Flywheel bet: recip: compressor and coupling

That was what we were talking about before. One way to deal with torsional vibration is to add a flywheel, and most recip compressors have a fly wheel. In that case, the coupling often is attached to the flywheel.

You need a torsional analysis first, but the flywheel will probably be there...

Hi Cherry

This as follows without flywheel is direct drive, motor via coupling to crankshaft

With flywheel is belt drive

If this is a refrigeration compressor there are differnt benefits to each.

Direct drive gives longer shaft seal life, all motor torque is distributed equally across the seal face.

Belt drive eventually wear the seal on the leading side to the drive motor, however there is the benefit of being able to change the rotational spead mechanically by pulley change

Sorry to disagree, but there are plenty of direct drive compressors with flywheels. I think perhaps you are familiar with smaller machines, but in gas production application with power on the order of 2500 HP or greater, many if not most of the machines have a flywheel.

Dear All

I would like to change my question that I will use natural gas engine to drive the reciprocating compressor for offshore application. In that case, would it be coupling with flywheel or without flywheel. Till now, I am not able to find torsional vibration analysis reports for all of current projects and past projects at our engineering department(Projects). I am working at application department. Unfortunately, I am totally new at these area. However, I am able to size/select compressor and motor or gas engine and cooler after one year.

OEM (compressor ) said that torsional vibration analysis would be packager's responsibility.

Thanks for all of your supports and guidance.

Have a nice day.

Best regards,

Cherry

It depends on the engine and the compressor. The engine has a flywheel, and so the compressor probably does not need one... An electric motor driven compressor very likely will need a flywheel.

I looked back through some pictures I have of Cat engine driven Arial machines in gas production service and they did not have a flywheel on the compressor. As I said the engine always has one.