Tagged With "attachment"

Topic

High 2x between 2800 to 3000 rpm on Gen DE

Nagaraja ·
Hi I am working on a 12 MW TG set vibration problem The history is generator was working fine with vibs in permissible limits. Due to earth fault there was a prob in stator. Stator was replaced. Both generator bearings were replaced. Now Gen DE...
Topic

Retest of attachment in IE 11

John from PA ·
Previous test which was successful was with the Intranet option disabled.  The normal default is to have this enabled (at least on my installation) so this is a test with the Intranet option enabled.   Unsuccessful.   It seems as though...
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Re: High 2x between 2800 to 3000 rpm on Gen DE

John from PA ·
Is this machine equipped with proximity probes, and if so can you collect data appropriate to generate bode, polar and cascade plots? [Preferably compensated]
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Re: High 2x between 2800 to 3000 rpm on Gen DE

Walt Strong ·
I suggest impact (bump) test on Gen DE and NDE bearing housing in axial direction and also on Gen housing end plate. I assume that both shaft alignment and possibly natural frequency was disturbed during the repairs. Walt
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Re: High 2x between 2800 to 3000 rpm on Gen DE

Nagaraja ·
I do not have instruments to generate bode and polar plots...I am sorry....I took the phase data...already posted...it shows common phase between Gen DE and GB DE....bump test done on coupling....I got 135 Hz....tom we are opening the bearings for inspection.....will do the bump test on that also.....only thing is what changes in dynamic behaviour might be happening for the 2x along Gen DE axial to increase in the last 200 rpm before reaching rated speed...of 3000 rpm....???
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Re: High 2x between 2800 to 3000 rpm on Gen DE

Nagaraja ·
Gen DE bearing found in damaged condition
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Re: High 2x between 2800 to 3000 rpm on Gen DE

Nagaraja ·
Dear Members I have a question....in which direction do 2x line freq showup on Generator.......DE, NDE or both... HVA....???? In this case 2x is appearing on Gen DE axisl once generator speed crosses 2800 rpm and shows 8 mm/sec at 3000 rpm It was found that Gen DE bearing top half was damaged that too only on one side left hand side where as no damage was found on right hand side and also bottom half bearing. In real time I can see 2x freq component was hunting....from 6-9 mm/sec. Is 2x...
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Re: High 2x between 2800 to 3000 rpm on Gen DE

William_C._Foiles ·
A planet earth fault can result in serious torsional oscillations in the shaft. Shaft asymmetry can cause 2X vibration. A generator running at 3000 (?) has some natural asymmetry. Torsional oscillations can result in a shaft crack, which usually shows up as a shaft asymmetry (for bending). It might be prudent to setup a monitoring plan for this.
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Re: High 2x between 2800 to 3000 rpm on Gen DE

oscarsaenz ·
Originally Posted by Nagaraja: Hi I am working on a 12 MW TG set vibration problem The history is generator was working fine with vibs in permissible limits. Due to earth fault there was a prob in stator. Stator was replaced. Both generator bearings were replaced. Now Gen DE axial vibs are high. Turbine speed 7066 rpm and Gen speed 3000 rpm. Ita a 2 pole machine. My observation was till 2800 rpm the Gen DE axial vibs are normal (1.5 mm/sec rms) with slight 1x ampl and very low 2x ampl. After...
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Re: High 2x between 2800 to 3000 rpm on Gen DE

oscarsaenz ·
Originally Posted by oscarsaenz: Originally Posted by Nagaraja: good day engineer your case is very interesting because it has shared behaviors of different faults. I think the vibration at 1500 rpm (0.5 X). possibly induced by the friction which to change the rigidity of the system, move the natural frequency of the system. besides possible rigidity of coupling.
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Re: High 2x between 2800 to 3000 rpm on Gen DE

Nagaraja ·
Hi generator was balanced after bearing change....now the set is running with both casing and shaft vibs in the permissible limits thanks for all your valuable inputs.
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Re: High vibration on the ball mill drive train A and B

Becar ·
Visually check the pinion teeth. More likely the source is a failure on the pinion support bearings or housing looseness. Therefore gear mesh is not working in the proper way. Due to described breaking bolts, the entire machine should be realigned. The machine obviously needs the immediate repair.
Topic

High vibration on the ball mill drive train A and B

Modupi ·
We are experiencing high vibration on our dual drive ball mill. The high vibration is on the motor DE bearing on axial direction. Dominant frequency is girth and pinion gear mesh. See attached spectrums and trends. Gearbox hold-down bolts are breaking due to high vibration.
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Re: High vibration on the ball mill drive train A and B

Copper Miner ·
I ran into a very similar problem and it turned out to be the encoder on the motor, basically it was unsynchronizing the motors.
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High 25x in Hydraulic piston pump

Alvin MC ·
Hello All, We were seeing high 25x on our turbine hydraulic piston pump, see attached spectrum. Since the vibration was high and the system pressure was swinging we went ahead and changed the pump. Teardown and inspection reveal nothing significant. Was wondering where that 25x might be coming from? Anybody here dealt with piston pumps or similar situation? Thanks
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Re: High 25x in Hydraulic piston pump

Alvin MC ·
Only on last 2 readings before we changed out the pump. We only take horizontal reading on this pump. It was showing up in inboard motor bearing as well. Since new pump installed it went away.
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Re: High 25x in Hydraulic piston pump

Beatnik ·
Did you see it on more than one measurement? It looks a bit like a natural frequency (elevated floor and harmonics around).
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Used SKF Microlog Analyser for Sale

abhishekagg ·
Hi, I own Used SKF Microlog Analyser Model No CMXA 70 E. Very less used Location in India, Shipping any Place in world. In Working Condition. Pictures Attached.
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Re: Used SKF Microlog Analyser for Sale

abhishekagg ·
Dear Mr CM Inspec. Kindly email at abhishek.a@aryasteel.in
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Re: Used SKF Microlog Analyser for Sale

CM Inspector ·
What is the selling Price in INR ?
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Re: Used SKF Microlog Analyser for Sale

Harout80 ·
Kindly send the selling price in USD to hartut@hotmail.com thanks
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Re: Used SKF Microlog Analyser for Sale

abhishekagg ·
Hello, Kindly check your email, the prices has been offered and waiting for your reply.... Thanks.
Topic

45000 dwt Chemical tanker Diesel Generator 4 high vibration on Alternator bearing

chary tatta ·
Greetings team, on 8th July I attended another Chemical tanker and DG no4 alternator bearing Horizontal overall vibration showing 23.4 mm/s in velocity scale. The Marine classification society satisfactory limit is 18 mm/s. Attached the engine and Alternator end vibration spectrum FFT in velocity. All engine details are available in photo sheet. Appreciate your feedback. Kind regards Chary TSR
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Re: 45000 dwt Chemical tanker Diesel Generator 4 high vibration on Alternator bearing

chary tatta ·
Greetings Mr. John, Thanks for your follow up. Please find attached at 5000 cpm HVA plot. Regards Chary
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Re: 45000 dwt Chemical tanker Diesel Generator 4 high vibration on Alternator bearing

John from PA ·
One thing that might be helpful would be to make the frequency scale 5000 cpm. Your engine plots for instance go to 60000 cpm and virtually everything of interest is crammed into the lower 10% of the plot.
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Re: Used SKF Microlog Analyser for Sale

Hello. Please informed price the microlog CMAX70, for e-mail. nunolaranjeiro000@gmail.com
Topic

Vibration at 5X NDE AND DE V for Centrifugal Pump

wss ·
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.
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Re: Vibration at 5X NDE AND DE V for Centrifugal Pump

wss ·
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...
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Re: Vibration at 5X NDE AND DE V for Centrifugal Pump

Rotating Guy ·
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,
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Re: Vibration at 5X NDE AND DE V for Centrifugal Pump

Dave Reynolds ·
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...
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Re: Vibration at 5X NDE AND DE V for Centrifugal Pump

Dave Reynolds ·
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...
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Re: Vibration at 5X NDE AND DE V for Centrifugal Pump

wss ·
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.
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Re: Vibration at 5X NDE AND DE V for Centrifugal Pump

wss ·
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.
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Re: Vibration at 5X NDE AND DE V for Centrifugal Pump

chary tatta ·
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
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Re: Vibration at 5X NDE AND DE V for Centrifugal Pump

chary tatta ·
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...
Topic

High vibration

Soumya Mishra ·
Please see the attachment for detail. Kindly suggest
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Re: High vibration

Soumya Mishra ·
The equipment (Main Air Blower) is having high vibration (axial direcction) and is dominant in 2*RPM. Detail is attached. Kindly suggest
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Re: High vibration

Kishore kumar ·
Dear Sir , yes it is 2X of Gear O.P shaft but what about the Fan readings , is not there provision to take Fan readings , i think fan directly mounted on out put shaft . 1. 4H to 4 V phase difference is 90 indicates Balancing problem . But 2. 1A to 2A ,2H to 2V and 4A to 3A Phase difference is nearly 180 indicates misalignment . as per the data i would suggest first to check & correct Machine train alignment then after you could check & Correct Fan balancing .If you have complete...
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Re: High vibration

Walt Strong ·
Is the fan impeller mounted directly onto gear out shaft?
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Re: High vibration

vigneshpillai ·
fan side its possible to remove and take reading whether its smooth means, fan to be dynamic balancing at 2.5 Grade on shop floor machine
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Re: Used SKF Microlog Analyser for Sale

Daniel170294 ·
hi sir, this item is availiable ?
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