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. A

    I Photon emission, power output (and black holes)

    I recently re-read an article by Muller (https://arxiv.org/pdf/1606.07975.pdf) about the flow of time, and the possibility of time reversal given sufficient energy dissipation (basically during black hole evaporation, he concludes). Although the paper is on arXiv and not peer reviewed, Muller...
  2. Poetria

    Addition of power series and radius of convergence

    Homework Statement ##f(x)=\sum_{n=0}^\infty x^n## ##g(x)=\sum_{n=253}^\infty x^n## The radius of convergence of both is 1. ## \lim_{N \rightarrow +\infty} \sum_{n=0}^N x^n - \sum_{n=253}^N x^n## 2. The attempt at a solution I got: ## \frac {x^{253}} {x-1}+\frac 1 {1-x}## for ##|x| \lt 1##...
  3. Poetria

    Differentiating a power series

    Homework Statement [/B] Differentiate the power series for ##\frac 1 {1-x}## to find the power series for ##\frac 1 {(1-x)^2}## (Note the summation index starts at n = 1) 2. The attempt at a solution ##\sum_{n=1}^\infty n*x^{n-1}##
  4. J

    Airplane question -- How to compensate for losing engine power on one wing....

    If the right wing right engine suddenly fails.which of the two rudders and how must be moved so that airplane maintains its attitude and flies straight (assuming the plane is on air not landing)
  5. A

    Plotting a Power Graph using Torque & RPM

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  6. A

    Relevant highest order harmonics in power systems

    i am learning about harmonic analyzers and i have a couple of questions concerning them that need some sort of practical experience to answer them ( and i have none :) ) : 1-can harmonic analyzer analyze up to any harmonic? or is there a maximum ? if there is no maximum what's the highest...
  7. P

    How Do You Calculate Power from Torque and Angular Velocity?

    Homework Statement Motor runs at a rate of four revolutions/sec has a torque of 20. What is it's power. Homework Equations T = (2π) / w f = w / (2π) w = 2πf P = T * w Power = Torque * angular velocity The Attempt at a Solution [/B] T = 20 Nm f = 4 * 2π = 8π w = 2π * (8π) = 16π^2 P = 20 *...
  8. D

    Generator Input and Output Power

    Hello I try to build a brushless Generator. Let me try to explain it. I have a brushless engine. max 6000 Watt 250KV. And I have combustion engine. 3500 Watt by 16k RPM If I connect the combustion engine with the brushless motor and the combustin engine turns with 16k the brushless motor...
  9. Muhammad Danish

    Calculating Current in Primary Coil: Where Does P = V^2/R Formula Come In?

    Homework Statement Homework Equations How will we calculate the current in primary coil? The Attempt at a Solution The current in the secondary coil will be 2 Amperes by I = V/R. So in the primary coil by using ratio proportion method, the current in the primary coil will be 5 Amperes. But...
  10. J

    Using the steady flow energy equation, find the power required

    Homework Statement A pump is used to move water through a pipe of diameter 150mm, Figure below. The water has a temperature of 20 Celsius and an absolute pressure of 100KPa. The pump moves the water up a vertical distance of 2m and the water exists at atmospheric pressure. Q1) Assuming the...
  11. I

    Leakage Reactance of a three phase power transformer using Ansys Maxwell

    Hello all; I am trying to calculate leakage reactance of three phase power transformer . I am using Ansys Maxwell final element solution to analyse it. The software gives me total energy and linkages and self and mutual inductances.By using this quantities how can ı compute leankage reactances...
  12. LippyKa16

    Engineering A car on a hill - power of motor problem

    Homework Statement A car is traveling up a slope. Given that a(t) is constant at 1m/s^2, find the expression of motor power in time. Assuming that the maximum power of the car is 215kW, for how long can the car maintain such an acceleration? Mass of car (m) = 2000 kg The hill has a constant...
  13. J

    Calculating 208V load, purpose of sqrt(3) and power factor?

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  14. A

    Average power dissipation for induced current

    Homework Statement A wire shaped as a semi-circle of radius a rotates about the axis OO’ with a constant angular velocity ω in a uniform magnetic field with induction B (attached figure). The plane of the rectangular loop is perpendicular to the magnetic field direction. The total resistance of...
  15. P

    Speed, energy, power and air resistance

    What is wrong here. If I double speed drag will be 4 times higher. The engine needs to put out approximately 4 times more power. Energy consumption will be 4 time higher for a specific time period. However if it is a fixed distance I will arrive in half the time an the energy consumption will...
  16. G

    Experienced with PQ Control and PI Tuning for Inverter Power Control?

    Does anyone have experience modeling active/reactive management in an inverter? I'm working on it for a project, more precisely I'm trying to implement that PQ control with references of voltage, as is seen in this image: Problem is I've tried many PI regulators, and my I_dq doesn't want to...
  17. A

    Iref extraction in active power filters using active filters

    i was doing a research on active power filters and i read about Iref ( the cancelation waveform) extraction algorithm, and they are using complicated algorithms like FFT or DFT in frequency domain or the park transform and clark transform in time domain, i was wondering, why isn't there any...
  18. Altagyam

    Write the Power Series expression for a given sequence

    Homework Statement http://sites.math.rutgers.edu/~ds965/temp.pdf (NUMBER 2)[/B]Homework Equations I do not understand the alternating part for the second problem and the recursive part for the first problem.The Attempt at a Solution The first answer I got was first by writing out the...
  19. R

    Arrow Pitching during the Power Stroke

    I am working on modeling the acceleration and initial launch angle of an arrow shot from a bow during the power stroke. From an aiming point of view, the launch angle of the arrow doesn't change with respect to the target. But changing the nock position where the arrow nock attaches to the...
  20. yecko

    Solving a Linear ODE using a power series

    Homework Statement Homework Equations Power series ODE The Attempt at a Solution [/B] Sorry for not typing all those things out from my phone.. How can I get C1? And how can I put the solution in the required format? (I don't know how to put it in summation sign... and i cannot even solve...
  21. Shadow89

    Optimal values for power in an induction heater?

    I really want to build a simple but powerful induction heater for hobby blacksmithing. Metal shaping and the design of the cooling system within the coils are not a problem. I need help understanding the electronics Obviously I must first use a transformer as a safety against "backlash" to the...
  22. yecko

    2nd order differential equation with power series

    Homework Statement Homework Equations Power series The Attempt at a Solution As I have to write in form of "x^2n" & "x^2n+1", I am totally have no idea with how can I go on to do the question. Those I have learned in lecture and online are mostly with only one part of summation... or two...
  23. K

    Other Undergraduate research or thesis topics in electrical power

    Hi I am an electrical engineering student, would like to do research and or a thesis in electrical power engineering. However, because our university does not offer any courses on this topic, I am left alone to peruse the books and literature and find some topic of interest. do not know if this...
  24. J

    Does Solar Power Contribute to Global Warming?

    Does use of solar panels or other radiation capturing technologies in itself warm the earth? Since solar energy is radiated partially back to space, then, when a portion of it is captured and converted to electricity which performs work and rseleases heat (e.g. in transmission lines) it would...
  25. E

    Why is a capacitor a generator of lagging reactive power?

    An ideal capacitor has power factor of zero degree leading as current leads the voltage in capacitor.But it also means that capacitor is generator of lagging reactive power.What does that mean.How does it do so.Capacitor is used for reactive power generation at inductive load sites.
  26. Alfredo

    Pelton Wheel for Power Generation

    I am a simple Newbie, wanting to make power, using Pelton wheel say 45 psi water pressure , 3/8 to 1/2 nozzle...is there a way to determine the results or is there a better psi/nozzle combo? Generator can be 12/24/48 volts
  27. K

    Finding power as a function of time in transferring water

    Homework Statement A completely filled cylindrical tank of height H contains water of mass M. At a height h above the top of the tank there is another wide container. The entire water from the tank is to be transferred into the container in time T such that level of water in tank decreases at a...
  28. Y

    Temperature multiplied by Power?

    Homework Statement I'm trying to come up with a situation, perhaps in a mathematical calculation, or characteristic describing physical phenomena that is related to temperature times power. I know that thermal conductivity is measured in temperature divided by power, but unsure of a scenario...
  29. F

    Understanding the Power of an Engine

    Hello, In mechanics, power is defined as the rate at which energy is either produced or consumer: ##\frac {E}{t}##. A different but equivalent definition is ##P= F v##. In the rotational world, we talk about rotational power and the expression becomes $$P= \tau {\omega}$$ where ##\tau## is...
  30. A

    Power dissipated by a Resistor

    Homework Statement What power is dissipated by the R2=3.0Ω resistor in the figure if R1=6.0Ω? Battery 1: 12 V Battery 2: 15 V Resistor 1: 3.0 Ω Resistor 2: 6.0 Ω Homework Equations P = V2/R Rtotal = R1 + R2 The Attempt at a Solution I started on the left side and used the formula, P = V2/R...
  31. J

    Engineering Circuit interconnection: power delivered

    The circles are referring to independent voltage or current sources, which maintain the same current/voltage regardless of the rest of the circuit. I'm confused because power delivered means they want the value of the "negative" power, which would mean only i*v1 would be the only power...
  32. Jucimar

    Can self induction increase power consumption?

    Hi folks, My question relays on the difference of consumption power of a coil when it's on AC and CC regime. A coild is made of copper wire with air core, aplied on it a CC current of 1 amp, a measure was taked and nottice a 5W of power consumption. Then the power supply is changed to and AC...
  33. H

    Power supplied by AC component + DC component = total power?

    Hi, I have a question about ac component and dc component of a source. For example, there is a current source connected directly to a resistor. If the current source supplies a sine wave with no dc offset, then I understand that power supplied by dc component is zero, and so power absorbed by...
  34. B

    Power requirements for an electric trike

    Hello, I may be thinking out of my element here but I am considering a project. I want to build a recumbent trike that is electric powered. I want to take a slightly different approach however. I want to use the pedals to turn a generator to assist in the recharging of the batteries...
  35. C

    How Do You Determine the Load Resistor Value for Maximum Power Dissipation?

    Homework Statement A constant voltage source V with internal resistance r is connected to a load resistor R. The dissipated power by the resistor R is P=RV^2/(R+r)^2. Show that the maximum power dissipated by the resistor R is achieved when R = r. The maximum of P with respect to R is achieved...
  36. opus

    Using Power Reducing Formulas to rewrite Trig Expressions

    Homework Statement Use the power reducing formulas to rewrite the expression that does not contain trigonometric functions of power greater than 1. Given expression: ##4sin^2xcos^2x## 2. Homework Equations Relevant Power-Reducing Formulas: ##sin^2x=\frac{1-cos2x}{2}##...
  37. yubson

    Question about measuring the internal resistance of power supplies

    In measuring the internal resistance of a power supply, why is a resistor with low resistance used?
  38. E

    Amount of computing power needed for whole-brain emulation?

    What is the approximate amount of computing power that is required for real-time emulation of the entire human brain? Such computing power would be necessary for theorized AI systems in the future. From my understanding, no computer that exists in the world today can do this, yet...
  39. K

    Why P = F*v = ε^2/R = (vBl)^2/R when there's no friction?

    Homework Statement This is taken from a problem with its solution. But there's one thing I didn't understand with the solution: A closed conductor loop is located perpendicular to the field lines in a homogeneous magnetic field B. The conductor slice CD is first in rest. Then we pull a...
  40. Kiwaho Kilowatthour

    Profit margin for Solar Chimney projects and land power density?

    It is said that the Madrid Spain solar chimney project occupies 110 acres land, but only output humble 50 kw: https://en.wikipedia.org/wiki/Solar_updraft_tower The fact: the average yearly solar power density of above powerplant = 0.11 W/m^2 Interestingly, there are many countries still...
  41. kstorm19

    Question about complex power in three phase circuits

    Homework Statement Assume that the two balanced loads are supplied by an 840-V rms 60-Hz line. Load #1: Y-connected with 30+j40 Ω per phase, Load #2: balanced three-phase motor drawing 48 kW at a power factor of 0.8 lagging. Assuming abc sequence, calculate the complex power absorbed by the...
  42. TheComet

    Series diode and a low power device

    I'm designing a device that consumes 450nA in idle (up to 2mA peak) and the maximum allowed voltage is 3.3V. The power is supplied by a battery with a voltage of 3.6V. One of the problems I've run into is: All LDOs I could find have a quiescent current consumption (Iq) greater than 450nA. The...
  43. S

    Is the relationship between power, torque and RPM a linear relationship?

    Hi I have a problem dealing with rpm power and torque. I have a motor powering a gearbox which has a 20:1 ratio. The power and rpm are not an issue so i have not looked at those figures but the motor produces 240Nm of torque. Since it is a 20:1 gearbox, i have assumed the torque is 20 times...
  44. H

    How to find the power consumed by the light bulb

    Homework Statement (Is the image read-able now? ) The fig 1 shows the relationship between voltage and current when voltage is applied to a certain light bulb. Next, in fig 2, the bulb is connected in series with a 12-V battery and a 5 ohm resistor. Question : what is the amount of power...
  45. Humbleness

    Calculating Power and Energy Consumption of Two Coffee-Makers

    Homework Statement Two 15Ω coffee-makers are connected to a 120V power supply for two hours a day each. Find the power and energy. Homework Equations P=V2/R ΔE=PΔt The Attempt at a Solution I am assuming, since there are two coffee-makers connected to one 120V power supply, that: P = V2/R =...
  46. J

    Power dissipated in a resistor

    Homework Statement Homework EquationsThe Attempt at a Solution Power dissipated in the 2 Ohms resistor will be maximum when current is maximum .This will occur when total resistance is minimum . If I think logically then I do get the right answer . But on trying to arrive at the result...
  47. T

    I How to calculate the tractive effort of a train?

    Hi there again, I am trying to correctly calculate the tractive effort pf a train, currently i do this: Power/speedMpS = TractiveEffort I got that from here. But it doesn't provide realistic values, so i am wondering, what is the correct way of calculating tractive effort of a train? Thanks
  48. S

    Torque and power calculation for a crank wheel

    How to calculate torque and power at 'drive wheel' with following inputs and also requirement shown in below picture- a. Gear ratio, 1: 6 b. Attached 10Kg weight for bigger wheel to make as a crank wheel and diameter is 30inch. c. Bigger wheel: Consider 180 degree is freely rotates(due to 10kg...
  49. Skrphys

    Power Equation: Instantaneous vs Average Velocity

    How does this version of the power equation relate to physical situations? Does the value you get give you an instantaneous power? Or is the velocity to be taken as the average velocity (an actual displacement over time)?
  50. T

    What does power have to do with the speed calculations of a Train?

    Hi there again, I have been wondering why train simulators(and trains themself) have a kW specification, AND a maximum force indication. If I would calculate the speed of a train using some formula, then where is the power value used for? Does it have something to do? Or is only the maximum...
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