The document summarizes the overhauling of Circulating Water Pump-A that took place from November 27, 2011 to December 1, 2011. It details the dismantling and inspection process where several worn parts including casing wear rings and impeller wear rings were found and replaced. Clearances and shaft run-outs were measured and found within specifications. The pump was then reassembled with new parts and grease applied. A final inspection confirmed the discharge bowl was properly seated with no gaps.

1.
Circulating Water Pump-A Overhauling Report
November 27, 2011-December 01, 2011
Prepared by
Md. Maruf Akhtar
Maintenance Planner
Haripur Power Limited
Co-Author
Ashik Ahmed
Maintenance Engineer
Haripur Power Limited
Checked by
A.B. Siddique
MMT Supervisor
Haripur Power Limited
Approved by
Kazi Samsul Alam
Plant Manager
Haripur Power Limited

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Equipment No: CW-M-PP-03A
Equipment Name: Circulating Water Pump-A
History
Haripur have two cooling water pump (CWP-A/B) each 50% capacity. According to
schedule maintenance plan each pump is overhauled after 16,000 running hours.
The overhauling work of cooling water pump is carried out in advance of schedule
outage for minimize the outage task and foreign vendor support. CWP-A was scheduled
for overhauling in Feb-2012 and it was decided to complete in Dec-2011.
The pump suction is from river water to discharge to water boxes of steam condenser.
It’s a vertical shaft, 1350 discharge bore mixed flow pump. It’s driven by an 1100 KW
vertically mounted motor with a rated full load rpm of 494. Rated flow rate of the
pump is 18, 600 m3/hr.
Before the overhauling CWP-A, NDE side vibration of motor as being monitored was too
high for its sound performance. Vertical vibration data at NDE was measured as high as
6.3 mm/sec which was way alarming.
Suspected regions were out-clearances of bearings and wear-rings. O & M came to a
decision for complete overhauling of the pump which started on November 27, 2011
and was completed on December 01, 2011.
Specification of the Equipment and History of CWP-A
overhauling works
Circulating Water Pump-A (Vertical Mixed Flow Pump)
Installed in year: 2000
PPPuuummmppp DDDeeetttaaaiiilllsss
Shop Order No KA0366
Serial No: KA0366-CWP-001 (or 002) For Pump A & B.
Tag No: CW-M-PP-03-1
Capacity 18,600 m3/hr
Total Head 16M
Speed 493 RPM
Power 1100KW

3. 3333
November 27, 2011-December 01, 2011
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MMMoootttooorrr DDDaaatttaaa
Manufactured By
Electric Motor Manufacture Dept.
Industrial & Power System Division
Hyundai Heavy Industries Co, Ltd.
1,CHEONHA-DONG,DONG-KU,ULSAN,KOREA
Tel: 82-52-230-6671,72
Motor Application C.W.Pump
Rated HP/KW 1474.5 HP/1100KW
Motor Type SQUIRREL, CAGE
Frame No HLA7 902-36Y
Rated Voltage 6600 V
Phase 3 phase Induction/50HZ
Full Load Current 134.7 A
Speed Synchronous 500/494
MMMaaaiiinnnttteeennnaaannnccceee HHHiiissstttooorrryyy CCCWWWPPP---AAA
CWP-A was overhauled in Feb-2006, Feb-2008 and Mar-2010 as a part of scheduled
maintenance. Next overhauling was scheduled in Feb-2012 but we started the work
two months earlier to reduce coming outage (scheduled in Feb-2012) activities and to
concentrate more on outage-2012.
Dismantling Procedure
The motor-pump assembly was disassembled with the following steps:
The stop gate
was inserted
into the intake
basin with the
help of gantry
crane.

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November 27, 2011-December 01, 2011
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Note: before inserting the gate, it’s important to grease the slots of the gate; the
slots will guide thru the railing inside the basin.
3 submergible pumps (ф4” & ф3”) were being placed inside the intake basin to
continuously pump out water.
Note: submerge pumps were drawn to the intake when inside water level was reduced
to 310 cm and this was done by running the main pump for few seconds after placing
the stop gate.
The pump was then stopped and motor was isolated.
Pump was decoupled from the motor and lift of the pump was noted as 11.1
mm

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November 27, 2011-December 01, 2011
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Note: there are 6 stud bolts and 6 reamer bolts in the coupling. Space nut is screwed
to the pump shaft and pump end hub is keyed to the shaft which drops down after
loosening the coupling bolts.
Cooling water lines had been removed.
The motor and motor pedestal was sequentially removed by gantry crane.
3 gland packing were removed by screw driver.
Gland and upper bearing housing (brg housing o-ring, P#1492 to be reused)
were removed afterward; all these were lifted using eyebolt-shackle-belt
assembly of appropriate sizes.
Elbow cover was lifted (after removing tow center pins) by the crane up to
when the top spider hoisted over the column pipe as it was to be supported by
H-beam underneath.
Elbow cover and upper shaft tube were unfastened sequentially.

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November 27, 2011-December 01, 2011
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Note: There is a distance ring which rests between elbow cover and upper shaft tube
which must be handled and kept safely.
Note: There is a tapering part in every leg of the spider and this side would face the
downside while assembling.

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November 27, 2011-December 01, 2011
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Upper spider along with the intermediate shaft tube was then dismantled after
lifting the resting assembly as long as the lower spider was supported similarly.
The upper shaft was then separated from the lower shaft by dismantling the
line shaft coupling & thrust ring using special tool as seen in the figure.
Lower spider, lower enclosure tube,
discharge bowl and impeller were then
taken out altogether and spider-tube
was dismantled in similar fashion.
Discharge bowl was separated from the
impeller-shaft assembly by removing
the stopper ring.

8. 8888
November 27, 2011-December 01, 2011
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Note: Match marking is provided in every part disassembled.
Shaft was disassembled separated from the impeller using an extractor.
Note: Impeller washer must be removed first before extracting impeller from the
shaft using special tool (mechanical jacking).
Casing wear ring was pulled using hydraulic jack & a fabricated special jack
with nearly 100 bar of pressure. Impeller wear ring was extracted by tapping &
unscrewing it.

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November 27, 2011-December 01, 2011
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Dummy Inspection
Dummy inspection refers to
checking whether discharge bowl
seats in its slots after assembling
it with only shaft tubes, spiders
and elbow cover.
After assembling all these and
tightening the elbow cover on its
bolts; a gap of 3 mm found
beneath the discharge bowl on its
seating slots. It had to be
compensated. A shim of 3 mm
was ordered instantly with same
shape of distance ring from
nearby workshop of stainless
steel.
Findings
Followings were the findings on disassembly:
 Stop ring set-screw (one out of two) was found loose when dismantling.
 Casing wear ring and impeller wear ring were found heavily eroded.
 Impeller blade edges were found rubbed (perhaps with the impeller liner).

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November 27, 2011-December 01, 2011
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 Discharge bowl anti-rotation pins were found partially sheared and were
repaired by build-up & grinding before assembly.
Note: Keys are marked as in the table:
Mark Position
1-1 Impeller-lower shaft
1-2 Lower shaft-line coupling
1-3 Upper shaft-line coupling
1-4 Pump end hub-upper shaft
Assembly
Before assembling, feroform bearings and sleeves were forcibly taken out. New
fabricated casing wear ring & impeller wear rings (from local workshop) were dressed
with set-screws being punched and countered on respective housings. Impeller liner &

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November 27, 2011-December 01, 2011
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basin surroundings were checked and declared fine to go in. Shaft run-out and sleeve-
bearing clearances were measured and found within the operative range. Discharge
bowl was painted by Barger Marine Black on its non-mating portions with inside
column. Elbow O-ring and bowl O-ring were fabricated locally from cord.
Clearances
Lower Sleeve Intern Sleeve 1 Intern Sleeve 2 Upper Sleeve
Brg Dia 180.40 mm 180.50 mm 180.30 mm 180.46 mm
Sleeve Dia 179.79 mm 179.90 mm 179.90 mm 179.86 mm
Clearance 0.61 mm 0.60 mm 0.40 mm 0.60 mm
Design 0.481-0.679 0.453-0.650 0.453-0.650 0.453-0.650
Shaft Run-out
Both shafts were properly cleaned; run-outs as measured are:
1 2 3 4 5 6 7
Upper ShaftMotor Side
1 2 3 4 5 6 7
Lower Shaft
Impeller Side

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November 27, 2011-December 01, 2011
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Dial gauge readings corresponding to the points on upper shaft
-0.01
0
-0.030.04
Point 1
-0.02
0
-0.01-0.02
Point 2
-0.11
0
-0.08-0.04
Point 3
-0.12
0
-0.11-0.02
Point 4
-0.11
0
-0.09-0.03
Point 5
-0.06
0
-0.050.02
Point 6
0.03
0
0.06-0.01
Point 7

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November 27, 2011-December 01, 2011
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Dial gauge readings corresponding to the points on lower shaft
0.13
0
0.070.08
Point 1
-0.09
0
-0.03-0.05
Point 2
-0.11
0
-0.05-0.10
Point 3
-0.12
0
-0.01-0.11
Point 4
-0.14
0
-0.01-0.11
Point 5
-0.08
0
0.01-0.04
Point 6
0.12
0
0.020.12
Point 7

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November 27, 2011-December 01, 2011
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 Maximum run-out noticed 0.14 mm and it was same as of previous overhauling.
 Feroform bearings were put in deep-fridge in the Canteen for long 14 hours.
Now they could easily dig-into the respective places.
 There was an obvious gap between the split pieces of the stop ring when they
were placed to screw over the shaft.
 Whole assembly was just the reverse of disassembly.
Motor Inspection
 Motor NDE side fan cover removed and cleaned.
 Motor DE side cleaned.
 Motor cooler’s all cooling holes cleaned.
 NDE side Bearing oil replaced with new oil (DTE 15M, approx-200 ltr.)
 Motor Insulation resistance checked & found IR-10 Gohm, WR-0.79 ohm.
 Motor space heater checked & found WR-29 ohm
 DE side bearing greased and grease chamber opened for checking the grease
condition of the bearing and found satisfactory.
Checks on assembly
To confirm whether the discharge bowl seats
on its slots with no unwanted gap after
inserting extra 3 mm shim (with existing
distance ring) underneath the elbow cover. It
was checked and found ok.

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Greasing to all spider leg sides, O-ring grooves.
Plating Molykote to the bolts, studs, sleeves, thrust rings, impeller washer,
shaft coupling & all other mating surfaces etc.
Tightening the bolts in a crisscross pattern like the following:
Alignment
After reinstalling motor pedestal and motor, gap between motor coupling and pump
coupling was kept 10.5 mm by turning the space nut toward the motor hub ensuring
the required gap.
A steel scale was kept stood
vertically in the hub surfaces
and motor jacks were adjusted
to bring the required alignment.
When the centerline of the
pump & motor was confirmed,
the hubs were coupled with
reamer bolts. Now the tip
Steel Scale

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November 27, 2011-December 01, 2011
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clearances (radial clearances of the impeller and impeller liner in the suction bell)
were recorded. The values are:
POS E W N S
1 2.8 1.60 2.95 1.65
2 3.2 1.80 1.90 3.40
3 1.80 2.70 2.05 3.00
4 1.95 2.45 2.90 1.85
Tip clearances were judged good. Now relative position of the shaft assembly against
static elbow cover-brg housing-gland was adjusted by adjusting motor. After
adjustment, alignment readings are as follows:
For example in the East side of the shaft; distance of the shaft from the gland is
109.84 mm as measured by inside micrometer. These readings show good centering of
the pump
W E
N
S
109.92 109.84
109.82
109.94

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Modifications
 Ladder arrangement (between band screen &
gantry crane entry hole) inside the basin has
been modified to facilitate larger size (ф6”)
submerge pumps to travel in.
 2 angle bars have been welded to the column
pipe outer body to ease climbing to the gland
packing area inspection while the pump is
running.
Start-up
Here is a comparison of data of vibration parameters of the M/C taken both before and
after maintenance:
Before Maintenance (9:00 hrs on 20-Nov-11)
Vibration in mm/sec
Temp (0C)
Motor Current
(amp)
Inside Water
Level (mm)Position H V A
Pump DE 1.5 2.3 0.9
117 5331
Pump NDE 1.0 1.4 0.6
Motor DE 2.6 4.4 1.0 48
Motor NDE 3.8 6.3 0.7 42
After Maintenance (After start-up at 20:15 hrs on 01-Dec-11)
Vibration in mm/sec
Temp (0C)
Motor Current
(amp)
Inside Water
Level (mm)Position H V A
Pump DE 1.1 1.4 0.6
114 4900Pump NDE 0.5 1.1 0.3
Motor DE 2.1 2.4 1.0 40

18. 18181818
November 27, 2011-December 01, 2011
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Motor NDE 3.2 2.8 1.0 38
Spares List
Following spares have been consumed:
SL Code No Description Qty
1 CW-M-PP-03--BRNG-01 Submerge Brg, Intermediate 02 EA
2 CW-M-PP-03--BRNG-02 Submerge Brg, lower 01 EA
3 CW-M-PP-03--BRNG-03 Submerge Brg, upper 01 EA
4 CW-M-PP-03--PACK-01 Gland Packing, P#1391 01 EA (03 pcs)
5 CW-M-PP-03--SLVE-01 Packing Sleeve, P#1227 01 EA
6 CW-M-PP-03--SLVE-02 Shaft Sleeve, upper P#1224 01 EA
7 CW-M-PP-03--SLVE-03 Shaft Sleeve, inter P#1225 02 EA
8 CW-M-PP-03--SLVE-04 Shaft Sleeve, lower P#1226 01 EA
9 CW-M-PP-03--RING-01 Casing Wear Ring, P#1261 01 EA
10 CW-M-PP-03--RING-02 Impeller Wear Ring, P#1262 01 EA
Workforce
Overall Supervision A.B. Siddique, MMT Supervisor
Craft Person: Md. Saiful Islam, MMT Engineer
HPL Working Person MMT Engineers-Hanif, Enamul, Ashik, Maruf
Maintenance Assistance
Amzad (Rigging), Islam (Crane Operation), Muktar
(Welding/heating)
Local Labor Tapas, Mahtab (High Skilled Technicians)

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Achievements
Spares (SL. 9 & 10) had been fabricated from local workshop. These are precision
items made from SS and this was a challenge for us. We have overcome the challenge
successfully and it saves significant amount of money worth USD 9,000.00. Previously
these two items were foreign purchased with USD 10,015.00 and this time cost was
around USD 1100.00 as made by local fabrication.
Conclusion
Pump overhauling is done earlier than scheduled time and it was put into service at
the 5th day from shutdown. Moreover an additional inspection (discharge bowl gap
checking by dummy assembly) is done this time. We also learn that a significant cost
can be reduced by exploring local manufacturing of such spares. Pump vibration and
other parameters became smoother after the overhauling.