Reply
Visitor

Re: 3508 Gen - 24V DC Power Supply -Activate Alarm -”Low insulation ”, when power load exceed 450-50

Hello all ,
I have replaced faulty injector . Engine operation is back to normal .
Thank you for your suggestions

Visitor

Re: 3508 Gen - 24V DC Power Supply -Activate Alarm -”Low insulation ”, when power load exceed 450-50

There is no alternator for charging batteries .

Power supply 24V DC set up as following :

Battery pack 4 x 200Ah - automatic charger .

I have monitor the voltage for some time :

min Volt during operation 24.5 V DC

max Volt 25.5

Thank you

Visitor

Re: 3508 Gen - 24V DC Power Supply -Activate Alarm -”Low insulation ”, when power load exceed 450-50

Many thanks for your input .

The earth fault was found in the negative line.

We have just  located  the low insulation in the injector solenoid  unit No 3   ; 4 K ohm to the ground .

Is strange that engine was still running ok at 65% power factor

 

Will revert with the outcome after replace faulty injector

Trusted Contributor

Re: 3508 Gen - 24V DC Power Supply -Activate Alarm -”Low insulation ”, when power load exceed 450-50

Is the low isulation ( earth fault) in the positive or negative?

Have you tried switching the exhaust gas temperature sensors with the other engine to see if the fault goes to the other?

I had a few times Isolation faults in them, they where mostly in the minus.

only happened when the sensor was hot.

Contributor

Re: 3508 Gen - 24V DC Power Supply -Activate Alarm -”Low insulation ”, when power load exceed 450-50

THERE CAN BE CHARGING ALTERNATOR WHICHDROPS CHARGING VOLTAGE BELOW 17VOLS OR REACHES ABOVE 28.5 VOLTS BY WHICH THE ECM WILLSHUT DOWN ENGINE OR DISABLE POWER SUPLLY BUTEVEN IF ONE OF YOUR BATTERY IS WEAK IT WILL GIVE U THIS SITUATION 

Highlighted
Visitor
Accepted Solution

3508 Gen - 24V DC Power Supply -Activate Alarm -”Low insulation ”, when power load exceed 450-500KW

Good day all ,

I appreciate if we can get any assistance to identify the cause of our problem.

 

3508 Diesel Generator – Engine running in normal condition , no active codes , events or alarms .
But , if the Power increase over 450-500KW , will be activated an alarm for Electric low insulation in the -24V DC Power Supply distribution board. Over 500KW Engine continue to run -no other problems observed
Once the Power drops below 450 KW , the low insulation alarm will clear again .
Please note that the Engine monitoring sys does not activate or log any diagnostic code .

 

The actual set up of Power Supply 24V DC sys ,  consist of two separate sources: – Charger –Batteries –Distribution board .Each distribution board is equipped with a Low insulation monitoring relay .
The alarm get activated in both distribution boards

Generators-onboard Vessel set up as following : 3 x DG , all same type .
All 3 DG supply with 24V provided from the same distribution boards .
Only DG No. 1 activate this alarm


My question is what component is affected by power increase ,in order to reduce insulation in 24V DC

 

Diesel Generator
Model :3508
Serial :2SB00171
Arrangement :232-2466

Thank you in advance