Power Definition and 998 Threads

Homework Statement Argo, in its gas form, is insterted into a spinner, with a rhythm of 80.0 kg/min = 1.33 kg/s, temperature 800 C (= 1073.15 K), and pressure 1.50 MPa. It's decompressed adiabatically, and "escapes" the spinner with pressure 300 kPa. a) Temperature when it "escapes" ? b)...

As someone who has had an interest in the potential outcome of various scientific en-devours, I have weighed potential outcomes of things that interest people to be good to potential outcomes they may not have yet seen as being bad. I wonder if anyone has asked the questions about how our...

Hi i recently completed my mechanical engineering and was interested in studying how power tools work! when i did some survey i came to know that they work on the basis of universal motor usually. So now the question rises whether it is a 2 pole or a 4 pole? what will happen if its is 2 pole and...

Hello, I am going to start school soon for E.E with an emphasis in Power Systems Engineering, I live in NYC and am 21 y.o. I've been reading forum responses across the web from unemployed engineers (Unhealthy habit I know), people don't specify what they specialize in hence the query. I am...

Does anyone have formulae to calculate the number of turns required on a coil to produce 10V at approx 5W. I wish to have a coil spinning on a 16" diameter former in a 0.25 gauss magnetic field at a minimum of 2.2Hz. I need to be able to work out the size of coil and number of turns to produce...

Hello. I'm in the process of teaching myself cell bio and I'm curious to find a good source with actual rates of glycolysis in cells. In a nutshell, I'm wondering what the maximum rate of ATP production within the cell is (assuming a normal yet constant extracellular concentration of glucose)...

I wasn't exactly sure which forum I should post this question in but I felt this was the most appropriate one. So if there is a more appropriate one, feel free to relocate it (whoever is responsible for that). I wanted strictly a scientific answer to this question. How does weight affect a...

So I am 21 years old, I only recently found out that I am interested in electrical engineering. I live in NYC and am heading into cuny city tech for my first semester. E.E is a very broad field and I think that going into power engineering would be a good career move because it cannot be...

Homework Statement As shown in Fig. P5.39, a system undergoing a power cycle develops a net power output of 1 MW while receiving energy by heat transfer from steam condensing from saturated vapor to saturated liquid at a pressure of 100 kPa. Energy is discharged from the cycle by heat transfer...

what is actually happening when an Inductor is connected with an ac source.(i mean at the very instant of connection is made).i know emf will be induced due to change in current.(curl of E is =-time derivative of B)here my confusion is,inorder to induce emf,current should flow first,then who...

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...

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...

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...

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...

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...

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...

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.

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...

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: $$v=\frac{\dot{V}}{A}$$...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

$\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...

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...

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)...

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...

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: $$h(t)=\sum_{l=1}^L \sqrt{g_l} \ \delta(t-\tau_l).$$...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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.

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...

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...