Electricity and Common Urban Myths

[Don1966]

Dan and Pat one of the things I love about being in this business is you never stop learning. Every day I work is a new challenge or a new adventure. This makes it hard to retire because I would miss it too much. How many people can say I look forward to work today or I love my job? It's like an addiction once you understand it, it leaves you thirsty for more. I have made it my point to learn every thing I can about it and this makes my job a whole lot easier. I love to read and my book shelf is full. Now i am filling it with model engineering books and this is getting addictive.

Don

 

[JorgensenSteam]

Don-

I like steam engines a lot, and I like electricity a lot, so Manfred's posts are just the cats meow to me, since I would use a steam engine to power a generator.

And I like my job a lot too, and can't believe people pay me to do something that I love to do.

But no matter how much I think I know, I never fail to learn from these posts.

Generally, when you post something on an open forum, if 10 people respond, then two will agree with you, two will disagree with you and be wrong, two will disagree with you and be right, two will add something that you did not know, and two will respond with things that are so far out they leave you amazed, but interested.

So that is what is good about forums, any way you look at it, you are going to learn if you post something.

Pat J

 

[Entropy455]

Without looking it up, can anyone name the six ways electricity can be generated?

Yes, there are only six ways - it's not a trick question. . . . .

 

[JorgensenSteam]

Man, I hate these quizzes.

Lets see, 1. Battery, 2. Thermocouple, 3. Generator, 4. Static Electricity, 5. Striking Crystals, 6. ?

I must have been asbent when they covered item 6.

Did you know that when you strike a crystal with a small hammer, it produces an electrical voltage/current, such as with a bbq propane lighter.

But when you apply electricity to a crystal, they vibrate, so they used crystals to shake the instruments on fighter planes when they were in a high-G situation to keep inertia from freezing the instrument movement.

And a thermocouple (to strips of dissimilar metals bonded together) will generate electricity, but if you provide electricity to a thermocouple, one side of the metal strips gets hot, and the other gets cold, which is how these 12 volt cooler/heaters that don't have compressors work (the ones that plug into your car 12 volt system).

Did you know you can buy a propane powered refrigerator? Yep. Many campers use them, but I have seen full sized units in houses too.

Did I get any answers correct?
If yes, do I win some sort of major award, such as a years supply of carbide tool inserts or something?

Pat J

 

[Entropy455]

Very good. You got the hard ones. . . .

The sixth is solar.

 

[Don1966]

Yes Pat it is called piezoelectric. And the old refrigators used to use ammonia in them for refrigent and were heated with gas,kerosene, and electricity. Did you know that air conditioners do not cool a room, they only remove the heat so the room feels cool.

Don

 

[JorgensenSteam]

Seems like I read somewhere about motor circuits originally operating at 30 Hz, and lighting circuits operating at 100 Hz, in order to maximize efficiency.

Separate systems were provided for each, with separate generators.

At some point (don't know when) a compromise was reached at 60Hz in the US, and 50 Hz in some other countries.

Generally people assume that things have always been the way they are now, but it developed over time.

 

[Ken I]

I really would like to know who and when they decided on 50/60Hz.

Higher frequencies give better performance at end user level (commercial airliners typically use 400Hz for high efficiency electric motor drives) but are lousy for power distribution efficiency.

So I would assume a bunch of engineers sat down and tried to determine the best compromise (and almost certainly got it wrong).

Does anyone know ?

Ken

 

[steamer]

I really would like to know who and when they decided on 50/60Hz.

Higher frequencies give better performance at end user level (commercial airliners typically use 400Hz for high efficiency electric motor drives) but are lousy for power distribution efficiency.

So I would assume a bunch of engineers sat down and tried to determine the best compromise (and almost certainly got it wrong).

Does anyone know ?

Ken

I suspect there was 1 too many cases of beer involved... ;D

Glad we're all having a good time...... :bow: I've seen similar conversations get down right ugly quickly.....must be the caliper of the people on this forum

Dave

 

[Ken I]

I suspect there was 1 too many cases of beer involved...

Glad we're all having a good time

O.K. time for a Geek joke

Two atoms are having a conversation...

atom1 "You know, I think I've gone and lost an electron."

atom2 "Are you Sure ?"

atom1 "Yes, I'm positive !"

Groannnnnn......

Ken

 

[steamer]

Where's the rim shot!
:big:
He's here all week folks...try the meatloaf and tip your waiter!

Dave

 

[Dan Rowe]

What about electric eels?

The process is similar to a battery but it involves living cells.
http://en.wikipedia.org/wiki/Electric_organ_discharge

Dan

 

[Dan Rowe]

I really would like to know who and when they decided on 50/60Hz.

Ken,
This wiki article covers it fairly well.
http://en.wikipedia.org/wiki/Utility_frequency

Dan

 

[Don1966]

Hey guys did you here about Henry the inductor catching Charlie capacitor playing with Diana Diodes anode.

Don

 

[rhitee93]

Hey guys did you here about Henry the inductor catching Charlie capacitor playing with Diana Diodes anode.

Don

Ahh, that Diana. She is a free-wheeling kind of gal...

(Well, the EEs in the room get it)

 

[JorgensenSteam]

Ken,
This wiki article covers it fairly well.
http://en.wikipedia.org/wiki/Utility_frequency

Dan

Dan-

That is a good article.
Seems like many things electrical in the US were defined with the Westinghouse electrification of Niagara Falls in 1895.

I have worked with 400Hz, and the voltage drop is huge, you can go about 50 feet with a circuit before you need a voltage regulator, but you can also have tiny little powerful motors on an aircraft. On a large aircraft ramp, which is the typical arrangement for large airports, you need a regulator at every gate.

Diesel-electric locomotives are also interesting, since the series-wound motor can produce a large amount of torque, thus eliminating the need for a clutch.

Pat J

 

[Dan Rowe]

Without looking it up, can anyone name the six ways electricity can be generated?

Yes, there are only six ways - it's not a trick question. . . . .

Okey I will admit I looked it up but the 6 ways mentioned are well known to most engineers.

Wiki makes no distinction about living cells so electric eels like a battery are classified as electrochemistry.

The method not mentioned is nuclear transformation.
http://en.wikipedia.org/wiki/Electricity_generation

Alphavoltaic and betavoltaic are two examples of the class.
http://en.wikipedia.org/wiki/Betavoltaics

Dan

 

[Mosey]

When you cool the room, isn't it correct that you remove the moisture ( not the heat) and therefore the temperature drops?

 

[Dan Rowe]

Diesel-electric locomotives are also interesting, since the series-wound motor can produce a large amount of torque, thus eliminating the need for a clutch.

Pat,
The thing I remember from school about series wound DC motors is they need an application that does not allow them to freewheel. The high starting torque will speed them up to destruction without a load. That is why they are only used on things like subway cars and locomotives or connected to gear trains.

Dan

 

[Don1966]

Negative Mosey, the AC refrigerant absorbs the heat in order to boil the gas which is a liquid to a vapor. This is why it works. Then you do what is call super heat the gas with a compressor elevating the boiling point of the gas to condense back to a liquid, it thus transferring the heat to the outside. I would say the movement of heat is like a heat exchanger just a different approach. The moisture is removed by the condensation from the cool coils.

Don