Greetings! We have been asked to help with the overhaul planning of an Ingersoll Rand gas compressor built in 1963. There are two problems with it. First, the maintenance staff doesn't have any documents about it. No O&M manual, no parts list, no drawings. Second, the brand representatives in our country (Colombia) neither have information about it. The only person who have intervened the compressor is an old mechanic that worked with that kind of machines thirty years ago, but again,...
Vibration was observed in a recently overhauled centrifugal pump in 5X at pump NDE and DE V.FFT is attached There is no chance of vane pass effect since the pump was overhauled recently and no damages where observed.
The pump was overhauled as a part of routine maintenance ,there was no indication of vibration prior to overhauling. LPT was carried out on impeller during overhauling and no damages where observed also when we calibrated the rotor for balancing we found that it was already under tolerance. This are the main reasons I ruled out vane pass. This horizontally mounted centrifugal pump acts as a overhung rotor,having a bellow in the suction side and connected to motor using a flexible...
WSS spectrum wasn't sufficient enough for analysing, if you could provide enveloping and TWF will help to know what is fault. try to run motor alone and gathered the data and check if this frequency arise. regards,
WSS Many styles of centrifugal pumps, can you add more detail Most of the time, pumps have 2-3 bearings/shaft/impeller/coupling. So if you truly have a 5x peak synchronous to machine running speed and you have 5 vanes on the impeller, then it is vane pass. Bearings will be non-synchronous data I also see what appears to be harmonics of vane pass, did you change impeller size recently, is there a check valve or valve in general that is stuck or not working properly? Just by "overhauling" a...
The pump was overhauled as a part of routine maintenance ,there was no indication of vibration prior to overhauling. ok, then it should not be vibrating now right....then something changed...is the pump running backwards, just because the valve handle moved does not mean the internals moved, did something fall/collapse and block pump inlet, are flows and pressure normal, did you change impeller size I assume "calibrated" means balanced the impeller This are the main reasons I ruled out vane...
Thank you guys for your reply.The pump is at site and we are service contractors.So is it safe to conclude that occurrence of vibration is not due to any wrong procedure in overhauling (ie. balancing,Replaced bearings and gasket,mech seal test)? Please note we had changed the bearings too.
Dear Mr.Chary, Its 4.8mm/s now.We are planing to take it down once it peaks over 5.5mm/s and give a check of the valves and other flow condition.The check valve on discharge line is normally on full open or full closed condition.
Greetings team Very Interesting case. only 5X dominating. No problems noticed in spectrum. All unique components are in good condition. 3.84 mm/s at 5X is still in normal condition. However, the cause of 5X dominant can appear due to flow conditions like impeller stall. Check the pump suction and delivery valves, system flow conditions (full flow or throttled flow) Load on motor etc., Pleased to see such isolated case. regards Chary
GREETINGS WELL NOTED. THANKS FOR YOUR FEEDBACK. PLEASE FOLLOW THIS METHOD AND TRY HOW YOUR VIBRATIONS ARE INDICATING. 1. CLOSE DISCHARGE VALVE AND START THE PUMP AFTER FEW SECONDS AT FULL SPEED AT MAXIMUM PRESSURE MEASURE THE VIBRATION SLOWLY OPEN DISCHARGE VALVE AND MEASURE THE VIBRATION. IF FLOW INCREASING TIME VIBRATION RISING IT IS RELATED TO FLOW SURGES CAUSING THE VIBRATION. IF STEADY AT EVERY DISCHARGE VALVE POSITION THEN THE VIBRATION IS NOT FLOW RELATED. ALSO TAKE RUN UP AND COAST...
Hi dear all ! I request once again your advices. I would like to know, without the support of a CMMS, how to plan midlife and overhaul of heavy equipment? I mean which strategy to adopt to follow a set of loaders, trucks, and plan correctly the future component changes (in other words the midlife and overhaul)?. Is there a well-known strategy that professionals uses, or templates of spreadsheet I can rely on, to do well? Thank you for your attention
Dear Sir, Can you provide us with the details of job carried out on motor. Mounting conditions during solo run i.e. soft foot or any such base related observation. DE and NDE phase relationship Regards
Dear Experts , yesterday i have tested a solo run motor with high vibration after overhaul at work shop . POLE : 2 ,Motor R.P.M : 2910 , Hz : 50 , 15 K.W , 415 V , 29.0 Amps . N.D.E Bearing : 6309 D.E Bearing : 6310 Stator slots : 24 Rotor Bars : Not known . Below i have attached Velocity , acceleration & Displacement spectrum .Please share your Findings .
Yes , yesterday balancing done on assembled motor .vibration reduced to 1.5 mm\sec .But I am concerning about high frequency peaks observed and side banda at line frequency or 1x .what will be the motor behaviour ,if it is installed on site to its equipment..
"But I am concerning about high frequency peaks observed and side banda at line frequency or 1x." It isn't clear if that last data is still from a solo test or coupled to a load. If it is loaded, the various small peaks seem to be about 0.15 mm/sec RMS or lower so I would not be overly concerned. If the data is solo, then I would proceed with loading the motor up while making observations.
Motor tested solo in workshop before and after corrections .Motor rotor balanced before on dynamic balancing bed , but found vibration after assembly trial run . Then balanced after assembly again , vibration lowered but found same peaks. What if it was unbalanced due to electrical issue (electromagnetical forced due to faults in stator or rotor )and then arrested by balancing .
If the motor is running uncouple to the driven machine, I would be a little concerned with the 9 rpm slip on an uncoupled motor, that is if the spectrum's cursor is displaying the correct 1x rpm. Sometimes, if the "Locate Peak" function is used to locate a frequency, it can give a, somewhat, wrong frequency, depending on the resolution and the amount of energy "riding" next to the frequency in question, in this case, 1x rpm. The use of the "toggle cursor" function to help align the...
The data you posted after a rebalance doesn't show any issues but as Barry pointed out a solo run on a motor leaves a lot to be desired. The points you bring out, what I've changed to bold text, need load to make potential issues evident.
Since this a vertical motor, do yourself a favor. Put the motor in, take readings and then trim balance the entire rotating assembly by adding weights to whatever is rotating on the top of the motor, fan, ring, etc.
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