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. P

    Relating propeller thrust, power, and rpm together

    Hi All, I am involved in a research project regarding electric aircraft. I've done a fair bit of research into this but am having trouble keeping all the different parameters and how they affect each other straight in my head. Fundamentally I am putting together a model whose parameters I can...
  2. T

    How is power transmitted in an exoskeleton arm?

    In an exoskeleton arm that is designed with the purpose of enabling the user to lift more weight than they can unassisted through multiplying the force / power applied by that user, where exactly does the power that is generated by the motor get transmitted to and how does it get transmitted...
  3. T

    Can hydraulic systems replace ebikes in power assisted cycle

    Instead of an electric motor, can it be substituted with an hydraulic force / power amplifying system instead? If yes, how would it work? Could chains still be used? Instead of an electric motor powering the hydraulic system, could the rider power the hydraulic system through force / power...
  4. anorlunda

    How can DC-to-DC power transformers improve efficiency in power electronics?

    I am sharing this to brag about my former boss and mentor Lionel Barthold. He is well into his 90s, but his mind is so sharp that he continues with brilliant inventions. I'm very proud of him. What would power level DC-DC transformers be good for? Connecting different voltage level HVDC lines...
  5. P

    Expressing series in terms of a Power Series

    Hello and thank you for trying to help. In spite of the fact that this seems a very simple problem, I do not find myself able to get a solution. Here it goes: Let $$f(x)=\displaystyle \sum_{k=3}^\infty a_k \frac{x^k}{k(k-1)(k-2)}$$ and $$g(x)=\displaystyle \sum_{k=0}^\infty a_k x^k$$. Express...
  6. T

    Understanding Nuclear Fission in Power Plants

    So I need some help verifying this information.(I had to dumb it down, for the younger ones) - The Nuclear Fission process is started when the Nuclear fuels rods are submerged in coolant water to moderate the Nuclear fission process. When the Fuel rods are put close together this sets of a...
  7. E

    What is the composite power of multiple RF signals?

    I need to calculate the composite power at the input of an RF distribution system, is it just the sum of the signals in milliwatts at the input? I can measure each individual signal with an a spectrum analyser but I do not have a power meter to anable measurement of the total power.
  8. R

    Question about the power rating of a transformer

    In some aerospace applications you need high voltages in the range of kilovolts. This is commonly supplied by transformers. However, transformers because of their iron cores are heavy. But in aerospace being lightweight is a key requirement. In the thread "Question about power capacity of...
  9. U

    Why is the Pumping Power Calculation Resulting in a Negative Value?

    Homework Statement (question one is irrelevant for my problem). What is the pumping power? From energy balance I got a negative value - but it should be positive since the mechanical work from pump is given into system. Homework Equations The input+output velocity: $$v=\frac{\dot{V}}{A}$$...
  10. Anugrah_kora

    Power Supply Problem: 19V 3A Laptop Charger + Solenoid

    I've got an old laptop charger 19v 3A for my solenoid. I used a multimeter to check the charger without and with load. I used a solenoid of insulated 22gauge of approx 150 turns as the load. On my first try without any load, it gave 20v DC on the multimeter. When I connected the load and...
  11. R

    Question about power capacity of electrical motors

    I read that the Tesla electric motor is able to achieve its remarkable power to weight ratio of 8.5 kW/kg, about 10 times better than a typical gasoline engine, because it tightly winds its copper wires in its coils therefore being able to carry more current in the same space. If so, then we...
  12. jaketodd

    I Cardinality of the Power Series of an Infinite Set

    According to this page: https://en.wikipedia.org/wiki/Cantor's_theorem It says: "Cantor's theorem is a fundamental result that states that, for any set A, the set of all subsets of A (the power set of A) has a strictly greater cardinality than A itself." Furthermore, it says: "Cantor's...
  13. J

    Carnot cycle - Zero Power Extremes

    Hey guys, I ran into this paper talking about the Maximum power you can obtain from a Carnot cycle: http://aapt.scitation.org/doi/abs/10.1119/1.10023 From what I understood, there are two extremes. To achieve maximum efficiency you have to make sure that the temperature of the system is never...
  14. J

    Assessing Power Rack Max Load: A Scientific Inquiry

    I'm a petroleum engineer, so this is outside of my wheelhouse... I'm also a fairly avid metal worker and fabricator. Also I ask this question out of a curiosity, not because I'm building a rack or basing a financial decision off of the verdict of any resulting calculations. I feel like the "max...
  15. J

    Making a solar powered battery with AC power socket

    It's mid summer and I think I need a project to keep busy. What better than a solar project? Problem is, I've never built a solar circuit before, let alone a battery charger. Ideally, I would like to build the equivalent of a solar powered generator. I know there's no way I'm getting as much...
  16. A

    Is my Cyclette Generating Enough Power at Resistance Level 4?

    Hi all! I have a cyclette with 8 resistance levels set magnetically using a knob (a magnet is moved near the rotating disk thereby increasing its rotating resistance). The distance from the pedal to the center is 0.165 m. At resistance level 4, if I put a weight greater than or equal to 0.750...
  17. T

    Filtering an LED light's power supply

    Hi, Out of interest, today I was mucking around with a 160W LED, 240V, 50hz, outdoor light. I looked at the Power Factor (it was 0.96) and the THD was 14.something %. I then wondered what would happen if I put a capacitor in parallel with the light. It was a three phase 90uF cap, so since they...
  18. Mzzed

    Decaying current power calculation

    I would like to find the power loss over 0.3 seconds due to a resistance of 0.0015 ohms with a current following the function: I = e-15.24t-e-39984.75t where t is time. I would have imagined summing all the current over that 0.3 second period via integration would then allow me to find...
  19. R

    Calculating Heat Loss in a Series Circuit

    Homework Statement Determine the heat loss in the circuit that is connected in series with two batteries (12 V and 6V) and two resistors (6ohms and 4 ohms). Homework EquationsThe Attempt at a Solution I used the difference in P = V^2/R, the power dissipated in the circuit, to calculate the...
  20. Baritone

    What is the Power of Sound Waves in a Tube Filled with Helium Gas?

    Homework Statement Suppose a tube is filled with helium gas at a pressure of 0.11MPa and a temperature of 297K. If a piston of area of 400mm2 at one end of the tube creates sound by moving sinusoidally with a frequency of 60Hz, creating a wave with amplitude of 3.8mm, what power goes into (I'm...
  21. Brandon91man

    Electrical DIY Solar Power System: Questions & Answers

    Hello, I've been building my own solar panel system and throughout this process I've accumulated a lot of questions. If anyone could help answer them I would greatly appreciate it! First I'll start off explaining what I have. A polycrystalline solar panel 17V 2.2A and a mono crystalline panel...
  22. karush

    MHB Find Power Series Representation for $g$: Interval of Convergence

    $\textrm{a. find the power series representation for $g$ centered at 0 by differentiation}\\$ $\textrm{ or Integrating the power series for $f$ perhaps more than once}$ \begin{align*}\displaystyle f(x)&=\frac{1}{1-3x} \\ &=\sum_{k=1}^{\infty} \end{align*} $\textsf{b. Give interval of convergence...
  23. Adriano Marcato

    Output power (torque-rotation) equivalent inertia

    Homework Statement A lot of people are familiar with equivalent inertia problems, where you have a drive train and inertia on different axis and you calculate the equivalent inertia on whichever shaft you want. This time I (try to) bring something new, trying to associate the output power to...
  24. A

    Calculating the reactive power of a transmission line

    I have a single machine connected to an infinite bus with the following parameters: - Sending end power = 3.75MW - RL=5.18 ohms - XL=130 ohms - VS (Generator bus)=161kV - VR (Infinite bus)=161kV - Sending end voltage angle (delta) = 0.01877 (Angle which allows 3.75MW to be transferred)...
  25. AdrianMachin

    Resistive dissipation and Ohm's law

    Homework Statement A potential difference V is connected across a device with resistance R, causing current i through the device. Rank the following variations according to the change in the rate at which electrical energy is converted to thermal energy due to the resistance, greatest change...
  26. M

    Power signal calculation using Parseval's Theorem

    Homework Statement Hi guys, I have the following transmitted power signal: $$x(t)=\alpha_m \ cos[2\pi(f_c+f_m)t+\phi_m],$$ where: ##\alpha_m=constant, \ \ f_c,f_m: frequencies, \ \ \theta_m: initial \ phase.## The multipath channel is: $$h(t)=\sum_{l=1}^L \sqrt{g_l} \ \delta(t-\tau_l).$$...
  27. P

    Calculating Belt Pull, Drum Torque, Motor Power & Speed

    Homework Statement Calculate the Belt pull, drum torque, motor power and speed required to drive a flat top belt given the following information: Belt centres are 4.0m Required speed is 18m/min Drum diameter is 300mm Belt mass is 3.0kg/m Belt is fully loaded with 32kg boxes 0.8m long Belt...
  28. Ella Reid

    Decreasing the power density of a laser

    Hello! I have an issue with the power density of a 488 nm continuous wave laser. I'm using this laser to excite my sample. The problem is that even at low power, the laser is causing the samples to form a burn deposit on the quartz sample holder. Between the laser source and the sample, there...
  29. R

    Near solar mirror for beam propulsion and space solar power

    NASA just announced a solar probe to travel quite close to the Sun, about 3.7 million miles from the solar surface: Nasa’s hotly anticipated solar mission renamed to honour astrophysicist Eugene Parker. Renamed the Parker Solar Probe to honour solar astrophysicist who predicted high speed solar...
  30. V

    How Does Power Dissipation in One Resistor Relate to Total Power from Batteries?

    Homework Statement Homework EquationsThe Attempt at a Solution [/B] The first and foremost thing which I do not understand in this question is that there are many resistors present in the circuit , so how is it that we could relate power dissipated in one resistor to the power supplied by...
  31. N

    Decrease in Laser Power: Why Is It Happening?

    Hi, So I am working with measurements using a laser. What I have noticed is that the power of the laser decreases from the time we start the laser until maybe an hour later. Today I noticed it has decreased 10%, from yesterday, which I think sounds like a lot. Does the laser have to warm up and...
  32. B

    Confused with the relationship between Volts, Current, and Power

    Homework Statement For an engineering assessment (first year with no electrical background), we are using a solar panel to power an element for a distillation system. we have calculated our heat energy output requirement that we need from our heating element as being 800 J/s. For simplicity we...
  33. O

    Suggestions for a Power System Analysis book?

    Hi, I want a book about power system analysis that I can have laying around and read from time to time. I have taken a course in power system analysis some time ago, where I was taught simple fault analysis including unbalanced faults, frequency and voltage control. So to maintain this...
  34. C

    Power of resistors in parallel vs series circuit

    Homework Statement Two Ohm's resistors in parallel consume power of 76 W and 24 W. What power will each of them consume if transfer them to the serial circuit with the same voltage of source. Sorry for my bad english translations I m not use to writing questions in English.. So what confuses...
  35. T

    VSD for induction motor maximum current

    Hi, I'm trying to ascertain when you're driving an asynchronous motor with VVVF or whatever else a VSD uses, when do you draw the most current? For instance, say you're talking about a train/tram: I would have thought intuitively that since power = torque / angular speed, that starting up, to...
  36. G

    What is the power of a car engine?

    Homework Statement The volume displacement in a car engine is 2000 cm3. During the power stroke, the mean pressure inside the cylinder is 15 bar. Compute the work performed by the engine in one revolution. Compute the engine's power assuming it runs at 3000 rpm. Homework Equations...
  37. Anugrah_kora

    Connecting solenoids to power supply

    For a project,we thought of making solenoid engine. We made everythig by hand, including the DC power supply. The power supply worked very well, it's puts out like 20v 1A, and it was fine still after testing it for a long time connected to DC motor. When we connected it to a solenoid coil...
  38. BillTre

    New Concept for Zero Emission Natural Gas Power Generation

    Science mag news article on a new electrical power plant being set-up by a start-up. It burns natural gas with pure oxygen and runs turbines with CO2. It makes water rather than using it and is in theory close to competitive economically. . Sounds good to me, but I'm no engineer.
  39. Kevin Shen

    Electrical Power Loss Equations Confusion

    Why is the equation Power Loss = I^2*R rather than Power Loss = V*I? What I mean is why use I/R to represent V? Also if Power Loss is equivalent to V*R, doesn't step up transformers which creating higher voltage also cause Power Loss to increase which contradicts to textbooks stating that power...
  40. B

    Losses on Power Transmission Lines

    Say a power station transmits 1008 MWh of power per year to a facility however they only receive 900 MWh say the transmission line is 15 km long how would you calculate average power loss per km, now I know that theoretically it will just be 7.2 MWh per km but what calculations would you make to...
  41. M

    MHB Power series and uniform convergence.

    Hi. I have this power serie (2^n/n)*z^n that runs from n=1 to infinity, and I have to show whether it's uniform konvergence on [-1/3, 1/3] or not. I hope someone can help me with this.
  42. S

    Power/Energy Signal Homework: u[n] - u[n-4]

    Homework Statement Determine whether u[n] - u[n-4] is a power or energy signal. Homework Equations The Attempt at a Solution I am stuck here. I don't know how to simply further. Please help.
  43. S

    Electric motor: power and RPMs

    I am helping a friend with a project, and am wondering if this statement is true. "To double the RPMs of a central drive shaft motor, you must quadruple the input." In other words, if an electric motor being supplied with 1 Watt spins at 500 RPMs, one would need 4 watts to spin at 1,000 RPMs...
  44. MikeTownsend

    DC motor voltage recommendations for a bike and power tools

    I have been working on some projects, I build a glass grinder, faceter with a 120v induction AC motor. Its not possible to effectively change the speeds with electronic controls being a single phase motor. It is using belts and pulleys for now. So I am wanting to build several tools, rock...
  45. S

    A Calculating the power spectra of scalar perturbation

    I'd like to numerically calculate the power spectra of the scalar perturbation at the Hubble crossing in warm inflation, my problem is that I don't know how to do it. As I know, the Hubble crossing happens at the onset of warm inflation where the different modes become larger than the Hubble...
  46. Henry Rufin

    Why does the power consumption of a plucker machine vary with rotational speed?

    hi, i have a study on a plucker machine and it came out that when the rotational speed of the plate is low, the power consumption rate is high and if the rotational speed is high, the pcr is low. what is the possible explanation for that? thanks in advace.
  47. EnumaElish

    What is the fixed cost vs. variable cost breakdown for a nuclear power plant?

    I am trying to understand the fixed cost of a nuclear power plant relative to variable cost. By fixed cost I mean "cost that does not vary with the amount of the power outputted over a given time period." By variable cost I mean "cost items that vary with the amount of the power outputted...
  48. J

    Directly power house with alternator

    My plan is to reduce electricity use supplied by the grid by having a waterwheel partially power a house. From my simple research I've learned that hooking an alternator up to the waterwheel would work. Since a house runs on 120V AC and an alternator produces (correct me if I'm wrong) 13.8 -...
  49. K

    Help with torque and power required please

    I am looking to build a skateborad like device that i want to power with electric skateboard-like system. However I only want it to go 1.1m/s using 60mm wheels moving a 100kg load for 12 km. I am looking for help determining gear sizes, motor sizes and specs, really anything. I have seen so...
  50. Ab Zar

    Please help to find the power supplied by the 4-A

    Homework Statement i solved 9 times all not correct please share with me what's wrong Homework EquationsThe Attempt at a Solution
Back
Top