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Walt Strong

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A 14000 HP feed water pump train was installed 7-years ago. The train consists of:
Booster Pump (1-stage, 1800 rpm, 1500-HP, ball bearings)
Induction Motor (1800 rpm, 14000-HP, journal bearings)
Gear-Fluid Drive (1800 rpm to 5400 rpm variable journal bearings)
HP-BFP (multi-stage, 5400 rpm variable journal bearings)

The Booster Pump has two Velomitors on bearing housings and all other bearings have Proximitors

Alert Time Delay: 3-sec

Danger Time Delay: 1000-msec = 1-sec
For ALL channels and for both case velocity (Peak) and displacement (P-P)
Ratio of Danger/Alert is 1.2 for Velocity
Ratio of Danger/Alert is 1.2 to 2.0 for Displacement

What is a good scheme for picking Time Delays and Alert-Danger Levels?

Walt


Shurafa

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Posts: 310
Reply with quote  #2 
Quote:
Originally Posted by Walt Strong
What is a good scheme for picking Time Delays and Alert-Danger Levels?

Walt




In the facility I work at, the classic delay is just like what you mentioned:

Alarm : 3 seconds
Trip: 1 second

Lately, there are changes that might be generalized to set Trip to 3 seconds though I do not agree on this default setting.

Regards- Ali M. Al-Shurafa
Walt Strong

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Posts: 889
Reply with quote  #3 
I thought John-PA would chime in. I am now working with two GE-Bently guys and to see if they can offer sound recommendations. The default values for proximity probes is not good for velocity on bearing housing.

Walt
John from PA

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Reply with quote  #4 
Quote:
Originally Posted by Walt Strong
I thought John-PA would chime in. I am now working with two GE-Bently guys and to see if they can offer sound recommendations. The default values for proximity probes is not good for velocity on bearing housing.

Walt


My general recommendation, which does not differ from when I was with BN/GE, is to go back to the OEM for their recommendations.  

Now, you might ask "why"; well as an example we had someone not too long ago asking about a gas turbine with rolling element bearings.  Had someone responded just based on that information, the alarms, limits, etc. would have been in error.  The simple matter was that after some effort the exact model of the GT was mentioned, and it was equipped with fluid film bearings!  The OEM in general is the best source of information.
Shurafa

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Posts: 310
Reply with quote  #5 
Do you regularly see time delay suggested sittings provided by rotating equipment OEM?

I cannot recall seeing this information in the manuals I read from many OEMs. Maybe this kind of information can be received based on a one-to-one communication (e.g. email).

But again my experience is small and I could be totally wrong.

Regards- Ali M. Al-Shurafa
John from PA

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Posts: 963
Reply with quote  #6 
Quote:
Originally Posted by Walt Strong


Alert Time Delay: 3-sec

Danger Time Delay: 1000-msec = 1-sec
For ALL channels and for both case velocity (Peak) and displacement (P-P)
Ratio of Danger/Alert is 1.2 for Velocity
Ratio of Danger/Alert is 1.2 to 2.0 for Displacement

What is a good scheme for picking Time Delays and Alert-Danger Levels?

Walt



At least with respect to the time delay, the values seem to be in line with the default values for a 42M monitor.  The ratio of danger/alert deviates from the default values but may be in line with the desires of an OEM or end user.

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