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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Which of the following motors best suit as a wind generator? [closed]

I'm watching some brushless outrunners with low kv as a generator for a simple wind turbine that I'm going to build soon. It might not be a scale or fully useful turbine, because I want to build it ...
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17k 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 ...
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4answers
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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 ...
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Converting a DC motor to a generator

Can ANY DC motor become a generator if torque is applied to the shaft? example: Produce-Electricity-from-a-DC-Motor And by any, I mean the really cheap ones too. Or is there a specific type of motor ...
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1answer
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DC Motor as a Generator Voltage and Current

Is there any way to calculate the expected voltage and current, assuming I am turning it at the specified RPM value, when using a DC motor as a generator without physically testing it? In my case I ...
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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 ...
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2answers
1k 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 ...
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5answers
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load sharing in parallel generators

My question is the following: We have two 220V 20A generators connected in parallel to total power 8.8 kw 220 v 40 A load is 5.5 ohms I'm interested how each generator sees this load since every ...
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4answers
812 views

small wind turbine pancake generator, force of magnets effect on rotation when charging a battery?

Contexte: a DIY small wind turbine pancake generator, made with 2 rotor plates of 12 rectangular magnets, and one stator of 9 coil wired. After the generator, the 3 alternative electricity phases are ...
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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 ...
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1answer
158 views

Single-Phase Generator

I have two pieces of single-phase fans and they are literally the same, it is ac motor and whenever I rotate it manually it produce voltage about 160-190vac. I just get the idea that it can be an ac ...
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1answer
194 views

Loop of a wire and right hand rule

When the loop is the figure shown below will be rotated in clockwise direction the the slip ring connected to the red segment of the loop will give us the positive voltage and the slip ring connected ...
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8k views

Using hard disk motor as generator

I have disassembled 20 broken hard disks and taken out the motors, thinking they might be useful. However, they didn't work using DC current, because they required some kind of control circuit. Now I ...
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1answer
682 views

How does a conventional generator produce only reactive power?

For a class that's rather far outside of my background, I am reading a paper about supply-demand balance in an islanded microgrid. The active power demand of the whole system can be met with ...
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1answer
2k views

Building a new dynamo bike light

So here is the deal, for the 2nd time in less than a year, my halogen bike light on the front has popped due to cold. This is rather bothersome and I can't find any nice inexpensive LED alternatives ...
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Rated current of a three phase DG set

When the rated current of a 250 KVA DG set is shown as 347.8 A, does it mean that it is the line current or phase current or sum of currents on all phases say R Y B phases
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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 ...
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Parallel generators don't divide reactive KVAR load equally

We have three generators cat 3412 800kW at our power station. They load in synchronization. But we have a problem in the sharing of the reactive power KVAR. The voltage regulator used in the system ...
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5answers
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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 ...
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If a large AC generator is overloaded, will it lose frequency or voltage?

If a large AC synchronous generator, like one from a hydro dam, were to receive overdemand from the grid, would it start losing frequency or losing voltage? I know they have several safeguards to ...
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2answers
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Pulse Generator - I (Art of Electronics)

In the Art of Electronics book, I don't understand the following phrase .. because current is flowing down through R3, trying to pull it up. Why does this current try to pull the cap up? ...
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2answers
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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? ...
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4answers
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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 ...
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570 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 ...
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Could a significant amount of electricity be generated from public hand-operated generators?

So imagine you're at a bus stop at a train station. You're bored and have got nothing to do. So you see a big crank-handle sitting there doing nothing, and because you're bored, you decide to spin it ...
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1answer
646 views

Earth Ground Portable Generator

I recently bought a pure sine wave 2kV portable generator to use for camping. In the manual it states that the generator should be grounded to actual earth through a metal stake and then attached to ...
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1answer
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LTSpice: active load current generator soft saturation

I would like to use a current generator to pull down the voltage to zero (there is a voltage generator with a series resistor). The current generator models the output of a specific circuit, so it is ...
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3answers
897 views

Generating electricity by moving door handle to produce 3 Watts?

I want to attach a generator to a door handle and have the output charge a battery. My system needs to provide about 3 Watts. A similar question was asked here and I referenced it to get an idea of ...
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How do I build a one shot non-retriggerable pulse generation circuit with 2 triggers?

I'm kind of a noob when it comes to electronics (I'm mainly a computer programmer), so please bear with me. I want to construct a one shot non-retriggerable pulse generation circuit that has two ...
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1answer
110 views

How do I correctly calculate the resistance (induced emf?) of a generated current against the flux? [closed]

I have all the basic physics working for every major section of the entire generator as correctly as I think I can (barring actual code implementation improvements) but just couldn't get the feedback ...
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1answer
539 views

dc brushless motor specs for generator

Hello i have done my research and have found varying information relating to the speed at which you must drive a motor to get a desired output and that it is dependent upon back EMF however i am very ...
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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 ...
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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 ...
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3answers
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Source of initial magnetic field in an alternator

I have been reading about how alternators work and I am wondering where the initial magnetic field comes from when no current is running through the field coils that excite the magnetic field in the ...
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1answer
558 views

3-phase Brushless Motor - Are Volts and Amps at (X)RPM equal/similar when used as Generator?

If I have a Brushless 3-phase motor that spins at 3000rpm when given 6.0A @ 20v (no load) will it produce 6.0A and 20v (or anywhere close) when used as a generator and spun at 3000rpm?? And i suppose ...
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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, ...
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3answers
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Building an Ultrasound Generator

I need to generate ultrasound with a frequency of 1.5 MHz. The ultrasound should be pulsed as shown here An ultrasound pulse should be 200 µs long, a pause (no ultrasound) is 800 µs long. The desired ...
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3answers
129 views

Whats the justification to determine the phase sequence?

I have been told many times that one way to determinate the phase sequence of a three phase system is to use two resistances and one capacitor (or inductor) in star (wye) connection, then connect two ...
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1answer
249 views

How to make 5V 650 mA on a summer camp?

On our summer scouts camp, I need to power a tablet (it simulates the computer from The Lost, and the children must activate it every 108 minutes). It requires 4.3 - 5.3 V and about 650 mA. I need to ...
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5answers
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Hand crank DC generator - a simple dummy load that won't burn out?

I'm working on a project that allows a user to crank a hand generator while current and voltage sensors measure the output. After the user finishes cranking, software displays information about how ...
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2answers
6k views

Best most efficient motor type to be used as a DC generator

I'm trying to design a system that requires a very light weight very efficient generator to be used from converting rotational motion into DC voltage(for say charging batteries) As far as I know BLDC'...
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2answers
2k views

resistive braking for induction motor?

It occurred to me that since single-phase AC induction motors can act as generators, it might be possible to brake an induction motor with a resistive load. The basic idea is that when you want to ...
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1answer
470 views

Working of a Doubly-Fed Induction generator (DFIG) in wind turbines

I am unable to understand how a Doubly-Fed Induction generator works (in Wind Energy conversion system)? I do not understand how the reactive power fed into the stator interacts with the rotor so as ...
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1answer
88 views

Loading an Asynchronous Generator

I am doing an experiment that involves loading an asynchronous 50 HZ generator. For the load to consume current it has to be a capacitive load to cause a phase shift between the current and the ...
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1answer
149 views

Are permanent-magnet motors equally (in)efficient as motors vs. as generators?

Given a permanent-magnet motor with an efficiency of 80% that converts 100W electrical input power into 80W mechanical output power, would the motor have the same efficiency if used as a generator? ...
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1answer
313 views

Does a Wimshurst machine work fine with normal glass disks?

I want to build my own Wimshurst machine and I cannot find plexiglass disks. However, in our town there is somebody that cuts normal glass circles–so I wonder if normal glass disks would replace ...
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1answer
663 views

Phasor Measurement Unit (PMU) vs Synchro-check Relay

What is the difference between a Phasor Measurement Unit (PMU) and a Synchro-check relay? I need to know if Synchro-check relay can be used as replacement for PMU in a Synchrophasor data system. We ...
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Change in frequency in a grid that has lost generation?

I have an example about droop and it asks to calculate final frequency in a grid after one generator power generation is lost. The answer is given as 59.889 Hz; however, I am calculating as 59.99 Hz. ...
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1answer
43 views

Calculate properties of electric generator?

I've got a miniature DC generator with 10 coils. If I knew the generated power and the size of the rotor, how would I calculate its RPM? Which other variables would I need? Is there a general formula ...
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2answers
157 views

Producing a small homemade generator with reduced cogging torque

Background: I'm working on my second hobby small generator design. Particularly difficult to source are (relatively) low speed permanent magnet motors that can be run in reverse as a generator with ...