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hauguelpa
Active Contributor

Join Date: Jan 2012
Posts: 24

Other Problem Generators 200kW Voltage Unstable

06/06/2012 1:21 AM

hello,

I have another kind of problem on the starboard diesel generator of my high speed ferry.

diesel generator 200kW:

-engine is caterpillar C9

-alternator is leroy somer LSA M 46.2L9 C6/4, 400V, 3P, 50Hz, 1500rpm, regul R448 AREP

two problems:

-sometimes (but not so ofen than on portside), engine is running, speed is OK but we have no voltage.

-3 months ago voltage starts to be very unstable and finally increased a lot (400V to 475V), we have changed the AVR and every things seems to be ok. But now, we have the same problem every 100h running. Each time we change the AVR, voltage is stable during 100h and then again...

All the broken AVR have the same problem: evidence of overheating of the two resistances close to P1. Leroy somer told us that these resistancesare for "parallel operation of diesel generators" but we NEVER run disel genrators in parallel.

what we did:

-changed the diodes , no change

-took mesurement of the resistances of the windings, nothing strange

We already saw 3 technicians for this problem but they have no idea...

do you have any idea? do you know any test we can do to find the problem?

thanks for helping

pa
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SolarEagle
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Join Date: Mar 2007
Location: at the beach in Florida
Posts: 5489
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#1

Re: other problem generators 200kW voltage unstable

06/06/2012 1:33 AM

You might try a higher temp class rating AVR...

http://www.baspower.com/uploads/products/LeroySomer/LSA%20series.pdf

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harry potter
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Join Date: Nov 2008
Location: India
Posts: 334
Good Answers: 6
#2

Re: other problem generators 200kW voltage unstable

06/06/2012 6:29 AM

Dear,

The problem seems to be with insulation of the excitor winding.

Since, you have mentioned this is a problem occurring after fixed time of Hrs. operation,, seems to be related to thermal. That seems to be with the insulation quality of excitation winding. that is getting on the point of break down, but not totally failed. with this, resistance of AVR may be getting hot.

Un stable voltage & some times zero voltage all tending to the same indication.

Why don't you just Over haul the alternator winding - revarnishing the winding, drying, etc... Just check the hot spots on winding, if any ....

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Bibo92004
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Join Date: Jul 2011
Posts: 29
Good Answers: 2
#3

Re: Other Problem Generators 200kW Voltage Unstable

06/06/2012 7:48 AM

I agree with harry potter.. I would advice you to check the insulation of your generator's field winding and inspect the rotor. A major overhauling could be your solution. I am afraid that what may caused your AVR to overheat is some current leakages in your excitation system.
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arifkunnath
Commentator

Join Date: Oct 2011
Posts: 96
#4

Re: Other Problem Generators 200kW Voltage Unstable

06/06/2012 8:08 AM

This type of problems happens when you run diesel generators for long hours continuously . That too at full load.

Is this ferry operates 100hr continuously ?
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SimpleMind
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Join Date: Sep 2009
Posts: 631
Good Answers: 52
#5

Re: Other Problem Generators 200kW Voltage Unstable

06/06/2012 8:18 AM

I am convinced that the two problems you encounter on this gen are absolutely related, and the problem is most likely on connections or adjustments. Verify from scratch that ALL connections are according to manual especially the ST5 LAM (load acceptance) function or possible reversed connection on S1,S2 (if used for current sensing). With decent troubleshooting on the starting problem, it CAN be diagnosed, but I am sure you are not the only one that has to deal with a less competent technician (that also possibly sells AVR's.) S.M.

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hauguelpa
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Join Date: Jan 2012
Posts: 24
#6

Re: Other Problem Generators 200kW Voltage Unstable

06/06/2012 4:35 PM

sorry, it was not clear in my first message.

It is not 100hours running continously.

It is 100h but running 12 hours and stopped 12hours etc....

thanks a lot for your help it is very helpful

pa
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hauguelpa
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Posts: 24
#7

Re: Other Problem Generators 200kW Voltage Unstable

06/07/2012 9:45 PM

no more ideas?
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PWSlack
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United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing. Kettle's on.
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#8
In reply to #7

Re: Other Problem Generators 200kW Voltage Unstable

06/11/2012 3:48 AM

What was the outcome of the telephone call to the original equipment manufacturer's technical helpline?

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arifkunnath (1); Bibo92004 (1); harry potter (1); hauguelpa (2); PWSlack (1); SimpleMind (1); SolarEagle (1)

Previous in Forum: Generators 200kW No Voltage   Next in Forum: Regarding Fittings Used For The ADSS.


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