MCM Case Studies - Ascenixascenix.com/images/4.2_Case_studies.pdf•MCM first gave a warning of a problem on 16th October 2005, and diagnosed a looseness problem. The decision was

March 2011

Artesis MCM Case Studies

Segment: Automotive

Company: Automobile Manufacturer A

Equipment: Pump

Fault: Stator Isolation Breakdown

Case 1

Decreasing current unbalance level

MCM gave alarm indicating a developing electrical fault. Thermal camera results verified MCM’s warnings. The pump motor was replaced.

Segment: Automotive


Equipment: Pump

Fault: Stator Isolation Breakdown

Case 1

Hot Spot on stator winding

• MCM first gave a warning of a problem on 16th October 2005, and diagnosed a looseness problem. The decision was to wait for further indications.

• Renewed alert on 19th November 2005 initiated an inspection and a loose attachment bolt was found on 14th February 2006.

Segment: Automotive


Equipment: Tower Fan

Fault: Imbalance & Misalignment

Case 2

Increasing unbalance parameter level

Oct 16 2005

Oct 24 2005

Nov 19 2005

Feb 14 2006

Segment: Automotive


Equipment: Tower Fan

Fault: Imbalance & Misalignment

Case 2

Oct 05 Nov 05 Dec 05 Jan 06 Feb 06 Mar 06

Looseness

indicated briefly,

but then

problem

disappeared

Consistent

alarm on

foundations,

imbalance and

misalignment

Continued

monitoring of

foundation

problem

Continued

monitoring of

imbalance and

misalignment

problem

Fixed

foundation

problem

Loose bolt correctly identified

Segment: Automotive

Company: Rubber & Tire Manufacturer

• MCM identified existing transmission and unbalance faults

• Later, MCM began giving “Rotor Fault” warning also

Equipment: Rubber Mixing Mill

Fault: Rotor Bar Crack

Case 3

• The “Rotor Fault” trend showed development of the rotor fault

• Vibration measurement also verified existence of broken rotor bars, confirming the MCM predictions

Increasing Trend

Segment: Automotive

Company: Rubber & Tire Manufacturer

Equipment: Rubber Mixing Mill

Fault: Rotor Bar Crack

Case 3

This case shows that MCM can be a very useful tool for quality assurance of maintenance work, showing whether alignment has been correctly completed following a maintenance task.

Segment: Oil & Gas

Company: Oil & Gas Company A

Equipment: Diesel Fuel Pump

Fault: Misalignment

Case 4

Diesel Fuel Pump

Trials of Axle adjustments

3th July; Change of Oil Felt

4th July; axle adjustment done

Segment: Aerospace

Company: NATO Radar Base

Equipment: Radar Antenna

Fault: Gear Box Defect

Case 5

January 24 2003, the problem starts

February 4 2003, the gear box changed

A gear box defect is detected at a NATO radar base. Early detection of this fault helped uninterrupted operation of the radar.

Segment: Water

Company: Water Distribution Co. A

Equipment: Pump

Fault: Loose Foundation & Unbalance

Case 6

Segment: Water

Company: Water Distribution Co. A

Equipment: Pump

Fault: Loose Foundation & Unbalance

Case 6

April 29, 2008 February 19, 2009

Before Maintenance

Unbalance Problem

April 29, 2008 February 19, 2009

After Maintenance

Loose Foundation Problem

Before Maintenance After Maintenance

Segment: Metals

Company: Iron & Steel Company A

Equipment: Reversing Cold Rolling Mill Fume Fan

Fault: Dirty Filter

Case 7

Segment: Metals



Fault: Dirty Filter

Case 7

• This fan discharges dust-laden air out of the factory via a filter.

• MCM started to warn the user by giving a “Watch Load” alarm on 15th April 2009.

• Examination of the motor current trend shows that the motor current had been gradually decreasing since 17th November 2008. This indicates that the filter blockage started on that date and had been gradually deteriorating to the point where it exceeded the MCM alarm level on 15th April.

• This drop off in current shows that the fan had not been extracting the desired volume of air, and hence the ventilation in the plant would be below design levels.

Motor Current

Motor Status 2 Parameter

Watch Load Level

11.17.2008 04.15.2009

05.25.2009

Segment: Metals



Fault: Dirty Filter

Case 7

• The maintenance team attempted to clean the filter with compressed air on 25th April 2009, but it was not fully successful. MCM started giving a “Watch Load” alert again after just 1 month of operation.

• The team changed the filter completely on 20th August 2009. After this MCM stopped giving alert signals and the motor current reverted to its nominal value.

• This sort of fault would not have

been possible to detect by

Vibration analysis.

Motor Current Maintenance 08.20.2009

Segment: Food

Company: Sugar Refinery

Equipment: Deep Well Pump

Fault: Cavitation

Case 8

• Just after MCM’s LEARN period was completed, the MCM warned about a fault in a frequency band associated with Cavitation.

• The maintenance team dismantled the pump and checked for cavitation. The photos show the damage of cavitation which can be observed as small pits on pump blade, hence confirming the diagnosis.

Increasing failure level

• After maintenance, MCM stopped warning.

Segment: Automotive

Company: Automobile Manufacturer B

Equipment: Exhaust Fan

Fault: Belt Looseness

Case 9

• MCM indicated a transmission fault, so the engineers looked at the trending data, which pointed to a loose belt.

• The maintenance team confirmed belt looseness.

• Belt looseness would tend to result in slippage, which in turn would mean that the motor could not transmit all the power to the fan. This was consistent with the decrease in the three phase currents.

Increasing failure level

Decreasing current level

Belt tension starts to loose

Segment: Power Generation

Company: Power Generation Company A

Equipment: Feed Water Pump

Fault: Bearing Fault

Case 10

One month after the MCM installation, MCM indicated a developing “Bearing” fault. Maintenance team verified the bearing fault and replaced the bearing of the motor. After the maintenance action MCM stopped giving alarm verifying the effectiveness of the maintenance action.

03.26.2009 03.30.2009

Developing bearing failure

03.26.2009 03.30.2009

MCM Alarm history Examine 1 Level

Segment: Water

Company: Saline Water Conversion

Equipment: Pump

Fault: Stator Failure

Case 11

• The frequency spectrum indicates stator winding problem in both pumps at 120 Hz as shown in the figure below.

• Both pumps are stopped and then restarted in the same day on May 14, 2007. MCMScada long term trending data shows an increase in current balance parameters and amplitude variations in currents before and after May 14, 2007.

Current Balance

May 14, 2007

S and T phase currents before May 14, 2007

Swapped S and T phase currents

Segment: Manufacturing

Company: Battery Manufacturer

Equipment: Compressor


Case 13

• MCM started giving intermittent warnings on September 2005, and a bearing problem was diagnosed by MCM. Deterioration was kept under review until January 2006. When carried out, maintenance and repair actions verified the diagnostic assessment of MCM.

• On later examination of the MCM trends, it was found that the bearing problem was detected even earlier that 13th September2005, but the severity was not sufficient to give rise to an alert. This demonstrates the capability of MCM to indicate developing faults at a very early stage.


Company: Battery Manufacturer

Equipment: Compressor


Case 13

Aug 05 Sept 05 Oct 05 Nov 05 Dec 05 Jan 06

No problem,

other than minor

supply issue Bearing problem

indicated, with 3

month warning

Progress of

bearing problem

monitored –

early indication

in August

Problem fixed,

having had 3

months to

prepare

Segment: Metals

Company: Iron & Steel Company B

Equipment: Pump

Fault: Coupling

Case 14

Coupling fault detected and remedied.


Company: Home Appliance Man.

Equipment: Phosphate Pump

Fault: Bearing Defect & Bent Shaft

Case 15

Change of bearings and shaft

Change of bearings

Increase in the 10th and 12th

mechanical parameters.

Bearing fault

detected. The same

fault indication

repeated again later.

Further analysis

indicated to an bent

shaft which was

causing the fault.

Segment: Automotive

Company: Automobile Manufacturer C

Equipment: Pump

Fault: Unbalance

Case 16

• MCM started giving ‘Unbalance’ warning and soon after it became nearly consistent, on 28 th May 2010.

• Maintenance team checked the motor and verified the imbalance.

Segment: Automotive

Company: Automobile Manufacturer C

Equipment: Pump

Fault: Unbalance

Case 16

• ‘Unbalance’ and ‘Motor Status 2’ parameters show the development of the fault.

Increasing failure trend

05.28.2010

Motor Status

Segment: Pharmaceutical

Company: Pharmaceutical Manufacturer

Equipment: Ventilation Fan

Fault: Turbulence

Case 17

• Discontinuous but frequent warnings regarding ‘Driven Equipment Fault’ were detected on a Ventilation Fan, that had been monitored by MCM.

• After a detailed investigation, it was realized that the warning was being given while the monitored fan was running together with the other fan supplying air to the same ventilation duct.

• It was observed that when two motors run together they will cause turbulence in air flow.

Baseline from June 2010 showing clear, valve related sideband energy

Baseline from October 2010 following an overhaul. It can be seen that the valve sidebands are no longer present but there is broadband noise from one of the piston baffles.

Case 18

Segment: Oil & Gas

Company: Oil & Gas Company B

Equipment: Reciprocating Compressor

Fault: Valve Leaking

LNG compressors were being monitored by VA, which was not detecting problems. MCM was then fitted to the compressors. We analyzed the results and advised that there were leaking valves that should be attended to at the next overhaul. When the equipment was stripped down, the diagnosis was confirmed. Following the overhaul, the MCM was put back into learn mode to give a new PSD curve, which had a significantly different shape from the earlier one, confirming that we detected the change resulting from the overhaul. Vibration Analysis detected no change whatsoever.

October 2010

• MCM correctly identified that the pump had no major faults

No major faults – all green

Case 19

Segment: Oil & Gas

Company: Oil & Gas Company C

Equipment: LNG Pump

Fault: Shaft Deflection

• MCM trends revealed that the pump was experiencing increased rub energy when the load was too high

• The cause of this was slight movement in one of the shaft bearings causing wear to the shaft and shaft deflection.

• This was confirmed during strip down work on the pump and was related to a design problem that has since been eliminated.

Case 19

Segment: Oil & Gas

Company: Oil & Gas Company C

Equipment: LNG Pump

Fault: Shaft Deflection

• MCM began giving load alarms in September 2010.

• Some inherent friction-related faults were identified in the frequency spectrum.

Segment: Water

Company: Water Distribution Co. B

Equipment: Pump

Fault: Pump Blockage

Case 20

• MCM began giving load alarms in September 2010 and the active power of the pump dropped drastically in December.

• The cause was a piece of wood blocking the pump inlet.

Case 20

Segment: Water

Company: Water Distribution Co. B

Equipment: Pump

Fault: Pump Blockage

• Power from waste generation station.

• Between shutdowns the ID Fan system fouls leading to reduced efficiency.

• MCM identifies this point by recognising the difference in the load conditions of the motor.

Load alarm as power drops off / increases!


Company: Power Generation Company B

Equipment: ID Fan

Fault: Fouling

Case 21

• The trends highlight the gradual change in current between shutdowns, indicating that the system is fouling and that the fan is working harder to overcome this.

• Temporary, short term, changes in power can also be seen to have a large effect on the vibration response of the machine.

Case 21


Company: Power Generation Company B

Equipment: ID Fan

Fault: Fouling

• Frequent alarm and trend responses indicated changes in internal motor conditions.

Green, yellow and blue lines correspond to internal electrical fault

Segment: Oil & Gas

Company:Oil & Gas Company D

Equipment: Pump

Fault: Stator Insulation Progression

Case 22

• The trending showed that there was significant phase current disproportionality in addition to the stator-related trend increases and alarms.

Red line (Ir) and yellow line (Is)

cross over frequently, indicating

inconsistent behaviour between

the phases

Currents in the three phases vary in

shape and separation

Case 22

Segment: Oil & Gas

Company: Oil & Gas Company D

Equipment: Pump

Fault: Stator Insulation Progression

Documents

MCM Case Studies - Ascenixascenix.com/images/4.2_Case_studies.pdf•MCM first gave a warning of a problem on 16th October 2005, and diagnosed a looseness problem. The decision was