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

    A Alpha Stopping Power Database for High Z Materials

    That's about it. I've been trying to do the calculation manually with Bethe-Bloche without corrections in the energy range I'm interested in (1-10 MeV) for the highest Z material with data available for validation (Uranium), but I can't get a result that agree well with the database, so I'm...
  2. bluesteels

    A.C. power supply voltage amplitude questions

    I know that the answer for A is 31.82. But when i look up B why is it zero? can someone explain please thank you
  3. naviakam

    Troubleshooting 30kV Power Supply: Possible Problems and Solutions

    I am using a power supply (30 kV, 20 kHz) to discharge in air between two electrodes separated by an insulator. For 30 kV applied voltage, oscilloscope shows only 6 kV, and no discharge occurs. What are possible problems and solutions?
  4. K

    Is the cable inside a socket outlet / power strip attached firmly?

    I have a power strip that has fallen from height accidentally for a couple of times, there is no observable crack or damage, however, could this lead to bad contacts or anything bad to the electrical/electronic appliance? I'm thinking if the power cable inside is usually well attached
  5. kara123

    V/I: Power from Potential Difference & Current

    e=QxV t=Q/I p=(QxV)/(Q/I) =V/I The expression I came up with for a) is the potential difference divided by current to get power but I have no idea if that is even right if someone could just prompt me in the right direction that would be greatly appreciated
  6. S

    Citizen explorer tries to explain the Ivanpah Solar Power Towers

    First, here is a riddle: Why did the tortoise cross the road? Because an under-pass was available. An adventurer and desert explorer visited and tried to explain the workings of the solar powered towers at Ivanpah, in the Mojave Desert in California. The person is not any kind of scientist nor...
  7. A

    How transmission lines deliver (established?) power from generator

    Hello: I'm confused about transmission lines. According to Faraday's Law, what's induced is an emf that depends on how fast the coils spin, or whatever equivalent to a simple model seen on Physics textbooks. Power, however, is then assumed constant when talking about the power loss due to...
  8. Tobias Holm

    Find frequency such that two components have same average power

    (This is my first time posting here, sorry in advance for any difficulties. ) All componenets of same type has same magnitude, so e.g. the two resistors both have $R$ resistance. Given the difficulty of the previous exercises, I believe I'm over complicating the problem. However, here is what...
  9. F

    I Mechanical power generated by a force F

    Hello, It is well understood that a constant horizontal force ##F_{applied}## applied to an object of mass ##m## over a distance ##d## in a direction that is not orthogonal to the direction of motion produces mechanical work ##W= F d ##. This work is a mechanism to inject (or subtract) energy...
  10. A

    B Unlocking the Mystery of Blackbird: Exploring Wind Power Leverage

    I see there has been threads about Blackbird and "Down Wind Faster Than The Wind" operating principle in general, and I see a good number of people (most?) in those threads seemed to pick up some understanding of how it actually works. So that's a good start and gives me hope. I had never heard...
  11. Leo Liu

    I Power of a complex conjugate

    Can someone please tell me why this is true? This isn't exactly the De Moivre's theorem. Thank you.
  12. F

    I EM Power transmitted from one region to another (normal incidence)

    High! I have a EM plane wave hitting normally a surface dividing universe in media 1 and 2, both without losses. So we have incident, reflected and transmitted waves. It's a simple exercise in which you are given the basic data about two media and wave incident amplitude H in medium 1. I get...
  13. G

    B How to estimate the heating power of warm air entering a room?

    In winter I heat my workshop with a radiant heater and an oil heater. Easy to know how much heat is entering the room. But in spring and summer I don't use those; I blow hot air from the ceiling cavity into the room, and I was wondering how I would estimate the heating power and the formula to...
  14. PainterGuy

    Signals with the same frequency spectrums but different power levels

    Hi, I understand that if there are two signals whose spectrums consist of different set of frequencies, they can be separated using a filter such as bandpass filter on the receiver end. Is it possible to separate two signals who frequency spectrums are the same but power levels are different?
  15. D

    Find the pressure drop and power loss of pipe when elevation changes

    Summary:: I can’t get the correct answers, I think I haven’t fully understand the theory behind them The answers are given in the picture
  16. Butterfly41398

    Three phase total power consumed

    Summary:: I don't seem to see any problem with my work. But my final answer does not match the correct answer. (In number 3) Here's my work
  17. arcTomato

    I Is my calculation of the power spectrum correct?

    Hello PF. I am thinking about the power spectrum when observing X-rays. We are trying to obtain the power spectrum by applying a window function ##w(t)## to a light curve ##a(t)## and then Fourier transforming it. I have seen the following definition of power spectrum ##P(\omega)##. Suppose...
  18. naviakam

    I What Specifications Are Needed for a Plasma Device Power Supply?

    In a plasma device, the plasma is generated by applying high voltage in a gas. What are the specifications for the power supply producing such plasma? The output must be AC or DC? Pulsed or not? What are the current, voltage, etc...?
  19. U

    Engineering Power Triangle and Power factor

    Induction motors: pf = 0.8 triangle: θ = arccos(0.8) = 36.86 degrees Pa = 500/0.8 = 625 VA Pr = sqrt(625^2-500^2) = 375 VAR Synchronous motors: pf = 0.707 triangle: θ = arccos(0.707) = 45 degrees Pa = 500/0.707 = 707 VA Pr = sqrt(707^2-500^2) = 499.85 VAR I am uncertain of how I can...
  20. M

    Engineering Induction motor calculation problems

    Given the following input parameters: Parameter Value Rs (Resistance through stator) 1.4 Ω Rr (Resistance through stator) 0.7 Ω Ls (stator inductance) = Lr (rotor inductance) 0.002 H xs = xr = 2*π*f*Ls 0.6283i Ω Lm(magnetic inductance) 0.01 H xm = 2*π*f*Lm 3.1415iΩ f (frequency)...
  21. patric44

    Power dissipated in this circuit with 2 batteries and 3 resistors

    Hi guys I am struggling to find the power dissipated in the total circuit , my answer didn't match the solution in the book the circuit is simple i used Kirchhoffs rules to find the following : loop 1 : $$10-10I_{1}-40I_{3} = 0$$ loop 2: $$20-20I_{2}-40I_{3} = 0$$ and $$ I_{1}+I_{2}=I_{3}$$...
  22. A

    Calculating Work, Energy, and Power: Integrating Force and Velocity

    I tried to solve it by integrating force from 0 to L dF=dm.g where dm=λdx And then I multiplied it with velocity to get power because velocity is constant ∫(vdF)=v ∫(dF) But the book used integration to find work done and divided it by time for power My answer was λlgv(Option B) Giving...
  23. P

    Help please with power calculations to turn a large flywheel at 1rpm

    How did you find PF?: Trying to find answers Hi I’m trying to solve this problem .hope someone can find the answers, I need to find the hp needed to run a flying wheel ring shape. 42 ft in diameter weight 200.000 lbs the wheel is Suport by bearing inside and out of the edge of the rim, the...
  24. Benjamin_harsh

    Can I power things even after Zener breakdown?

    I understand that Zener Breakdown occurs when the reverse current starts flowing in the junction because of which depletion region entirely vanishes. Can I power things using this reverse current ? Or will it damage the appliance?
  25. M

    Voltage regulation in transformers at unity power factor

    So I've done part a) Primary current = 200000/415=481.9 Cos θ = -0.8 Sin θ = 0.6 Reg=(481.9 ( 0.014*-0.8 + 0.057*0.6))/415 = 0.0267 Reg% = 2.67% Part b I simply used the same equation but for secondary: @ unity p.f., cos θ =1, sin θ = 0 secondary current = 200000/11000 = 18.18...
  26. M

    Engineering Calculating Power Losses in an AC Induction Motor

    Given the AC Induction (asynchronous motor) in 3 phases: Parameter Value Pn (Nominal Power) = Pmechanical (output power at the shaft) 5 kW = 5000W uls (Voltage through the stator line) 220 V fstator (stator frequency) 50 Hz p (Number of pole pairs) 2 LFe (Iron loss) = Lmechanical...
  27. bob012345

    Electrical Emergency Battery Backup System for TV/Internet During Power Outages

    I am looking for the right size of battery/pure sine-wave inverter to power a system for a few hour when there is a power outage. The system of TV/DVD/Internet uses less than 200 watts at about 1.6Amps. I could just buy a commercial system which runs about 1000$ or assemble a similar design for...
  28. R

    Stirling's Approximation for a factorial raised to a power

    Using log identities: ##log((\alpha - 1)!^2) = 2(log(\alpha - 1)!)## Then apply Stirling's Approximation ##(2[(\alpha - 1)log(\alpha - 1) - (\alpha - 1)## ## = 2(\alpha -1)log(\alpha -1) - 2\alpha+2## Is this correct? I can't find a way to check this computationally.
  29. M

    Work done on moving a submerged object

    I first worked out the buoyant force using rho = 1000, g = 9.8 and V = 1. (this gives Fb = 9800) I then worked out Fg of the tank (5 x 9.8 = 49) Then I used Fnet = Fb - Fg - T = 0 to work out tension as 9751. I thought the work done would be the work done by tension (9751 x 50.4), but I'm not...
  30. arcTomato

    I The power spectrum of Poisson noise

    I thought that if we Fourier transformed the counts of the sum of the signal from the source and the Poisson noise, and obtained the power spectrum, we would get the following, ##P_{j}=P_{j, \text { signal }}+P_{j, \text { noise }}+\text { cross terms }## but I found the following description...
  31. mapika123

    Power calculations for a motor spinning a turntable

    Hi, I have a 1 HP motor spinning a turntable (just a wheel) weighing 1kg, diameter 25cm speed 2000rpm. (Arbitrary specs). If I have to spin a turntable with the same weight (1kg) but double the diameter (50cm) at the same speed, would I necessarily need a motor with double the power (2 HP)...
  32. A

    Is There Still a Market for Mechanical High Power DC/AC Generators?

    Hello, back in the day motor-generator sets were far more frequent before the advent of high power semiconductors etc. So they were used for many applications where a variable frequency high power was necessary or a purely DC output was needed. There were even some special generators that could...
  33. N

    Calculate the individual voltage, current and power in series and para

    To determine the voltage I did voltage/number of globes: 24/16 = 1.5V per globe - Not sure if this is correct or not To determine current, I figured out using resistance formulas that the resistance for each set of 8 globes is 15 ohms R = V/I 24/3.2 = 7.5 ohms total resistance 7.5-1 = 2 * 15-1...
  34. R

    Stargazing Calculating the Resolving power of a Telescope

    Lets assume I have a telescope with an aperture of 200 mm, if we also assume λ has a wavelength of 500 nm According to; http://labman.phys.utk.edu/phys222core/modules/m9/resolving_power.htm θ = 1.22 λ/d, where θmin is the angular separation that can be resolved. 1.22 * 500 nm / 200 mm = 3.05...
  35. L

    Plugging Power Strips Together in Series?

    I have read one shouldn't plug a power strip into another power strip. Why might that be? I don't mean to exceed the number of outlets of the first strip. I just don't have enough space between outlets to plug everything in. Like a 1/2" between the outlets would be fine.
  36. O

    AC power loss in lossy dielectric (capacitor) with DC-bias field

    Hi there, if a dielectric (capacitor) is described with a constant permittivit eps (or C) and loss-tangent DF, how much energy ist lost when charging the capacitor by 1V? For example: C=1, DF=0.1. When charging from 0 to 1V, the lost energy (in J) is ...? When charging from 1V to 2V, the lost...
  37. Narayanan KR

    Resonant Frequency for a Coil-Only Antenna

  38. BWV

    Halite / Centurion and fission - fusion power plants

    Its unclear to me what exactly these tests entailed and how much today is still top secret. They involved inertial confinement fusion with x-rays from a fission explosion. never see this discussed - forgetting about political issues with fission, how feasible is a fusion reactor utilizing...
  39. ikihi

    I Power equation using heat instead of work

    So the formula for power is Power = work / time. There's two types of energy transfers: heat and work. How do you calculate the power of something using heat energy in BTU/hr when BTU isn't work?
  40. T

    Key fob only works on battery and not power supply. What?

    Yesterday the batteries died on my key fob and I didn't have the appropriate batteries to replace them. I thought I could use my power supply to operate the key fob to open the car door but it did not work. I thought that it may be caused by a noisy power supply at the higher frequency range of...
  41. Omega0

    The Power of 10: Exploring Decimals & Beyond

    We use the 10 as a base for numbers because we have 10 fingers, right? The 10 commandments, awesome... we have the system of numbers to the power of 2 which makes much more sense to me. Of course feel free to pack them together to octs or hex numbers but wouldn't you say that decimals doesn't...
  42. S

    Current and resistance in the power loss of a transformer

    a) Output voltage = 2 x 6 = 12 V Current in R = 12 V / 13.5 kΩ = 8.9 x 10-4 A That is the correct answer based on the solution but I don't understand why when calculating the current in R, the resistance of secondary coil is not considered. I thought it should be like this: Current in R = 12...
  43. S

    Power lost during transmission

    The current in transmission cables = 20 MW / 240 kV = 250 / 3 A Power loss in cables =(250/3)2 x 20 x 103 = 139 MW , which is not possible Where is my mistake? Thanks
  44. Fisherman199

    Power Consumption Characteristics of Crypto Mining Rigs

    I have occasion to attempt to alleviate a lot of confusion on behalf of my utility (and me). Despite a well-trained search engine I can't seem to find a white paper from another utility/IEC/IEEE that tackles this question. Does anyone here have a good source?
  45. C

    350W car power inverter vs tiny generator

    I need to power a 350W thing inside the car. And I googled about it. What I learned was that there was a 100W fuse inside car lighter jacks so you can't run a 350W inverter. So I have some questions. 1. If you remove the 100W fuse and put a 400W fuse. Can the 350W power inverter sucked up the...
  46. M

    What is the relationship between weight of car, power needed and speed

    Hi, I'm working on a project to see if deliveries, pick ups, or both combined are better for the environment / more energy efficient / more time efficient. For example, (a) everyone collecting from a farm by bike, (b) vans bringing to supermarkets and then people collecting from supermarkets, or...
  47. SpinnerDude

    I Calculating power output on a spin bike

    So...I have a home spin bike which unfortunately lacks the sensors of some of the more expensive models. What I'm trying to do is work out if I can dynamically calculate my power output. The spin bike itself has: - An 18kg flywheel of radius 30cm - Direct drive between the crank and the...
  48. S

    MHB Work energy principle and power

    Particle X of mass 2 kg , and particle Y of mass m kg are attached to the ends of a light inextensible string of length 4.8m. The string passes over a fixed smooth pulley and hangs vertically either side of the pulley. Particle X is held at ground level, 3m below the pulley. Particle X is...
  49. S

    MHB Work energy principle and power

    A car of mass 1200 kg accelerates up a hill inclined at 10 degree to the horizontal. The car has initial speed of 10 m/ s and final speed of 12 m/s after 60 s. Air resistance and friction may be ignored. Find the average power generated by the engine. The and in the textbook is 36000 W, iam...
  50. G

    Circuit breakers trip on *power* overload?

    Old style electrical panels protected residential circuits with fuses which tripped (and were destroyed) when the internal wire got too hot and melted. What is it exactly that causes a modern residential circuit breaker to trip? They are rated by amps, but heat correlates to power (volts x...
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