Basic electrical lesson

[dave1949]

I have a dryer that has a dial that goes to eleven.
Can I play in this conversation?

Only if it also has a "damp dry" setting. :laughing:

 

[xtn]

Thank goodness. :laughing:

To be picky, I didn't think my original sentence was all that bad. The discussion was about the electricity cost of operating a clothes dryer.

If I had included the implicit information such as: "[Operating a dryer rated at] 7200 watts per hour [of use] = 7.2kWh." Would I still be guilty?

Ahhhhh... the difference context can make, huh? It would still be clearer if you just said "operated for an hour." Hmmmm, I wonder if sentences like yours are the real reason people so commonly get it wrong. I mean your sentences is technically accurate, but then some guy's going to later try explaining to his wife and what she's going to hear is "7200 watts per hour = 72 kilowatt-hours."

 

[CobyRupert]

I have a dryer that has a dial that goes to eleven.
Can I play in this conversation?

- Yes Nigel. Why didn't you just make the 10 setting hotter?

 

[dave1949]

Ahhhhh... the difference context can make, huh? It would still be clearer if you just said "operated for an hour." Hmmmm, I wonder if sentences like yours are the real reason people so commonly get it wrong. I mean your sentences is technically accurate, but then some guy's going to later try explaining to his wife and what she's going to hear is "7200 watts per hour = 72 kilowatt-hours."

It sounds like I'm still guilty of something. Nothing new there. :laughing:

 

[CobyRupert]

A beautiful mind?

Ha ha, true story, I guess there is some similarity, though I never won any Nobel Prizes or went to MIT.

 

[troutsqueezer]

Ha ha, true story, I guess there is some similarity, though I never won any Nobel Prizes or went to MIT.

Technically, that would be "NOR went to MIT". :laughing:

 

[JerryK]

In the sixties, before I got to go play in Vietnam, I was taught that the holes flow from Positive to Neg, and the electrons flow from Neg to Pos... [ so there, pppppppppffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffftt ] [ I assumate that raspberries are allowed on this forum.. ]

 

[CobyRupert]

It gets confusing because nobody knows what a Joule of energy is, or the relationship between (total) energy, (instant) power and time.
A Watt is the power being applied in that instant, whereas a Joule represents the total energy required, regardless of time. See, a Watt already has a time component in it, in that 1 Watt= 1 Joule/sec. Or conversely, consuming 1 Watt for 1 second = 1 Joule of total energy used.
(Example: It might take 100 joules of total energy to pick up a rock into a truck. You can use a 25 watt motor (and gears/pulleys) to do it in 4 seconds, but you would need a 200 Watt motor if you wanted to do it in a 1/2 sec. Understand?

So when you talk about 7.2 kilowatt-hours, that is the (total) energy that 7200 Watts (of instantaneous power) consumes in an hour. (Or 7200 Joules/sec x 3600seconds = 25.9 mega joules (or about 24,000 BTU's using imperial uits), but nobody says " Hey the electric bill last month was 25.9 mega-joules, cause it would be even more meaningless than saying it's 7.2 kilowatt-hours."

Its a way of using units that don't make logical sense but are familar, sort of like answering "How far is it to the dealer?" With "About an hour if you drive the speed limit" [Hint: An hour is not a unit of distance!- pet peeve!]

 

[CobyRupert]

Technically, that would be "NOR went to MIT". :laughing:

See, that proves my point. :laughing:

 

[mikehaugen]

Imagine my surprise when I first heard a boiler rated in hp. I know it's the type of measurement, but it seemed strange. Hmm... makes me wonder how my tractor's 38 hp converts to btus/hr.

Not quite electrical I know, but I thought it was relevant nonetheless.

 

[JerryK]

And, when grounded plugs first came out.. I was taught that the proper way to install them was with the ground up. In fact, Bryant, a premier maker of quality plugs and recp's used to picture their grounded plugs on the front of their 10 pack with the ground up.... I still mount them that way, in memory of the fine person that taught me that many years ago... Bud Taylor. There was a big stink about that at first, the ground up folks went with ' things sliding down the wall would contact the ground first ' and ' that the male plug actually is harder to yank out downward that way '... You can argue for hours with the inspectors about it, if you have a slow day..... and arn't really worried about final approval...

 

[dave1949]

Imagine my surprise when I first heard a boiler rated in hp. I know it's the type of measurement, but it seemed strange. Hmm... makes me wonder how my tractor's 38 hp converts to btus/hr.

Not quite electrical I know, but I thought it was relevant nonetheless.

James Watt first defined horsepower.
Horsepower

 

[CobyRupert]

Imagine my surprise when I first heard a boiler rated in hp. I know it's the type of measurement, but it seemed strange. Hmm... makes me wonder how my tractor's 38 hp converts to btus/hr.

Not quite electrical I know, but I thought it was relevant nonetheless.

1 hp = 2546.699 BTU/hr = 746 Watts = 550 lb-ft/sec.

 

[Daver1963]

Originally Posted by rsallen

I have a dryer that has a dial that goes to eleven.
Can I play in this conversation?

- Yes Nigel. Why didn't you just make the 10 setting hotter?

".....but this one goes to 11."

 

[CobyRupert]

And, when grounded plugs first came out.. I was taught that the proper way to install them was with the ground up. In fact, Bryant, a premier maker of quality plugs and recp's used to picture their grounded plugs on the front of their 10 pack with the ground up.... I still mount them that way, in memory of the fine person that taught me that many years ago... Bud Taylor. There was a big stink about that at first, the ground up folks went with ' things sliding down the wall would contact the ground first ' and ' that the male plug actually is harder to yank out downward that way '... You can argue for hours with the inspectors about it, if you have a slow day..... and arn't really worried about final approval...

-Yep, that's a classic. The ol' paper sliding down the wall hits the ground prong first is a good thing, but if being yanked out from below, the ground plug is the first to break contact which is not good. - Use a twist lock!

 

[reb]

....then there are many of us who operate with "fuzzy logic".

..

I remember reading in technical magazines in the 90s about "fuzzy logic" being used in smart appliances, such as clothes washers. As I understood it, fuzzy logic doesn't follow the rigid rules of the logic in our computers. Somehow it seemed reasonable to use fuzzy logic in appliances commonly used by the female of the species, tho I never mentioned that to the wife .

 

[dave1949]

We have a "Neuro Fuzzy" automatic rice cooker made in Japan. It's smart about rice cooking :laughing:

The booklet doesn't explain what is fuzzy about it. I think the Japanese like these catchy tech names.

 

[LD1]

1 hp = 2546.699 BTU/hr = 746 Watts = 550 lb-ft/sec.

Hmm... makes me wonder how my tractor's 38 hp converts to btus/hr.

Not quite electrical I know, but I thought it was relevant nonetheless.

So your tractor is just shy of 100,000BTH/hr:thumbsup:

 

[sd455dan]

A beautiful mind?

or Good will hunting- Matt Damons role??

 

[mikehaugen]

or Good will hunting- Matt Damons role??

You sir, are correct... that's what I was thinking of. Oops.