ep-5-pms-failure analysis (mekeni food corp).ep

8/10/2019 EP-5-PMS-Failure Analysis (Mekeni Food Corp).EP

http://slidepdf.com/reader/full/ep-5-pms-failure-analysis-mekeni-food-corpep 1/18



Color SurfaceShape CorrosionDimensions Photograph

Fracture Type Pits



Spot tests OdorSp. gr. tests Vise

Hammer Magnet



Problem statement Analysis ProcedureConclusions Economic impactRemedy



Motor System



A

PRIMARYMOTORFAILURE(OVERHEATED)(1)

EXCESSIVE

CURRENT TOMOTOR

B

EXCESSIVECURRENT IN

CUIRCUIT

FUSE FAILSTO OPEN

C

PRIMARYWIRINGFAILURE(SHORTED)(3)

PRIMARYPOWERSUPPLYFAILURE(SURGE)

(4)

PRIMARYFUSEFAILURE(CLOSED)(2)



The analysis starts with theevaluation of the first gate, gate Aand proceeds downward. This

procedure is based in thesuccessive elimination of causes toobtain the minimum cut set.



1. The first gate A is putin the top left-handcorner.



2. A is an OR gate and isreplaced by its inputsvertically.



3. B is an AND gate andis replaced by its inputshorizontally.



4. C is an OR gate and isreplaced by its inputsvertically.



This means that overheating of the motor can be causedby either of the following events:

Primary motor failure (1),Primary power supply failure (4) and primary fusefailure (2),Primary wiring failure (3) and primary fuse failure (2).



Diagram of Compressed Air System

PC

NON-RETURNVALVE

PRESSURERELIEF VALVE

PRESSUREREDUCING VALVE

INSTRUMENTAIR SYSTEM

AIR RECEIVER



RECEIVEREXPLODES

AIR FLOW INTO RECEIVEREXCEEDS FLOW OUT ATPRESSURE DANGER LEVEL

PRESSURE RELIEF VALVE FAILSTO GIVE ADEQUATE DISCHARGEAT PRESSURE DANGER LEVEL

PRESSURE REDUCINGVALVE FLOW LESSTHAN COMPRESSIONFLOW

PRESSURE CONTROLLOOP CAUSESCOMPRESSOR TO RUN

IN – CORRECTDESIGN

OTHERCAUSESDIRT

G H I



PRESSURE REDUCINGVALVE FLOW LESSTHAN COMPRESSIONFLOW

IN – CORRECTDESIGN

INSTRUMENTAIR SYSTEMPRESSURE

ABNORMALLYHIGH

SEE SUBTREE

A

B

PRESSURE CONTROLLOOP CAUSESCOMPRESSOR TO RUN

INSTRUMENT AIRSYSTEM PRESSUREABNORMALLY LOW

OTHERCAUSES

B * F

AIR FLOW OUT

OF AIR SYSTEM(DEMAND +LEAKAGE)ABNORMAL ANDEXCEEDSPRESSUREREDUCING VALVECAPACITY

AIR FLOW OUT OF AIRSYSTEM NORMAL BUTFLOW IN ABNORMALLY LOW

SEE SUBTREEE

SUBTREE

PRESSURE REDUCING VALVEPARTIALLY OR COMPLETELYSEIZED SHUT OR BLOCKED

DIRTOTHERCAUSES

C D

ep-5-pms-failure analysis (mekeni food corp).ep

Documents