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Questions tagged [power-engineering]

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How is a Steam Power Plant designed?

I asked this question at physics but i think this suits it more. I'd like to know few things about how does one design a Thermal Power Plant? There is something fundamentally lacking in my knowledge ...
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0answers
12 views

Axial flow compressor derivation

We find isentropic pressure drop in axial flow compressor, we do so by using Bernoulli's equation, by neglecting potential energy term (taking it to be constant) and using other two, i.e pressure and ...
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24 views

Relationship efficiency and capacity

FYI I am an economist so please forgive my lack of understanding of subtleties and interpret my question in the best spirit! When different documents, e.g. by government agencies or electric ...
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1answer
33 views

Relationship heat rate with capacity

I am an economist, so please keep replies simple ;) I am searching for the relationship between heat rate and capacity for gas-fired power plants. Here is what I refer to as heat rate, i.e. the ...
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2answers
49 views

Power torque and rotational speed of a not running yet DC motor

If the power $P = C\omega$, so how a DC motor powered by $P = 10\text{ W}$ can work as $\omega$ is of course 0 rad/s at first, because if $\omega = 0$, then $P = C\omega = C\cdot0 = 0$?
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Need help with question regarding RLC Circuit and Transfer Function

See below problem from our final lab in circuit analysis 2: We are completely stumped. We tried to calculate the impedance and use the voltage divider equation, but we could not get it to look like ...
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0answers
73 views

How to calculate the register draught/draft loss (RDL) of a burner?

I am aware this is a vague question but it is something which has been on my mind. Would anybody know the steps used to calculate the draught loss across a burner in the furnace of a boiler? Would ...
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0answers
31 views

Ineffective purging of a flame monitor lens

There is a wall-opposed flame monitor detecting coal, oil and gas combustion in the burners, attached to the furnace walls in a coal-fired power plant. I'm looking for suggestions to clear the dust ...
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1answer
68 views

How Can I do punching of 0.22mm in stainless steel sheet (Sheet thickness 0.5mm)

Wanted to press punching of 0.22mm dia (Bottom) and on (top) 0.6mm dia Please suggest how can I make such die?
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2answers
61 views

Working mechanism of photovoltic cells

In the textbook : Electric Power Principles, in Chapter 1 on the working of a pv cell : The source current Is is the result of absorption of photons in sunlight that cause separation of ...
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4answers
133 views

How does power generation (hydro, wind etc…) account for variable power consumption?

I know in a power distribution system, the power is generated (from a dam or turbine or something) and consumed immediately. But the power consumed is variable. So how does the generation system take ...
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0answers
21 views

What is the twisting rate to reduce capacitance load on DC power transmission line?

I need to carry dc (direct current) electrical power from a solar array to point of use. I know that an undesirable capacitive load will develop if I just run the power and neutral wires parallel to ...
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0answers
26 views

How to calculate and common capacity factors for gas power plants

I am wondering the following, and didn't find anything online or here in the forum: 1) How is the capacity or load factor of a gas power plant calculated: (GROSS electricity generated)/(maximum ...
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0answers
36 views

I would like to run a smartphone using a primary battery instead of rechargeable for a project. What are the 4 contacts used for on the factory LiPo?

Most phone batteries will have a connector of some type with 4 contacts. Of course two of those I'd expect to be +- Voltage, but the other two compose some sort of mystery input to the phone (...
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1answer
35 views

Choosing the best type of portable cord for a consumer electronics product

Consumer-level electrical portable cords come in a variety of types (and gauge, but that's not the subject here) and each must have its rationale, considering the cost constraint (performance/price ...
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1answer
176 views

What ramping constraints for gas plant - CCGT, combustion and steam turbine?

I am using the publication Current and Prospective Costs of Electricity Generation until 2050 to source ramping constraints for an economic model of three different gas power plants - CCGT, combustion ...
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7answers
5k views

Why do electric trains arc at high speeds?

When I watch videos of high speed trains I always see explosions of electricity near the top, or arcing. Why does that happen? I know that the Acela does it a lot but other high speed trains have it, ...
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1answer
386 views

Difference between gas combustion engine and gas turbine?

I am a non-engineer and I am using a gas power plant data base. Some plants listed are of the type "combustion engine", some of the type "gas turbine", some "steam turbine" and some "combined cycle". ...
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1answer
71 views

Extracting power from fusion?

If we are able to create a fusion reactor so there is a net gain in energy how can we turn the heat into electricity. I know how it is done normally for fission, steam, but how could this be adapted ...
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1answer
386 views

What is the maximum efficiency of a mechanical electric generator?

If we apply a simple push to rotate a system of gears to generate electricity, what is the maximum practical and theoretical power efficiency of the system, assuming the push as the only source of ...
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2answers
83 views

Power assist mechanism for double pendulum?

I'm making a double pendulum for an art installation, and I would like to add energy to the system to compensate for friction and air drag losses so it can run more or less indefinitely. The design ...
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1answer
48 views

How many batteries can I charge and how long would it take?

Using a hydro generator which gives an output of 4.838KW, I am trying to figure out how many batteries I can charge and how long it would take. I am doing the calculations based on 12V, 17Ah ...
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2answers
845 views

How to calculate hydropower in kW without water head

I am trying to do some calculations to figure out how much power output would be produced from a water powered generator that uses horizontal current flow to move the generators coils rather than ...
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1answer
18 views

If I made a incandescent light bulb filament smaller what would happen? [closed]

If I took the filament in the bulb and made it smaller, and also increase the thickness of it, what would happen?
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1answer
17 views

Doubt on power generation by hydraliuc turbine [closed]

What happened to the final power generation if the hydraliuc turbine rotates discontinously for example if a turbine runner rotates with 2000 rpm for 2 minutes and stop rotating for 4 seconds and ...
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1answer
285 views

Series or parallel overloads in control circuits controlling several motors?

I think that putting the OLs of all the motors in series { figure (1) } provides better protection such that if any one of the motors is overloaded the circuits trips preventing the rest of the motors ...
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4answers
182 views

Why shouldn't we put high voltage cables physically underground?

sorry for the odd title. We're working on a project to find a cheaper and safer way to install high voltage power lines in the Scottish highlands. One of my group mates had a really cool idea to ...
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2answers
125 views

What is the rated tensile strength of 2000 kcmil stranded copper conductor?

All the documentations I could find goes upto only 1000 kcmil. Please direct to a reference for larger cables. Is there a method to extrapolate from smaller cable sizes?
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0answers
35 views

How to solve power surge caused by curing oven PWM cycle?

I have a Despatch LBB 1-69 lab oven in my shop. It is a single-phase, 110-volt, 30-amp unit. It is wired to a 220 volt, 2-phase, 40-amp panel (on a single 110 volt phase), which is fed by the 100-amp ...
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2answers
136 views

Equation for comparing force delivered to road at wheel based on varying gear ratios?

By introducing many new gears and changing the tire size I am altering the torque delivered to a rear bicycle wheel from an electric motor. This then changes the "power where rubber meets pavement". "...
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2answers
1k views

Advantages/Disadvantages of two-bladed windmill?

The vast majority of wind turbines I have ever seen feature 3 blades, as shown here: Recently while driving through western new York state, however, I passed by several turbines featuring only two ...
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6answers
1k views

Working hours of power plant generators

My question might seem a simple one, but it has been troubling me for a while. How many hours in a day do conventional electrical generators work (the ones in large power plants)? Do they by any ...
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1answer
111 views

What theoretical efficiencies can wind / hydro turbines achieve? [closed]

The high water has some energy E = mgh. In the basic school, we were told that hydropower plants extract the energy of "falling water". Now, that banned principle says that if your water falls upon ...
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2answers
2k views

How is the shift map of an automatic transmission constructed?

Figure 2 in this tutorial represents the shift map/schedule of an automatic transmission. How is this map constructed? I want to know how to design a shift map myself for another transmission. The ...
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1answer
287 views

What is the difference between an automatic transmission and an automated manual transmission?

What is the difference between an automatic transmission (AT) and an automated manual transmission (AMT)?
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0answers
109 views

Switching transient of a transformer on no load

Is there any equation to calculate the switching transient of a power Transformer? How much it will be for a 30MVA transformer (33/11kV) at no load?
3
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3answers
497 views

Efficiency of wireless charging for moving cars

The UK is about to start trials of wireless charging for moving cars. What kind of power transfer efficiency is likely to be achievable in such a system, compared to just plugging in the car directly?...
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2answers
374 views

Can large capacitors allow power plants to run at full load and store excess electricity?

We know that demand for electricity is not constant. Power plants are not operated under full load conditions. What if power plants were operated under full load condition and excess electricity was ...
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1answer
414 views

What limits a power plant's load gradient?

Each power plant has a load gradient characteristic, describing to what extent it can change the output of its generators in a given timeframe. Reading the literature, I know that, for example, a gas ...
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2answers
5k views

Quantifying inertia on the electricity grid

A lot of discussion about the modernisation of electricity systems is about "inertia". This is usually a qualitative discussion about how turbines (in hydro, coal & gas plants) with lots of ...
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2answers
220 views

How to correctly size the blades for a small educational wind turbine?

I want to design a small wind turbine that can be easily carried out of the classroom into the sports field in relatively low-wind conditions (5-15km/h) that can power a small ultra-bright 5V LED - ...