Im really struggling with this Q expecially at transposing the formula

[helio007]

A motor has a synchronous speed of 50rps and runs at 2850rpm when connected to a
230-volt 50Hz supply. Calculate:
a) per unit slip
b) percentage slip

 

[timhoward]

If it runs at 50 revolutions per second, how many revolutions per minute would you expect?

 

[helio007]

If it runs at 50 revolutions per second, how many revolutions per minute would you expect?

Tim you got to transpose the formula in order to find out
Nrps=f/p my question is how do I find P ?

 

[timhoward]

Tim you got to transpose the formula in order to find out

In my little world, I would just say that if it were running flawlessly it would be the rps figure multiplied by the number of seconds in a minute. Then compare that to the rpm figure (which is what is actually happening, and is different)

Nrps=f/p my question is how do I find P ?

It's hard to demonstrate without a whilteboard, but....

If you multiply both sides by p, and removing the p/p on the right as that equals 1, you get
Nrps x p = f

Then divide both sides by Nrps and remove the Nrps/Nrps on the left because that equals 1, you get
p = f / Nrps

Does that help you?

 

[helio007]

In my little world, I would just say that if it were running flawlessly it would be the rps figure multiplied by the number of seconds in a minute. Then compare that to the rpm figure (which is what is actually happening, and is different)

It's hard to demonstrate without a whilteboard, but....

If you multiply both sides by p, and removing the p/p on the right as that equals 1, you get
Nrps x p = f

Then divide both sides by Nrps and remove the Nrps/Nrps on the left because that equals 1, you get
p = f / Nrps

Does that help you?

That's better explained than what was shown in the classroom, the reason I think I didn't get it right was because how and why I would have to add 1 however your explanation was top notch

 

[plugsandsparks]

To calculate the per unit slip and percentage slip of a motor, we need to compare its actual speed with the synchronous speed.

Given information: Synchronous speed (Ns) = 50 rps (revolutions per second) Motor speed (N) = 2850 rpm (revolutions per minute) Supply frequency (f) = 50 Hz

First, we need to convert the motor speed from rpm to rps: N = 2850 rpm N_rps = N/60 (conversion from rpm to rps) N_rps = 2850/60 = 47.5 rps

a) Per unit slip: Per unit slip is calculated as the difference between synchronous speed and motor speed, divided by the synchronous speed.

Per unit slip (S) = (Ns - N) / Ns

Substituting the given values: S = (50 - 47.5) / 50 S = 2.5 / 50 S = 0.05

b) Percentage slip: Percentage slip is calculated by multiplying the per unit slip by 100.

Percentage slip = S * 100

Substituting the value of S: Percentage slip = 0.05 * 100 Percentage slip = 5%

Therefore, a) The per unit slip is 0.05. b) The percentage slip is 5%

Courtesy of chatgpt, a students dream come true

 

[helio007]

To calculate the per unit slip and percentage slip of a motor, we need to compare its actual speed with the synchronous speed.

Given information: Synchronous speed (Ns) = 50 rps (revolutions per second) Motor speed (N) = 2850 rpm (revolutions per minute) Supply frequency (f) = 50 Hz

First, we need to convert the motor speed from rpm to rps: N = 2850 rpm N_rps = N/60 (conversion from rpm to rps) N_rps = 2850/60 = 47.5 rps

a) Per unit slip: Per unit slip is calculated as the difference between synchronous speed and motor speed, divided by the synchronous speed.

Per unit slip (S) = (Ns - N) / Ns

Substituting the given values: S = (50 - 47.5) / 50 S = 2.5 / 50 S = 0.05

b) Percentage slip: Percentage slip is calculated by multiplying the per unit slip by 100.

Percentage slip = S * 100

Substituting the value of S: Percentage slip = 0.05 * 100 Percentage slip = 5%

Therefore, a) The per unit slip is 0.05. b) The percentage slip is 5%

Courtesy of chatgpt, a students dream come true

Thanks mate you answered the whole Q i really appreciate your effort to help me good night .

 

[Lucien Nunes]

Courtesy of chatgpt, a students dream come true

As soon as I started reading the post I had a hunch about the source, before reading that comment.

A cheat's dream come true, perhaps. Or perhaps not. I have been experimenting with it, testing its knowledge and problem-solving abilities on technical topics that are not well documented on the www. Depending on how I ask the q's, it has been averaging maybe 50% correct answers. Some topics were complete failures, e.g. one on calculating cine film speeds I managed to coax out 12 different answers to the same question, all wrong, some subtly wrong by a few percent, some complete nonsense, out by a factor of a million or more.

A hippopotamus only has one nostril. Some organs only have three pipes. The piston of a Cornish steam engine comes out of the cylinder for half the cycle and goes back in again at the end.

Fascinating discussions, some of them, but utterly useless for learning.

 

[plugsandsparks]

Hi Lucien, i am currently at Uni , doing some further studies. The Uni has acknowledged that chatgpt is being used and is asking for the questions put and acknowlegdments given, just as you would reference another piece of published work.
I am a mature student and back in the day we would sit exams to get a qualification etc. Todays academia does not lend itself to AI and i suspect a return to exams will be the future.
Chatgpt is rife and some students are getting the same results that i can achieve the old fashioned way.
The trick apparently is in the refining of the first answer given.
BTW - as a proof of concept, i needed to write some code to pull out some important data from 500GB of stuff.
Chatgpt , created the code, i tweaked it, and it succeeded in solving the problem given by the lecturer. This was done in the lunch break prior to the lab where we were expected to solve the problem, it saved doing the whole lab, and i was thinking , "OK AI is a given, lets move onto higher things..."
Personally, i think AI is going, (already is) a massive change (for the better).
I cannot think of anything more mind numbing that code syntax, the codes i have to juggle are linux, windows command line, windows powershell, python, php, C++, js, Bash, and quite frankly i would sooner use my efforts elsewhere.

 

[Lucien Nunes]

I'm not saying it's not a powerful tool when used appropriately. Merely that it can produce utter train wrecks if relied upon to answer questions by itself in the absence of constructive input and collaboration from its human handler.

 

[Rockingit]

BT to axe up to 55,000 jobs by 2030 as it pushes into AI - https://www.theguardian.com/business/2023/may/18/bt-cut-jobs-telecoms-group-workforce

Be careful what you wish for

 

[plugsandsparks]

Left BT in 2010, saw the writing on the wall, lol
Just had an encounter with AI running Amazons customer service, was having some difficulty getting the call handler (chat) undertsnad the issue, in the end i did have to ask whether i was talking to a human, AI had meltdown and did not respond for 3 days.....
I would expect humans will still be around to take your money, but after that all bets are off.
Its a brave new world......
With regards to Chapgpt you can go the subscription route for around £15/month and you get the super version which apparently can easily pass the law exam.
I can think of a few professions where i would sooner deal with AI that a human, especially in Gov