Oil Pressure

[CHIEF DELPAC]

The MYCOM screw compressors that are in my engine rooms on start up have a delay to allow oil pressure to build up before the compressor starts. However on shut down the oil pump stop as soon as the power to the compressor is shut off. Is there any benefit to changing the oil pump control to allow the oil pumps to run until the compressor stops turning? I am wondering if the lack of oil pressure and flow could accelerate bearing wear. C.D.

[Grizzly]

Chief Delpac.
I suspect some of your countrymen who are quite conversant with Mycoms, will probably be able to advise better than me.
Not naming any for fear of offending the others that i cannot remember.
Anyway unless I am way off the mark.
Most screws rely on the oil being pushed through them using discharge pressure.
So the pump is really only to assist with flow and ensure lubrication of the bearings and lobes upon start up.
With this principle sufficient oil pressure is maintained even as the pump is turned off and the screw ramps down.
I am not sure of the Mycom system but if it behaves like most.
You will see the slide valve returning to-wards resting position. Which is in itself proof of the remaining oil pressure / Discharge Pressure
after shut down is initiated.
I may be totally wrong as i say because I don't know Mycoms. But it is relevant to other systems!
Grizzly
(this week I Be Drinking.... Exmoor Gold!!!)

[josef]

Grizzly Yes, you are right and Mycom employs a discharge pressure, Mycom has some compressors without oil pump

[PaulZ]

Hi Chief Delpac
I would agree with Grizzly.
If your Mycom has an oil pump it should be set up to run on after a loss of compressor call until the compressor has reached minimum load and can stop when the compressor stops. There is still plenty of oil in the bearings and on the rotors so no damage would be done.
When the compressor turns off it would only be turning for a few seconds plus it is not under load as it is fully unloaded.

Paul