I need to reduce the noise level in a parallel shaft speed multiplier

I NEED TO REDUCE THE NOISE IN A PARALLEL SHAFT SPEED MULTIPLIER ACOPPLED BETWEEN A 700 HP ELECTRIC MOTOR AND A SCREW REFRIGERATION COMPRESSOR, IF SOME BODY KNOWS HOW IS THE NORMAL PARAMETER OF NOISE IN THIS EQUIPMENT LET ME KNOW?, AND WHAT CAN BE THE CAUSE OF THIS LEVEL OF NOISE (102 dB)

 

[ronfrend]

Alex,
I can't help you too much with the "normal" level of noise from a unit like this but I can tell you that the noise is created (usually) by the meshing of the gears. At any event the value of gear mesh vibration should be no more than 1mm/s RMS (approx) and there should be minimal harmonics. If you are getting higher levels than that you have a mechanical problem.

One consultancy job I had was to reduce noise in an automotive gearbox. The cause of the vibration was poor surface finish on the gears causing metal-to-metal contact during meshing. The cure was to fine grind one of the gears to allow the luboil to keep the gears separated during meshing. Obviously you can't achieve that, but what you should be able to do is critically look at the qualities of the luboil you are using. Get your luboil supplier talking to the gearbox manufacturer and get them to sort out a good quality oil that will still offer protection at the temperatures and loads that are expected.

Good luck

Ron Frend

 

[Mpino]

Really the noise is too high, but, first, you have to know the noise character to can know what machine or element is causing it. Maybe the noise is generated by the motor, or compresor or a misalignement between both of them that cause a overload and noise.
The first step to attack noise is know the character, (spectrum) and if there are vibrations in the shaft, that can generate noise too.