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what is the working of AVR in a Generator ?

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what is the working of AVR in a Generator ?

Difference between home portable generator & prime generator ?

thanks
 

munzir said:
what is the working of AVR in a Generator ?
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I cannot figure out what does this mean...

munzir said:
Difference between home portable generator & prime generator ?
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Home portable generator is a device. Prime generator is an algorithm. What differences are you referring to?
 
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munzir said:
what is the working of AVR in a Generator ?
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You probably mean the Automatic Voltage Regulator, though AVR can mean other things in electronics, such as the AVR family of microcontrollers. The AVR in a generator does exactly what its name implies: It regulates the voltage output.

Difference between home portable generator & prime generator ?
Click to expand...
I'm assuming that by prime generator you mean one of those big ones used by a public power supply agency. Apart from size and power capacity, the differences can be major or minor depending on particular models. Some simple portables are nothing more than a powerful magnet rotating inside a coil. The AC voltage and frequency are controlled only by the engine speed. Others have a basic AVR and still others are quite sophisticated. All but the simplest ones have some kind of feedback that monitors the output and adjusts it by varying the current in the field coil.

One thing common to most 'prime' generators which is less common in smaller ones is how the field current is supplied. Most big ones have a separate DC generator whose sole function is to supply the field coil. The DC generator is often on the same shaft as the main alternator and is run by the same mechanical engine.
 
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Some "home" type generators use diodes built into their rotors, so that they are rotating a "DC" field. These use the saturation of the iron to provide some slight voltage regulation function. They use the force of the oil rotating in the crankcase to provide feedback to the carburettor so as to keep the engine speed constant as the voltage output is normally proportional to the engine speed. This means that if you are fault finding a generator set, the first thing to do is to set the engine speed correct to to get your 50 HZ mains frequency, and then try to set the voltage.
Frank
 
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what are the electronics & electrical parts present in a home portable generator ?

thanks
 

munzir said:
what are the electronics & electrical parts present in a home portable generator ?
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phatcreators said:
Of what parts an AVR is build up ?
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To both questions: All the usual active and passive electronic components - ICs, transistors, diodes, resistors, capacitors, thyristors, etc.
 
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For controlling the field current. Like any other electronic product, an AVR may be designed in many different ways and the components used differ from model to model.
 
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how can i get to know that this generator whether industrial or home portable has AVR in it ?
Generally, where it is connected or present inside the generator ?

thanks
 
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how can i get to know that this generator whether industrial or home portable has AVR in it ?
Generally, where it is connected or present inside the generator ?

thanks
 

munzir said:
how can i get to know that this generator whether industrial or home portable has AVR in it ?
Click to expand...
If there are some fairly complex electronic circuits somewhere on the generator (not just rectifiers), they are most probably the AVR circuits. An AVR is also likely to have at least one adjustable component for adjusting the output voltage.

Generally, where it is connected or present inside the generator ?
Click to expand...
There is no standard location for the AVR. You'll just have to look and see for yourself. Some large industrial generators may even have the AVR in a separate box that's not attached to the generator body.
 

The system behaves as though it has an AVR, suppose the engine revs are 2000 RPM when its delivering 230 V at 10 Amp. So the engine is delivering 2300 Watts- 3 HP. If you just disconnected the load, if nothing was adjusted, the motor (still trying to deliver 3HP) would rev itself into oblivion with a short term generation of 2000 V or so. So as I said there is some sort of crude regulator adjusting the fuel and an electronic (fine adjust) regulator getting the output voltage correct.
Frank
 

Did I miss something here? Your post implies that the OP reported certain behavorial patterns of a particular generator but I don't see any such account.
 

Pjdd, engines work by converting the chemical energy in their fuel into physical energy, such as shaft rotation. A generator converts the energy in its shaft rotation into electrical energy. So we have fuel going in at one end and electrical power coming out at the other. If we cut off the electrical output power by opening a switch so there is no current, then where does the energy in the fuel go to? Or do we turn the fuel down?
Frank
 

I think we're having a communication gap here. I wasn't asking about elementary thermodynamics or the basic principles of a generator. This is what I meant: Your previous post sounded like you were replying to specific quesions asked by the OP about one particular generator that he was working on. I didn't see any such post by the OP or anyone else in the thread. All I see are some very general questions about AVRs.

In fact, that post of yours looked to me as if it had more to do with a different thread not long ago in which the OP asked about one recalcitrant portable generator that they were shipping off to Haiti.
 

I don't know what the "prime" generator set up does but I have worked on Diesel generators of about 500KVA ratings and the main problem we had with them was that the speed governor hunted, giving a +- 1Hz deviation on the 50HZ. We were happy enough to use them because the AVR system kept the output voltage constant. Our problems stemmed from the battery powered UPSs that maintained the load while the generator was starting, they would not switch to the diesel because they had a very narrow frequency window on the incoming mains (WHY?). So we ended up with a fully up and running diesel and a flat UPS and no service from our equipment!
With equipment connected to a national grid, I believe there is a natural tendency for the generator to lock its self up to the grid.
Frank
 

Mains frequencies are used as a reference for many industrial and domestic machines, especially in advanced countries, and are maintained to very tight tolerances. That's probably why your UPSes were built to accept only a narrow frequency window.

I too have worked on small petrol generators and diesel gensets from 1kVA to 1MVA. I live in a remote part of a developing country and I spent more than ten years helping my state's government-run electricity department mature into a competent agency. I designed and built substitutes for some expensive imported products including AVRs. The diesel generators are all phased out now except as emergency backup units.

Yes, the generator will tend to lock to the grid. But unless the frequency, phase and voltage are not carefully synchronised first, it will result in a large circulating current that not only wastes energy but also doesn't do the machine any good.
 

phatcreators said:
how can i get to know that this generator whether industrial or home portable has AVR in it ?
Generally, where it is connected or present inside the generator ?

thanks
Click to expand...

It looks something like this :-D

Untitled.jpg
 

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