Examples are provided explaining the fuse graphs of a current limiting fuse. CLS Fuses - Time Current Curves. It is important that the current multiplier and reference voltage be indicated on the TCC plot to avoid misinterpretation. CLPT and NCLPT Fuses - Time Current Curves. We provide sustainable solutions that help our customers effectively manage electrical, hydraulic and mechanical power – more safely, more efficiently and more reliably. The following illustration shows how a time-current curve works. Take note of the current axis. While the primary objective of power system protection is to isolate faults as quickly possible, limiting service interruptions to a minimum cannot be discounted. A fuse’s time-current characteristics can help. Application of Primary Fuses. Eaton’s mission is to improve the quality of life and the environment through the use of power management technologies and services. The current axis may be expressed in amperes and can be scaled in multiples of 10 while the time axis is usually in the range of 0.01s to 1000s. Time-current characteristics are presented graphically on standardized “log-log” paper. In general, time-delay fuses hold 500% of the rated current for a minimum of ten seconds, yet will still open quickly on higher values of current. From these operating times, we can calculate the time interval between the operation of these devices. This is illustrated in figure 6. TIME DELAy /CLASS CC FUSES. continue, fuses must then open before system components are damaged. Transformers - JCQ-(amp)E, E-Rated for Potential & Sm. Time-current characteristic.-The fuse time-current characteristic should be compatible with the time-current characteristic of the load and the time- current characteristic of the circuit components to be protected. A TCC is a two-dimension plot with the current at the x-axis and the time at the y-axis with both axes are in logarithmic scale. privacy, cookies and data protection page, Automotive Reset Circuit Protectors - 120 Series, Fast-Acting Automotive Blade Fuses - ATC Series, ATM Automotive Blade-Type Fuses - ATM Series, Maxi Fuse In-Line Fuse Holder - HHX Series, Limitron Class CC, Time-Delay Fuses - FNQ-R, Limitron Fast-Acting Class CC Fuses - KTK-R, Low-Peak Time-Delay Class CC Fuses - LP-CC, Fast-Acting CUBEFuse 600Vac/dc, 1-100A - FCF_RN, Low-Peak Class CF CUBEFuse With and Without Indication - TCF/TCF_RN, Privacy, cookies & data protection policy, General Purpose Size-Rejecting Class G Fuses - SC, Replacement  fuse links for 250V REN and 600V RES renewable fuses in ratings from 1-600 amps - LKN / LKS, General Purpose One-Time 250V Class H & K5 Fuses - NON, General Purpose One-Time 600V Class  H & K5 Fuses - NOS, Renewable 250V REN and 600V RES Fuses in Ratings from 1-60 Amps - REN / RES, Limitron Fast-Acting 600V, Class J Fuses - JKS 1-60A, Limitron Fast-Acting 600V, Class J Fuses - JKS 70-600A, Low-Peak Dual-Element, Time-Delay, Class J Fuses, 0-60 Amp - LPJ 0-60, Low-Peak Dual-Element, Time-Delay Class J Fuses, 70-600 Amps - LPJ 70-600, Low-Peak Time-Delay Class L Fuses - KRP-C 2001-6000, Low-Peak Time-Delay Class L Fuses - KRP-C 601-2000, HI-CAP, Current Limiting 225-600A Class L Fuses - KRP-CL, Limitron Fast-Acting 250V Class R Fuses - KTN-R, Limitron Fast-Acting 600V Class R Fuses - KTS-R, Low-Peak Dual-Element, Time-Delay 250V, Class RK1 Fuses - LPN-RK 1/10-60A, Low-Peak Dual-Element, Time-Delay 250V, Class RK1 Fuses - LPN-RK 70-600A, Low-Peak Dual-Element, Time-Delay 600V, Class RK1 Fuses - LPS-RK 0-60, Low-Peak Dual-Element, Time-Delay 600V, Class RK1 Fuses - LPS-RK 70-600A, Fusetron Dual-Element, Time-Delay 250V - FRN-R (1/10-60A), Fusetron Dual-Element, Time-Delay 250V - FRN-R (70-600A), Fusetron Dual-Element, Time-Delay 600V - FRS-R(1/10-60)A, Fusetron Dual-Element, Time-Delay 600V - FRS-R(65-600)A, Limitron Fast-Acting  300V Class TFuses - JJN, Limitron Fast-Acting 600V Class T Fuses - JJS, 1⁄4 x 1-1⁄4 Fast-Acting Ceramic Tube Fuses - ABC/ABC-V Series, 1/4" x 5/8" Fast-Acting Glass Fuses - Axial lead discontinued - AGA, 1/4" x 1-1/4" Fast-Acting Glass Fuses. Related Post: Difference Between Relay and Circuit Breaker Characteristics of Fuse and Circuit Breaker. This is illustrated in figure 7. In other words, as the current increases, the pre-arcing time decreases. A typical fuse time current curve is s… S&C also offers Coordinaide™ — The S&C Protection and Coordination Assistant. Time-Current Curves Fuses 16 . Time-Current Curves Circuit Breakers No action to left of curve Trip or clear on and to right of curve All devices should be considered at same voltage 18 . S&C’s Time-Current Characteristic (TCC) Curves are available in Adobe® Acrobat® format as well as in Microsoft® Excel format for your use in other applications. A time current curve (TCC) plots the interrupting time of an overcurrent device based on a given current level. \$\begingroup\$ "the curves for fuses with >= 800mA asymptotically approaches a value that doesn't match their rated current" - I see no evidence for that; all of the graphs still have some slope to them. Figure 1 shows a TCC plot of a fuse and an overcurrent relay. Every circuit breaker has a characteristic curve that reports the manner in which it trips. the melting time) as a function of the prospective current under specific operating conditions. In an article on the Application of Primary Fuses by Hubbell Power Systems, Inc., in order to provide a safety margin against operating variables, the maximum clearing time of the downstream fuse should be no greater than 75% of the minimum melting time of the upstream fuse. TIME-CURRENT CURVE:The graphical presentation of the fusing characteristic, time-current curves are generally average curves which are presented as a design aid but are not generally considered part of the fuse specification. CURRENT IN AMPERES X 10 AT 13800 VOLTS CURRENT IN AMPERES X 10 AT 13800 VOLTS TIME IN SECONDS FS-1 S&C SMU SMU-40 100E FUSE TIME/CURRENT CURVE This side of curve: Fuse element melts, current flow interrupted. 25 and 38 kV Type CLPT current limiting fuse trip curve. 160-630A - Square Body DIN 43 654, 1000V (IEC/U.L.) ABB (ABBN: SIX Swiss Ex) is a leading global technology company that energizes the transformation of society and industry to achieve a more productive, sustainable future. Transformers - JCI-(amp)E, R-Rated for Motor Circuit Protection - JCK/JCK-A, R-Rated for Motor Circuit Protection - JCL/JCL-A, E-Rated for Potential & Sm. Why do we need coordination of overcurrent protection devices? • Select very fast-acting fuses to protect very low withstand components, such as semiconductors. A Time Current Curve (TCC) is a graphical representation of the operating characteristics of overcurrent protection devices at different magnitudes of fault currents. This will bring down the recommended CTI to 0.17s in the above example. IEEE Std 242-2001 [The Buff Book]: IEEE Recommended Practice for Protection and Coordination of Industrial and Commercial Power Systems.(2001). TC curves.png 432×508 73.9 KB 250-800A - Square Body DIN 43 655, 1000V (IEC/U.L.) Short Time (i.e., motor starts/stops) Long Time (i.e., TOL) Table 15-3 recommends a CTI of 0.20 for electromechanical-to-static relay coordination. CLE, HLE, and HCL Fuses - Time Current Curves. The recommended CTIs for coordination of various overcurrent protection devices are listed in IEEE Std 242. In other words, it always up to you! Transformers - JCD-(amp)E, E-Rated for Potential & Sm. Click the +/- accordions below to see the TCC Curves. In order to make the curves more readable, the performance Boca Raton, FL: CRC Press. This was taken from Table 15-3 of IEEE Std 242. Fuse Time-Current Curves. However, when coordination is very difficult, if not impossible, a compromise should be made. Coordinaide lets you quickly and easily select the optimal protective device (e.g., power fuses, TripSaver® Dropout … A time current curve (TCC) plots the interrupting time of an overcurrent device based on a given current level. At this value of fault current, the fuse is expected to operate in 0.074s while the overcurrent relay will operate in 5.73s. 8–15 kV Type CLPT current limiting fuse trip curve. Time-current curves for Littelfuse POWR-GARD®.3 fuses can be found online at littelfuse.com/technicalcenter. Fuses are essentially made up of a metal wire or strip that melts when excessive currents flows through. The figures … The figures along the bottom (horizontal axis) represent current in amperes. Eaton uses cookies to help us give you the best experience on our website. Characteristic curves (time/current characteristic curves) The time/current characteristic curve specifies the virtual time (e.g. The "Time-Current" Fuse Curves indicate how fast a fuse will interrupt the circuit based on a varying amount of current. These curves are provided by the manufacturers of electrical overcurrent interrupting devices, such as fuses and circuit breakers. Fuses Time Current Curves Eaton’s mission is to improve the quality of life and the environment through the use of power management technologies and services. Table 15-3 recommends a CTI of 0.22 for fuse-to-electromechanical relay coordination. The area to the right and above the device time-current curve is the ‘operate’ region while the area to the left and below the device time-current curve is the ‘no operate’ region. It trips Difference between relay and circuit breakers at littelfuse.com/technicalcenter a specific value of fault current the! 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