Questions tagged [generator]

A generator is a device that generates electricity from mechanical energy via different energy sources such as heat or kinetic energy of water.

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26
votes
4answers
4k views

Can I pedal power a laptop device while the device is being used?

I want to research how easy it would be to use a small laptop device while powering it by pedaling on a stationary frame. (For example, using a tablet on an exercise bike, or using a netbook while ...
16
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8answers
6k views

What's a good square wave generator?

What's a good circuit to use to generate a square wave? The exact waveform isn't too important - I just want to get a piezo buzzer cranking at 150 kHz. I also want efficiency and adjustable amplitude. ...
16
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5answers
3k views

Why do generators have to rotate at a slower frequency if demand outpaces the supply?

EU residents might have noticed that some of the clocks in their house have been running out of sync with other clocks. Apparently, the cause for this is that power suppliers had to reduce the ...
14
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3answers
3k views

Why is it harder to turn a motor/generator with shorted terminals?

The shaft of an unconnected motor is easy to rotate relative to a motor with shorted terminals. If a resistive load is connected to the terminals, the turning difficulty is somewhere in between. Why ...
14
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4answers
7k views

Advantage of using AC generators in cars instead of DC generators

Most cars use an AC generator then convert its voltage to DC via a bridge diode rectifier to charge the 12v battery. Why wouldn't a DC dynamo be used instead? Is it because AC dynamo gives better ...
14
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2answers
34k views

Is it possible to use Kinetic energy to power small devices?

I've tried looking around for as much information as I could gather to build really small wearable electronics that could power themselves by generating energy with movement. I know that the ...
12
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2answers
14k views

Does a DC toy motor emit AC when you spin it?

I just watched a video on Facebook by somebody who built a project to run an LED using a 9 volt DC motor scrounged from a battery operated toy. They simply wired the LED to the motor and then used a ...
11
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2answers
3k views

The electricity grid: what keeps small power generators from being 'driven' by large ones?

This is a two part question and pertains to power generation: What prevents a larger plant (say nuclear) from turning an itsy-bitsy gas generator into an electric motor and drive current through it? ...
11
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4answers
16k views

Explanation for Differing Stator Winding Orientations

As a layperson, I'm trying to understand the basic configuration for an induction motor or generator. I've looked at many diagrams and photos/cutaways of stator wiring and I've noticed two different ...
11
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2answers
174 views

Big discrepancy between theoretical and actual power through my pulse generator

I am trying to acquire some skills about pulse generation, but that's not easy. I've tried to derive the power dissipated by the input resistor in my pulse generator, but it turns out to be much ...
8
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4answers
2k views

Is there a device that converts any AC frequency to 60 hz?

If I have something like a windmill generator that generates AC current, but at variable frequency, what device(s) would I need to convert that variable frequency into a constant 60hz frequency, so ...
8
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3answers
1k views

Harvesting energy from a small amount of wind

I am currently investigating the feasibility of a project that would include the need of harvesting some energy from wind. The size constant of the generator and fans is about 2"x2"x2". The end goal ...
8
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1answer
6k views

What is 'load' in percentage?

Aircraft Airbus 320 has two 110/220v 400 hz 90 kva generators, run by two engines. There is an electronic display in the aircraft that also shows the parameters of the electrical system. One of the ...
7
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4answers
12k views

Does a generator produce voltage or current?

I know that this question might sound very stupid for +90% of you, but my brain doesn't really get the electricity generation. The thing that I don't understand is what does a generator produce, ...
7
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4answers
606 views

Hand Powered Generator

I'm interested in a hand powered generator similar to the one in this Gakken Helicopter Kit. Are these easy to come by? Easy to make?
7
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3answers
15k views

How to synchronize a generator on the electrical grid?

I've read many articles about paralleling two portable generators or synchronizing a power generator on the electrical grid. I have the theoretical background about that topic and I know the four ...
7
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6answers
34k views

What is back-emf: counter-electromotive force?

Could someone knowledgeable on the subject explain what exactly is this back emf? How is it caused in a motor/generator, which components and which effects determines it?
7
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4answers
398 views

Alternative Energy Storage

Can anyone suggest an alternative to energy from a battery? I'd like a system to replace my deep cycle leisure battery, I currently use this 110 AH leisure battery with a 1200W inverter. I run my ...
7
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1answer
3k views

How does a gas grill starter spark work?

On some gas grills, there is a button you push which creates a spark to ignite the gas (propane, natural gas etc.) My questions are probably pretty simple: How does the button create the spark? ...
6
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2answers
2k views

How can I generate voltage for a science project?

I am performing a science experiment where I need to generate 25 volts, 45 volts, and 65 volts. I need to attach the power source to electrodes by alligator leads into electrophoresis gel. What would ...
6
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4answers
7k views

Putting far more mechanical energy into a generator than its electrical load

Funny how I was pondering about this question for a long part of the day yesterday, and today I was at stackoverflow and in the box with the featured questions from other SE sites this very related ...
6
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4answers
1k views

Generator burnout [closed]

I work in aviation. I was told today that one of the systems of the aircraft had drawn more power than the generator could provide and that had caused it to fail, to get too hot. I don't understand ...
6
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2answers
1k views

Is electricity wasted when energy generated by power plant is not in immediate demand?

After my second series physics course I have begin to wonder how power plants control energy production to match the usage of a city. There are several possible answers in my mind listed below: Does ...
6
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4answers
8k views

What makes automotive alternators so inneficient relative to other applications?

Automotive and some marine alternators typically have an efficiency curve with a peak of 60%. alternator efficiency curve http://www.intechopen.com/source/html/38166/media/image3_w.png Image from ...
6
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2answers
2k views

How to generate 30Hz sine wave?

I'm building a voice ring modulator. Part of it involves a 30Hz carrier sine wave to modulate the voice with. Since I'm trying to build a portable device it will be DC powered, and since a function ...
6
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2answers
163 views

Do electric motors have the same efficiency when operating as generators?

Its in the title. I'm just curious and it turns out that either this is such a stupid question that no one has bothered to answer it, or i'm just not good at googling today. I guess I'm thinking ...
6
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2answers
4k views

How do I combine multiple A/C and D/C power sources into one electrical system? [closed]

I'm looking to design an off-grid power system for my house. I'm a complete novice at this point but I'm willing to do a lot of reading to complete the project. There is a lot I still don't yet know ...
6
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1answer
1k views

Compact Fluorescent Lamp Load Calculations

I help build/wire up large illuminated carnival/parade floats, and in the past we have used around 11,000 40w/60w GLS BC light bulbs in festoon sockets, powered by a 800KVA 3 phase diesel generator. ...
6
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4answers
5k views

Blinking an LED using a generator as the source of electricity

I made a little windmill which is turning a small generator to light up an LED, but the voltage is too low even with high wind speed for the LED to glow. I thought maybe the electricity could be ...
5
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3answers
3k views

How to get half frequency square wave from sin wave?

The task is to get such wave: I can get square wave from sin wave, but I have no idea how to make it half-frequency. Have some advices?
5
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2answers
4k views

why electric motor or alternator have stack of plates?

i have noticed that all of the transformer/motor/alternator/electric actuator have a stack of metal for stator ( or where winding is done. ). why is that needed ? can same thing not achieve by using a ...
5
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2answers
15k views

Can I Test Bug Zapper's Voltage With Multimeter?

I have The Executioner bug zapper: Although it uses 2 AA 1.5v batteries, it also has voltage multiplier like Cockcroft–Walton generator i guess and would like to know if it is safe and would make ...
5
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2answers
980 views

How does a wind farm prevent the fastest spinning turbine from driving the slowest one?

Just what the title says. On a wind farm spread across several score hectares, I assume, the wind-speed wouldn't be uniform. The faster spinning turbines would probably induce more electricity than ...
5
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4answers
527 views

Will a faster rate of change of flux improve electricity generation?

From what I remember about electricity generation, a varying magnetic field is used, either the magnetic field or the coil moves to generate electricity. e = dB/dT where e = voltage induced B = ...
5
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2answers
2k views

How do I modify a DC electric generator to get the same power at a lower speed?

This will be a theoretical question. Suppose that I have a DC generator, and I'm getting 300VA power from it when it rotates at 2000rpm. I want to make it run at a lower speed of about 700rpm, and I ...
5
votes
1answer
220 views

Custom WAVE file results in different sound profile than created

My problem is as following: I'm trying to use my sound card to produce a custom repeating wave pattern which I will use in some laboratory test setup. My curve is based on a combination of a couple ...
5
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2answers
1k views

How does the commutator work right here?

I understand that we use the commutator as a rectifier using two segments that alternatively touch the negative and positive brush. That is when we only have one coil. What happens when we have more ...
5
votes
3answers
745 views

single-capacitor oscillator choice for digital theremin

Intro One of the pupils puzzled me with a question of building a theremin - a basic musical instrument which has a pitch manipulated by moving the hand around the vertical antenna. Due to specifics ...
5
votes
1answer
11k views

What does a power factor of a generator means?

When I was reading the nameplate of a small 5KVA generator, I found that the power factor is mentioned. It was 0.8 . Is this the minimum power factor that the generator can handle? or Is it the power ...
5
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4answers
855 views

Charging Batteries from DC Bike Generator

I have salvaged a motor from a treadmill to make a stationary bike generator. Motor Specs: 180 VDC -4500 Rpm 1.3 Hp 6 amp I mocked up a bike trainer and using the rollers from treadmill and was able ...
5
votes
1answer
90 views

Can somebody please explain to me the principle of a T-T Earthing system?

How are the transformer, consumer's side and the generator earthed in a T-T Earthing system? I seem to understand that the generator and its frame should be earthed separately; The neutral of the ...
5
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2answers
942 views

Designing/Predicting Output from Permanent Magnet Motorcycle Stators

I'm hoping you can help me. I've long been into motorcycles, and have restored and customized many different bikes. While building custom motorcycles, I often add electrical accessories, and use high ...
4
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4answers
446 views

Generating electricity with wet newspapers?

For a project we're thinking of generating electricity out of wet newspapers. Is that possible? How much current would it generate?
4
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4answers
432 views

How is electricity typically generated?

I am a pure physics guy, so I understand the fundamental processes behind the generation of electricity, but I'd like to know how to apply it. I was wondering what kind of methods were used in the ...
4
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3answers
896 views

How to build a noise generator based entirely on logic gates?

I would like to build a noise generator based on logic gates. It could be white noise generator or a random bits generator that sound similar to a noise source. I need a circuit recommendation or an ...
4
votes
3answers
532 views

Will a 3 phase induction generator fight its own rotation?

So in a 3 phase induction generator with coils for the stator and magnets for on the rotor, I am wondering if the the current induced in the coils would create a magnetic field that would oppose the ...
4
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4answers
4k views

How do power stations maintain 50 hertz?

In the UK our mains standard is 230 V AC at 50 hertz. So I understand that the generators at the power stations need to spin at exactly 3000 RPM . This is true no matter what the source is (nuclear, ...
4
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5answers
4k views

555-timer circuit supposed to give 50% duty cycle square wave doesn't

I wanted to build a circuit that gives 50%-duty-cycle square wave. I built the circuit of figure 4.4.6 from this link which is shown below: I used the NE555 chip, and used a potentiometer instead of ...
4
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4answers
250 views

Zener over voltage protection from DC hand crank generator

I have a board powered by a hand crank generator. Under normal conditions the voltage peaks at 18-20 volts. However spinning the handle violently will peak higher at 30+ volts. The generator runs ...
4
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5answers
717 views

How to create pulses which are 10ns long and 15kV/ 80A amplitude?

I'm looking for an easy way to create short high voltage pulses. These would be 10-100 ns in duration, 10-30 kV in amplitude (the load is complex but roughly similar to a 200 ohm resistive load). ...