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4 comments
Participant

Join Date: Nov 2006
Posts: 2

How to make a trouble free AVR for Generator

12/27/2006 12:17 PM

Please Help me.

I have 3.phase AC Generator which have the following specification.

Voltage 440. volts ac

Power 4000 Kva

Cos phy .75

This generator was purchased from Reliance company from Germany in 1990. Up-to date it was working satisfactorly.To day i find some problems that as load is increasing hunting have ben seen in the voltage .I try my best to occupie this problem by vary the ncessory potentiometers but cant succed.I try to contact the supplier in Germany but not find them.AVR is built-in PID function . It had 3 phase winding at the pilot generator which have the 180 volts ac as a power supply to AVR then the output from avr is 30 volts dc at 10 ampare going to excite the main exciter which have the output ac and is converted into dc by rotating rectifiers. this dc is going to excite generator fields.Please i request all the experts to help me to solve above mentioned problem .

THANKS

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Participant

Join Date: Dec 2006
Posts: 3
#1

Re: How to make a trouble free AVR for Generator

12/28/2006 4:32 AM

Hello,

Before you start modifying to use different AVRs you will need to do a little research into it. A common AVR such as the LS r448 can run around $4000.00usd.

There are three main manufactures of alternators: Leroy Somer, Stamford, and Newage. There are more but it is fairly easy to research them. Go to their web sites and you will find more than you will ever need on AVRs in the down load sections.

Have with you as much information as possible on the alt while looking it up. Mfr, Mod, Kva, Kw, Type….i.e.…Shunt, PMG, AREP…

Use the contact section of the Mfr site. It can save you both frustration and money.

I hope this helps, I was looking up a problem myself when I came across yours.

Have a good one!

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Participant

Join Date: Dec 2006
Posts: 3
#2
In reply to #1

Re: How to make a trouble free AVR for Generator

12/28/2006 8:24 AM

Hello again,

I just passed through again and reread the post.

It is very probable that it is problem totally unrelated to the AVR.

I'll start with it is an older unit and some questions need to be asked. How much is it run? What kind of load? Wet stack? Quality of fuel?

Two units this past week I inspected with the exact problem, one was a 1.4meg and it just needed new fuel filters. The other unit was a small 400kw with a worn mechanical governor. In both cases I was called out for control problems but it was fuel related. If the motor starts to hunt a little even only +/- 1hz (can be caused by a bad bat alt or grnd in an electronic gov sys) The AVR tries to keep up with the surging magnetic field in the Alternator and can produce 10-20vac swings from nominal set point. I have also been out to generators that were not producing anything. The customer said he needed an AVR. It took 3 weeks for us to get it and it was not the problem. The Hz meter was reading correct on the unit but when I installed my instruments It was running 4hz below rated. I replaced the fuel filter and recalibrated the meter and was on my way. I saved him $3500 and now have a new part in stock.

I guess what I am saying is look for the simple and not so obvious things first.

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Participant

Join Date: Jan 2007
Posts: 1
#3

Re: How to make a trouble free AVR for Generator

01/21/2007 8:40 AM

Assalam O Alikum Mr. Abdul Shakoor

I am located in Pakistan & develop Digital AVRs and speed control units for Diesel Engines. I have a battery operated AVR that will solve your problem.

If you have a digital multimeter test the resistance of Main Excitation Winding and send me a message. This will help me assess how much current this winding requires.

Our AVR is highly adabtable and i am confident it will resolve your problem.

I am not sure this site allows to insert an email or not so i will not mention my email

right now.

Regrds,

Avais Ahmad Qureshi

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Engineering Fields - Electrical Engineering - New Member Engineering Fields - Mechanical Engineering - New Member

Join Date: Jan 2011
Location: Jakarta
Posts: 160
#4

Re: How to make a trouble free AVR for Generator

01/26/2012 1:45 AM

Does the set run in parallel ?

What type of load ?

How is the frequency when the volt unstable ?

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