AFMC Case Studies # 25 - Beat IT Presentation Jun 17R2€¦ · Blowers replaced but do not seems to...

“BEAT IT”

AHU Extreme High Vibration

## “910 mm/s RMS” ##

� Change out that NEWLY Installed vibration sensor !!

1VTC/nk/cs25 040516 AFMC

Technical Presentation

As the shaft turns, there are

frictional and rotational forces.

That vibration created by those

forces is transferred via the bearings

to the machine housing.

What Causes Vibration?

VTC/nk/cs25 040516 AFMC 2

Project History

NEWLY Commissioned AHU #10Information Available to Students

Situation : Newly constructed Bio chemical plant you are servicing have been hired your expertise to conduct Analysis (All technology) with plants Reliability engineer (Certified Cat II Vib specialist) to identify the sources of Extremely high Vibration on AHU #10 . . This unit had already 2 new Blowers replaced but do not seems to have High Vibration Reduced. Client requested to have Vibration sensors replaced as its newly installed for less than 1 months.

Your cost of time: Each time you use reviewing the data, performing tests or discussing the problem is 10 points towards your total cost for the case study history. Any special test you request will be discussed with you to insure proper understanding of procedures involved. You have 90 minutes available to review the data you’ve collected and make up a report on your assessment and highlight findings done.

Information Provided : You are on site collecting all the data that your requires. The collection display of the spectrums collected are listed below. The significant motor nameplate info is as follow

Motor RPM : 2,700.00 , Fan RPM : 2,625.00 Loading : Variable Speed Drive

Your Observations: The unit is obviously Vibrating Heavily . Humming noise was heard emulating from AHU units . You feel high vibration of this unit even as you approach it. The vibration collected form on line mounted sensor on Fans and motors are the only FFT Spectrum analysis available.


AHU 10

5

Diagram of AHU Belt Driven Fan

Figure 1: Schematic Measurement Location and Orientation of AHU Fan

FNDE FDE

Vertical

Axial

Horizontal

MDE MNDE

Motor

Fan

VTC/nk/cs25 040516 AFMC

6

AHU 12 Vibration Analysis –

Live View

AHU 10 Video - WMA folder VTC/nk/cs25 040516 AFMC

Accelerometer Overloaded !!!


Initial Vibration Results

8

Vibration data were logged for AHU 101) Vibration survey indicated was within Unacceptable operation zone of ISO 10816-3

(OEM Standard was not imposed). Recommended to have access into ahu for inspection to

identify the cause(s). 2) Vibration data was collected from permanent mounted Vibration in 4 locations Motor DE , NDE,

Fan DE &NDE. Saturation of Vibration sensor at Fan DE Location causing

exceptionally high readings was detected. Recommended to access ahu for inspection to

identify the cause(s).

3) FFT Spectrum Collected indicated Mechanical Misalignment & Frequency @42 - 45Hz hunting in system. More field testing required to identify root sources.


9

Period Reported:

30/11/2015 - 1/2/2016

Location

Schedule Entry Type Latest Units Date Time

AHU 10

Motor DE -

HorizontalVel 6Pack 1000 Hz Spectrum Overalls 11.2 mm/s RMS 20/1/2016 2:47:05 PM

Motor DE -

HorizontalVel 6Pack 1000 Hz

Demod Spectrum

Overalls0.2237 g RMS 20/1/2016 2:47:05 PM

Motor NDE -


Motor NDE -


Demod Spectrum

Overalls0.2001 g RMS 20/1/2016 2:47:26 PM

Fan DE – Horizontal Vel 6Pack 1000 Hz Spectrum Overalls 910.3 mm/s RMS 20/1/2016 2:51:18 PM

Fan DE – Horizontal Vel 6Pack 1000 HzDemod Spectrum

Overalls1.762 g RMS 20/1/2016 2:51:18 PM

Fan NDE -


Fan NDE -


Demod Spectrum

Overalls0.2573 g RMS 20/1/2016 2:48:14 PM


10

SG00134510AHU10 : Sampling Area - Fan NDE - Radial - Vel 6Pack 60000 CPM

High Freq SpectrumHz

0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,000

g R

MS

0O/All 15.83 g RMS

Demod SpectrumHz

0 100 200 300 400 500 600 700 800 900 1,000

g R

MS

0O/All 9.031 g RMS

Spectrum

Hz

0 100 200 300 400 500 600 700 800 900 1,000

mm

/s R

MS

0

20

40

60

80

100

O/All 950.2 mm/s RMS

Pow

er

(mm

/s...

71

0


FAULTY ACCELEROMETER ??

Spectrum FFT Graphs

11

Graphical Report Ahu 10 Motor DE Spectrum

20/1/2016 2:47:05 PM

Hz

100 200 300 400 500 600 700 800 900

mm

/s R

MS

0

1

2

3

4

5

6

6.32 mm/s28.75 HzCursor A:

O/All 11.2 mm/s RMS

43.75Hz

Print For CS 25 Pg3


12

Graphical Report Ahu 10 Fan NDE

Spectrum20/1/2016 2:48:14 PM

Hz

0 100 200 300 400 500 600 700 800 900

mm

/s R

MS

0

1

2

3

4

5

6



45Hz


Time Waveform

13

SG00134510AHU10 : Sampling Area - Motor DE - Radial - Vel 6Pack 60000 CPM


0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,000

g R

MS

0O/All 0.6559 g RMS

Demod SpectrumHz

0 100 200 300 400 500 600 700 800 900 1,000

g R

MS

0O/All 0.1996 g RMS

SpectrumHz

0 100 200 300 400 500 600 700 800 900 1,000

mm

/s R

MS

0O/All 14.09 mm/s RMS

High Freq Waveformsecs

0 0.01 0.02 0.03 0.04 0.05 0.06 0.07

g 0O/All 0.626 g RMS

True pk-pk 3.631 g

Crest Factor 2.901

Demod Waveformsecs

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7


True pk-pk 1.086 g

Crest Factor 2.675

Waveform11/2/2016 9:40:18 AM

secs

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

mm

/s

-30

-20

-10

0

10

20

30


True pk-pk 63.75 mm/s

Crest Factor 2.108

11/2/2016 9:40:18 AM O/All 15.12 mm/s RMS <set RPM>

SG00134510AHU10 : Sampling Area - Fan DE - Radial - Vel 6Pack 60000 CPM


0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,000

g R

MS

0O/All 0.5343 g RMS

Demod SpectrumHz

0 100 200 300 400 500 600 700 800 900 1,000

g R

MS

0O/All 0.2484 g RMS

SpectrumHz

0 100 200 300 400 500 600 700 800 900 1,000

mm

/s R

MS

0O/All 6.518 mm/s RMS

High Freq Waveformsecs

0 0.01 0.02 0.03 0.04 0.05 0.06 0.07


True pk-pk 4.058 g

Crest Factor 3.568

Demod Waveformsecs

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7


True pk-pk 1.799 g

Crest Factor 3.488

Waveform

secs

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

mm

/s

-20

-15

-10

-5

0

5

10

15

3.791 mm/s0.06372 secsCursor A:


True pk-pk 35.96 mm/s

Crest Factor 2.703

18/4/2016 2:04:49 PM O/All 6.652 mm/s RMS <set RPM>

Print For CS 25 Pg5


14

Remedy : Additional Stronger Reinforce on Blower Foundation To eliminate BEAT


15

Remedy : Additional of Reinforce on Blower Foundation

Before After


16

LocationSchedule

EntryType Latest Units Date Time

SG00134510AHU10 : Sampling Area

Motor NDE -

Radial

Vel 6Pack

60000 CPMBrg Condition 0.2675 g RMS

31/5/2016

1:33:21 PM

Motor NDE -

Radial

Vel 6Pack

60000 CPM

Spectrum

Overall5.111 mm/s RMS

31/5/2016

1:33:21 PM

Motor DE -

Radial

Vel 6Pack


31/5/2016

1:33:41 PM

Motor DE -

Radial

Vel 6Pack

60000 CPM

Spectrum


31/5/2016

1:33:41 PM

Fan DE -

Radial

Vel 6Pack


31/5/2016

1:33:57 PM

Fan DE -

Radial

Vel 6Pack

60000 CPM

Spectrum


31/5/2016

1:33:57 PM

Fan NDE -

Radial

Vel 6Pack


31/5/2016

1:34:13 PM

Fan NDE -

Radial

Vel 6Pack

60000 CPM

Spectrum


31/5/2016

1:34:13 PM

Final Vibration Results


Vibration Sensor is Resonating at its Natural Frequency During BEAT

17

SG00134510AHU10 : Sampling Area - Motor DE - Radial - Vel 6Pack 60000 CPM


0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,000

g R

MS

0O/All 0.3656 g RMS

Demod SpectrumHz

0 100 200 300 400 500 600 700 800 900 1,000

g R

MS

0O/All 0.1303 g RMS

Spectrum31/5/2016 1:33:41 PM

Hz

0 100 200 300 400 500 600 700 800 900 1,000

mm

/s R

MS

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8



Po

we

r (m

m/.

.. 11

0

43.75Hz

z


18

SG00134510AHU10 : Sampling Area - Fan NDE - Radial - Vel 6Pack 60000 CPM


0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,000g

RM

S

0O/All 0.3113 g RMS

Demod SpectrumHz

0 100 200 300 400 500 600 700 800 900 1,000g

RM

S

00.0176 g45 HzCursor A:

O/All 0.09821 g RMS

Spectrum31/5/2016 1:34:13 PM

Hz

0 100 200 300 400 500 600 700 800 900 1,000

mm

/s R

MS

0

0.5

1

1.5

2

2.5

3

1.746 mm/s45 HzCursor A:


Pow

er

(mm

/... 11

0

45Hzz


Root Cause Analysis


Motor RPM : 2,700.00 Fan RPM : 2,625.00

Dia Dia


3D Analysis (ODS)

Operating Deflection Shape

Functions:

� To produce animations of the deformation characteristics of a vibration

mechanical system at any discrete frequency.

� Provide information regarding operating equipment that can be made into an

animation

� Define areas of structure weakness

� Identifying areas with mechanical looseness

� Provide an estimate of the mode shape for the natural frequency that is being

excited.


ODS in Operation – Blower speed at 1796 rpm


ODS in Operation – Blower speed at 3593 rpm


ODS in Operation – Oven speed at 1514 rpm


ODS in Operation – Oven speed at 1433 rpm

Exhaust Fan MCSA Case Study

• AC Induction

• General Electric

• 400 Horsepower

• 1780 RPM

• 509LL Frame

• 460 Volt

• 442 Amps

PdMA Corporation

Problem Description

• Four (4) Variable Frequency Drive failures

within a short life span (all within 3 years)

• Electric Motor recently refurbished

• VFD’s always replaced with new components

at a cost of $45,000 each

• Frequent trips of the motor causing additional

process problems

PdMA Corporation

Initial Standard Test

• Data collected from

local disconnect

• Quickly noticed the

corrected Mohm value

was only 145

• All other data

appeared to be within

acceptable limits

Test Date 07/28/2003

Test Time 09:17:08 AM

Frequency 1200 Mohm Ph 1 to Gnd

Charge Time 60 Voltage 1000

Motor Temp 30 Measured Mohm 289.3 Corrected Mohm 145.0

pF Ph 1 to Gnd 41750 ohm Ph 1 to 2 0.01951 ohm Ph 1 to 3 0.01956 ohm Ph 2 to 3 0.01952 mH Ph 1 to 2 2.775 mH Ph 1 to 3 2.575

mH Ph 2 to 3 2.790

Avg. Inductance 2.713 % Res. Imbalance 0.15 % Ind. Imbalance 5.10

$ Power Loss 10.37 Test Location T-Leads

MCE # 030452HV User

Notes Yes

PdMA Corporation

Polarization Index Test

PdMA Corporation

Final value less than 400 Mohm

Erratic graph indicative of moisture

and/or contamination

Standard Test - At Motor Leads

Test Date 07/28/2003

Test Time 10:08:57 AM

Baseline

Frequency 1200

Mohm Ph 1 to Gnd

Charge Time 60

Voltage 1000

Motor Temp 30

Measured Mohm 3400.0

Corrected Mohm 1700.0

pF Ph 1 to Gnd 40500

ohm Ph 1 to 2 0.01925

ohm Ph 1 to 3 0.01913

ohm Ph 2 to 3 0.01918

mH Ph 1 to 2 2.830

mH Ph 1 to 3 2.780

mH Ph 2 to 3 2.615

Avg. Inductance 2.742

% Res. Imbalance 0.33

% Ind. Imbalance 4.62

$ Power Loss 24.90

Test Location Motor Leads

MCE # 030452HV

User

Notes Yes

• Data collected from

motor leads to isolate

circuit from motor to

disconnect

• Quickly noticed the

corrected Mohm value

increased from 145 to 1700

• Began to suspect a

problem within the conduit

between disconnect and

motor

Polarization Index - At Motor

PdMA Corporation

Final value increased to over 12000 Mohm

Graph has more slope - less erratic

Remedial Actions

• Due to problem with low Mohm values

apparently residing between the local

disconnect and motor junction box, we

suspected water in the conduit

• Conduit was removed

• NO water found

• Spirits were low

PdMA Corporation

Remedial Actions (Continued)

• Due to some abrasions on lead-wire jacket, it

was decided to have it replaced

• Would allow further investigation of the

conduit - still leaning on water in conduit

• Would allow further investigation of the circuit

for other possible sources of our problem

PdMA Corporation

New Lead Wire

• Old lead wire was removed from conduit

• New lead wire was brought to project site for

measurement and cutting

• We were faithfully inspecting conduit for

water

• During lead wire measurement, our problem

was found!

PdMA Corporation

Root Cause

PdMA Corporation

Phase 1 Phase 2 Phase 3

Before/After Lead Change

PdMA Corporation

Test Date 07/28/2003 07/28/2003

Test Time 10:08:57 AM 03:03:13 PM

Baseline

Frequency 1200 1200

Mohm Ph 1 to Gnd

Charge Time 60 60

Voltage 1000 1000

Motor Temp 30 38

Measured Mohm 3400.0 1745.0 Corrected Mohm 1700.0 1500.0

pF Ph 1 to Gnd 40500 42250

ohm Ph 1 to 2 0.01925 0.02000

ohm Ph 1 to 3 0.01913 0.02000

ohm Ph 2 to 3 0.01918 0.02000

mH Ph 1 to 2 2.830 2.780

mH Ph 1 to 3 2.780 2.860

mH Ph 2 to 3 2.615 2.620

Avg. Inductance 2.742 2.753

% Res. Imbalance 0.33 0.00

% Ind. Imbalance 4.62 4.84

$ Power Loss 24.90 0.00 Test Location Motor Leads Bot Fuses LD

MCE # 030452HV 030452HV

User

Notes Yes Yes

• Corrected Mohm

value now very close

to when tested at

motor

• Corrected Mohm

value increased from

145 to 1500

• Resistive

Imbalance, although

low before now at

0.00

Problem Follow-Up

• Unit has operated flawlessly for 9 months without

as much as a nuisance trip

• Process problems have as a result been

tremendously reduced

• Maintenance budget has experienced a much

needed rest from drive replacement costs

• Huge “round of applause” for our PdMA MCE

Testing Technology

PdMA Corporation

Nick Kang

• 25 Years– Field Vibration Diagnostic

– Certified Vibration Institute VI (USA) –

Course Trainer

* Certified Infrared Thermal Inspection Specialist


The End


AFMC Case Studies # 25 - Beat IT Presentation Jun 17R2€¦ · Blowers replaced but do not seems to...

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