Short Circuit Connection

My customer says that his LV network short circuit (SC) current is 65KA and peak SC is 137 KA. Please tell me how does it affect the motor designer. E.g is my customer expecting 65 KA to flow through the motor windings (stator/rotor) for certian duration e.g 65KA for 0.25 sec.? Please clarify.

Difference Between Iu & Ith

Can you help me guys know the difference between Ith & Iu rating in MCCB?

I have an MCCB with the rating of Ue = 660 volts & Iu = 1250 Amps

It as a rating also of Ith = 800 amps max @ 45 deg C & Ir = 6300.

I have a motor for my chiller which requires a MCCB wit

MCCB Ith & Ir Acronym Meaning

We are planning to replace our Chiller with bigger capacity.

The motor rating of old chiller is 375 kw whhle the new one is 570 kw, all at 380 volts, 3phase , 60 hz. The suppllier required us to a circuit breaker with minimum ampacity of 911 amps.

our existing Circuit Breaker is SA

Reflections on “Unruly Democracy” from Bioephemera (Jessica Palmer) | The Intersection

I think I can safely say that our event on Friday at the Harvard Kennedy School, entitled "Unruly Democracy: Science Blogs and the Public Sphere," was a success, and perhaps even exceeded expectations. The room was full; the presentations were great; we had a historic first panel bringing together representatives of Seed, Discover, and The Boston Globe to talk about three different approaches to science blogging; we had a real debate about whether blogs are "good" or "bad" for science--and we had a move towards some constructive suggestions for finding better norms in the blogosphere. If you want proof that the event has caused some very important thought and reflection, you need go no further than this lengthy post from Jessica Palmer of Bioephemera, who attended and gave a rockin' talk on my panel. Jessica is, broadly speaking, in my camp--or what on Friday was called the "Sunsteinian" camp--when it comes to the negatives of blogging. Why? Some excerpts from her post:
My big concern? While individual blogs often have communities who are internally civil and share norms and history, when you move from blog to blog, those norms and history break down. There are no universal norms in the science blogosphere, ...


How the Universe Works | Bad Astronomy

A new science show premiered on The Discovery Channel last week called "How The Universe Works". I just watched the first episode, and it’s pretty good!

howtheuniverseworks

The first show was about the Big Bang, and hits all the right notes. The graphics are pretty good — that’s de rigeur for modern TV shows — but the music is nice, too. The writing is engaging, and Mike Rowe is a terrific narrator. All in all, I recommend it… tonight’s (Sunday) episode is about black holes. I have word that a certain Bad Astronomer is interviewed for that one… and I did a bunch of other topics for them as well, so I assume you’ll be seeing more of me on the show in later episodes, too!


Chemical Safety Act: Boon or Bane?

The proposed Chemical Safety Act creates some significant changes in the way that chemical companies would be required to provide safety information. While the legislation may have a positive affect on consumer safety, it could mean significant changes for the chemicals industry. What changes do you

Barefoot Revolt?

Is Puma setting a new trend by using the science of saving resources rather than eco-hype with its new packaging? Their new shoe bag/box touts savings in resources across the board as well as reductions in carbon emissions. The packaging is made of recycled PET and is itself recyclable. Do you think

ismc weight

hi this is mahesh raja. i have the question for how to calculate the weight for the ismc 100 and i need the formula for calculating the weightage....it's very urgent pls help me in this.

People of class drink alcohol | Gene Expression

don-draperOn his twitter feed one Conor Friedersdorf made a comment about how beer unites people across the ideological spectrum. I raised my eyebrows at this, because I know that a substantial number of Southern white Protestants do not drink alcohol. With a name like Friedersdorf I suspect that Conor probably didn’t consider this because of the normative nature of beer consumption in his social circles. I’ve always meant to look into the differences in alcohol consumption by demographic because I’m sure you’ve seen all the medical “studies” which claim that drinking in moderation has benefits toward your health. The main concern I have is that a lot of these seem to be correlational studies (though not all), and there are also often conflicts of interest with the funding (the alcoholic beverage industry is naturally happy to front the cash to pursue research so as to make the correlation firmer in the public mind). Now, I have nothing against alcohol personally, I like dark beers and white wines. But I’m a little skeptical when people promote health benefits of a class of product with which a non-trivial minority of the population have substance abuse issues.

To sate my curiosity, I decided to look at the GSS. So you can replicate, here are my variables:

Row: Drink

Column: Year Race Sex Region God(r:1-3″Non-theist”;4-5″Believe, But Doubts”;6″Know God Exists”) Relig Polviews Degree Wordsum

Some of the variables are obvious, but in regards to the somewhat garbled gibberishy looking section I “recoded” it so as to combine classes with very small N’s and such. Since you have the variable names you can follow up and see what I did if you’re curious.

Here are some results….

Not too much change over the years.

drinkyear

Now, some demographic variables of interest. Not too surprising. I knew that blacks were more likely to be teetotalers, and expected that women would be as well. Note the big difference by religion.

drinkdemcat

As I said, people in the South are less likely to drink. This partly tracks religion, but I’ve poked around these particular data and in New England both Catholics and Protestants drink a fair amount, so it is a regional Protestant subculture which is fostering teetotaling (here are the labels geographically by the way).

drinkregion

Some more variables, though note the spectrum. The conservative tendency toward teetotaling probably has something to do with the correlates of extreme conservatism (higher religiosity, tendency to live in the South, be Protestant, etc.). Keep an eye on the education though….

drinkideology

This chart pretty much floored me.

drinkwordsum

I was expecting it. That is, that the more intelligent, who scored high on a vocabulary test, would drink more than the dumb, who scored low. Look at the other correlates above. But I’ve rarely seen such a stark near-monotonic trend with Wordsum.

You can try to control for variables. Race doesn’t matter much for what it’s worth, the trends stay pretty much the same if you constrain to whites. I decided to check the “Bible” variable, which measures literal interpretation. As expected controlling for fundamentalism eliminates much of the Protestant vs. non-Protestant difference, as well as exacerbates the sex difference (fundamentalist women are much more teetotaling than men), but it really didn’t effect the rank relation on many categories. The regional and Wordsum difference remains even among those who are fundamentalists or irreligious. I think this points to the social aspect of drinking. Even if you like to drink, if you’re circle of acquaintances tends not to, you won’t get a chance to drink as much. Conversely, if drinking is expected, there’s more pressure to bend your norms to please your friends.

Anyway, just be careful of studies extolling the virtues of alcohol unless they control for confounds. It’s just a fact that stupid people tend to die earlier, because they often make life decisions in keeping with their nature.

Image Credit: AMC