Electronics Fuseology Selection Guide 2017 by Littelfuse

More catalogs by Littelfuse | Electronics Fuseology Selection Guide 2017 | 22 pages | 2017-11-12


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Electronics Fuseology Selection Guide 2017 is listed under these categories

Industrial Supply > Electrical & Test > Electronic Components

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fuseology selection guide fuse characteristics terms and consideration factors continued designation was modified to ab in place of ag indicating that the outer tube was constructed from bakelite fibre ceramic or a similar material other than glass the largest size fuse shown in the chart is the 5ag or “midget,” a name adopted from its use by the electrical industry and the national electrical code range which normally recognizes fuses of 9/16”× 2” as the smallest standard fuse in use fuses up to 200,000 amperes for the 600vac klk series information on other fuse series can be obtained from the littelfuse fuses listed in accordance with ul/csa/ance 248 are required to have an interrupting rating of 10,000 amperes at 125v with some exceptions see standards section which in many applications provides a safety factor far in excess of the short circuit currents available fuse sizes size 1ag 2ag 3ag 4ag 5ag 7ag 8ag diameter inches 1/4 – 1/4 9/32 13/32 1/4

fuseology selection guide fuse selection checklist the application guidelines and product data in this guide are intended to provide technical information that will help with application design since these are only a few of the contributing parameters application testing is strongly recommended and should be used to verify performance in the circuit/application ambient temperature effects are in addition to the normal re-rating see example example given a normal operating current of 1.5 amperes in an application using a traditional slo-blo® fuse at room temperature then normal operating current catalog fuse rating —————————————————— 0.75 or 1.5 amperes ——————— 2.0 amp fuse at 25ºc 0.75 many of the factors involved with fuse selection are listed below for additional assistance with choosing fuses

fuseology selection guide fuse selection checklist continued figure 1 chart 1 waveshapes a ip formulas i=k i2t ip2 t t ib current amperes 10 b ip 8 t i ip-kt i2t 1/3 ip2 ipib ib2 t t i ip sin t i2t 1/2 ip2 t 6 c 4 2 l2 t pulse energy .001 ip normal operating current .002 .003 .004 .005 time seconds d .006 ip figure 1 10 fuseholder features and rerating for information about the range of littelfuse fuseholders and specific features and characteristics please consult with a littelfuse products representative or visit our web site www.littelfuse.com e ip or t for 25ºc ambient temperatures it is recommended that fuseholders be operated at no more than 60 of the nominal current rating established using the controlled test conditions specified by underwriters laboratories the primary objective of these ul test conditions is to specify common test standards necessary for the continued control of manufactured items intended for protection against fire etc a copper dummy fuse is

fuseology selection guide ptc characteristics and terms continued leakage current when a ptc is in a tripped state it protects the circuitry by limiting the current flow to a low leakage level leakage current can range from less than a hundred milliamps ma at rated voltage up to a few hundred milliamps ma at lower voltages fuses on the other hand completely interrupt the current flow when tripped and this open circuit results in no leakage current when subjected to an overload current time-current characteristic comparing the timecurrent curves of ptcs to time-current curves of fuses show that the speed of response for a ptc is similar to the time delay of a littelfuse slo-blo® fuse temperature rerating the useful upper limit for a ptc is generally 85ºc while the maximum operating temperature for fuses is 125ºc ambient temperature effects are in addition to the normal rerating ptcs hold and trip rating must be rerated when applied at conditions other than room ambient for

fuseology selection guide typical ptc circuit protection designs the following are examples of typical circuits using littelfuse ptcs in combination with other littelfuse circuit protection devices to provide a comprehensive protection solution contact a littelfuse application expert for design assistance or visit www.littelfuse.com/designcenter or www.littelfuse.com/ptcs for additional information be sure to to veryify specifications and test device performance before use in the end application power over ethernet li-ion battery pack switch/hub powered end station ptc ptc battery connector data pair battery controller ic data pair battery cell phone battery power source equipment pse powered device pd data pair control 3 v5.5mla0402 multilayer varistor data pair signal ground shield ground usb 1.1 usb 2.0 ptc ptc usb port usb port usb controller outside world vbu v5.5mla063 1206l150 outside world v5.5mla0603 1206l150 usb controller d d 2 v0402mhs03 vbus d d 2 pgb1010603

fuseology selection guide standards continued voltage rating parts rated at 32 63 volts must pass a test of 35 amperes or ten times rated current whichever is greater parts rated at 125 volts must pass a test of 50 amperes or ten times rated current whichever is greater parts rated at 250 volts are further defined as either low intermediate or high breaking the low breaking capacity fuses must pass a test of 100 amperes rated current while intermediate breaking capacity fuses must pass a test of 500 amperes and high breaking capacity fuses must pass a test of 1500 amperes ul/csa/ance mexico 248-14 vs iec 60127 part 2 fuse opening times vs meti/miti percent of ul csa iec type f iec type f iec type t iec type t meti/miti rating std 248-14 sheet 1 sheet 2 sheet 3 sheet 5 100 4hr.min — — — — 130 — — — — — 135 60 minutes max — — — — 150 — 160 — 200 2 minutes max 210 —

fuseology selection guide standards continued military/federal standards federal specification w-f-1814 this specification governs the construction and performance of fuses with high interrupting ratings that are approved for federal applications fuses approved to these specifications are on the federal qualified products list write to the following agencies for additional information on standards approvals or copies of the specifications underwriters laboratories inc ul 333 pfingsten road northbrook illinois usa 60062-2096 canadian standards association csa 5060 spectrum way suite 100 mississauga ontario canada l4w 5n6 international electrotechnical commission iec 3 rue de varembe 1211 geneva 20 switzerland naval publications and military standardsform center for military and federal standards 5801 tabor avenue philadelphia pennsylvania usa 19120 defense supply center columbus dscc 3990 east broad street columbus ohio usa 43218-3990 ministry of economy trade and industry meti 1-3-1

fuseology selection guide fuse and ptc products selection guide fuse products fuses provide protection by completely stopping the flow of energy to sensitive circuits if current exceeds the fuse’s operating range the metal wire or strip melts safely within an enclosure littelfuse offers the most extensive range of fuses available and for easy replacement of cartridge fuses littelfuse offers a wide selection of fuseholders including panel mount in-line and surface and thru-hole circuit board mount devices lead free 125 63 32 50 • • • • 0.25 6 32 24 50 • • • • 440 • • 1206 • 1.75 8 32 50 • • • • • 441 • • 0603 • 2-6 32 50 • • • • • 469 • • 1206 1-8 24 32 24 63 • • • • • 501 • • 1206 10 12 15 20 32 150 • • • • • • ul umf 0.25 8 • pse

fuseology selection guide fuse and ptc products selection guide continued ptc products size hold current ihold tuv halogen free rohs lead free agency approvals ur operating temperature range max voltage vmax cur order samples series name 1 view datasheet ptcs positive temperature coefficient increase resistance as temperature increases they are designed to prevent unsafe levels of current while allowing constant safe current levels and their resistance will “reset” automatically when the current and temperature returns to a safe level ptcs are typically used in applications where automatic reset is desired 0402 0603 0805 1206 1812 2920 0603 0.1 0.5a 0.5 2.0a 0.75 3.0a 0.75 4.5a 1.9 3.7a 7.0a 6 12 v 50 a • • • • • • 0.04 0.5a 6 15 v 40 a • • • • • • 0.10 1.10 a 6 15 v 100 40 a • • • • • • 0.10 2.0a 6 30 v 100 a • • • • •

fuseology selection guide legal disclaimers liability disclaimer littelfuse inc its affiliates agents and employees and all persons acting on its or their behalf collectively “littelfuse” disclaim any and all liability for any errors inaccuracies or incompleteness contained here or in any other disclosure relating to any product littelfuse disclaims any and all liability arising out of the use or application of any product described herein or of any information provided herein to the maximum extent permitted by law the product specifications do not expand or otherwise modify littelfuse terms and conditions of purchase including but not limited to the warranty expressed therein which apply to these products specifications descriptions and data contained in this document are believed to be accurate however users should independently evaluate each product for the particular application littelfuse reserves the right to change any information contained herein without notice