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Questions tagged [energy]

Energy is defined as the amount of work that can be performed by force, measured in Joules. Energy is Power over Time. This is a poor tag to use. Please consider if your question relates to Energy as defined in physics, not as a synonym for Power or capacity.

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1answer
24 views

Time it takes for B to go to zero with R and L given

Given that your solenoid has inductance L and resistance R with initial current I such that there is uniform B inside the coil, I would like to figure out how much time will pass before B goes to zero....
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0answers
58 views

Much higher energy use, maybe due to an old electrical heater? [migrated]

We had an 100% increase of power consumption last and this year. It is mostly the night-tariff, which we now consume 27'000 kWh The day-tariff is only around 2'500 kWh. First we thought this may be ...
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0answers
31 views

How to safely switch a big inductive load with a Triac using a capacitor snubber?

I am building a Spot Welder with a big powerful transformer. I have to switch a big inductive load of 70mH (input of a transformer) The switching will be done with an SSR (Opto Triac Zero crossing SSR-...
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1answer
15 views

Why are thresholds for energy detection and preamble detection different in 802.11 standard?

Assuming a 20 MHz band, it is -62 dBm for the data and -82 dBm for the preamble. Source: August 2013 doc.: IEEE 802.11-13/0994r0
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2answers
68 views

What is the effect on kWh if the power company reduces line voltage to a residence? [closed]

We just received our power bill and it is showing a 30% rise in kWh for the past month. Nothing has changed in our home. We were even gone one full week in the month. To make it more interesting, ...
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0answers
33 views

how to compute battery charging power

I have a very basic question about battery charging power. In a very simplified scenario, assume a battery with voltage 3.7 is connected to another rechargeable battery with voltage 3.2 which results ...
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0answers
42 views

RS485 registers for calculating total power consumption (kwh)

I have an energy meter (OHIO A2000) which has been now discontinued by the manufacturer. Anyway, I'm following the manual for extracting energy parameters through Modbus RS485 communication. I'm ...
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1answer
55 views

Determining Battery Charging and Discharging Rate Based on Max Current and Nominal Voltage

I am having difficulty in figuring out some basic stuff and confused with multiple equations. I am working on a simulator which simulate a hybrid vehicle journey for some period of time. During ...
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1answer
28 views

About parallel circuit [duplicate]

Consider a power source supplying 240 v 50/60hz 6amp I know that there is nothing like it but I chose that for my comfort of understanding now if I connect 15 loads drawing 240 v 0.35 amps in parallel ...
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2answers
46 views

In AC circuit will there be a voltage drop or current drop [closed]

For reference purpose consider an AC voltage source of 240v 1amp and there are 3 loads connected to same 240v line one consuming 600 milliamps and another one consuming 300 milliamps.now if i add ...
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1answer
44 views

How is the energy consumption of a ciruit component calculated?

I know that watts are equal to amps times volts, and that watts are a rate of energy consumtion. I have looked at some circuits, but I am unsure of how the total energy use is being distributed. My ...
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0answers
27 views

Yagi-Uda antenna - energy flow density calculation

There are given two, identical, parallel, short dipoles perpendicular to the OX axis connecting their centers, located at a distance of λ / 4 and supplied with a phase shift of π / 2 (figure below). ...
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0answers
12 views

Load Curve Analysis

I am not able to understand the difference between load curve and load duration curve. I know how to plot load curves. But do not know how to draw load duration curves. Can someone explain this with ...
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4answers
665 views

Relationship between I2C drawn energy / power consumption and data rate

Referring to just what the I2C lines draw, am I wrong thinking that the higher the clock frequency the shorter the time there will be (the same amount of) current flowing through the pullups and thus ...
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2answers
50 views

Do “standby switches” consume energy?

Suppose I have a TV plugged in and it is connected to a power outlet which is also turned on. This appliance is "turned on" and on "stand by mode". It consumes energy I think just to light up that ...
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0answers
28 views

Generator RPM and Energy Relation

If a 3 phase AC generator rated 5 kW @300 RPM generates 5 kWh in one hour of continuous operation, is it possible to find how many rotations of the generator at 300 RPM will generate 10 Wh? Thanks in ...
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1answer
33 views

Instantaneous power consumption value

If, for a large motor, you are given cumulative kWh values at 5-minute increments, how would you determine an instantaneous power consumption value?
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0answers
39 views

Hamiltonian-inspired energy function for power grid stability

I'm looking at this paper which proposes an energy function for a 3-bus power system example. I'm trying to replicate the results in the paper but am uncertain about the ...
1
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1answer
136 views

Is electricity saved by switching off the lights when leaving a room? [closed]

Incandescents are very energy inefficient for sure so they have to be turned off whenever you leave the room. But I have tried to find the answer for CFL lights, some say that it's more efficient to ...
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0answers
25 views

Battery capacity for optimal life

I am planning to construct a small electromobile for which I will use a 3kW electric motor which will be powered by li-ion batteries. It would be sufficient for the vehicle to run for about 1 hour ...
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votes
1answer
69 views

Can I use a USA Led Bulb in Europe? [closed]

I am a software engineer working with an IOT company in the states, Right now I am located in Europe for a month and a half, and have some hardware (light bulbs) that I need to use to finish some ...
0
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1answer
166 views

Battery Charge and Discharge Time

I am doing a case study on battery back up of a wind system with the following specification: System size: 10 kW which runs continuously for 5 hours per day. Battery Calculations: Battery type: ...
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2answers
65 views

Electrical energy saving [closed]

"You can not pay for the light! This CUTE for years was..." I wonder, what will happen if to do what is illustrated on the picture. I think there are two cases: Hot terminal of left outlet connect ...
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2answers
510 views

How to compare mAh to Watt hours?

I have a laptop with a battery described as: 3 cell Li-Ion 57Wh I would like to know how this compares to a powerbank with 26500 mAh capacity. How do you perform these kind of comparisons? What ...
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0answers
76 views

Is there a theoretical performance limit for Lithium Ion batteries?

Is there a theoretical performance limit for Lithium Ion batteries? I'd like to compare energy density of Petroleum Products based upon what limits can be obtained from stored energy in Lithium Ion. I'...
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1answer
105 views

Calculating energy of transient/surge handled by metal oxide varistors (MOV) or surge suppressors?

As I get to know more about the MOV operation, there are more things needed to understand. My MOV (V420La20AP) has Varistor voltage of 680 Vrms (10%) at 1 mA, and maximum clamping voltage of 1120 V ...
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2answers
148 views

How does programming code provide power to electronic circuits? [closed]

I've been thinking about a question and haven't been able to find an answer. The question is that: For instance, an Arduino has a 5V output pin to feed any electronic component. When you code ...
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1answer
49 views

Dual axis solar tracker with singlr LDR

I'm working on dual axis solar tracker project, but the task I was given was to make a solar tracker work with a single LDR (Light Dependent Resistor). The LDR would be placed in a pipe which is ...
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2answers
79 views

In an ideal transformer circuit, how is power transferred?

If I have a system of circuits like this: where Circuit 2 is providing power the Circuit 1, where does the energy come from? Do the inductors store energy? If not, how is power transferred from the ...
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1answer
96 views

How much capacitance/joule/watt is needed on average household' energy storage system with supercapacitor?

I am on the process of making assumption how much capacitance/joule/watt is required on average supercapacitor as household' energy storage system. I plan the design for energy hub to be charged by ...
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1answer
73 views

If counter-emf is zero, why is COE violated?

I've been modeling this thought experiment a for a while now: If in a electromagnetic system, the induced emf wasn't opposing the change, but increasing it, we're getting energy from nowhere, that ...
1
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1answer
78 views

How does electrical signature devices work when there is more than one load connected?

Now more than ever I see energy monitoring devices like this one that uses "AI" to detect the loads connected to your home electrical network, like the washer or a hairdryer. These devices use ...
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4answers
104 views

Is it really that the electrical energy consumed by a resistor totally transform to heat energy?

My notes say that electrical energy and power consumed by a resistor is totally transformed to heat energy. Is this true? Or could it be transformed into also some other kind of energy?
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2answers
42 views

How to model electric power consumption in verilog-a?

I am modeling an analog device using verilog-a (to which I am quite new). I would like the model to match the power consumption of the physical device, for which the energy cost associated with state ...
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0answers
69 views

Electronic load battery testing - Honda NiMH batteries - Energy storage

I recently found a way to recondition used cylindrical NiMH batteries pretty well (typically those used in the Honda Insight series). However, I want to know whether the batteries will hold ...
0
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1answer
933 views

What is the difference between inductive coupling and resonant inductive coupling?

The resonant inductive coupling is better than inductive coupling, the difference between them, is that resonant inductive coupling use the "resonance" in their favor. But what is the difference in ...
3
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2answers
168 views

How does the diagram really work? [closed]

Good afternoon, I am a high school student and in my scientific fair project, I would like to do an experiment about wireless energy. I want to implement the resonant inductive coupling. According ...
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1answer
56 views

What does the 20-80A rating on an energy meter mean?

On the energy meter nameplate is a current rating 20-80A, which I can assume has something to do with max current. I'm particularly interested in the "20" part, though. What does this rating mean? I ...
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1answer
58 views

267 3MW wind turbines can produce 960MW?

WINDFARM PROPOSAL In the proposal above, it states that 267 3MW wind turbines are used to provide 960MW. but using a very simple calculation: 267 * 3MW=801MW. So how is it that the windfarm is ...
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0answers
91 views

STPM33 UART read/write

I'm working on project, using the energy sensor STPM33 in order to measure energy consumption. I can't understand how to read the register values, documentation seems unclear. There's a similar ...
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1answer
70 views

What does a 10MW wind turbine mean?

So if a wind turbine has a capacity of 10MW, what does that exactly mean? does it produce 10MW every hour, or is it the peak power it can generate at any time? the following question is how to know ...
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0answers
92 views

How to deal with low pass filter questions if Fourier transform of signal does not exist?

I found this question in a previous test paper: I'm having a few confusions: 1) Low pass filters are supposed to block signals below a certain frequency. Here that certain frequency is \$w_c=a\$. I'...
2
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3answers
110 views

Faradays law of induction - where does the energy for the current in second loop come from?

Lets say each of the loops have the same resistance \$R\$ and the emf of the battery is \$V\$. Case1 : There is no second loop. Then if I close the switch for \$t\$ seconds, then the energy supplied ...
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2answers
715 views

What is the power / energy of a discrete time constant signal?

I know that this is a very fundamental (and maybe vague) question. But I'm not sure what period I should use. I read somewhere that a constant signal doesn't have a fundamental period but is periodic....
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1answer
44 views

Energy in a wave

The energy of a wave is defined as w=a^2. w=energy a=amplitude. Does this formula also apply to AC or rectified AC? When two waves with identical polarization, frequency, phase and amplitude ...
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2answers
75 views

When a utility company uses the term “installed capacity” does it mean energy or power?

This is directly from this website: "The current installed capacity on Ontario’s transmission grid is more than 36,800 MW". Does it mean total energy generated & transmitted in a year OR the grid'...
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1answer
145 views

How to process energy (kWh) meter reading data of half-hour interval

If I am to process time series of energy data (point estimate every half-hour interval), and fit it into the following formula for dimension reduction: Haben's paper I was advised to use power, not ...
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3answers
104 views

Small Electric motor to turn generator to turn electric motor to turn generator chain [closed]

This might be a silly question but is it at all possible to use a small electric motor with a small battery to turn a small generator then connect the generator to a slightly larger electric motor to ...
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2answers
46 views

How to know / test a supercapacitors really store the energy [duplicate]

If i charge a supercapacitor, how do i know or test this supercapacitors that it really store the energy (like a battery) and doesn't discharge ? Can anyone give some reference or method? Can i use ...
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2answers
84 views

Energies carried by electric and magnetic fields in plane waves

This is a newbie question. I'm trying to understand what I think must be a very basic concept with an obvious answer, but I want to be sure. Do plane wave electric and magnetic fields of equal ...