What is Power: Definition and 999 Discussions

A power outage (also called a power cut, a power out, a power blackout, a power failure, a power loss, or a blackout) is the loss of the electrical power network supply to an end user.There are many causes of power failures in an electricity network. Examples of these causes include faults at power stations, damage to electric transmission lines, substations or other parts of the distribution system, a short circuit, cascading failure, fuse or circuit breaker operation.
Power failures are particularly critical at sites where the environment and public safety are at risk. Institutions such as hospitals, sewage treatment plants, and mines will usually have backup power sources such as standby generators, which will automatically start up when electrical power is lost. Other critical systems, such as telecommunication, are also required to have emergency power. The battery room of a telephone exchange usually has arrays of lead–acid batteries for backup and also a socket for connecting a generator during extended periods of outage.

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  1. S

    Power and Efficiency without mass?

    Really perplexed me as the answer provided does not solve for mass ... seemingly wants to use mass as a unit of height? Or perhaps I'm off base ... really just curious if this is even correct or possible? Thanks in advance
  2. C

    Graphing Power vs Polarizer Angle using Intensity

    The data collected from the experiment is, The first column is the polarizer angle measured in degrees. The second column is recorded intensity measured in lux. The third column is the transmitted intensity measured in lux. This is equal to the recorded lux - ambient lux The fourth column is...
  3. A

    MCNP FMESH for Plotting power distribution

    Hello I'm trying to use FMESH command to get power distribution of this core geometry. I want to use xyz coordinate in a 1/12 slice of a core so I could use the output of the MCNP sim for a CFD input How should I approach this? Thank you
  4. emilmammadzada

    How can I find the stopping power for a single energy value in FLUKA?

    Hello friends. How can I find the stopping power for a single energy value in the fluka? Which card should I add to the input file for this?
  5. A

    Conservation of power in a traveling wave on a string

    The statement of the problem is: Consider a taut string that has a mass per unit length ##\mu_1## carrying transverse wave pulses of the form ##y = f(x - v_1 t)## that are incident upon a point P where the string connects to a second string with mass per unit length ##\mu_2##. Derive $$1 = r^2...
  6. T

    Power, Rpm, Torque - Horsepower increase for my small engine

    Hello all, the short story is, I am basically trying to get the same ( or a little more) “power” out of a larger lawn mower type gas engine ( vertical shaft) as one of the largest (120 ish cc) chainsaws ( ref the Stihl MS 880 or newer 881 at approx 10-12k rpm and 9 Hp) The parameters are : a...
  7. S

    Power Fluctuations in our AC Mains Power Generation Facility

    I am currently at a power plant here in Texas and the 480VAC system swings from 480 while equipment is on line and as high as 536VAC when equipment is off line. They tell me that this is prefectly normal but I have never seen swings like this at any power plant. So, is this normal???
  8. argeus

    Pumping power calculation of a vertical closed-loop system

    Hi there, I hope that somebody can help me with this.. Any response is much appreciated! Let's have a vertical closed-loop system where the fluid circulates using the pump. The temperature in both sections gradually changes (the upcomer section is heated up) so that the densities, velocities...
  9. C

    Power Rule Proof: Get Help with Line 3 to Line 4

    For this proof, I am unsure how they got from line 3 to line 4. If I simplify and collect like terms for line 3 I get ##f'(a) = 4a^{n-1}## Would some please be able to help? Many thanks!
  10. C

    Electric motor problem -- Power to accelerate a toy train

    For part (b), The solution is, However, if the acceleration was not constant during the 21 ms, then would the power required be larger? I believe the average power required would be larger because if the train started off at a lower speed and then speed up very rapidly towards the end...
  11. emilmammadzada

    How can I calculate the stopping power for aluminum in Fluka?

    How can I calculate the stopping power for aluminum in Fluka? I want to send 100 kevlik proton, I add deltaray card to target aliminuma.input file and this card is processing 10 MeV for some reason. TITLE * Set the defaults for precision simulations DEFAULTS...
  12. hilbert2

    A The eigenvalue power method for quantum problems

    The classical "power method" for solving one special eigenvalue of an operator works, in a finite-dimensional vector space, as follows: suppose an operator ##\hat{A}## can be written as an ##n\times n## matrix, and its unknown eigenvectors are (in Dirac bra-ket notation) ##\left|\psi_1...
  13. F

    Magnitude of the Line Charge Density of a Power Line

    Okay so I am a little confused as to where I made a mistake. I couldn't figure out how to program Latex into this website but I attached a file with the work I did and an explanation of my thought process along the way.
  14. M

    I Grating Resolving Power of Laser Beams with Gaussian Distribution

    All resources I’ve found for grating resolving power assume uniform distribution on the grating and produce airy disks. Resolvance is determined by the Rayleigh criterion where the peak of one wavelength is at the minima of the adjacent one. This definition doesn’t seem applicable for Gaussian...
  15. emilmammadzada

    Stopping power and projected range for FLUKA code

    How do I calculate the stopping power or projected range for aluminum in Fulka. And in which output file is this data located?How can I edit a change in the input file?
  16. A

    A Completeness of the formal power series and valued fields

    I had difficulty showing this no matter what I tried in (a) I am not getting it. Here for p(t) in K[[t]] : ## |p|=e^{-v(p)} ## where v(p) is the minimal index with a non-zero coiefficient. I said that p_i is a cauchy sequence so, for every epsilon>0 there exists a natural N such that for all...
  17. F

    B The historical war of currents in Mains Power Distribution: AC vs DC

    So, if I get it right, the basic argument goes like this: AC was preferred to DC because its voltage can be stepped up by a transformer. This limits losses while the current is transported from the production plant to the final user. The voltage is subsequently stepped down when delivered to the...
  18. R

    When is power constant in this scenario?

    Power P = F x v,where F is force and v is velocity, if power remains constant then i think force can not remain constant as it will change the velocity v, but the solution I found is, F = ma, v = at, so, P = F x v = ma x at = ma2 t, after that calculus comes to show that displacement is...
  19. J

    Fried my power supply by doing a bad thing

    I have a Multicomp 0-30V 0-5 amp power supply. I did some tests using it as a battery charger. It worked very well the first few times, then I accidently hooked it up backwards and killed it. There was light sparking when this happened. No fuses blew. It powers up normally, and I can...
  20. Evari5te

    Solving Current & Power in 4 & 3 Wire Circuits

    My thoughts were I could use mesh current analysis to derive equations for current hence power in each case in terms of ωC and R, set the equations for real power equal to each other and solve for R. While ωC are known I opted to leave them as letters thinking this might make life easier when...
  21. N

    I 3D Printed Piston | Lower mass = Power

    This is a piston I had DMLS printed from AlSi10mg - the geometry is derived from generative design using some basic inputs and a starting shape. It's really just an experiment whether a consumer grade design and print can be bolted in and work for a time. After machining, it is predicted to...
  22. electrodacus

    I Equation for power required to overcome drag

    Here is the link to the equation I consider to be correct https://scienceworld.wolfram.com/physics/DragPower.html Is anyone disagreeing with that and if so can you provide a link or screenshot from a proper textbook ? The v in that equation is defined as speed of the fluid relative to the body.
  23. emilmammadzada

    MCNP5 stopping power for input file

    Where can I find stopping power input file examples for mcnp5?
  24. H

    Prof. Mattuck's Lecture 20: A Divine Power of Speech & Laplace's Elegance

    Lecture 20 by Prof. Mattuck is simply great. I don’t think there can be any better communication than that, it seemed as if what was in his mind simply got teleported in to mine, and that’s why, it seems now, Aristotle gave so much importance (and almost considered it as a divine power) to the...
  25. Al-Layth

    To transmit from 2 counter-rotating shafts into 1 perpendicular shaft?

  26. M

    Power Tower in Space: Feasibility & Practicality

    Hello, I'm wondering about the practicality and feasibility of building large power tower structures in space. I could imagine something like follows: Take a long structural beam which is positioned in alignment to the sun rays. At the end closest to the sun a receiver is placed. Consisting...
  27. Differentiate it

    Work, Power and Energy — Lifting a coiled rope up off a surface

    The solution said that Average power= net change in energy/time, but why is that true? If you have a different way of solving it, it would be helpful too
  28. G

    Power generated by this current source

    Figure: My attempt at a solution: 1st kirchoff law: $$J=2I_0+I_0=6\, \textrm{A}$$ $$V_1+8=10\rightarrow \boxed{V_1=2}$$ $$V_1=6-V_S\rightarrow \boxed{V_S=-4\, \textrm{V}}$$ We are looking for ##P## generated in ##J## $$V_J=V_1-2\cdot J=2-2\cdot 6=-10\, \textrm{V}$$...
  29. core7916

    Designing a 28V --> 200V power converter

    I need to design a circuit which takes around 28V of input and outputs the 200v with 20A. Can any one help me.
  30. electrodacus

    I Power available to a wind powered vehicle traveling directly downwind

    I will like the equation describing the amount of wind power available to a wind powered vehicle driving directly downwind. I'm interested in the ideal case so max theoretical power available to a wind only powered vehicle driving directly downwind. I do know what the equation is but I like to...
  31. Marah Elisabeth

    Power Line Dangers: Is My RV Safe?

    There is a power line of undetermined voltage hanging just 4 feet above my RV and the stream running next to us. If during the rain, a branch from the redwood tree above us falls and causes the hot line to land on the RV and stay there, is there a way to prevent us being shocked while we try to...
  32. Pythagorean

    Stirling Engines for Home Power

    Would it be a feasible power source to have several Stirling Engines sticking through an outdoor wall near your fire place in a cold climate? Issues I can think of: Presumably it would be a heat sink and require you to consume more firewood. Engineering it to not have passive leaks might be...
  33. abolfazlghasemi

    Hydrogen dew point in power generators

    Large power generators (for example 200 MW) are cooled by H2 in gas form. H2 temperature is +45 to +75 "C. So why hydrogen dew point is important in generator while the lowest hydrogen temperature is 45 "C? And in some Power Stations is monitored online... Thanks, a lot
  34. K

    How do I properly connect a bench power supply to a pulse generator for testing?

    Hello! I am sorry if this questions is silly but I really don't know much about electronics. I have a pulse generator (this one) and I want to test it with a low voltage for now. I have a bench power supply (something like this). I am confused about how to make the connections. For the pulse...
  35. M

    Find the highest power of ## 3 ## dividing ## 823 ##

    Let ## n ## be a positive integer and ## p ## be a prime. Then the exponent of the highest power of ## p ## that divides ## n! ## is ## \sum_{k=1}^{\infty}[\frac{n}{p^{k}}] ##. Observe that ## n=823 ## and ## p=3 ##. Thus \begin{align*}...
  36. S

    Power Amplifier and Exciter, Impedance / Power

    Hello. I have a question regarding an power amplifier (signal generator). I have three exciters and want to connect them to the power amplifier. One exciter have a impedance of 8ohm and power of 25 watt. The ampliefier have one output with the electical data: 4 ohm : 500watt; 6ohm: 330 watt and...
  37. R

    "Ground" and "Center Tapped" Power Transformer Secondary in guitar amp

    Hello - thank you for reading this, and thank you in advance to anyone who replies and clarifies the mystery of "ground." I have finally gained a full understanding of how a full-wave rectifier, two-power tube electric guitar amplifier works in a push-pull manner, but one thing remains after I...
  38. E

    I Acceleration From Rest Under Constant Power

    Impossible?!? By my estimation the equation that describes this motion is given by: $$Pt = \frac{1}{2}m{ \dot x}^2$$ or $$\dot{x} = \sqrt{\frac{2P}{m}} \sqrt{t}$$ but this implies: $$\ddot{x} = \sqrt{\frac{2P}{m}} \frac{1}{\sqrt{t}}$$ So, no matter how small we make the power, we appear...
  39. D

    Uninterruptible power supply output specifications

    Why do some UPSs have both Volt-amp and watt rating? According to APC, the connected load shouldn't exceed the UPS's VA and watt rating. Why? If I had a UPS with 1000VA and 500W rating, why can't it power a load consuming 1000VA @ 900W? If a UPS can output 1000VA, why does it care how much...
  40. WumTrudo

    How Do You Calculate Engine Power for Semi Trucks in Various Conditions?

    Summary: Calculating engine power required for semi trucks under different circumstances. Hello everyone, I would like to ask you for help if that is allowed. For a current project I need to calculate engine power needed in watts under different circumstances. This is something that I will...
  41. E

    This is a 3D model I made of a nuclear power plant control room

    I spent the past several weeks making this 3D model of a nuclear power plant control room.
  42. M

    Prove that ## n ## must be a power of ## 2 ##

    Proof: Suppose for the sake of contradiction that ## 2^{n}+1 ## is prime but ## n ## is not a power of ## 2 ##. Then ## n=ks ## for some ## k\in\mathbb{Z} ## where ## 1\leq k<n ## and ## s ## is an odd prime factor. This means ## (a-b)\mid (a^{q}-b^{q}) ##. Let ## a=2^{k}, b=-1 ## and ## q=s...
  43. Martinz

    Power factor of motor with VSD?

    If I have a motor with a full load power factor of 0.8 and starting power factor of 0.3 and I install a VSD to run it with a datasheet power factor of 0.95, will the power factor during starting be 0.3 or 0.95? And at full load? Cheers!
  44. rsc9421

    A Power consumed by electron gun

    First Assume the following basic circuit: I read in many textbooks that the electrons in the circuit are accelerated by the positive voltage and decelerated by the collisions, so the speed is constant. We also know that the circuit current is I = 10A so the power consumed is P = V * I = 100W...
  45. anorlunda

    The History of 3-Phase Power, (and AC/DC, 50/60 Hz, US/Euro, ....)

    Kathy Joseph makes wonderful videos (and now a book) about the history of electricity. Her research is very thorough. I just watched the video below, and found it instructive. Especially interesting is how Nikola Tesla and Westinghouse in the USA got the fame and credit for three phase power...
  46. J

    How Do You Find a Recurrence Relation for a Power Series Solution of an ODE?

    I believe I am doing everything right up until the point where I have to try and find a recurrence relation. I honestly have no idea what to do from there. I've listed my work in getting the powers of n and the indicies to all match. Any help appreciated. Here is the original DE...
  47. K

    What does the 'power' vs 'time' graph look like for a 3 phase AC supply?

    Hi, For years I wanted to understand why we have a 3 phase supply and not a 2 phase supply in AC. In Quora I found an interesting answer and was convinced about the purpose mentioned: Answer to Why there is no two phase electrical inputs instead of three phase and single phase? by Paul...
  48. M

    MCNP Flux and Power Calculation

    During a reactor assembly calculation, I need to determine axial and radial flux distribution over the surface. When I use F2 and F4 tally I get some value with unit 1/cm**2 What does the value means, neutron flux is supposed to be in the 10^14 range but output values are 10^2 range. Can anyone...
  49. J

    How are coils arranged in a power station generator?

    Hi, I wanted to know a couple of things regarding the construction of the stator and rotor of a generator in a power station. Firstly, how the copper windings inside the stator are arranged. I understand it’s a three phase winding where each phase has a set of two coils like this: Source...
  50. Y

    Funny observation in matching BJT power transistors

    THIS IS NOT HOMEWORK I design audiophile power amps as hobby. I need to match power transistors. It is A LOT HARDER than I thought. I built a test fixture to hold up to 50 transistors at a time. I try to match sets of 13 to about 1mV which is very tight as Vbe change is about -2mV/deg C. I have...
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