Oil with higher viscosity

Hi StressLess

Now that question is too hard in it's present form
we need application, RPM, lube system, pumped not pumped, filtered, rpm and KW/hp pop that info up on the board and you'll get some good advice.

regards


Rob S

Good point rttech, would this happen to be a lube oil system for a power gen turbine?

Ok.

The equipment is centrifugal overhung compressor. This compressor is driven by a 320 KW motor through a gearbox. There's a lube system which pumps oil to the compressor and the gearbox. The lube system has filters and cooler.

P.S. compressor speed is 5813 RPM

StressLess, when you refer to the viscosity grades, do you mean ISO 150 & ISO 220? (SUS is mostly used for base oils these days.)

A general rule of thumb is that you can usually go up or down one ISO grade without cratering a unit. But you should have a reason. Are you seeing excesive wear, indicating inadequate film strength, even though you're running at the recommended temp? Then going up one grade may be a legitimate approach.

But, going up a grade will increase internal friction, making the motor work harder and increasing oil temperature. (You'll need to crank the cooler a little harder.)

There's no free lunch in this world.

Also, compressors can be tricky. Sometimes they like to foam for no apparent reason, other times they like to make varnish. If everything is running well, I'd take the "if it ain't broke, don't fix it" approach.

Now, if it's 10 PM on the B-shift and the level is low and all you have is the ISO 220 grade OF THE EXACT SAME OIL THAT IS ALREADY IN THERE, I'd say you're safer running with a full reservoir of a slightly higher viscosity than running low with the right stuff.

quote:

What do you think might happen ?

What do you think might happen ?

as others have siad and IMHO not much will happen.
bruce

Dear StressLess

The delivery of the lubricant will be by a pump ( Gear pump in this instance). The pump will be rated to deliver a flow rate decided by the OEM. A substantially higher, viscosity will mean a lower flowrate. Thus less lubricant will be in circulation or athe site of lubrication.

Secondly, the higher the viscosity the lesser the heat dissipation, thus the fluid capacity in circulation can be increased or additional cooling imparted.

In short, heat related issues will arise more than anything else.

Hussam