Abut Fusetek FUSETEK is a 100% family wned Canadian cmpany and we have been serving the Canadian electrical industry and it s custmers fr ver 37 years. Originally, under the name f Tekelek-Drman Smith, we brught the first dual CSA/IEC apprved fuses t the Canadian market. We have dne much pineering wrk that has since becme an accepted standard with equipment builders and users alike. Tday, Fusetek is partnered with Littelfuse, SIBA and GEC and tgether we ffer the mst cmprehensive range f fuse prducts available in Nrth America. Our services run frm c-rdinatin studies t fuse surveys t fuse seminars. We can custm design and manufacture fuses fr a specific applicatin r surce an ddball fuse frm anywhere in the wrld. With distributrs and agents frm cast t cast, we can quickly respnd t ur custmers needs. N matter what aspect f fusing yu re invlved with - Fusetek can be f service. Abut Fusesft On-Line Over the years, Fusetek has prvided many fuse seminars acrss the cuntry in an effrt t educate custmers abut fuses and fuse applicatin. Always, we have stressed prduct understanding befre prduct specificatin. This sftware is a natural extensin f what we have been preaching fr the last 35 years. The fact that there has been much talk and debate ver crrect fuse prtectin fr cntrl (and IEC cntrl in particular) and mre recently a resurgence in fuse interest due t Arc Flash cnsideratins nly underscres the imprtance f crrect fuse applicatin. Until nw there has been n ecnmical and easy way t prtray the interactin f the varius circuit cmpnents that cme int play in tday s electrical systems. FUSESOFT simplifies the selectin f fuses ver a brad range f applicatins. It cntains many mre device chices, and where the riginal Fusesft was table driven, ur new Fusesft On-Line determines fuse chice by cmparing curves and znes, s the variables can be infinitely changed and Fusesft On-Line will keep up with inputs. Whether Fusesft On-Line is used t select prper fuse size fr a prject r mill applicatin, r used as an educatin tl, there has never been a clearer, easier way t understand fuse applicatin. As everything these days, Fusesft On-Line is evlving t meet the requirements if ur custmers and markets. If yu ntice any errrs, r have suggestins t make it better, we d appreciate hearing frm yu. E mail inf@fusetek.cm Tll free tel. (800) 479-3875 Tll free fax (800) 866-7690
Fusesft On-Line - General infrmatin Fusesft On-Line will run in any f tday s ppular brwsers such as Internet Explrer r Mzilla Firefx. Yu may save Fusesft On-Line as a bkmark as yu wuld any ther website. Screen reslutin Fusesft On-Line was designed t run with a screen reslutin f 1280 x 800 r greater. Althugh Fusesft On-Line will start and run at lwer screen reslutins, sme screen elements may be misaligned r ff screen - requiring scrlling t see them all. Starting Fusesft On-Line When yu first start Fusesft On-Line, yu will be taken t the hme screen. The hme screen has the Help icn with the Mdule and hme page icns are arranged alng the bttm. Click n the mdule f yur chice. T return t the hme screen, click n the Hme Page icn. The mdule tlbar will remain at the screen bttm in all the mdules. When a mdule is first started, yu will be presented with essentially a blank screen. When a mdule is first started, mst f the input fields will be blank, as will the main graph area. Input parameter area Graph Area As yu enter the basic circuit parameters int the input area, the graph will be generated shwing yur selectins. Navigate frm field t field by clicking r tabbing t the new fields. Once the fuse type is selected, Fusesft On-Line will select and draw the apprpriate fuse curve. This icn will draw yur attentin t hints r warnings.
File saving and printing Print an applicatin by selecting Print frm yur brwser s tlbar. T save yur applicatin, click n the Save t PDF buttn and specify the flder t save the file in. Yur applicatin can als be printed frm this PDF file nce dwnladed. Befre starting a new applicatin, click the Reset Frm buttn t clear the data. Failure t d s may result in inaccurate results, r delays in redrawing the screen elements. Help File On-screen help is available by clicking n the be printed ut t serve as a handy reference. icn n the Hme page. This manual can als
Mtr Applicatin Mdule Click n the Mtr Applicatin icn This mdule selects apprpriate fuse ratings fr full vltage acrss-the-line mtr starting applicatins. See nte at The end f chapter re: reduced vltage starting applicatins. When the mdule in first started, the fields will be blank as will the chart area. As yu select data frm the drp dwn fields, the graph will start t fill in. Default full lad and starting currents are supplied by the prgram. Yu may alter these default values t match actual knwn values if different frm thse supplied. Small differences between yur actual values and thse supplied by the prgram will nt have any impact n fuse sizing. Similarly, slight difference is system vltage (eg: 600V vs. 575V ) will nt affect the fuse sizing. Cntinue dwn the input fields entering r selecting data. System vltage: select frm the available drp dwn chices. 1 r 3 phase. In mst cases, this will be pre-selected fr yu. Mtr HP (if 600V r less) Run-up time. (the default is 8s.) Overlad relay mfr./type Fuse I type. Select the type f fuse t use. Fuse II type. Select the 2 nd fuse type.(ptinal) Mem field (cmments will be saved r printed with file) Reset and File save buttns
Once the basic circuit data is input, Fusesft On-line will draw the graph. After the first fuse type is selected, Fusesft On-Line will aut-select a fuse rating based n yur inputs and draw the fuse s time current curve n screen. Yu may verride the recmmended rating by selecting a different amp frm the Fuse Amp Rating drpdwn bx. The screen will re-draw t shw yur new chice. Use this functin t d what-if scenaris r duplicate a field cnditin. A secnd fuse type may be selected. In this way, it is pssible t chse alternate fuse types and ratings fr cmparisn with the first fuse type. The aut select feature and manual verrides functin as fr the 1 st fuse chice. Once yu have cmpleted an applicatin, yu can save it as a PDF by clicking the Save t PDF buttn, print it using yur brwser s print cmmand, r clear the frm and start anther applicatin. r clear the frm by clicking n the Reset Frm buttn. Click the Reset Frm buttn t clear all the variables frm memry. Failure t d s may result in slw screen re-draws.
What is Crdinatin? Crdinatin is the prcess f selecting prtective devices t interact in the best way pssible t prtect the cntrl equipment. In the mtr starting circuit, the mtr, the verlad relays and the fuse all interact with each ther t prvide running (verlad) prtectin fr the mtr and ver current (shrt circuit) prtectin fr the mtr cntrl. Ideal mtr/fuse/verlad c-rdinatin is achieved when the fuse is selected such that the mtr can perate thrughut its nrmal range f running/starting currents withut verlad r fuse peratin. The verlad relay can perate under all nrmal cnditins withut nuisance fuse peratin, but the fuse will still perate quickly n levels f current that wuld therwise damage the cntrl. Fusesft On-Line uses the fllwing prtectin parameters: 1. The verlad relay must perate befre the fuse n lcked rtr currents and less. The fuse must nt be damaged during this prcess. A fuse that perates at the same time as the verlad makes the verlad redundant. Overlad relays are designed t prvide clse running verlad prtectin fr mtrs a functin that fuses are nt designed fr. Fuses cannt prvide the same clse verlad prtectin, s resist the urge t undersize yur fuses thinking yu are getting better mtr prtectin. The mtr must start and run up t speed withut fuse peratin r damage. This seems bvius but many fuse utages ccur simply because the fuse is t small. 2. The fuse must perate befre the verlad relay n currents apprximately 10-12 times mtr full lad amps and greater. This is t prtect the cntrl cmpnents frm excessive interrupting duty. These parameters give us a "crdinatin windw" bunded by the; Overlad relay cld trip (light blue) Overlad relay ht trip (light red) Mtr Lcked rtr (green) Damage pint f cntrl (Yellw) The fuse curve (dark blue) must pass thrugh this "windw" t meet the abve requirements. This crdinatin will ffer the ptimum cmbinatin f mtr starting capability and ver-current prtectin. It will result in less fuse peratins (dwntime) and enhanced prtectin fr the mtr and cntrl gear. Any fuse whse curve passes thrugh this "windw" will give gd ver-current prtectin and shws why fuses shuld be chsen n the basis f their curve - nt their amp rating.
This methd f selectin will als ensure that yu have the smallest practical fuse rating, which will enhance yur verall cmpliance with Arc Flash requirements. A suitable fuse chice will be cnfirmed with a message - Fuses t small r large will result in a red warning message. r In sme applicatins, Fusesft On-Line will nt be able t find a suitable match and will display a message similar t; This can result if the fuse series chsen des nt have a high enugh rating available, r if the available chices are t far ut f range in either directin (t small r large) t fulfill the prgram parameters. In this case, manually select a fuse rating t draw the curve n screen, r chse a different fuse type. Sme cmmn field cnditins. Fuses t small. Fuse curves that pass t the left f the crdinatin windw risk nuisance blwing during nrmal mtr starting cnditins. These cnditins are nrmal and shuld be cleared by the mtr starter verlad relay/cntactr. In ur example n the right, althugh the 100A fuse may allw this mtr t start, it culd be damaged and perate at a later time. If there are any variances in mtr accelerating time r starting current, the fuse wuld blw. On lcked rtr, the fuse will definitely perate in advance f the verlads relays. This situatin culd arise due t; Imprper sizing. Using a fast acting in place f a time delay fuse Nt wanting t g up t the next switch r clip size t accmmdate the crrect fuse. Deliberately putting in fuses n the small size t prtect cntrl better r t reduce Arc Flash energy This type f crdinatin will result in high fuse cnsumptin and excessive dwntime as a result. Generally, if yu are cnstantly blwing fuses fr n apparent reasn, they are t small fr the applicatin.
Fuses t large Fuses that are installed t large fr an applicatin are a much bigger prblem. Because they are s large, they will nt perate as ften, lulling the user int thinking everything is kay. Fuse curves that pass t the right f the crdinatin windw frce the cntrl gear t perate n current levels beynd their rated breaking capacity (yellw line). This situatin culd arise due t: Indiscriminate use f the 300% CEC sizing rule. Replacing a fast acting with a time delay fuse. Nt wanting t g t a lwer switch r clip size. Imprper sizing Fuse ver sizing will result in mre wear and tear n the cntactrs and verlads and in wrst case cnditins, the cntrl culd fail cmpletely. If yu are ging thrugh a lt f verlads and cntactr kits, check t make sure yur fuses are nt t large. Sme cmbinatins f vltage/mtr/fuse type may result in nt being able t select a curve that is ideal. This culd be because: Excessive lcked rtr currents (particularly n small HP mtrs) have reduced the crdinatin windw size. Eurpean verlad relays generally have a lwer breaking capacity and s reduce the crdinatin windw. Fuse curves in lwer ratings having large 'gaps' between ne rating and the next, making it harder t find an ideal match. This is nrmal. In these instances, yu must chse t d ne f the fllwing: Chse a fuse curve that passes t the left f the windw. This will increase the risk f nuisance blwing and dwntime. This risk is reduced by the fact that mst small mtrs are ften up t speed in less than 5 secnds. Chse a fuse curve that passes t the right f the windw. This can put additinal stress n the cntrl cmpnents as the takever pint f the fuse has been increased. This risk is reduced by the fact that the current levels in questin are seen infrequently. There are a few cmbinatins where Fusesft On-Line may select this ptin. This is likely because the next lwer size wuld nt allw a mtr start.
Standard vs. Heavy Duty applicatins The recmmendatins f this prgram are based n the fllwing assumptins: Lcked rtr (starting current) f 6X the nrmal full lad amps. 4 evenly spaced starts per hur. An ambient enclsure temperature f 32*C max. An accelerating time f 10 secnds max. If any f yur perating parameters exceed the abve cnditins, it may be necessary t increase yur fuse size. Hw this affects yur crdinatin can be seen by manually selecting the desired fuse amp rating. Reduced Vltage starts Althugh this prgram is fr full vltage direct-n-line starting applicatins, it can als be used fr reduced vltage starting applicatins if the actual starting current is knwn. Select yur mtr Vltage and HP rating and accelerating time as yu nrmally wuld. Then manually alter the starting current value t match yur applicatin. Fusesft On-Line uses starting current t calculate fuse sizing, s the prgram will still select the crrect fuse. Because reduced vltage starters result in lwer inrush currents t the mtr, it is pssible t chse smaller fuse ratings as a result. Smetimes t small! Fusesft On-Line will nt allw a fuse rating t be chsen less than 125% f the circuit FLC and will display the fllwing message: N Damage Prtectin The IEC 947.4 is an elabratin f the ld Class "C" prtectin intrduced t Canada several years ag. Bth these specificatins aim at prviding "n damage" prtectin limits fr cntrl gear. N damage is defined as: ".. light cntactr cntact welding easily separable with a screwdriver, and n permanent alteratin f the Overlad relay trip curve.." Fusesft On-Line identifies the verlad relay as the weak link in the cmbinatin starter chain and it is verlad withstand that is shwn in the c-rdinatin. The cntactr s withstand will always be greater that the verlad relay's, s fuses that prtect the verlad will als prtect the cntactr. Fr instance, a 20A cntactr may have an verlad relay blck, r heater installed t prtect a small mtr rated at say, 5A. The withstand limit f this small verlad is much less than that f the cntactr. Therefre, devices chsen simply t prtect the cntactr wuld nt prvide adequate prtectin fr the verlad relay.
Arc Flash cnsideratins. Arc Flash is prmpting users t re-examine their electrical systems, and in particular, their vercurrent prtectin. In the case f fuses, the tendency is t try t reduce the fuse size t as lw a rating as pssible t reduce the incident energy during a fault. It is ur view that the fuse rating shuld be applied as small as practical. A fuse size that is t small fr an applicatin will trade lwer Arc Flash energies fr increased dwntime. This is nt a practical slutin in the real wrld. In practice, mst HRC fuse installatins using 600A r smaller fuses will result in a Hazard Risk Categry 0 s there is little t be gained by reducing fuse sizes trying fr that nth degree f energy reductin. Fusesft On-Line will select the fuses with the ptimum balance f mtr starting capability and prtectin fr yur cntrl. In General Class C, Class J, Class RK1 r Class CC fuses will prvide Type 2 d damage prtectin fr IEC cntrl. Fr Nrth American NEMA rated cmpnents, any HRC fuse will effectively prvide "n-damage" prtectin. Series rated requirements will als be satisfied by sizing the fuses as recmmended. HRC fuses up t 600A prvide the lwest Arc Flash Hazard Risk categry pssible (0). Incremental reductin f fuse size is cunterprductive.
Transfrmer Applicatin Mdule Click n the Transfrmer Applicatin icn. This mdule selects the apprpriate fuse rating based n user input transfrmer circuit variables. When the mdule in first started, the fields will be blank as will the chart area. As yu select data frm the drp dwn fields, the graph will start t fill in. Default full lad and inrush currents are supplied by the prgram Select transfrmer type. This makes a difference t the inrush characteristics Enter system vltage n primary Select 1 r 3 phase (this is usually preselected fr yu) Enter transfrmer size in kva Enter magnetizing inrush factr (12 is default) Select if secndary vercurrent prtectin is present r nt. Chse first fuse type Chse secnd fuse type and rating (ptinal) Enter any ntes befre saving r printing. Reset frm and Save buttns Basic circuit data is calculated frm the vltage and Kva inputs. It is nt changeable. Selecting whether the secndary has verlad prtectin r nt has n impact n the prgram s selectin criteria, but will alter the maximum CEC allwed fuse size as a percentage f the primary FLC. This is nly an infrmatin field. Once yu have cmpleted an applicatin, yu can print it, save it as a PDF by clicking the Save t PDF buttn r clear the frm and restart by clicking n the Reset Frm buttn. Click the Reset Frm buttn t clear all the variables frm memry. Failure t d s may result in slw perfrmance.
Ntes n use. When a transfrmer is energized, the primary windings draw a surge current while the magnetic flux is being established. The primary windings are their wn lad, and this inrush ccurs any time the transfrmer is energized, regardless f whether the secndary side is laded r nt. A fuse curve will be selected s that it allws this magnetizing inrush t pass withut fuse peratin. This means the fuse curve must pass t the right f the magnetizing inrush curve by a suitable margin t allw fr tlerances. Fr the magnetizing inrush factr field, the prgram defaults t the rule f thumb 12X FLC inrush. If yu knw the inrush characteristics f yur transfrmer, enter a number that is a multiple f the transfrmer FLC. Smaller inrush currents allw smaller fuses t be used. Fusesft On-Line will chse a fuse that passes the inrush pint by a minimum f 20% t avid fuse damage r nuisance utages and prvide a message similar t; Selectins t far ut f range will shw ne f the messages: r A secnd fuse type may be selected fr cmparative purpses. The aut-size functin wrks the same way as fr the first fuse type. In this way, it is pssible t chse different fuse types and fr cmparisn with the first fuse chice. In sme instances, a fuse selectin may seem large relative t the transfrmer inrush. The smallest fuse that can be used is 125% f the circuit FLC. This is dictated by ur Canadian Electrical cde which impses a maximum 80% circuit lading (125% f circuit FLC). S even thugh a fuse s characteristic may be capable f energizing the transfrmer, it still has t meet these CEC minimums. A message will be shwn if a fuse is t small t meet these requirements. Transfrmer size is expressed in kva. Imprper entry here will result in incrrect inrush and full lad current values. Examples; 4MVA = 4000 1000kVA = 1000 1000VA = 1 100VA =.1 50VA =.05 Transfrmer magnetizing inrush defaults are as fllws. The inrush factr verwrite field alters the 0.1s inrush nly. 0.1 secnd inrush 0.01 secnd inrush Pwer Distributin Transfrmer 12X FLA 20X Cntrl Transfrmer 12X FLA 25X Lighting ballast 12X FLA 40X
Fuses in parallel. Large transfrmers may require a larger fuse rating than is available in a single bdy fr a given series. It is permissible and standard practice t parallel fuses t get these higher amp ratings. Selectins are prvided fr duble and triple barrel arrangements n certain fuse types. Fr fuses in parallel, general cnsideratins are; Interrupting rating Minimum breaking current Amp rating Time current curve is the same as fr a single barrel f the same series. - is a multiple f the single barrel m.b.c - is a multiple f the single barrel rating - is multiple f single barrel curve rdinates (current)
Capacitr Applicatin Mdule Click n the Capacitr Applicatin icn This mdule will select a fuse based n the calculated capacitr full lad amps and any de-rating factrs selected. Enter system vltage Select 1 r 3 phase.(this is nrmally preselected) Enter capacitr size in kvar Select Yes if yur installatin meets these Chse fuse type Enter any ntes r cmments befre saving r printing Reset Frm and Save buttns. When the mdule is first started the fields and the graph area will be blank. Once yu input vltage and kvar infrmatin, the graph will generate. The red line is the damage curve f the capacitr enclsure. T prvide adequate prtectin against capacitr case rupture, the fuse curve must lie t left f this curve. This capacitr damage curve prtrayed is an average f several different mfr s and types f capacitrs. If a suitable fuse cannt be fund fr yur applicatin, it wuld be best t btain the specific capacitr data frm ur supplier and give us a call. The prgram will calculate the nminal capacitr FLA and select a fuse rating based n the input vltage and calculated capacitr FLA. The initial fuse selectin is based n 175% f capacitr FLA. This factr takes int accunt the charging currents f the capacitr it is installed n, as well as variables such as harmnics, manufacturing tlerances, and ver vltages.
De-Rating cnsideratins. If capacitrs are subjected t repeated switching duties, r are part f a larger capacitr bank, the fuse size must be increased t allw fr the additinal charging currents present. If Yes is selected fr the Des this installatin experience repeated switching. Field, the fuse size is increased by a factr f 1.6X the nrmal size. This is t ensure that increased heat generated by repeated switching can be dissipated, and that if healthy capacitrs dump int failed units, that the fuses n the healthy capacitrs are unaffected. When assessing the fuse selectin, check t ensure that the fuse curve (blue line) lies t the left f the capacitr damage curve (red line). This will ensure that the capacitr is nt subjected t current levels that culd cause case rupture. Sme time delay fuses cannt be selected using this 1.6X factr withut tuching r crssing the capacitr rupture curve. In this case, it is best t select a fast acting fuse instead. If a fuse curve tuches r crsses the capacitr damage curve, the fllwing message will be displayed; If a fuse is chsen that is less than 125% f capacitr FLC the fllwing message will be shwn. Open Letter t all users f fuses n capacitr circuits. Over recent years, there have been many questins regarding fuses used n capacitr circuits. The use f capacitrs fr pwer factr crrectin/pwer cnditining is increasing daily, and many capacitrs use external HRC fuses t 'prtect' the capacitrs. The area f fuse/capacitr applicatin is a difficult ne due t the large variatins in cnnectin variatins, field and circuit cnditins, and lack f specialized knwledge in all these disciplines frm any ne surce. We are issuing this bulletin t address sme f the cncerns and applicatin variants. Althugh this article is aimed at medium vltage users, the cmments still apply t 600V r less circuits. Generally, the cnsequences f misapplicatin n lw vltage are nt as spectacular as medium vltage. The Fuse's Rle First, we must understand several aspects f HRC fuses as used n capacitrs. The fuse des nt 'prtect' the capacitr - but acts as an emergency 'discnnect device' shuld the capacitr develp an internal fault, the whle idea being t discnnect the capacitr frm the supply befre its case ruptures. The fuse cannt ffer any degree f verlad prtectin fr the capacitr due t the necessity f using a high amp rating (relative t the capacitr FLA) t pass the charging current withut nuisance peratin.
Mst medium vltage fuses are what are termed 'partial range' devices in as much as they are nt capable f reliably interrupting lw vercurrents n the rder f less than 300-400% f the fuse rating. Generally, the shrt circuit perfrmance f tday's current limiting fuses is s gd, that the use f higher fuse ratings still prvides excellent prtectin against capacitr case rupture. If we cnsider the abve, it is apparent that there is nthing t be gained by fusing t small, and indeed, putting the fuse in a situatin where nrmal perating transients culd cause peratin is t be avided. With this in mind - it is advisable use larger fuse ratings while still prtecting the capacitr against case rupture. In this manner, the fuse is kept frm perating until the capacitr actually develps an internal fault. In terms f applicatin n capacitrs - the fllwing cnditins must be kept in mind. Prximity f ther capacitrs. Other capacitrs can 'dump' int failed capacitrs causing premature fuse peratin f the fuses n the gd capacitrs. Tlerances n capacitrs can run as high as 15%, s this verage has t be allwed fr. Harmnics. The higher the harmnic current r frequency - the mre heating effect it has n the fuse, s this must be addressed thrugh de-rating f the fuse (ie: a larger rating) Repeated switching duty. This creates greater heat buildup in the fuse, s it has t be increased in size t be able t absrb and dissipate this additinal heat. High ambient temperatures (greater than 32 deg. C) inhibit the fuse's ability t dissipate heat t surrunding air and may require fuse de-rating (ie: higher rating). Lse cnnectins can als cntribute additinal heating int the fuse. Failure t replace fuses in sets f 3 n 3 phase circuits. Circuit cnditins that cause ne fuse t perate, culd have damaged ther fuses. Unless these fuses are replaced als, they culd perate prematurely r unpredictably at a later date. In many cases, particularly if any f the abve cnditins are encuntered it can result in a fuse that is underrated fr the applicatin. This in turn results in nuisance peratin at best, r catastrphic failure in wrst case scenaris (particularly in HV circuits).
Prgram Limitatins and Disclaimer Certain assumptins have had t be made in the interests f simplicity and prgramming. Prgram defaults and assumptins have been discussed in each mdule. This prgram has tried t prtray the characteristics f the varius devices as accurately as screen reslutin, scaling allws. The device infrmatin prtrayed is accurate t the best f ur knwledge. Hwever, it is the respnsibility f the user t verify the infrmatin supplied. This prgram is intended as a truble shting and educatin tl. Althugh the results will be reasnably accurate, Fusesft On-Line is nt intended t replace r be used in lieu f frmal engineering practices. In the case f Arc Flash, where legal cnsequences are tied t the Arc Flash certificatin prcess, frmal third party assistance shuld be sught. The infrmatin in this mdule, while reasnably accurate, is nt a substitute fr this prcess. There may be sme cnditins that Fusesft On-Line cannt cater t. In this case, we wuld encurage yu t cntact ur ffices. Agents and Dealers Our prducts are available acrss Canada thrugh a cmprehensive netwrk f dealers and representatives. Fr a cmplete listing r t find the ne nearest yu, please visit ur website at: www.fusetek.cm Updates and crrectins Updates will be psted n ur website as and when they becme available. Like any new prgram, there are bund t be errrs and missins that have nt been tested fr. If yu encunter prblems r have any suggestins t imprve this prgram, we d like t hear frm yu. Our E mail is: inf@fusetek.cm