Instruction Manual IR30 BEARING MONITOR “Sentinel” Model
APDD 766A MARCH 2003
IR-30 SENTINEL
IR 30 Shock Pulse Instrument Manual Contents List Section
Title
1
IR 30 Sentinel Instrument Parts List
2
Shock Pulse Monitoring, A Snapshot
3
Data Acquisition with the IR30
4
When Is There A Problem?
5
Required Documentation for Airend Replacement
6
Measuring Points on Ingersoll-Rand Units
7
Data Acquisition on a Nirvana
8
dBi and dBm values for Ingersoll-Rand Units
9
SPM Logs
Confidentiality The contents of this publication may not be reproduced in any form without the permission of Ingersoll-Rand.
IR30 © 2003 Ingersoll-Rand Company Date of Issue: March 2003
IR-30 SENTINEL
IR 30 “SENTINEL” Shock Pulse Instrument
54636536 Kit Contains: Quantity
CCN
Part Name
1
54636519
IR 30 Sentinel Instrument
1
39262837
TRA 22 Probe
6
39262928
9022 Batteries (AA Size) ( Installed In Instrument )
1
54636527
Instruction Manual Package APDD 766A
1
CAS-09 Carrying Case
Possible Upgrades CCN
Part Name
39262845
TRA 31 Quick Connector (for stud mounted units)
38034872
Vibration attachment kit
38332284
IR30 Sentinel Upgrade to Logger (unit upgrade only, no additional attachments included)
42464602
Set of 50 Adapters and Caps to stud mount units
39262993
Chamfer Drill (to drill holes for studs)
IR30 © 2003 Ingersoll-Rand Company Date of Issue: March 2003 IR Confidential: The contents of this publication may not be reproduced, in any form, without the permission of Ingersoll-Rand.
IR-30 SENTINEL
SHOCK PULSE MONITORING, SPM INSTRUMENTS, IR-30 "A SNAPSHOT" Unless an individual is involved with some form of machinery vibration analysis, the term "Shock Pulse" (Monitoring) is unknown and somewhat foreign. Officially, and accurately, it is a technology relying on the physical principle that sound travels undiminished through metal objects for gr eat distances. The second principle involved is that of resonance. The measuring instrument is equipped with a 30,000 Hertz electrically tuned device, which resonates and records certain shock frequencies emitted by roller bearings.
This explanation, while accurate, loses most people, and leaves them cold.
A simpler, if somewhat inaccurate, illustration enables an easier visualization, and invites very good credibility.
Using a freight train as an example, visualize sitting at a rail crossing waiting for the train to pass. We've all done this at one time or another. As the train cars pass, you hear the usual sound of the wheels rolling against the steel tracks, and the normal "clickety-clack" as the wheels cross the rail joints. The sound varies, louder as the heavier cars pass, less intense as the empty cars pass. That is the usual sound, and can be called in Shock Pulse terminology as "Decibel Carpet". Floor, bottom, average sound of a freight train rolling by, if you will.
While the train is passing, a car, loaded with coal approaches. This particular car has a flat spot on one of its wheels. Rail car wheels get flat spots when the car is empty, has been sitting in the yard for a long time, and a brake shoe sticks to a wheel rim. The car is coupled to a train for use, and when it starts to move, the wheel can't turn because of the stuck brake shoe. Eventually, speed, vibration and sheer impact will tear the brake loose and the wheel begins turning. However, after being dragged for some distance on a steel rail unable to turn, the wheel now has a flat spot.
It is easy to imagine how this flat spot will sound as it hits the rail with each revolution. This sound, a repetitive "banging", heard well above the "Decibel Carpet", now becomes "Decibel Max", (maximum), the second term to be understood in Shock Pulse terminology. The third term is "Decibel Initial", and this is a factor, which can be likened to calibrating the listener's ear as the train passes. This "calibration" regulates the intensity with which ear perceives Decibel Max, and Decibel Carpet. These terms are abbreviated, "DBI", "DBM", and "DBC". IR30 – Snapshot © 2001 Ingersoll-Rand Company Date of Issue: January 2001
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IR Confidential: The contents of this publication may not be reproduced, in any form, without the permission of Ingersoll-Rand.
IR-30 SENTINEL
Applying the technology to steel roller bearings requires only reasonable access to the outside diameter of the monitored bearing through an uninterrupted metal path. Permanently attached metal studs are best for this purpose. A mechanical "clip-on" accelerometer is used to anchor to and read the acoustical signature from the bearing, through the housing to the studs.
A hand held, contact probe can also be used with good results. The Instrument, which reads the shock pulse DBM/DBC values and displays them as t wo numerical values is called the "I R-30". Any type of steel roller bearing can be monitored. The technology has no application to sleeve bearings. Data acquisition is a simple process. First, Decibel Initial value for the particular bearing(s) must be determined. For this, the inside diameter of the bearing must be known. Shaft diameter upon which the bearing is mounted is usually easiest to determine. Where two different diameter bearings are used on a shaft with near equal loads on both ends, an average of both diameters is used. Shaft rotative speed is also needed. Entering t hese figures into the IR-30 yields the Decibel Initial (DBI) value for those bearings.
The sites on the machine for bearing probe points are then determined. We try to use bearing housing flange edge surfaces, since these areas have ample depth, are free of air or oil passages, and provide a direct (if somewhat curving) solid metal path to the outer race of the subject bearing. Studs are fitted by drilling and t apping sites with M8 or 5/16" - 18P threads, 1/2" deep, with a 90 Degree entering chamfer.
Manual data acquisition consists of operating the machine in loaded and in unloaded condition, while measuring DBM/DBC values with the instrument. As each site value is determined, it can be electronically stored in the instrument for later downloading to a PC and printing. Electronic recording requires use of "CondMaster Pro" software provided by Ingersoll-Rand with purchase of the “Logger” (full package) instrument.
Manual recording of the data can also be done on paper logs, designed by the user to suit the purpose. Normally, data is taken monthly for the first three months of operation of a new machine, then quarterly. DBM/DBC values are indicators of bearing condition, and of bearing deterioration. As a general rule, DBM values, on new equipment of oil flood/ oil free compressors, will run in the 20 to 40 range. DBC, about half DBM. Data is reviewed, and DBM values which rise in the 45 range and above, particularly when unit is loaded, are to be noted. DBC will also rise, coming close to DBM. Two consecutive DBM readings at or above 55 in 700 hours signal need to consider bearing overhaul.
IR30 – Snapshot © 2001 Ingersoll-Rand Company Date of Issue: January 2001
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IR Confidential: The contents of this publication may not be reproduced, in any form, without the permission of Ingersoll-Rand.
IR-30 SENTINEL
Sudden changes are to be especially noted, and monitor fr equency "doubled up". A cracked or loosened inner race will result in such drastic changes, and must receive immediate attention.
Oil Free Compressors will display consistent DBM as 10, 15 points higher than DBC in normal running condition, loaded or unloaded.
Oil flooded single stage units seem t o display closer DBM/DBC points than oil free, and when running unloaded DBM/DBC will be equal to or higher than loaded. When gas load is relieved, rotors seem to become more unstable and "rattle around" in the bearing clearances more.
Oil flooded two stage units display DBM/DBC loaded points consistent with single stage and oil free machines. However, unloaded DBM/DBC seem t o run at or considerably higher than loaded figures. Therefore, on oil flooded units, loaded DBM/DBC figures are to be considered dominant decision points. Drive motor bearings behave in similar manner.
Two stage units have four bearing points per casing. The shock pulse emission from the four points radiates and overlaps as it is read from the casing flanges. However, trending, and observing loaded DBM/DBC using these guidelines should yield accurate indications of repair requirements.
IR30 – Snapshot © 2001 Ingersoll-Rand Company Date of Issue: January 2001
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IR Confidential: The contents of this publication may not be reproduced, in any form, without the permission of Ingersoll-Rand.
IR-30 SENTINEL
Key Path
Display 16x Characters
Instrument Type Light Sensor Measuring Key
Set Key
Select Key
Left/Right Arrow Keys Up/Down Arrow Keys
Input Connector SPM Input Connector Software + Input Connector Vibration
IR30 – Data Acquisition © 2001 Ingersoll-Rand Company Date of Issue: August 2001
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IR Confidential: The contents of this publication may not be reproduced, in any form, without the permission of Ingersoll-Rand.
IR-30 SENTINEL
Instrument Type IR30 Sentinel Measuring Key Function key used to record IR30 measurements Set Key Function key used to set in menu options Left/Right Arrow Keys Keys used to scroll around menu options Input Connector SPM Connection point for SPM instruments. Input Connector Software Data communication to to interface to PC (if applicable) Display 16x Characters Text Menu (Available in muli-languages) Light Sensor Sensor to detect light level and automatically switches on
background light if selected. Select Key Function key used to enter fields from menu Up/Down Arrow Keys Keys used to change options highlighted and move up and downloaded rounds. Input Connector Vibration Connection point for Vibration instrument .
IR30 – Data Acquisition © 2001 Ingersoll-Rand Company Date of Issue: August 2001
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IR Confidential: The contents of this publication may not be reproduced, in any form, without the permission of Ingersoll-Rand.
IR-30 SENTINEL
DATA ACQUISITION, I-R 30 “SENTINEL” INSTRUMENT Step1: Press “M” on instrument keypad, Screen should show “SPM”; dbm, dbc lower left, and dbi lower right. If screen does not show “SPM” press the Left or Right Arrow until it does. Press “SET”, Screen will appear; see “Bearing Data” “TLT’ (Transducer Line Test) Off or On. Using the Up or Down Arrows, Set to “On”. After a reading has been taken, TLT values above 15 will indicate no signal loss between the instrument and the transducer.
Bearing data TLT on …. rpm …. dmm dBi 26
If BDI is known for a particular reading point (see dbi tables), press “SET” until the cursor is at dbi ____. Using the Up or Down Arrow adjust field to register desired dbi value. Press “Ent", see return to SPM screen. You are now ready to take data, using the hand held probe. (Go to step 2) If dbi is unknown, then: Press “Set”, see _____rpm. Using the Left or Right Arrow, traverse blank fields to desired point. Using the Up or Down Arrow, with Left or Right Arrow, adjust field to register desired shaft speed. Press “Set”, see _____dmm or inch. This is shaft diameter. Using the Up or Down Arrow, with the Left or Right Arrow, adjust field to register desired shaft diameter. Press “Set”, see dbi ____ which is decibel initial. This is the calculated dbi value for this shaft size and bearing speed. If shaft size, speed and dbi are unknown, use an arbitrary 25 dbi for any oil flooded single or two stage compressor. Use an arbitrary 35 dbi for any oil free “Sierra” single or two stage compressor. Once initial dbi is selected for subject compressor, do not use any other dbi value on subsequent readings for subject compressor. Press Ent, see return to SPM screen. You are now ready to take data, using the hand held probe. Step 2: Attach the hand held probe to the left threaded “SPM” connector on the instrument. Determine the probe contact point on your subject machine. See attached Photos for general reference. Contact point should leave the probe “pointing” at the outside diameter of the bearing within the housing. The acoustical path for the shock signal from the bearing should be as short and direct as possible, with no bolted joints in this path. Bearing housing flange edges make good locations. Take one set of data loaded, a second set unloaded. dbm is Decibel Maximum, dbc is Decibel Carpet.
SPM TLT 18 dBm 16 dBc 8
dBi 25
With unit running, dbi set in the instrument and SPM Menu on instrument screen, press spring loaded probe tip to the designated area in the loaded zone of the bearing housing. Holding the tip compressed to the length of the rubber grommet, press “M” on the keypad and hold for about 1 second. Release “M”, continue to hold the probe tip in place, approximately 5 seconds, or until dbm and dbc values appear. Refer to “Snapshot” for further explanations, and upper limit points for Maximum and Carpet values recorded. Record data on a log sheet, with any other physical data from the compressor or motor you deem pertinent. IR30 – Data Acquisition © 2001 Ingersoll-Rand Company Date of Issue: August 2001
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IR Confidential: The contents of this publication may not be reproduced, in any form, without the permission of Ingersoll-Rand.
When Is There a Problem? What are Good Bearings?
*
•
Typical dBm less than 40
•
Note levels higher than 45 dBm
•
One reading greater than 55 dBm* , retest un it withi n 500- 700 hour s
•
Two readings hi gher than than 55 dBm* withi n 700 hour s signal s a need for ser vice or replacement.
* Refer to dBi data pages in Section 8 for specific dBm limits
What are Damaged Bearings? •
L arge dif ference between dBm and dBc. This difference
will also increase over time. •
If a damaged motor bearing is greased, the dBm wil l decrease, but r ise again qui ckl y.
What are Dry Running Bearings? •
L ittl e diff er ence between dBm and dBc.
•
When the bearing is greased, these values wi ll drop and r emain l ow. From reading to reading, dBm and dBc will increase and decrease. However, the distance between them will stay relatively the same. When the dBm and dBc start getting further apart or closer together, scheduling of future replacement or rebuild should be considered.
IR Confidential: The contents of this publication may not be reproduced, in any form, without the permission of Ingersoll-Rand.
Required Documentation, Oil Flood / Oil Free Air End Replacement Occasionally, it becomes necessary to replace a Rotary Screw Compressor Air End in a machine that is still in use. This may be caused by High Shock Pulse Data, Mechanical Vibration, (movement), or High Operating Noise Level, or a combination of the above. The following information is required when an air end is removed from a compressor, and the compressor is still operational, and the air end is subject for warranty. Include this report with the Air End Return. Compressor Model_____________
Compressor Serial #______________
Air End Size___________________
Air End Serial #__________________
Hours in Service_______________
Air End Turns ?
Yes___ No___
Shock Pulse Data: MR 1 _____ MR 2 _____ MR 1 _____ MR 2 _____
DBI _____ DBM _____ DBC _____ DBI _____ DBM _____ DBC _____ DBI _____ DBM _____ DBC _____ DBI _____ DBM _____ DBC _____
Loaded Loaded Unloaded (Single Stage Only) Unloaded (Single Stage Only)
Second Stage MR 1 _____ DBI____ DBM____ DBC_____ Loaded Second Stage MR 2 _____ DBI____ DBM____ DBC_____ Loaded (If air end is two stage, take both first and second stage male rotor only. Do not include unloaded 2 Stage.) Vibration Data:
MM/Sec.
Vertical, Loaded____ Unloaded____ Horizontal, Loaded____ Unloaded____ Axial, Loaded____ Unloaded____ Sound Level: Describe____________________________________________
A Copy Of the Oil Analysis Report Must Be Attached to this Form. If a decision to replace the air end is made, please indicate the individual at Davidson Technical Service with whom the decision was discussed. Name_______________________ Date__________________ Your Signature___________________ Organization_____________________ Today’s Date_____________________
Pjm/03/24/03 RequiredAirEnd/pjm/03/24/2003
IR Confidential: The contents of this publication may not be reproduced, in any form, without the permission of Ingersoll-Rand.
