AVRs and Parallel Generators

I would first check the load for integrity- assume batteries- well known that s/c/ faulty batts can burn out alts/gens/avr,s. Other thing is synchro of parallel alt systems- critical.

Both generators had problems even they are sorted out.

The best way of inspection is to run each generator individually up to the full load for few hours.

If they are working without problem when not paralleled, then the decision is there is problem when paralleling. Coinsiding to counter phases during paralleling is generaly the main enemy of the AVR's and exciter windings.

One another main reason may be the engine failure, after paralleling, and in the position of the alternators are electromechanically interlocked (Clutched). If one engine goes out of control due mechanic reasons, the power, of which trying to interlock the alternators gets bigger and bigger to damage it's excitation system, as well as the AVR

Most of the alternators are equipped with balancing windings for a precaution in parallelling anomalies.

Kindest Regards

nezihozfirat; if they are paralleled, and for some reason one engine lacks fuel, the remain generator will continue to drive the fuel less generator as a motor, perry

hello there,

i will like to comment that

1)you have to check your Generators (All Testings) and for that you can search by the name of "motor winding status" forum applied before...

2)Your have to also check Your' site's AVRz

for testing of AVRs i did not find any refrence but you can google that and find it easily.

moreover, i will be in touch with the forum's notes and details if somthing come first in time

you can contact me at

moeezikram@aol.com...(Possibly reply in 24 Hrs from posting the mail)

also if you cannot find it (The mentioned forum) i can e-mail a .pdf file containing the details for testing the field and the stator for your generators...

Thanks

basically the AVR is also to be tested...

Check linearility according to the Variable input...

moreover check the input voltage keeps steady for the output at the minimum level...

Gentlemen,

thank you for your time and comments.

I have managed to locate some local experts who will replace AVRs and at the sametime investigate the cause at site.

Once truth is out, i shall post the results,..

AS PER INCIDENTAL DATA,

A single generator was on load.

A newly repaired/ rewound alternator was to be commissioned.It was started and while attempting paralleling, the AVR blew.They removed an AVR from the 3rd generator panel and fitted it in place of this one, its fuse blew...implying that there was either 1) over current drawn for excitation 2) AVR had malfunctioned and unable to handle normal excitation current.

A RESIDUAL Voltage test showed , 10 volts across each phase equally.

With an excitation voltage of 12 V dc through a battery , the alternator built 62-66 V across each phase. and with 24 V excitation, built 120 V.

It appears therefore that the alternator is healthy and no error in rewinding???

( meanwhile, I apologise for stating in the first post that both WERE running parallel, incident occured while ATTEMPTING paralleling )