High vibration of diesel engine

Dear all,

I have an issue with a diesel engine. The vibration at all positions, all directions is very high, 14-22mm/s. The speed is 2100 rpm (the speed on the images is wrong). You can see there is harmonic of 17.5Hz (half of rpm). I don't have much experience on this case. Please give me some advices and your experience.

Thank you!

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Original Post

In a 4-stroke engine half orders are present but they won't generally be found in a 2-stroke engines.

Have you compared the levels to the applicable ISO specification?  How about the details of the engine, inline or v-type, number of cylinders, power, etc.  What else is in the machine train?  Gearbox, what is driven machine, types of couplings?

 

John from PA posted:

In a 4-stroke engine half orders are present but they won't generally be found in a 2-stroke engines.

Have you compared the levels to the applicable ISO specification?  How about the details of the engine, inline or v-type, number of cylinders, power, etc.  What else is in the machine train?  Gearbox, what is driven machine, types of couplings?

 

Dear John,

I don't have information about this machine. My friend from the plant sent the spectrum to me and he doesn't have too. I think is 4-stroke because of the present of half orders.

Ask your Friend for the following:

Horsepower (hp or KW)
Rpm (and fixed or variable)
# Cylinders
2 or 4 cycle
Driven load
Shaft coupling type
Foundation Type and Details
Measurement Points (on shaft elevation or higher on engine block or accessory housing)
Photos or machine arrangement

The spectra should be restricted to 500-Hz or less to see the important part (low frequencies) of the spectrum.

Walt

Great Answers from Mr. John PA & Walt Strong highly appreciated.

As a marine engineer working with Condition monitoring technologies, with part information it will be difficult to make out the real problem.

For Diesel Engines, Classification societies for marine industry referred to 18.0 mm/s and 1x above 7 .0 mm/s then trouble to be investigated.

Power balance is the most important one to cause the high vibrations. 

If e get the correct values of the vibration, spectrum and coupled machine with the engine like alternator, Compressor, Gear box and pump etc., to address the problems.

regards

chary

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