hi Rizal,
As far as I know, the one times TS around your 9X seems like it's being modulated by the turning speed of your shaft...For my case with turbines, normally i judge how bad a situation is based on how many TS sidebands are around the blade pass. Do correct me if i am wrong.

Hello Rizal,

Apa Khabar? Any updates on the BFWP vibration concern...you've gone quiet again??
If you have any findings, please share with us so that we can all learn.

Tahnks... Rajan

Not really connected to this problem but Ramesh - Abu Dhabi - why does your name ring a bell??? I used to work in ADNOC at Umm Al Nar refinery. Any connection??

Hello…sorry for late reply….ermmm….I need to upgrade both CPU and internet connection…hahaha.

Hi Rajan,
Kamal kassim already resign after receives VSS. Lim soon hua send his regards to u. And lastly the young & beautiful lady Sharipah Jalil also say hi to you. Are you still at Canada? Finally I found the pioneer of our CBM program…haha. You remember Felix fung? He’s now joining Turcomp as manager. Now Reliability has shifted under maintenance and lead by Hj Khairul Safian Tahar. What’s your e-mail add? You can e-mail me at abangzaki@yahoo.com boleh kita sembang-sembang. I also think there is something wrong with the 1st stage impeller. The humming sound still there when motor solo run. Is it possible that the humming sound contributed by uneven air gap between rotor and stator??? Or stator/rotor dirty???Or winding problems???

The vibration reading still fluctuating……still waiting for vendor…….

Ramesh thanks for your input….sorry I couldn’t send you the waterfall spectra now…I’ve been busy lately…taking route…attend mechanical run….follow up any vibration issue….analyzing…sending report….teaching new vibration collector staff which doesn’t even have any mechanical background….sometimes I just feel I couldn’t take all of this anymore… should I sell tomatoes???

Wookp,
Thanks for sharing. Where’s your location???

Sorry guys I will gather latest update reading tomorrow.

Regards,
Rizal[03:17hrs]

Hi Rizal,

The 'Humm' could be very well be rotor eccentricity and hence air-gap off-set, seen this in TPE and fixed it with alignment correction.
Personal communication will contact via my email.

Cheers...Rajan

We often see blade pass frequency with harmonics when operating in abnormally low flow configuration such as you mentioned (3 pumps running instead of 2 normal).

Note your pump curve mentions speed 4592rpm, but I think you are operating at least 6% higher speed than that. Should be taken into account if you try to use the curve.

How would the 9x peak on the motor fit into it.. that's a tough one. Does that frequency show up on the gearbox as well?

Hi Rizal,
I am currently working in Paka, Terengganu.

Ramesh Rao,
I was wondering at your statement earlier regarding manufacturers refrained from making 9 vaned impellers? Any reason behind this?

Good day everyone,

Rajan,
Based on the hum sound level, A motor was more obvious than B motor. I never encounter any humming problem with 415V motor compare with 6.6KV motor here. Do you remember BFW motor at TPC 2 & Naphtha pump? They also have this humming sound but compare the vibration level it’s very low.

The Motor vendor said there is 2 possibilities of humming which is either the bearing cover not properly placed and resulting uneven air gap or stator lamination loose. Anyway we will send the motor to the vendor and I will update the findings then.

Hi pete Good to hear from you.
Yes the problem still occurred when the pumps running parallel. Currently 2 pumps were running B & S.

Wookp r u working with Petronas?

I’m posting the A pump spectrum & waterfall. On the 4th Nov 2006 was during Motor Solo Run & 2nd Nov 2006 was during running with S pump meanwhile B pump was put on standby.

Cheers,
Rizal

P-3200A.pdf (219 Kb, 19 downloads)

B pump spectrum & waterfall
Take note that on 15th Nov 2006 B pump running with S pump & 28th Nov 2005 was the last reading before the vibration goes up

P-3200B.pdf (487 Kb, 11 downloads)

S pump spectrum & waterfall

P-3200S.pdf (82 Kb, 9 downloads)

Hi Rizal,

From what I see on the spectral plots you've posted above. The following are my observations:
P-3200A
Motor DE Axial plot dominated by 8.7XRPm, and
Pump DE Horz/Vert plot dominated by 6.9 XRPM
Gearbox plots N/A...Could you post these please?
Nov.01/06 your trend indicates a level of 21.9 mm/s dropped to 8.3 mm/s after 2 Hrs. what happened at M-DEA??

P-3200B
Motor & Gearbox vibration levels are acceptable but, 6.9XRPM present.
Pump DE, 6.9XRPM dominant, amplitudes are high
Pump NDE, 1X/6.9XRPM dominant but, amplitudes are low.
Suspect Wear-Ring & 1st Stage Impeller defects. Motor & Gearbox not a concern.

Which Motor is being pulled out to be sent to Vendor? If it is P-3200A, have you pulled out the Motor already?

Regards...Rajan

This message has been edited. Last edited by: RajSha,

Pump performance (efficiency) is ok ? Motor current is comparable to that of parallel operating pump ? Balance line pressure is increased ? Pump axial displacement / thrust brg. temp is increased ? .......may be answer of this questions will give clue whether any damage happened inside the pump....

I had similar problem at Co-generation plant in UK.

The high vibration on the pump NDE at vane pass was a result of the 'Motor' not sitting on Mag Centre causing moderate axial vibration to the gearbox. This axial was passed through to pump. This moderate axial vibe (at 1x Motor) affected the pump alignment allowing the vibration at pump vane pass (variation in pump clearences?). Pump NDE has sliding feet to allow for thermal expansion, the axial misalignment causing a nodding donkey affect on pump free end. The clearences on the NDE were excessive giving rise to a similar fault as posted. Some clearence must be allowed.

RCA - Poor foundation for Motor. The Stator was distorted causing Mag Centre fault. Not an easy one this?

Sorry..I'm late again.

Rajan,
Thanks for your analysis. I'm posting the gearbox spectra. on 1st Nov 06 the MDEA reading suddenly give fluctuate reading between 3mm/s to 20mm/s. The machine has been stop due to 20mm/s reading to prevent further damage to the motor. After 2 hours, the machine has been start again to see the changes but the reading still fluctuate.
I believe A motor will be sent first to the vendor. The motor still not be send because production need to catch up the target. I will post the report after motor overhaul.

Raj,
I'm not really sure about the pump performance but the pressure header seem to be normal and not fluctuate. I will find out about the actual current recorded but as far as i know the current is not much defference and 3-phase for both A & B was balanced. Balance line pressure is increased ?<<<< i will confirm this. We not measure the axial displacement. The temperature looks fine 2 weeks ago. Anyway i will update the latest temp. readings. Thanks.

Wayne A,
Thanks for sharing. That's the good one. Is the trend increased at gearbox???

Regards,
Rizal

P-3200A(GBOX)2.pdf (1,065 Kb, 19 downloads) Pump_A_GBox

Hi Rizal,

P-3200A Gearbox vibration seem to be impacted by Gear mesh/backlash fault. The intermittent spiking/fluctuation of levels at Gearbox may very likely be alignment related. As Wayne A has indicated, the root cause may very well be poor foundation conditions.
Look for loose anchor bolts and cracked foundation. Your problems may be this that is causing the alignment to shift and hence, impose stress on rotating components along the train.
Rizal, gather your data and draw a scenario on the machine problem and state the case/report, to justify the shutdown. Otherwise, operations will always need the machine for production. You do not want a totally wrecked machine. Part of being a good vibration analyst is making sound decision and calling the shot.

Good Luck...Rajan

Hi Rizal;

Hope now your problem is now solved !

How did you won the situation! what are your learnings in this case

Share it with us,

Thanks in advance