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.

View More On Wikipedia.org
Recent contents Top users
  1. G

    Power grid & generator questions

    Before I begin I have to note that my last thread of this kind got heavily moderated and closed because the moderators did not like the specific way in which I was formulating my questions, so now I want to clarify and reaffirm some of what I have learned through questions without making any...
  2. J

    Power generated by the steam turbine

    Homework Statement Shown in the figure Homework Equations W= (p2v2-p1v1) / (1-n) The Attempt at a Solution I am not sure where to start and where to use all the data given in the table. Please help. It would be nice if someone could explain the basic nature of the steam turbine, how it...
  3. J

    Power generated by the steam turbine

    Hello, I'm trying to solve a question, please help me.
  4. S

    Fundamental confusion about THREE-PHASE electric power setup

    Homework Statement Hello to everyone who's reading. :) I hope I posted this in the right place; while this is not exactly a homework problem, I am trying to improve my understanding of the background information before proceeding with course-style problems. This post is because I'm trying to...
  5. N

    High Power Amplifier for Acoustic Transducer

    Hi all I am in search of a Power Amplifier (preferably Solid state pulsed amplifier ) which is able to output around 340 Vrms across 25 ohm impedance load (acoustic transducer operating at approx 4.5 KW) in pulsed mode with duty cycle less than 1%, maximum pulse length of 5 ms and operating...
  6. G

    Power plant generator improvement

    I have looked over the types of generators used in most power plants (Hydro, Nuclear, coal etc) and with different sized and rotor rpm's they all basically share the same principle of operation if I'm not mistaken, which is that the rotor gets supplied via brushes and slip rings with a DC...
  7. pslarsen

    Understanding how to calculate power from force

    Hi all I have been looking at understanding power for a simple energy generation concept, and I think that I originally made an error in my calculations because I wasn't considering the relative velocities. So I basically generated the force made by a kite in static conditions, but if I need to...
  8. F

    Harnessing Solar Power for a Sustainable Farm

    I am working on a solar trough power plant to power my farm and greenhouses.
  9. berkeman

    New Medical Equipment Standards Impact Power Supply Selection and More

    Interesting article sent out by Digikey just now...
  10. J

    LED to come on with battery power when it's too dark for the solar panel

    I am trying to get relay to come on when it gets dark outside this works with one LED and 600 ohm resistor but it does not seem to turn on relay I get 20 ma draw when applying 12 volts to coil it seems you need transistor or SCR to to turn on relay. Relay I think was from a TV it's only 1/2" X...
  11. S

    Problem about power absorbed & dissipated by voltage sources

    Homework Statement Problem in Fig 2-18 and its solution: Homework Equations Passive Sign Convention, I think. The Attempt at a Solution Let's say i is counter-clockwise. Then, it's going from - to + of v_b. Why is there not an additional negative sign in computing p_b, and why is there one...
  12. M

    Solving for Attenuation Constant with Power Relations

    Hello. In fields and waves and transmission lines We have a attenuation constant formula with power relations: 1- Alpha = 1/2R0(R+G|Z0|^2) 2-Also we can calculate attenuation constant from these : Z0= radical[(R+jwL) / (G+jwc)] gamma = radical[(R+jwL)(G+jwc)] I want show alpha from 1...
  13. Mzzed

    Creating oscillations on the output of a DC power supply

    Is there some common parameter for DC power supplies that provides the maximum oscillation amplitude allowable at the output? For some context - I would like to generate an oscillating signal powered by a DC power supply, but to prevent most of the oscillations reaching the DC supply I am going...
  14. C

    I Total or kinetic energy in Bethe Bloch stopping power?

    The average loss of energy in a material per unit length of a particle (in particular an electron, which is stable) is described by the quantity ##dE/dx##. - for ionization it is given by the Bethe-Bloch formula $$-\left\langle {\frac {dE}{dx}}\right\rangle ={\frac {4\pi }{m_{e}c^{2}}}\cdot...
  15. E

    Power required to rotate a load of specific weight

    Homework Statement Weight - 200kg RPM - 5 Diameter - 6m Homework Equations Moment of Inertia I = (weight/9.8).r^2 Torque t = I * (angular velocity / t) Power = Torque * speed The Attempt at a Solution First I calculate Moment of Inertia Using I=(weight/9.8) * r^2 = 183 kg. m^2 Then I...
  16. W

    PC beeps when power goes on, does not complete POST

    Hi, I have a Dell Inspiron core i5 PC. It beeps in sequences of 4 bbebeeps at a time shortly after power goes on , won't boot up nor complete Post . It may have to see with ram problem I have been told. Is this correct? Ultimately, what can I do?
  17. G

    Selecting an MOV for a power supply

    I have a 30V 5A variable linear power supply, which has failed twice from transients killing the LM358 quad op-amp IC that controls the output. These transients are from driving things like a car ignition coil, for making an electric fence energiser. Simply replacing the LM358 gets it going...
  18. D

    Single phase AC 3 wire neutral conductor shock potential?

    I have a question with regard to split single phase (in United States) electricity. I understand that there are 2 hot legs each 180 degrees out of phase at +120v and -120v (240v between hot legs) going from transformer to breaker box and a center tapped neutral Earth bonded wire at 0v with...
  19. C

    Physics Equations for Electrical Power

    I'm in year 11, doing Physics for GCSE and my actual ending GCSE is on Friday which Is where I finish school. I'm 16 and in the UK, I need help with the following equations: P = I^2 x R (why is this equation used) - all the power equations - How to calculate uncertainty << Mentor Note -- OP...
  20. Z

    Where can I find common parameters of power transformers?

    As common I mean inductances and eq resistances. I've been searching for high voltage transformers (to use with a 12-pulse rectifier) but I only see catalogues just trying to sell the thing. Do you have any recommendation as a book or another reference?. Thanks in advance!
  21. N

    Convert Power to a Peak Voltage, when to multiply by sqrt(2)

    I have a dBW value and dBW I understand to normally be given as representing a RMS Power (however this is not specificically ever stated and I am told its just assumed?) from dBW to Watts = 10^(dBW/10) This then gives RMS power in Watts At what point do I convert this from a RMS to a peak...
  22. T

    Can a Copper Coil Harvest Power from Power Lines for an FM Radio Receiver?

    I had an idea of building an FM receiver that is powered from the electromagnetic fields generated by power-lines. My question is , how can I make the electromagnetic field receiving antenna? Will a simple copper coil work? If so, can the same coil be used as the RF antenna or will that have to...
  23. M

    Effect of load and load distance on peak and avg power

    I am trying to create a lever which has mass on one end and i need to lift the lever. A picture showing the lever setup is in this link: https://imgur.com/WeH4oK7 The system is like seesaw ( from -20 degrees to +20 degrees at constant angular velocity for time period 't') The input angular...
  24. S

    Simplification step: solving a diff eqn using a power series

    Homework Statement Hello, I suspect this is an easy answer but I am not seeing it. I am reviewing (more so for fun / hobby) some differential equations – I’m not in school. I’m needing help with an example problem in Differential Equations With Boundary-Value Problems Zill 2nd edition. In...
  25. J

    Potential energy loss related to force applied?

    How can I calculate the loss of potential energy when forces are applied but no motion in the system occurs? Here's an example: Let's say I build a battery operated car that is set to drive forward, but I put it right in front of a wall. It attempts to drive forward, but instead it just pushes...
  26. G

    Powerline cable count and engineering question (HV power distribution lines)

    I have seen that typically most 110Kv and 330Kv lines around my place have not 4 wires on them (3 phases and one neutral) but rather 7 wires on them, which I suppose is 3 phases x2 which probably means two cables for each phase and a common neutral wire at the top of each post. Now is my...
  27. g98

    To reduce cost and weight, power transmission lines are made

    Homework Statement Determine the resistance of a 30 km long wire. b. Assume that the line transfers 1000 MW of power at a potential difference of 500 kV. What is the current through the wires? c. How much power is lost during transmission? What fraction of the transmitted power is lost...
  28. vysqn

    Ek vs engine power in cars and space

    Help me please:) (1) An idealized engine with constant torque curve means constant acceleration. So for example if there is no air resistance and no frictions and car is on fixed gear and at 3000Rpm it produces 50Hp so at 6000Rpm will produce 100Hp. So he doubles the speed , doubles power and...
  29. T

    I Axiom of Choice: Disjoint Family ##\Rightarrow ## Power Set

    So apparently the proof involves a trick that converts the problem of a general power set ##\mathscr{P}(M)## of some set ##M## which has of course the property of not having pairwise disjoint set-elements to a problem that involves disjoint set-elements. I do not understand why this trick is...
  30. J

    Schematic for a Tenma DC Power Supply 705-72

    I am searching for a legible schematic diagram for a Tenma 705-72 DC laboratory power supply. Each of its two channels uses a LM723 regulator and a pair of 2N3055 power transistors. One of the channels operates normally; the second channel puts out the maximum voltage (37 volts). Any help...
  31. entropy1

    How does a force get transmitted through power lines?

    Why does a turbine in an energy plant experience more resistance if the electrical load on the other end increases (electrical resistance decreases)? What I don't understand is how the force that drives for instance a washing machine gets through the power lines that don't seem to experience...
  32. Ventrella

    I Would the opposite of a perfect power be called a "root"?

    I would like to know if there is an official name for the class of integers that are (not) perfect powers. A perfect power is a number that can be expressed as xn, where x and n are both integers > 1. I have been calling these integers "roots" - since they do not have any integer roots of their...
  33. T

    How do computers keep time without power?

    I know the CMOS battery keeps the time and BIOS settings , but what is powered by the batter to keep time? A crystal oscillator? And why is it so crucial to keep time on a regular desktop computer?
  34. K

    What is the power of the lens in diopters?

    Homework Statement It is desired to magnify reading material by a factor of 3.5× when a book is placed 9.5 cm behind a lens. What is the power of the lens in diopters? Homework Equations 1/f = 1/di + 1/do M = -di/do P=1/f The Attempt at a Solution I set equal the magnification to -di/do and...
  35. Casper Hansen

    Accelerated lifetime / thermal ageing of power cables

    Hi PF Is it possible to perform accelerated lifetime test of thermal ageing on power cables? Let's assume that the cable manufacturer guarantees a service life time of 20 years at max operation temperature 90 [degC]. Is it possible to estimate the expected life time of a cable if I choose to...
  36. C

    Finding a the value of 30th derivative given power series.

    Homework Statement The problem is attached as pic Homework Equations ∑(ƒ^(n)(a)(x-a)^n)n! (This is the taylor series formula about point x = 3)The Attempt at a Solution So I realized that we should be looking at either the 30th,31st term of the series to determine the coefficient. After we...
  37. P

    Single Line Diagram - Power Systems

    Hey everybody, Its recurrent in Power System Analysis and Electrical Instalations the SL diagram. I need recommendations of books in which I can read about it. I've done a little research but couldn't find anything. Thats amusing, in which classes are this diagram teached for the first time...
  38. W

    Calculating Power Requirements for Blending Granular Materials in a Machine

    Hello pleas i need help how to calculate needed power(of engine) for blending granual material in machine. Machine looks like on pic below thank you
  39. joyxx

    Why are transformers important to electric power distribution

    Homework Statement Give two reasons why transformers are an important part of the power distribution grid My lessons don't have any information regarding this topic. I have read everything in my lesson and can't find anything to answer this question. please help. thank you
  40. M

    Health Risks Living Near Power Lines

    Hello Please give me some advice on a lot my wife and 2 kids are thinking on building our home on in SC. It will be located next to a large power line right of way. Its near a lake so we have those big metal towers. I'd say the nearest tower from my house will be like 50 to 75 yards. I took a...
  41. isukatphysics69

    Radius of convergence of the power series (2x)^n/n

    Homework Statement in title Homework EquationsThe Attempt at a Solution so i know that i have to use the ratio test but i just got completely stuck ((2x)n+1/(n+1)) / ((2x)n) / n ) ((2x)n+1 * n) / ((2x)n) * ( n+1) ) ((2x)n*(n)) / ((2x)1) * (n+1) ) now i take the limit at inf? i am stuck here i...
  42. M

    Power margin of a fiber-optic system

    Homework Statement Im going over some revision for fibre optics and I've come across an example question to calculate the power margin of the system with the following info is given: transmitter power = -10dBm Connector loss = 1.5dB Attenuation = 3dB/Km Total length= 2KM Receiver threshold =...
  43. V

    Automotive How to calculate brake power in IC engines?

    Can somebody explain how to calculate brake power in IC engines ?
  44. Eric Song

    Power Series and Convergence for ln(x+1)

    Homework Statement What is the power series for the function ln (x+1)? How do you find the sum of an infinite power series? Homework Equations sigma from n=1 to infinity (-1)^n+1 (1/n2^n) That is the power series, how is that equivalent to ln (x+1)? How do you find the sum, or what does it...
  45. B

    Gaussian Smoothing of the Matter Power Spectrum

    Homework Statement Consider the density perturbation smoothed with a Gaussian of scale ##\sigma##, ##\Delta_{\sigma}(\vec x') = \int d^3 \vec x \frac{e^{- \frac{(\vec x - \vec x')^2}{2 \sigma^2}}}{(2 \pi \sigma)^{3/2}} \Delta (\vec x)## Calculate the power spectrum ##P_{\Delta_{\sigma}}## of...
  46. D

    Loss of energy in DC and loss reduction in AC circuits

    Homework Statement similarities and differences of AC and DC current in simple circuits. Outline using diagrams and a clear desciption the loss of energy in DC circuits and power loss reduction of AC when transmitted. Homework Equations N/A The Attempt at a Solution DC loses energy over long...
  47. A

    Calculating the power output from a persons mouth

    Homework Statement Speech at a distance of 45.1 cm has a sound level of 59.3 dB. Assuming that the energy in the sound spreads out equally in all directions from the person's mouth, calculate the total power output from the person. Given: Distance= 0.451m Sound level 59.3 dB P=? J Homework...
  48. Deacon James

    Can Compact Fusion Reactors Power Small Cities?

    https://lockheedmartin.com/en-us/products/compact-fusion.html HOW COMPACT FUSION WORKS Nuclear fusion is the process by which the sun works. Our concept will mimic that process within a compact magnetic container and release energy in a controlled fashion to produce power we can use. A reactor...
  49. niaz

    Cylindrical rotor generator power under loss of excitation

    Hello all, I want to know about turbo alternator real power producing capability under loss of excitation condition. Normally in salient pole rotor have capability to supply real power under field current=0 condition, as there is reluctance power developed. But what about non salient pole...
  50. Z

    Calculating Power for a car, and relating it to the motor curve

    Hello all, I am trying to build a simulation to understand what power is required by an electric car in order to accelerate from 0-50kmh. As per my understanding the total power required by engine is calculated using Total Power required at given velocity formula as stated below. I am...
Back
Top