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

    What limits superconducting machine power density?

    Hi. There has been a fair amount of research into electric generators and motors with superconductive coils. If traditional iron cores is used that obviously limits the power density because of the iron cores magnetic saturation point. But for coreless/ironless designs i don't understand what...
  2. E

    Engineering Electric Power Systems book recommendation

    Summary:: Electric Power Systems book recommendation Hi everyone, I finished my Electrical Engineering degree 15 years ago and wanted to refresh/review/update my knowledge on Electrical Power Systems. I'm looking for a book recommendation that has: components of a power system, control of...
  3. L

    Engineering De Moivre's theorem to express power

    A)Use de moivres therom to express power in simplest polar form Workings Do i need to divde the 60^o by 10 aswell
  4. M

    Discover the Surprising Power of Water: Tap vs. Fire Hose vs. Pressure Washer

    Okay, so I don ' t have any real specs but i just want to know how big is the difference between water from tap versus the one from fire hose versus the pressure washer?
  5. W

    Motion equation problem -- Car accelerating with a constant power engine

    So I tried to solve this in two methods, but I keep getting different results, and I don't know why.
  6. E

    Conservation of Energy Problem (Power)

    Hello there, I was trying to solve this problem. I have no problem with part A and C. But in part B, my guidebook arrived with different answer. Can anybody point out what my mistake is? I am using the same method as the elevator motor problem which states : "A 650-kg elevator starts from rest...
  7. greg_rack

    Average power used to stretch a spring

    First and foremost, I found the max stretch of the spring using the strain energy formula(x=√((2*0.25J)/k)) ). Then, the maximum force exerted(Fmax=k*xmax), in order to find out the seconds needed for the force in [N/s] to reach its maximum value. Now, I got confused about how to find the...
  8. DarkMattrHole

    Does the world really need 'more power'?

    The answer should depend on the result. If the result is more of what's going on and what's going up, like pollution, extinction, and temperature, then no, the world doesn't need more power, and the solution lies elsewhere. If we can stop polluting with particles and gassing out as we...
  9. pandamonium_

    AP Physics Momentum, Impulse, Collisions, and Power

    1/2mv^2 = 1/2mv^2 - 1/2kx^2 but can't plug in numbers for x or m mv+mv=mv+mv but no mass given very lost
  10. patric44

    Solving a Gaussian integral using a power series?

    hi guys i am trying to solve the Gaussian integral using the power series , and i am suck at some point : the idea was to use the following series : $$\lim_{x→∞}\sum_{n=0}^∞ \frac{(-1)^{n}}{2n+1}\;x^{2n+1} = \frac{\pi}{2}$$ to evaluate the Gaussian integral as its series some how slimier ...
  11. greg_rack

    Efficiency of a hydroelectric power station

    I have found the input power through the efficiency formula, and I deducted that the input energy must derive only from water's kinetic energy... from which have mass/s and then finally the volume/s. After all the calculations and having multiplied the volume/s by 60, I get the result of 6.48 x...
  12. C

    I What powers the quasar magnetic beams that power jets?

    I am reading up on quasars because I am interested in the magnetic beams that emanate from their poles, accelerating material. I read that the magnetic beams are generated by the orbiting debris the quasar is consuming. Sorry, that doesn't sound right to me. I assumed the black hole core is...
  13. P

    Peak Power vs Average Power

    It is an example problem and i could understand the solution and the answers are ## R = \frac {V_{rms}^2} {P_{av} } = 9.6 \Omega## ##I_{rms} = \frac {P_{av}} {V_{rms}} = 12.5 A## ##p_{max} = VI = 2P_{av} = 3000 W## But main problem is the statement given by the author below the solution which...
  14. karush

    MHB S8.2.6.3 differenciate by separation and power rule

    $\tiny{s8.2.6.3}$ Find y' $\sqrt{x}+\sqrt{y}=1$ \begin{array}{lll} \textit{isolate }y &\sqrt{y}=1-\sqrt{x} &(1)\\ \\ \textit{square both sides} &y=(1-\sqrt{x})^2 &(2)\\ \\ \textit{differentiate both sides} &y'=2\left(1-\sqrt{x}\right)\left(-\dfrac{1}{2\sqrt{x}}\right)&...
  15. John321

    A Relationship between the angular and 3D power spectra

    I have the following equation, $$ C_\ell(z,z') = \int_0^\infty dkk^2 j_\ell(kz)j_\ell(kz')P(k),$$ where $$j_\ell$$ are the spherical Bessel functions. I would like to invert this relation and write P(k) as a function of C_l. I don't know if this is a well known result, but I couldn't find...
  16. jisbon

    Engineering Computing the Maximum Power delivered to a Resistor

    Hi all, Checking my answers here as it doesn't seem to match with the answers given to me. Would appreciate if anyone could point out the mistakes I made. First I will compute Rth. Offing all independent sources, applying a known voltage across R (in this case 1v) and using mesh analysis...
  17. DaveC426913

    Tethered aircraft lifting power, low gee world

    I may have written myself into a corner. I am not looking forward to your answers. It involves the very core of my story, so I can't be coy with the deets. I know there are way too many factors for proper analysis, just looking for rough ideas. There are a couple of parts to this, I'll start...
  18. Mayan Fung

    How to get maximal power output from solar panels in reality

    I learned that solar panels have their maximal power output at a particular voltage and current level. If we want to get the max power, we have to connect a load with a specific resistance. However, in reality, how does the solar plants solve this problem? I guess they won't allow the power...
  19. Mayan Fung

    Controlling output light power by constructive/destructive interference

    In optical communications, one of the modulation methods is to control the optical power (Simplest case, for example, bright = bit 1, dim = bit 0). I learned that we can achieve this by a Mach-Zehnder modulator (MZ modulator). Simply speaking, the principle of MZ modulator is to split the input...
  20. gumby4231

    12V Tractor Battery supply: Losing Power Supply

    I want to mount a camera on the front of a tractor(Sony RX0M2, similar to a gopro). The camera will eventually be used for image processing. A PQ-12 micro linear servo (see here) will be used to turn the camera on/off. It is being run by a Raspberry Pi 4B. All components in this project will be...
  21. M

    Engineering Calculating Power Lost in a Resistor (within Transformer Circuit)

    Hi, I have a simple question that I don't have a fundamental understanding of: do resistors dissipate reactive power (in addition to active power)? For context, when we are looking at a transformer (single phase) equivalent circuit (similar to the one in the image attached), we are asked to...
  22. S

    Energy consumed for same work with different power?

    As per me the energy required by a man with 60 age and 21 age to cover same distance is same.
  23. Schwann

    I Linearity of power spectral density calculations

    I have a question related to linearity of power spectral density calculation. Suppose I have a time series, divided into some epochs. If I compute PSD by Welch's method with a time window equal to the length of an epoch and without any overlap, I obtain this result: If I calculate the...
  24. J

    Estimation of the power in a received radio signal

    I would like to estimate the magnitude of a radio signal received from a transmitter by first principles: Transmitter antenna length ##L=1## m Transmitter antenna area ##A=1\hbox{ cm}^2## Number of electrons per unit volume in antenna ##n_e=10^{28}## Radiation resistance of antenna ##R_R=10\...
  25. H

    History Why didn't ancient civilizations harness the power of electricity?

    I think the greek knew about magnets and magnetic stones. They also knew about statistic electricity the Egyptian knew about a fish which would shock you . My question is why did it take so long for someone to wrap a magnet around a coil. What is the earliest in human history that humans could...
  26. Leo Liu

    I A Sequence in a Power Series

    I tried to use the ratio test, but I am stuck on finding the range of the limit. $$\because \left|x-1\right|<1.5=Radius$$ $$\therefore -0.5<x<2.5$$ $$\lim _{n \to \infty} \left| \frac{A_{n+1}(x-1)^{n+1}}{A_n(x-1)^n} \right|$$ $$\lim_{n \to \infty} \frac{A_{n+1} \left|x-1\right|}{A_n} <1$$...
  27. chriscarson

    "To the power of" (powers in division have to be subtracted)

    Our teacher said that powers in division have to be subtracted when the same base , but still , I am not getting the right answer.
  28. Math Amateur

    MHB ZFC and the Axiom of Power Sets ....

    I am reading Micheal Searcoid's book: Elements of Abstract Analysis ( Springer Undergraduate Mathematics Series) ... I am currently focused on Searcoid's treatment of ZFC in Chapter 1: Sets ... I need help in order to fully understand the Axiom of Power Sets and Definition 1.1.1 ... The...
  29. Athenian

    Fresnel Equations for the Power of Reflectance and Transmittance

    I understand that the power of reflectance and the power of transmittance (regardless of it being S-polarized or P-polarized light), when added together, would equal to one. In other words, ##R+T=1##. However, how do I go about checking for this fact? Using the equations from the "Relevant...
  30. W

    Power/Torque of Large Hauler, Tank & Bulldozer: Comparing Trees

    I was trying to do some research to find the difference in power of different vehicles. Mainly the difference between a Large hauling semi truck A battle tank and a bulldozer like a d11t. Let's say I hooked up a chain to the back of each of these vehicles and rapped it around a large 3 foot...
  31. A

    How does electron speed affect electric power?

    I've got a quick question on the relationship between the kinetic energy of individual electrons and the total electrical energy they create. I have a radioisotope - a beta emitter - which produces electrons with around 1 MeV (1.60218×10-13 Joules / 4.45049×10-17 Watt-hours) of energy. I keep...
  32. Rx7man

    What Could Be Causing My 3 Phase Motor to Lack Power and Torque?

    I have a small 1hp 3 phase that really lacks torque, it was on a big lathe (12hp) and the entire rest of the machine was wired for 240V delta.. but this motor only has 3 wires coming into the connector box, so there are no options for changing the voltage, yet the nameplate says 220V Delta or...
  33. jisbon

    Engineering Finding the maximum power delivered using Thevenin's theorem

    Using mesh analysis, my simultaneous equations seem to be wrong and I can't figure out why. Any stuff that I should take note of? Attempt:
  34. WonderfulWorld

    Long Distance Wireless Power Transmission

    Hi Everyone, I wanted to get the communities take on this. Long distance wireless power transmission. I know that you cannot accomplish this with magnetic fields or with radio waves because the energy falls of with the square of the distance but I have been reading about some unique methods to...
  35. R

    How the power of the voltage supply can be calculated?

    I know only these relevant equations for power. But here there is a different situation, we have a parallel plates which we don't have to know I current. How should I think of about this? I wonder if it can be thought of a capasitor or something? Assume that also we know E, B and velocity .
  36. G

    Why is the power of a particle on a wave zero in a stationary wave?

    I've marked the right answers. They mainly indicate at power carried by the particles being zero, and here is my doubt- why should it be zero? Shouldn't it have some definite value? I do understand that the kinetic energy is max at the y=0 and potential energy is max at y=A, but I don't know...
  37. G

    How do you calculate power from a magnet in a coil?

    I don't really know but if I were to guess it would be based on how many turns are in the coil, the diameter of the coil and the flux of the magnet. Unfortunately I couldn't find a formula anywhere.
  38. N

    I A question about operator power series

    Hi All, I've been going through Shankar's 'Principles of Quantum Mechanics' and I don't quite understand the point the author is trying to make in this exercise. I get that this wavefunction is not a solution to the Schrodinger equation as it is not continuous at the boundaries and neither is...
  39. Nexus99

    Understanding Work Calculation in an Engine: External vs. Internal Forces

    I'm really struggling with this problem. I can't understand which are the forces that i need to calculate work. Probabily when the sand falls the force of which i need to calculate work is weight force, but which is the force that carries the sand at the top of the roller?
  40. W

    B Nearly Scale Invariant Power Spectrum in inflation

    I recall hearing once a very intuitive explanation as to why inflation is thought to lead to a nearly scale invariant power spectrum but i can't recall it. Can anyone offer an explanation that might help me? Why is it nearly scale invariant and not perfectly scale invariant? many thanks
  41. N

    Mechanical engineering: Maximum Power Transmitted by a V-Belt Assembly

    Summary:: Hi I’m in second year mechanical engineering and I really need help with this question! Sorry about my handwriting in the attachment I’ve put in, I've written the question out but there is an image of figure one on the file attached. Many thanks! [Mentor Note -- Thread moved from a...
  42. bbbl67

    I Power output of red dwarfs turning yellow and blue?

    Although the universe is not old enough to experience these yet, but near the end of the lives of red dwarf stars, they will go from red to yellow, to blue eventually. Does this result in additional heat being given off of the surface of those stars? And if so, then does the habitable zone of...
  43. jasmin_89

    Calculating Minimum Power for Perception of Radiation from a Point Source

    Hallo, can anybody help me and check if i have the right result: What is the minimum power P that a point source of radiation (I=8*10^(-7) W/m^2) at a distance of l=10 m from the listener must have in order to still be perceived? (Note: The emitted energy per area can be related to a spherical...
  44. A

    Power required to reach X velocity in X time with drag

    Hello, I wrote a program that adds force to a car like so: Engine Force = Power / Velocity Drag Force = -Velocity² Net Force = Engine Force - Drag Force = Power / Velocity - Velocity² I'd like to determine power based on how fast I want a car of a given mass to reach a given speed, for...
  45. samstergurl

    Concentric coils for power generation

    Most generators work by rotating a coil within a magnetic field. This induces a current in the coil and can be harnessed as electricity. I was wondering if it would be possible to generate more power by using more than one coil with each one being progressively larger wrapped around the others...
  46. B

    Engineering RLC Series Network: Impedance, Current, Power Factor, Phasor Diagram

    Hello. I have completed the following question. My answer: i) Circuit Impedance Reactance = XL = 2 x pi x F x L = 2 x pi x 50 x 0.15 = 47.12 Ohms Reactance of Capacitor = XC = 1/2 x pi x F x C...
  47. M

    I Power Broadening: Explained & Resources

    Hello! I have seen mentioned in several papers the concept of power broadening, which (if I understand it right) means that the linewidth of a transition (say, in an atom) get wider with increasing the power of the laser used (even if the linewidth of the laser is kept constant). I am not...
  48. Russ Edmonds

    Power absorbed and B vs H plot for microwave oven transformer

    A DI-149 data acquisition module was used to record a microwave oven transformer (MOT) primary voltage and current time histories. The secondary of the MOT was open. The DI-149 analog input specs are: +- 10 volts full scale, 5000 samples per second for each channel (assuming two channels being...
  49. andyskin

    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

    Please can you have a look at the file at point me in the right direction if I'm wrong. Thank you
  50. C

    MHB Finding a formula for the multiplication of multiple formal power series

    Dear Everyone, I am having trouble with finding a formula of the multiplication 3 formula power series. \[ \left(\sum_{n=0}^{\infty} a_nx^n \right)\left(\sum_{k=0}^{\infty} b_kx^k \right)\left(\sum_{m=0}^{\infty} c_mx^m \right) \] Work: For the constant term: $a_0b_0c_0$ For The linear...
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