Diesel Generators

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utility Participant Join Date: Aug 2011 Posts: 1	Diesel Generators 08/09/2011 12:06 AM
	One of our 320 KVA Greaves Dg set is having hunting & high vibration problem.The Engine starts hunting after aload of 170 amp. Before that the engine (on load & off Load ) is working all right. This problem is some times not seen even at a load of 300 amps. We have got our fuel system checked thoroughly by recalibrating the FIP & Injectors,Cleaned the tank & replaced the suppply pipes. Even than the engine is having the problem. We also changed the AVR but the problem persists. The engine has amechanical governor. Please help.
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coolyaar Power-User Join Date: Jul 2011 Posts: 286 Good Answers: 1	#1 Re: Diesel Generators 08/09/2011 8:32 AM
	r u operating the genset in isolated mode( i.e. not in prallel with mains or other genset ) or in prallel mode. if you are operating it in parallel mode then set your settings as follow : AVR droop settings = 2% and speed droop /governor droop settings = 3% to 5% (recommended value is 4% speed droop ), if you are operating it in isolated mode then just set speed droop to 0% . start your genset and run it in test mode i.e. with no load for about 3 minutes .then put a load on the genset and change carefully the settings of governor for speed droop between 3% to 5% unless you get a stable genset operation without hunting. disclaimer : kindly do these settings by a genset expert.governor is very sensitive equipment and need very careful handling during settings modification. also sever hunting may occur during the droop setting change before getting a stable operation.so take care of these factors.
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Darrinstntn Member Join Date: Aug 2011 Posts: 7 Good Answers: 2	#2 Re: Diesel Generators 08/09/2011 11:41 PM
	Every hunting problem I have had with deisel and petrol engines has turned out to be air starvation. Changing the air cleaner always cured the problem. You no doubt have checked this but you didn't mention it so I did.
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brich Guru Join Date: Oct 2009 Location: sometimes Wales,UK.. was Libya, now Oman! Posts: 1715 Good Answers: 117	#4 In reply to #2 Re: Diesel Generators 08/10/2011 3:48 AM
	GA.. Yes that happens.. check your air intake, if you haven't already. Another thing to check is the exhaust.... any changes to it recently? __________________ The square root of nothing is what you make it!
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cwarner7_11 Guru Join Date: Dec 2006 Location: Panama Posts: 4273 Good Answers: 213	#3 Re: Diesel Generators 08/09/2011 11:48 PM
	You do not tell us enough about your gen set for a real analysis. 1. What voltage are you operating at? 2. Is the load balanced across all three phases? 3. What power factor is the generator seeing? 4. Have you tested the insulation resistance of the windings lately? Mechanical governors do wear out, and if this happens at a lower load range, then settles down as the load increases, this could indicate that the governor needs rebuilding...
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roy hammy Guru Join Date: Jun 2009 Location: Ontario Canada Posts: 930 Good Answers: 31	#5 Re: Diesel Generators 08/10/2011 8:09 AM
	After reading the comments and they are all good may I suggest that you observe the governor if possible, some have external lever to operate the rack. If it is moving back and forth it may indicate a governor issue. I have had governors that were the problem due to worn or contaminated bearings as well as the centrifugal mechanism binding due to wear. If the power output is within specs and balanced then a safe bet is to have the governor inspected. __________________ The fine line between cuddling and holding one down to prevent escape must be learned
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Gazu Power-User Join Date: Dec 2010 Posts: 166 Good Answers: 4	#6 Re: Diesel Generators 08/10/2011 2:45 PM
	On first glance, the problem appears it be load related. I'd begin with a thorough search for loose/dirty connections.
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sblandes2010 Active Contributor Join Date: Sep 2010 Posts: 22	#7 Re: Diesel Generators 08/14/2011 6:53 AM
	Have you got operation manual,if yes check trouble shooting column.Is it marine or industrial engine?Apart from mechanical governor some diesel engine has fuel line filters/strainers situated in suction line leading to fuel injection pump,clean/change them.
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