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. iVenky

    Power of noise after passing through a system h(t)

    **Reposting this again, as I was asked to post this on a homework forum** 1. Homework Statement Hi, I am trying to solve this math equation (that I found on a paper) on finding the variance of a noise after passing through an LTI system whose impulse response is h(t) X(t) is the input noise...
  2. opus

    Intervals of Convergence- Power Series

    Homework Statement Hello. I'm not entirely sure what this question is asking me, so I'll post it and let you know my thoughts, and any input is greatly appreciated. If the series ##\sum_{n=0}^\infty a_n(x-4)^n## converges at x=6, determine if each of the intervals shown below is a possible...
  3. Benjamin Sorensen

    Calculating the Power Dissipation of a Wire

    I'm having trouble verifying an experiment I ran to determine the power dissipation of a heating element. 13.15W of power was applied to 3ft nichrome wire. Temperature readings were collected until they stabilized at 128.5F (room temp was 70F). I want to create a mathematical model of the system...
  4. navneet9431

    B 1 to the power of infinity, why is it indeterminate?

    I've been taught that $$1^\infty$$ is undetermined case. Why is it so? Isn't $$1*1*1...=1$$ whatever times you would multiply it? So if you take a limit, say $$\lim_{n\to\infty} 1^n$$, doesn't it converge to 1? So why would the limit not exist?
  5. V

    Electrical Designing an off grid power plant

    Hello! I have some plans that i want to share and get some feedback on before i start construction and buying parts. I have some land next to a lake that i can build a dam with head of 30m around 10000m2 and almost 50000m3. I am thinking of solar panels and wind turbine to generate electricity...
  6. Sid55

    How to power up a DIY LED panel with a PC PSU?

    Thanks to anyone who likes to chime in and help out this newbie. :smile: I bought some CC CV buck converters to power my DIY LED panel project using a perfectly working PC power supply unit that was collecting dust inside a fairly old and unused PC but unfortunately the buck converter does not...
  7. Jalo

    I Photodiode bandwidth: why does power decrease with frequency

    Hi, I'm studying p-i-n photodiode (PD) at the moment and understand that the photodiode's response will depend on the frequency of the light signal going into it. I am struggling however to understand the concept of bandwidth, and why is it that the photocurrent at the PD decreases with higher...
  8. german_cargo

    Need motor help with Electric Power Brush project for clearing snow

    I'm in the snow removal business and am unhappy with my snow plow on residential driveways. I am going to fabricate a light duty power brush for my vehicle, and I am going to power it with an electric motor and battery pack for quiet operation and relative simplicity. The demands on this power...
  9. T

    Small & Lightweight High Voltage Power Sources: Ideas?

    << Mentor Note -- thread moved to the Sci-Fi writing forum after starting in the technical forums >> Hey folks, I'm interested in the feasibility of providing high DC voltages (~kV) in a physically small and low mass package (~grams). The power source does not actually need to be very energy...
  10. K

    What is the Power Output of Gravity?

    Homework Statement : It takes gravity 1.43 seconds to pull a 3.67 kg cat down from a 10m tall ledge. What is the power output of gravity? [/B] Homework Equations P=mgd/t P=w/t P=power M=mass G=gravity D=distance W=work T=time[/B] The Attempt at a Solution P=(3.67)(9.81)(10)/1.43 P=251.77
  11. J

    Fourier transform of a power signal or a voltage signal

    Homework Statement By using Fourier transform, I want to calculate power of signal. I confuse that f(x) in attached equation represents voltage or power. Is that possible when f(x) means power to use Fourier transform. Homework Equations The Attempt at a Solution
  12. F

    How to use a bench power supply

    Hello, I understand that a bench power supply (see picture below) is mainly used as a constant voltage source: once the load is connected to the two terminals, we set voltage ##V_{supply}## by turning the voltage knobs on the right and find that voltage across the load. At the same time, the...
  13. D

    Determining the flow rate for a cooling system

    MODERATOR'S NOTE: HOMEWORK INCORRECTLY POSTED TO CLASSICAL FORUM, SO NO TEMPLATE I need help with the following question: Please have a look at the question and my attempt at the solution. Alternative cooling systems are considered for a large computing centre requiring 1 MW of cooling...
  14. J

    Definition of isolation and pulse response time for a 3-way power splitter

    I will use 3 way power splitter and power detector. 1. This is power splitter data sheet. In this data sheet, there are different isolation values. What does it mean?? Also in that point, I wonder definition of isolation at power splitter. 2. This is power detector data sheet. In this data...
  15. B

    Worksheet Problem about Power (average power of a car accelerating up a hill)

    Homework Statement A 1130 kg car is initially at rest when it accelerates up a 21 m high hill. When it reaches the top of the hill it is traveling at 18 m/s. If it takes 6.5 s to reach the top of the hill, what was the average power of the car? Homework Equations W = Fd P = w/t The Attempt at...
  16. Ventrella

    I Iterating powers of complex integers along axes of symmetry

    I am exploring the behaviors of complex integers (Gaussian and Eisenstein integers). My understanding is that when a complex integer z with norm >1 is multiplied by itself repeatedly, it creates a series of perfect powers. For instance, the Gaussian integer 1+i generates the series 2i, -2+2i...
  17. M

    A couple of questions about antennas, bandwidths and power

    Does it take more electrical energy to transmit HF and lower frequencies than it takes to transmit VHF and above? Are there any wavelengths beyond radio waves and gamma rays? Is it true that the lower the frequency, the lower the amount of data that's being sent? I read on this wiki that...
  18. J

    RF pulse detection with Power Detectors

    How can I use power detectors for RF pulse detection? RF pulse has a symmetric Gaussian-like shape. Is the output of power detectors continuous line or point?
  19. N

    Received power for free space optics

    Hello everyone, I have calculated the received power for free space optic (FSO) using the equation: Lsystem (system loss) is set to 8dB. PTotal can be calculated as: where Ntx (number of receiver) = 1 and PTx (transmitted power) =7.78 dBm. LGeo can be calculated as: where d2R (receiver...
  20. marino

    Power generated by a coil rotating in magnetic field

    The problem: a coil of radius r, length l and N turns, rotating with constant angular velocity ω around an axis perpendicular to its simmetric axis and passing for the center of the coil. The coils is submersed in a static magnetic field, intensity B0, perpendicular to the axis of rotation of...
  21. phyzguy

    What if we had commercial fusion power?

    There have been several recent threads on the feasibility of fusion power. There is reason to be hopeful. This study from MIT claims, due to the breakthroughs in high-temperature superconductors, that an economically feasible Tokamak can be built in the foreseeable future. For the purpose...
  22. Potential Energy of a Particle | Work done by Conservative Forces

    Potential Energy of a Particle | Work done by Conservative Forces

    What is a conservative force and how do you determine the work done by it. It is an interesting relation between the work done by such a force and the potential energy and kinetic energy of a particle.
    • Vish
    • Media item
    • Conservative force Potential energy Power
    • Comments: 0
    • Category: Classical Mechanics
  23. Jason-Li

    Parallel Capacitance - Power Factor Question

    Homework Statement A 50 kW load operates from a 60 Hz 10 kV rms line with a power factor of 60% lagging. Determine the capacitance that must be placed in parallel with the load to achieve a 90% lagging power factor. The Attempt at a Solution For Z at 0.6pf S=P/pf = 50000/0.6 = 83333.33VA I =...
  24. Ventrella

    I Mutually disjoint sets of all integer powers?

    I identified what appears to be a partitioning of all integers > 1 into mutually disjoint sets. Each set consists of an infinite series of integers that are all the powers of what I am calling a "root" r (r is an integer that has no integer roots of its own, meaning: there is no number x^n that...
  25. MeAndMyLucidLife

    Electric Power - Which formula to use and when?

    Homework Statement : [/B] If the length of the filament of a heater is reduced by 10%, the power of the heater: Options are- a) increases by about 9%. b) increases by about 11%. c) increases by about 19%. d) decreases by about 10%. Homework Equations : P[/B]=I2R Or P=V2/R Where P=power...
  26. Fisherman199

    LV Harmonic Filters for Utility Customer's Power Outages?

    Seeking the guidance of the Physics forums gurus, I was told this would be a good question to contribute to the community. Perhaps it will lead to an in-depth discussion of harmonics: Their creation, implications to power quality, and how to mitigate them. I've been looking at some power...
  27. DariusP

    Why laser output power decreases with increasing temperature

    Why laser output power decreases with increasing temperature? By increasing temperature, I mean increasing temperature of the active medium. I think that thermal lensing alone should not have effect on output power? Just different focusing (focal length). What happens with energy levels in...
  28. stipan_relix

    How to use Thevenin to find R and I?

    Homework Statement In the circuit shown, in the image, the variable resistor R is consuming maximum power. Determine: a) resistance for R b) power for R c) current for R3 and its direction Homework EquationsThe Attempt at a Solution I tried getting IA(the direction is shown with arrows in...
  29. stipan_relix

    How to find power and voltage using the mesh current method?

    Hi. I am practising for my test and since I don't have the correct answers, I don't know if what I'm doing is right. I tried to solve this problem, can you check it and correct if it's wrong? Here's a clearer picture of the circuit. I suspect Uab isn't right, but am not sure. Thanks...
  30. S

    Determining Work Done by a Person on a Luggage

    I'm trying to determine the work done by a person as they pull a luggage up a ramp. The ramp has a height of 5 m and the distance the person walks up is 20 m. The weight of the bag is also 10 kg. I am trying to compare the work done by pulling the luggage up a ramp to carrying an equally heavy...
  31. T

    Shooting bullets, work & power

    Homework Statement When bullets are shot on Superman, they bounce off of his chest. 100 Bullets will be shot on his chest per minute, each with a mass of 9g and v= 1000m/s. Assume that the bullets will bounce off elastically back in x-direction. a) What is the average power of all of the...
  32. ajohns2000

    Remote control of a Walker Scientific Magnet & Power Supply

    Hello and good day. I am currently involved in research that seeks to utilized a Walker Scientific power supply and magnetic. The system is old but functional. We seek to utilize the magnet in order to conduct some low temperature experiments. We need information on this power supply, of which...
  33. M

    I Raising the ladder operators to a power

    Hi! I am working on homework and came across this problem: <n|X5|n> I know X = ((ħ/(2mω))1/2 (a + a+)) And if I raise X to the 5th, its becomes X5 = ((ħ/(2mω))5/2 (a + a+)5) What I'm wondering is, is there anyway to be able to solve this without going through all of the iterations the...
  34. TechTree

    Computer What device would I need to send data over power lines?

    Hello, I'm trying to send binary data over the power lines to a microcontroller, which triggers a relay turning on a light. I was wondering what kind of device would I need to use to achieve this? And how would I connect it up to the microcontroller? I'm fairly new to this, so if someone could...
  35. Cocoleia

    Power loss in a transmission line

    Homework Statement Homework EquationsThe Attempt at a Solution I have posted the whole solution so it is more complete, but I really only need help with part c (I think) My output power is higher than my input power, I'm not sure where I'm going wrong
  36. A

    MHB How Do You Evaluate the Indefinite Integral as a Power Series?

    Evaluate the indefinite integral as a power series ∫[ln(1−t)/7t]dt. Find the first five non-zero terms of power series representation centered at t=0. Answer: f(t)= What is the radius of convergence? Answer: R= 1 Note: Remember to include a constant "C". This problem has been difficult...
  37. H

    Current State of Nuclear Fusion Power

    When I was an undergrad doing research in a university lab, the director of the lab also consulted at a Nuclear Fusion company. I remember like it was yesterday him making a statement that commercial Nuclear Fusion was going to be a reality within 10 years. That was 1977. What happened? Lack...
  38. W

    Set Theory: Power sets of Unions

    Homework Statement I'm having issues understanding a mistake that I'm making, any assistance is appreciated! I know a counterexample but my attempt at proving the proposition is what's troubling me. Prove or disprove $$P(A \cup B) \subseteq P(A) \cup P(B) $$ Homework EquationsThe Attempt at...
  39. FreeForAll

    Front brakes provide 70% of stopping power. But why?

    I'm not disputing that front brakes on a vehicle provide the majority of stopping power, but why is that? I originally thought it was because of added traction at the front due to weight transfer, but even my bike moving at a walking pace has more powerful front brakes than the identical rear...
  40. H

    Initial and final power supplied by a person pushing a stone

    Homework Statement Homework Equations The Attempt at a Solution I solve question a) by rearranging the F=m*a equation, which makes the acceleration equal to (24N/18kg)=1.30m/s^2. And I find the final speed using equation W=1/2*m*v^2 and rearranging it to solve for v, which gives me a value...
  41. DracoMalfoy

    Power and temperature of stars

    Homework Statement Star 1 emits energy at a rate that is 2 times that of Star 2. If Star 1 also has a radius that is 3 times larger than Star 2, how do the temperatures of the stars compare? a. Star 1's temperature is 2.58 that of Star 2. b. Star 1's temperature is 3.75 that of Star 2. c...
  42. jack action

    Insights When Vehicle Power Dictates Acceleration - Comments

    Greg Bernhardt submitted a new blog post When Vehicle Power Dictates Acceleration Continue reading the Original Blog Post.
  43. H

    How many Peltier elements can I use in my power outlet?

    Hi! I want to build some cooling with peltier elements. At home I get 230V from power outlet and the maximum allowed power consumption is 15A. However, when I look at peltier elements at online store I notice that amps go up fast. Like some 12V 180W peltier is already 15A. Does this mean that I...
  44. S

    Differential equation with power series method

    Homework Statement I need to solve the DE y’ = x^2y using the power series method Homework Equations y = sum(0->inf)Cnx^n y’ = sum(1->inf)nCnx^(n-1) The Attempt at a Solution I plug in the previous two equations into the DE. What is the general procedure for these problems after that...
  45. N

    US solar power generation for 2014-17

    Solar generation results for US are out for 2017. Year over year: http://www.eia.gov/electricity/annual/html/epa_01_02.html https://www.eia.gov/electricity/annual/pdf/epa.pdf US: Net Generation (Thousand Megawatthours) 2014 Solar: 17691 (that's 0.43%) All sources: 4093606 US: Net Generation...
  46. S

    Induction Motor Auto-Transformer Starter - Power and Torque

    Homework Statement Describe an auto-transformer starter. From the expression for power input per phase (∝ torque) show that for a turns ratio (n) of √3:1 , for the auto-transformer: Homework Equations Pin (phase) = 3 V I cos∅ I = V/Z cos∅ = R/Z T∝I∧2 T∝V∧2 For auto transformer with...
  47. Math Amateur

    MHB Power Series .... Abbott, Theorem 6.5.1 .... ....

    I am reading Stephen Abbott's book: "Understanding Analysis" (Second Edition) ... I am focused on Chapter 6: Sequences and Series of Functions ... and in particular on power series ... I need some help to understand Theorem 6.5.1 ... specifically, some remarks that Abbott makes after the proof...
  48. K

    Find the expression for the sum of this power series

    Homework Statement Hello, I need to find an expression for the sum of the given power series The Attempt at a Solution I think that one has to use a known Maclaurin series, for example the series of e^x. I know that I can rewrite , which makes the expression even more similar to the...
  49. B

    Engineering Competency matrix for a power engineer?

    What competency matrix are suggested for power consultant engineers? My work organization has a competency matrix of different skills. The skills included different software packages and engineering practices for low/medium/high voltage power design and instrument and controls. Some of the...
  50. M

    Question about finding av. Power from V(t) and I(t)

    Homework Statement We know that V(t) = f(t) and I(t) = g(t), which have been found by Fourier Series analysis and some approximations. The next part of the problem is about finding the average power disappated by the system. I was wondering whether I would be able to take averages of both of...
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