AVR's

See Wikipedia.

Audio-Visual Recording?

All-Vehicle Road?

Air Velocity Reduction?

Automatic Voltage Regulator?

Automatic Voltage regulator yes!!!

Thanks

T. Mattheos

I worked on Kirlosker make Generators that use AVRs. AVR takes feed back from Generator 3 Phase AC (feedback from any two phases) and alter the Exitation current of the alternator so as to keep the our put voltage constant.

yes indeed! Does anyone however have by any chance any template circuit of AVR to study?

Hi presently in our plant we have skoda DG sets actually... if u know that setting of AVR pls help.. in One DG we r facing a problem relating with AVR... OVER EXCITATION 8 KV instead of 6 KV auto excitation.... may be a problem in port.. if u know pls replay..

Raghav Sharma

mathiodor,

1) Like pwslack has demonstrated, AVR could be a number of things. Tell us what AVR you are talking about (I suspect that you mean the AVR RISC μController from Atmel).

2) "basic principles" is extremely broad. Be more specific.

Mike

thanks for the comment

I was basically looking for what an AVR (Automatic voltage regulator)actually does in a electrical switchboard system. Starting from the very functionality to analysing the components of an AVR.

I am not familiar with electrical installations to a professional level but i have to quick grasp the basics as i am going to take part ina shipbuilding project, which ofcourse involes a power pant, powered by diesel engine driven alternators.

So i am checking out the various safety arrangements of the main swicthboards.

thankssss

I have a question - maybe you can help PW. Isn't the Automatic in Automatic Voltage Regulator redundant? Don't voltage regulators automatically regulate a variable incoming voltage and output a constant voltage by definition?

Mike

An AVR Onboard ship depends on the design. Generally the system involves a motor control console that will control the speed of a motor (and generator) by measuring the current phase of the load and comparing it with the setting. As a load increases (thus lowering the voltage) the current phase will shift. By adjusting the speed (power) of the motor driving a generator, the load is compensated.

A more complex system may require the bringing on of additional motors and generators, synchronized exactly in phase with currently operating power system. This may be done manually or automatically. The critical system is the synchronizer. the synchronizer measures the phase differences between the operating systems. It must be set to only allow a new power source to join within a narrow phase tolerance. If for example, the two power systems are connected out of phase, a catastrophic situation will occur... involving loud noises and lots of smoke.

Other critical systems are the over voltage protection circuits, and the emergency shut offs. There should be both a remote and local shut off switches, or fuel cut offs.

Techno thanks for the info! I think that pretty much describes the situation...

Yes a governor indeed regulates the speed of the generator driving engine, however it takes a feedback signal i suppose through its regulating motor, and in return fluctuates the load of a diesel generator engine via fuel supply...

i disagree with Techno. The AVR regulates the excitation or field to the gen. The AVR does not regulate the speed. The speed is regulated by the governor.

In some cases yes you are correct,

I simply quoated some of the systems that I have seen where the fuel was controlled proactively (quicker than a reactive governor). It all depends on who designed the system.

Without the System schematic, it is all a guess.

Its a popint to start from!

Thanks!!!!

P.S Would you have any idea on where to find some typical AVR circuit arrangement drawings? I hope i am not asking for too much

Thanks again

Unless we know the Make and Model you are using, this would be futile.

There are so many variations in design, it would be dangerous. Your best bet is the manufacturer, or the tech manual that comes with the equipment.

AVRs are of many types:

Notes:

======

1. A sense cicuit is a MUST in all AVRs which senses Voltge at the Feed-piont [Output]

2. Upper & lower limits of output are defined, eg 105 to 120V for 110 & 190 to 240V for 220V supply.

3. Type 1. below intrupts the output during operation while & produces surges

4. Typess 1 thru 5 keep the wave-form as original, while Types 5 to end re not Sine-wave outputs.

Types of AVRs

=============

1.) A tapped-Transformer's output is switched up or down to keep within limits with change-over relays. Intruptions during chang-over are inherent.

2.) A Variable-Transformer [Variac] driven by motor-control is fully or partly used.

3.) A secondary winding of a variac is connected in series with mains volage as in-phase or out-of-phase voltage.

4.) A Saturated-Core used partly in addition to main core in ferro-resonent transformers type AVRs. These are manufactured for specific freq 50 or 60 Hz, as the saturated core has the winding & a capacitor connected in series to make an ACCEPTOR-Circuit at 50 or 60 Hz

5.) Rotary-converter Field-exitation-controlled [of Alternator] AVR

6.) Rectifier-Inverter type

7.) Phase controlled regulators [like in dimmer-swithes]. Angle of conduction in primay is controlled by SCRs or Triacs

8.) PW [Pulse-width control] technology is used

There may be lot more ...

Reply to:

mikey Associate #6

******************* Quote ***************

I have a question - maybe you can help PW. Isn't the Automatic in Automatic Voltage Regulator redundant? Don't voltage regulators automatically regulate a variable incoming voltage and output a constant voltage by definition? Mike

******************* Quote Ends ***************

No sir. Automatic & Manual

"Automatic" means every-where "Work being done without manual intervention

"Manual" means continuous monitoring of process [work] & adjusting manually.

For your info all the devices like & controls have Manual & Automatic Correction/adjustments

like speed, voltage, Power, Volume [sound's], brightness, contrast [in TVs], Temperature, [in Airconditioners etc], Frequency [In radio, tv Communication] and a lot more processes.

Reply to: techno #7

****************** Quote ******************

An AVR Onboard ship depends on the design. Generally the system involves a motor control console that will control the

** speed of a motor (and generator) **

by measuring the current phase of the load and comparing it with the setting. As a load increases (thus lowering the voltage) the current phase will shift. By adjusting the speed (power) of the motor driving a generator, the load is compensated.

****************** Quote Ends ******************

Speed cotrol of motor driving a generator [Alternator] will vary the Frequency which is not desireable & tolerated in AC supply. This will surely have the "Fiel-Excitation-control" of Generator/Alternator if Supply is not DC. I know a little about ships Power system

Hajee,

Thanks for all the info. Being a ChemE, I have only been dipping into EE stuff for a short time - very interesting to me! I didn't realize the breadth of application for these devices. Again thanks!

Mike

Hajee,

One more thing. The LM7805 would be more accurately called an "Automatic Voltage Regulator" rather than just a "Voltage Regulator" (how it is described in the data sheet) right?

Mike

Yes but with a suffix of "IC" ie "Automatic Voltage Regulator IC" & not AVR is only for Devices [OEM ] Manufactured Equipment.

AVR also control the Reactive power sharing between the generators which are in synchronisation same as Governor controls the active power.Both power sharing is important if you have different rating generators are in sync.

If Generators are in individual mode It provides Output voltage control thru closed loop system by controlling the DC current supplied to Rotor of an alternator in proportion with Voltage output of an alternator.

Please See also [In English] :
http://cr4.globalspec.com/thread/7742/AVR-s
and

Automatic-voltage-Regulator-AVR
| Electrical Engineering | Automatic voltage Regulator (AVR)
http://cr4.globalspec.com/thread/14252/Automatic-voltage-Regulator-AVR?frmtrk=CR4digest5th comment ? ]