What is Power calculation: Definition and 55 Discussions

The power of a binary hypothesis test is denoted by "(1−β)" and is the probability of a "true positive" conditional on a positive outcome. It is the probability that the test correctly rejects the null hypothesis (



{\displaystyle H_{0}}
) when a specific alternative hypothesis (



{\displaystyle H_{1}}
) is true. The statistical power ranges from 0 to 1, and as statistical power increases, the size of "β" - the probability of making a type II error by wrongly failing to reject the null hypothesis - decreases.

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  1. S

    Engineering Intro to Power Systems: Calculating Power

    Help me understand what I am missing. So this is the circuit: Given: ##V_{RMS} = 120V## ##I_{RMS}= 10A## ##v=Re \{Ve^{jwt}\}## ##i=Re \{Ie^{j(wt-\psi)}\}## (a) Calculate and sketch real and reactive power P and Q as a function of the angle ψ (b) Calculate and sketch the instantaneous power...
  2. argeus

    Pumping power calculation of a vertical closed-loop system

    Hi there, I hope that somebody can help me with this.. Any response is much appreciated! Let's have a vertical closed-loop system where the fluid circulates using the pump. The temperature in both sections gradually changes (the upcomer section is heated up) so that the densities, velocities...
  3. R

    When is power constant in this scenario?

    Power P = F x v,where F is force and v is velocity, if power remains constant then i think force can not remain constant as it will change the velocity v, but the solution I found is, F = ma, v = at, so, P = F x v = ma x at = ma2 t, after that calculus comes to show that displacement is...
  4. M

    MCNP Flux and Power Calculation

    During a reactor assembly calculation, I need to determine axial and radial flux distribution over the surface. When I use F2 and F4 tally I get some value with unit 1/cm**2 What does the value means, neutron flux is supposed to be in the 10^14 range but output values are 10^2 range. Can anyone...
  5. PhysicsTest

    Power Calculation of general electric circuit

    I am trying to calculate the power calculation of a general circuit with voltage leading the current by a phase difference of ##\theta##. The instantaneous voltage is given by ##v = V_m\sin(\omega t +\theta) ; i = I_m\sin(\omega t) ##. The instantaneous power is then ##p = V_m I_m \sin(\omega t...
  6. 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...
  7. 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...
  8. H

    Enqiry about an electrical motor's power

    Any clue to to show that it is 10kW? Please tell me where i went wrong and thank you. I tried and i just couldn't figure it out.
  9. S

    Automotive Motor Selection for Roller: Diameter 300mm, Length 1350mm, Inertia 3.95 KG.M

    i need to select the motor for a roller of Diameter 300mm , length 1350mm having inertia 3.95 KG.M ,Which needs to accelerate from 0 to 600MPM at 20 sec . Assuming existing web tension acting on the roller 20 N/M. THANK YOU
  10. T

    Measuring the Power Output of a Generator

    Hey folks, I built a generator for fun and I would like to find out how much power it is producing when I use it. I have a way of measuring mechanical power in but I am not quite sure on how to measure electrical power out. I'm thinking I could use some LEDs to create a load (or maybe...
  11. Jhon Paul

    How to Configure a Power System for High Current and Low Voltage Demands?

    I have to configure a power system for a furnace which demands very high current of the order of 50KAmps with low voltage of the order of 100 volts. Can anyone help me to get insight into how to configure the power system in boarder way. I am planning to use a transformer with thyristors .
  12. T

    Compressing a gas above compressor's discharge pressure

    A 2 stage compressor has a final delivery/discharge pressure of 250 bar. hydrogen is been compressed and stored in vessels. The pressure in the storage vessel reaches the delivery pressure(i.e.250 bar) and the compressor is still running ( vessel has a safety pressure of 450 bar) and the...
  13. 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...
  14. P

    How do I design a Permanent Magnet Synchronous Generator?

    Hi, I'm trying to do a very simple analysis on Simulink where I am applying a speed to a Permanent Magnet Synchronous Generator with a purely resistive load. I'm not familiar with PMSGs so the results I'm getting don't really make any sense to me. Could anyone go through some simple design...
  15. G

    Evaluate Fourier series coefficients and power of a signal

    Homework Statement Derive the expression for coefficients of Fourier series in exponential form for the sequence of rectangular pulses (with amplitude A, period T and duration θ) shown in this image: Derive the expression for signal power depending on the coefficients of Fourier series...
  16. Erik Bethke

    Optimizing Robot Design: Heuristics for Efficient Performance

    Hello all, I am designing a lay-person-facing simulation that includes robots performing a broad array of tasks. I do not want to create magical can-do-anything robots that collapse all work to be performed to a simple abstraction. Rather, I would like to have relatively dedicated and...
  17. S

    Q3.10: Power Calculation w/ Reduction Gear

    Homework Statement : [/B] Qstn no. 3.10 in the attached image. [ Moderator note: Copy of relevant portion of attachment inserted to make it visible here] Homework Equations : For power calculation, [/B] Power = torque * angular velocity... Also, reduction gear is used to deliver lower outout...
  18. S

    How to calculate the wattage needed

    I have a project in which a client is wanting an outside glass deck floor to be heated to keep from freezing. Below the floor is ambient temperatures. The glass is 1.25 ( 3 layers of 3/8" with a /060 inter-layer between each lite of glass) thick each panel is 30" x 60". I don't want to...
  19. CasVS

    What is the best battery for a Search & Rescue Robot on a budget?

    Hi All! I am a Dutch university student and I have an assignment to make a Search & Rescue Robot. Because we have to work with a budget, we have decided to make our own batteries (using AA penlights). Now while calculating the required capacity of the battery pack, I encountered some...
  20. S

    Automotive Calculating engine parameters from power requirement

    Hi, I've defined engine power requirements based on driving dynamics, but am not sure how to extend this to engine parameters. From design requirements, I've fixed my gear ratios, and hence can determine how much power and torque is required from the engine at a particular speed. I want to then...
  21. Le_Anthony

    Instantaneous Power calculation

    Homework Statement The energy of a system increases at a rate of 3.5t + 6.2t^2, in joules. What is the instantaneous power at t=3.1 s? Homework Equations P=dW/dt J/s=watt The Attempt at a Solution dW=3.5 + 12.4t P=(3.5 + 12.4t joule) / (3.1s)=1.12 + 4t, in watts Yes/ no?
  22. Bhavik Panchal

    Power calculation for Ribbon blender for dry cement mixing?

    density -1600 kg/m3 dia -1m lenght -2m material to mix - Dry cement mixing abt 2 tones please suggest me the power in hp...
  23. S

    Efficiency of a synchronous machine.

    Homework Statement The armature resistance per phase is given as 24.7ohms. Delta configured machine. Open circuit voltage is 220v, short circuit current is 1.1A at 3000rpm. Rpm is dropped to 1500rpm and no load line voltage is 100. Find power and efficiency if an inductive load of 1.4H is...
  24. T

    Phase Power Calculation: Determining Total Power Input into System

    Homework Statement I need to calculate the power for phase A, B, and C so that I can determine the total power into the system. I have measured the following data: VA magnitude = 117.7 [v] VA angle = 0° IA magnitude = 7.5 [A] IA angle = -25.5° VB magnitude = 117.7 [v] VB angle = -124.1° IB...
  25. S

    Power output of automobile at different engine rpm

    I figure my 2.4 liter Volvo will burn about a liter of gasoline over an hour of idling (source: Natural Resources Canada). Since a liter of gasoline contains roughly 33.8 million joules (~9.4 kilowatt-hours) of energy, I figure that that means my car idles at a power output of around 9.4...
  26. Moteor

    Machinery Rated Power Calculation

    Hi everyone, Thanks for the help in advance. I have a project with a piece of machinery that is rated to 105 HP @ 540 RPM. I was wondering what the torque rating for the machine would be, whilst its being driven from a diesel engine? I believe there is a direct relationship between Torque and...
  27. smruti

    Power Calculation: S=VI & V*I Meaning

    in the calculation of complex power S=VI we sometimes use S=VI* and sometimes as S=V*I.what is the physical significance of these two notations and in which case these two expression has different meaning?
  28. P

    Will house burn down enclosing camera in foam ball?

    Homework Statement This is not exactly homework, but is homework level so this is probably the best place to ask rather than the more learned sections. However, I'm prepared to defer to your better judgement. I want to put a web camera inside a foam ball. The camera is a retail product so...
  29. K

    Required current rating of 3-phase power system

    My background is mechanical engineering so not great with the electrical side. I plan on buying a air-preheater (resistive wire heated) which has a power rating of 30kW, supplied by 3-phase. I need to determine whether my 3-phase supply (415V 32A) has a max current that can cope with this. My...
  30. R.C

    Power Generation (Optimization) in a Car Engine

    **Long Post** 1. Homework Statement The Mazda MX5 (2001-2005) comes with two engine sizes, 1.6 litre and 1.8 litre which are rated as 110 bhp and 146 bhp respectively at 6,500 rpm. You are required to choose one of the two engine sizes and analyse the system with a view to improving the power...
  31. J

    Power-split planetary gear set power calculation

    I think we have a problem with this rule. This is my understanding of the existing rule. Am I close? The rule for calculating the power distribution on a power split planetary gear system is based on the equal force rule. To calculate the power on the sun and ring of a planet set with input...
  32. U

    Is Ohm's Law applicable for only DC or for both?

    Is ohm's law (V=IR) works for both AC and DC. PLz explain in details Also let me know which formula is right for power calculation for AC and DC circuits. (P=VI or P=VICos)
  33. H

    Measuring power output by modified prony brake

    Hi guys I have problem, basically I want to measure the power output from a water wheel. so basically I measured the power output by connecting the pulley that attach on the shaft of the water wheel. then this pulley is connected to other pulley which sit on the shaft of the DC motor. this DC...
  34. P

    Torque and power of electric motor

    Hallo Currently I am engaged with my Company's Project and it is about Electric motor as my Knowledge is not that good about Electric motors, I need your help. I want to move 80 kgs of Weight with the speed of 80 km/h with a motor and a 260 mm pulley. The motor is standing vertically and the...
  35. R

    Wind Turbine Power Calculation Equations

    Glad it's Friday? I will be if you can help me with this :D : I'm trying to understand an equation about calculating the power extracted by the blades of a wind turbine. I have spent a couple of hours going over it but still not making much more sense. I'm trying to find out why P =...
  36. L

    Power Calculation for Ski-Elevator: Double Check My Work for Accuracy

    I don't feel all the way safe with my knowledge of power and work, so I am basically asking for someone to take a look at my work, and see if I am off base or not. Here is the problem (of which I do not know the answer to): A ski-elevator consists of a rope that skiers hold on to. The rope...
  37. B

    Help with power calculation please.

    I have designed and built a device that harnesses centrifugal force.The power output is in the form of 2 x 10mm steel rod "pistons" that move up and down a distance of 15mm. I have measured the weight these pistons can lift to be 122lbs when the device is operated @ 4000rpm. Each piston moves...
  38. C

    Instantaneous power calculation between equal time increments.

    Homework Statement If given cumulative (Adding up every increment to the next) KWh values at an interval of 5 mins each. is it possible to determine instantaneous power from it? Homework Equations P=IV P(t) = VI cos(ωt) cos(ωt −θ )The Attempt at a Solution Well, because the question is more...
  39. A

    What Is the Apparent Power in a Circuit with a Power Factor of 0.72?

    A circuit has a power factor 0.72 lagging and the power dissipated is 375w. Determine: (A) Apparent power Relevant equations: ohms law V = I x R apparent power (S) = supply voltage (Vs) x Current (I) Attempt: Current = Voltage Resistance 120v 10Ω = 12Amps ∴...
  40. J

    Portable compressor power calculation

    Hello I have been trying to calculate the theoretical power required for compression of a small portable 2 stage compressor with the following spec. Volume flow rate Q = 2x10-5 m3/s Inlet pressure P1 = 1 Bar (105Pa) Outlet pressure = 200 Bar interstage pressure Px = 14 Bar k = 1.4 N...
  41. P

    What is measured in a fast reactor for power calculation : fast neutron flux or

    What is measured in a fast reactor for power calculation : fast neutron flux or overall ( fast + thermal) neutron flux ? My doubt is : The fission chambers used for measuring neutron flux undergo chemical reactions due to which type of neutron : fast or thermal ?
  42. F

    Is my power calculation correct?

    I am currently working on designing a conveyor for feeding 1t material to a furnace. Not going into detail of how it works, I would just like to confirm my approach. Goal: To move 1000 kilograms of mass using steel rope/pulley system. Determining power requirement It would be a bucket...
  43. M

    Why Does My Power Calculation Yield Half the Expected Result?

    Can anyone see where i have went wrong? I keep getting the same wrong answer. A 1100 kg car accelerates from rest reaching a distance of 110 m in 8.7 seconds, determine the average power in KW required to achieve this acceleration (your answer should be to 2 decimal places). ANS = 40.43...
  44. C

    Rotating half cylinder energy and power calculation

    Hi folks, I'm an ocean engineer who's getting old and slow. If I have a half-cylinder mass on a shaft where I'd like to be able to quantify energy (which I think I have right) and then have some way of relating that to potential power output. What I have so far: m=18.6 kg Length=0.305m...
  45. H

    Engineering Power Calculation in a Circuit

    Homework Statement vT = 10.3[V], vW = -7.6[V], vX = -8.4[V], vY = -9.5[V], vZ = 1.9[V] iM = 3.3[mA], iN = 24.1[mA], iP = 15.2[mA], iQ = -18.5[mA], iR = 5.6[mA], iS = -8.9[mA] Homework Equations P = vi or P = -vi mA = miliamps The Attempt at a Solution Well I used the...
  46. J

    3 phse power calculation with out remove load

    Homework Statement sir am new technician my boss told me that to find 3 phase power without off the machine . i have single phase clamp meter can measure voltage and current . how to find total power. Homework Equations \sqrt{}3* V line *I line * cos$ The Attempt at a Solution find...
  47. Y

    Specifications for Wind Generating Device

    I made a wind generating device that produces 120 lbft static torque with a 30mph wind. The paddles that interface the wind have rotational center of 4.5ft(radius). My device will be rotating at 15rpm. How do I calculate how much power is produced at any given wind speed? Kirk
  48. G

    Car Work and Power Calculation

    Homework Statement A car of mass 840.0 kg accelerates away from an intersection on a horizontal road. When the car speed is 37.4 km/hr (10.4 m/s), the net power which the engine supplies is 4300.0 W (in addition to the extra power required to make up for air resistance and friction)...