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1 vote

Can the Dynosheet be read as a Fourier transform of some sorts?

I'm not sure if it's logical to think that since a car has 5-6 gears (unless if it's an electric motor car, but even if it's a DC motor of one gear, it'll still apply), it'll have different responses ...
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Is there any way to relate the induced EMF from an alternator to the DC current that is used in the field winding?

As you pointed out, the induced voltage and the magnetic flux are related. According to Faraday's law, this gives : Using the definition of an inductor, we can obtain: Note that in your case, the ...
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1 vote

In a AWD Tesla Model 3, why is the front and back motor different?

As SolarMike suggested, available volume is part of the deal. The second motor is actually idle most of the time, being called upon for dramatic acceleration or when wheel slippage is detected. As ...
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0 votes

What's the minimum torque needed for 2 DC motors for moving a 1 kg object on top of them?

one kilogram meters per second is 9.8 Watts. Ignoring the friction, this is the power you need. then divide by two and that's each motor. Then you need a motor drive controller which is available in ...
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2 votes
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Find the values of resistance R and inductance L in the R-L-C circuit

Yes. Since the phase of the voltage is not explicitly mentioned, it can be assumed that it is the reference and hence aligned to the OX axis. The current phase is specified in the question. The ...
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6 votes
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How friction between stator and rotor is dealt with in an electric engine/motor

... there's no space between the rotor and the stator. There is always an air gap between the rotor and stator. Iron has a permeability of about 1000 times that of air so the trick for maximum ...
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72 votes

Why are two wires used in railway overhead equipment?

Overhead line worker here. It's about speed. To answer your question, the purpose of the catenary wire is to get the contact wire to lay flat, so it isn't catenary itself. In your second photo, there ...
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6 votes

Why are two wires used in railway overhead equipment?

Why two wires: A wire hanged at two points sags (it forms a "catenary curve"). The pantograph can only handle a certain sag before losing contact and arcing. The acceptable sag depends on ...
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12 votes

Why are two wires used in railway overhead equipment?

It isn't to do with current-carrying capacity; it is to maintain good contact between the current-carrying wire and the pantograph pickup on the locomotive, as it allows the contact wire to be ...
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0 votes

How do 120V AC dimmable LED bulbs advertised as "flicker free" work?

I understand (more or less) that this flickering is the result of alternating current and the LED's binary nature, it's either on or off; and because it runs cool there's no "afterglow" of a ...
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2 votes

How do 120V AC dimmable LED bulbs advertised as "flicker free" work?

Flicker can be minimized by choosing a phosphor in the design of the full-spectrum white LED that has a long persistence time. When you turn off one of these LED arrays, you can see that the light ...
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2 votes

Would the below thermal generator work properly and provide surplus energy?

Could it work? Yes. Is it practical for any scale? No. As @DKNguyen says in their comment, if you had a free source of these components you could generate this heat and use it to do things. But it ...
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0 votes

What are the conditions for a signal to be an energy signal and a power signal?

That logic specifies that x(t)=0 cannot be a "power signal" (assuming x is power or energy over time). This is thanks to the non-zero requirement. Funny thing about energy is that while we ...
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0 votes

Faraday's law applied to a coil in an electromagnetic field

"what would happen in a practical sense if the formula were positive?" Nothing, except the calculated voltage would have opposite direction than we have used to see in electromagnetic vector ...
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Inductor Voltage at t=0

The whole idea of using inductors is the fact that their currents do not change instantly. You assumed infinite di/dt, but that doesn't happen. The inductor generates just as high voltage as needed to ...
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0 votes

Measurement of actual carbon dioxide mass emitted from a diesel engine

Your problem isn't a trivial one; it actually falls into R&D. I disagree that the gas concentration is not a useful measurement--you could convert it into ppm/ and then into mass, even though that ...
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0 votes

Measurement of actual carbon dioxide mass emitted from a diesel engine

I think that Phil Sweet has the right idea in a comment above - measure the fuel flow and apply an emission factor. But if you really need to measure it, my thought would be to run the gas stream ...
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1 vote
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Measurement of actual carbon dioxide mass emitted from a diesel engine

Pull off a sample of the exhaust gas of known volume and bubble it through a calcium hydroxide solution, to convert all the CO2 to CaCO3. filter, dry, and weigh the CaCO3. knowing how much CO2 was in ...
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