect it isn't just due to the stroke, but the fact that the entire engine is designed for lower RPM and higher torque. On the flip side F1 engines run at absurdly high RPM and have exceptionally short stroke, that comes down to piston speed I think. If you had a 6 inch stroke and tried to spin the crank at 15k RPM the piston speed and resulting forces would be ridiculous.

[Circlotron]

I'm going with the assumption that when he said "engines of equal capacity" that he meant equal displacement.

Yep. My bad. I'll edit that.

My thinking is that an engine with a long stroke relative to its bore (very undersquare) would not have space for large valves so it may run well chugging away at low rpm but run out of breath pretty quick at high rpm. Some people without an engineering background may get to thinking that torque is a description of how an engine behaves at low rpm.

[opabob]

For your standard SPST light switch, UP is ON, DOWN is OFF.
Also, American 120v receptacles, the Ground is on the bottom with the Hot and Neutral on top.
.

[sibeen]

For your standard SPST light switch, UP is ON, DOWN is OFF.

No. You're completely wrong there I'm afraid. Completely.

[TimFox]

opabob and I are from the US, where light switches on the wall and toggle switches on front panels are always as he describes.  Is your common practice antipodal?

[rdl]

For your standard SPST light switch, UP is ON, DOWN is OFF.

And I would add, for on/off applications the switch should always operate up/down never side to side. For push buttons, in is on, out is off.

[james_s]

opabob and I are from the US, where light switches on the wall and toggle switches on front panels are always as he describes.  Is your common practice antipodal?

UK is opposite, down is on, it's one of the first things I noticed when I visited there and it felt very odd to me. Of course it doesn't apply to 3 way switches in which it's what is on depends on the state of the other switch, or the occasional horizontal switch.

Obviously on an international forum what is "wrong" depends on where an individual lives. Every country has its own codes and conventions.

[james_s]

For your standard SPST light switch, UP is ON, DOWN is OFF.
Also, American 120v receptacles, the Ground is on the bottom with the Hot and Neutral on top.
.

There's actually no code requirement on whether ground is on the top or the bottom, and if you look closely at most spec grade and hospital grade receptacles the writing is such that it's rightside-up if the receptacle is installed with the ground hole at the top and the live and neutral below. I've heard an electrician advocating installing them that way so that if something conductive drops on a plug that is not fully inserted it will contact the ground pin first. It's uncommon though, most are installed the other way around but it's legal (in the US) to put them in any orientation, including horizontal.

[sibeen]

opabob and I are from the US, where light switches on the wall and toggle switches on front panels are always as he describes.  Is your common practice antipodal?

Yeppers. Generally down is on.

[opabob]

I understand every country has it's customs.  But me, here, I like my light switches UP ON, DOWN OFF.   

Pet Peeve.  Just like the thread title.

Interesting story about receptacle orientation
.

[Labrat101]

 Up Down !!  So why are fuses when tripped are always DOWN
 And only Blow UP  ?? 
Why are Main Isolator Switches DOWN is Off . 
 Simple reason if your getting electrocuted  your arm is Only able to Pull Down .
 So if your lucky and the Non ISO standard is down for ON ..  Smoke bacon flavour  .
 Down was Made the ISO standard take it or leave it .

Domestic Light switches are not covered and seem to be ether or .
Double pole or reversed light switch's 1 has to be up and the other down for the light to be On.
Or visa versa   

[TimFox]

Your recitation omits which country is being discussed.  We have already established that these functions vary from jurisdiction to jurisdiction.

[james_s]

My circuit breakers flip horizontally, the vast majority of those in the USA do. The panel bus bars run from top to bottom and the breakers sit perpendicular to this.

[Monkeh]

My circuit breakers flip horizontally, the vast majority of those in the USA do. The panel bus bars run from top to bottom and the breakers sit perpendicular to this.

Which is also how 3-phase boards are arranged, because it's practical.

[Circlotron]

The standard of up for on might have originated from the days of Frankenstein and his monster and similar, where he used a knife switch in the lab. Gravity would keep the switch harmlessly in the off position with no chance of falling to the on position like it would if down was on.

[PlainName]

There seems to be an assumption that the default should be off. Fine for the techy handling the bare wires, but for the other 99.999% of the time a user would be really badly put out if the lights go out accidentally. For that and similar reasons, down = on makes more sense.

Also, with down = on, the tops the switches can be coloured red to show they are on. With up = on, you'd never see that

[james_s]

The most common switches in North America have a protruding toggle rather than a rocker and the words ON and OFF are embossed on the moving assembly. This of course does not apply to 3-way switches and I don't know whether anyone actually relies on the printing. Personally I find it's easiest to just look at the light and see if it's on. If the light is not on when I think it should be then I can investigate further. For lights located remotely and not visible from the switch, there are switches that have a pilot light.

[E-Design]

The standard of up for on might have originated from the days of Frankenstein and his monster and similar, where he used a knife switch in the lab. Gravity would keep the switch harmlessly in the off position with no chance of falling to the on position like it would if down was on.

Yes the knife switch.. a sensible answer to the possible origin of the convention!