1. On analyzing electrical systems
On electrical systems,like mechanical systems,thereare manycalculationswhichdefine
acceptable limitsof functionality. Similarlyalso,withindustrial benchelectrical systemsmanyevents
can occur whichare createdaftera repairor modificationto functionalityhasoccurred. Knowledgeof a
systemalone isnotsufficienttomaintainit,youmustunderstandthe nature of electronicsystems. As
well,knowledge of onlyelectronicsisnotsufficientbecause youmustknow aparticularsystem’s
modificationsandidiosyncrasies.
Whenwe approach a systemcompletelyunknowntous,ourfirsttask isit learnthe system. To
do thisone shouldpayattentiontobigthingsfirstandthenlittle things. The bigthingsare rather
obvioustomost. What is the functionof the equipment? How muchenergyshoulditconsume? What
type of safetymechanismsdoesitemploy? Whatisits mainpowersupplyandwhere doIshut that
supplyoff? Are there anyotherpowersuppliestothe bench? How muchis the benchworthand what
isits life expectancy? Whatisthe life expectancyof the individual components? Isitcurrentlybeing
usedproperly? Doesregularmaintenance indicateareoccurringproblem?And,How muchdoesthe
environmentinfluence the operatingof the equipment?
The little thingstogetto knowinclude wire routingandthe routing’sinfluence oneachcircuit,
programmingcode andshortcomingsof the currentcode,desiredfunctionalityfrommanagementand
operators,the equipmentreactiontopoweroutage orpowersurge and, completenessof drawingsand
modificationsrelatedtothe equipment.
Once we understandthe equipment,we mustunderstandwhatisexpectedof the equipment.
Otherthan alwaysworkandcost the companynomoney,whatismanagement’sunderstandingof how
it functionsinthe businessplanandcan the equipmentbe modifiedorre-taskedtosave the company
moneywithoutsacrificingoutputqualityorquantity. These willguide yourgoalsasyouproceed.
Specifically,observationisthe bestwaytodefine the expectationsfromthe operatorregarding
the equipmentandyouwill be luckytogetan indepthconversationfromsome managersregardingthe
future or eventhe ideal taskof the equipment. There isjustanunderstandingthatitmustdo itsjoband
do itwell. Usuallymanagersdonothave time to understandwhatcouldbe done and,can not sell to
theirsuperiorsthattakingthe equipmentdownforupgrade savesthe companymoney,soyouare stuck
withtryingto make simple repairs quicklysothe equipmentisrunningagain. Thismeansyoumust
understandandknowthe equipmentindepthtogo rightto the problem, thenreportpossible
improvementstodowntime throughupgrade whilethe equipmentisrunning. Powerpointcanbe a
handytool for thistask.
Once you understandthe political environment,youshouldtrytoget the electro/mechanical
environment. Usuallythisisaquicklookaroundthe benchand perhapssome tracingof mainpower
lines,pneumaticpressurelinesand/orwatersupplylinestosee whatcircuitsare influencingthe
operationof the equipment. Manyproblemsgounsolvedbecause plantmanagersandmaintenance
teamshave not lookedatthe buildingasa whole. Iworkedwithone groupthatneededconvincingto
install betterroomairconditioningwhilethe benchwastryingtorate the insulationonacalorimeter
tank. Thisfluctuatingairmade the ratingtask impossible andrequiredsome technical walkthrough
before itwasunderstoodwhatwasneeded. One frequentlyoverlookedaspectof the electronic
environmentisthe powerfactorforsupplypower. Manyinductionmotorsandvariable speeddrives

2. put higherfrequencyenergybackontothe 3 phase linesonlytoinfluence otherequipmentinstrange
ways. A powerfactor metercansolve a lotof burnedoutpowersupplyandunusual fuse blowing
conditions. Onolderequipmentthere waslessknowledge of these issuesand they canfail withgreater
frequencyif notprotectedproperly. WhenIwasworkingwithmercurycontactorsI learnedabout
electromagneticspikingfromrelays. Thisairborn spike causedlocal ramto lose integrityina‘80s built
system.
Afterthe internal andexternal environmentisexamined,youshouldstart tolookat the actual
wiringand the componentsonthe equipment. Electrical drawingsare veryhelpfulfortroubleshooting
but notfor explainingtootherswhere the problemsare unlesstheyhave electrical experience aswell.
Checkfor transformersinsidethe benchthatmaybe overusedand mechanical relaysthatmighthave
become oldor have arcingdamage. Rememberthe relaysinside the componentsaswell. Manyolder
devicesuse mechanical relaysforalarmor on/off control. Proportional on/offcontrol usingmechanical
relayscreatedmanyproblemsbymyexperience.
If there are no electrical drawings,tracingindividual circuitsisthe quickestwaytoa solution. It
isalwaysbetterto have a full drawinginhand,butgettingone made tendstotake time and money
away fromthe immediate problemandcanbe suggestedasan upgrade fora laterdate.Whena wire
leadstoa box,understandingthatbox becomeskeytounderstandingthatcircuit. Hopefullythe box has
a make and model thatis legible. Manycompanieshave instructionmanualsin.pdf formatfor
download. Thisappliestopneumaticandmechanical boxesaswell.
More and more componentsare beingreplacedbyPLC. I watcheda rebuildof arefrigeration
durabilitybenchandthe same functionalitywasputintofive timesless space withsimilarenergy
savingsas well. Butthe costof thisreductionisthe necessityof ladderlogicprograming. Rungs,timers
and,countersreplace wiresandmechanical reedrelays. Now,insteadof searchingthroughelectrical
drawings,yousearchthrough rungsand variablessolvingnetworkproblemsandPLClockupissues.
Once you understandwhatthe code shoulddo,youstill mustverifythatafterthe PLChas done itsjob,
the wiresandswitchesfeedingtoandfromthe PLCdo theirjob.
More to be said,but muchmore to be done.