This is what elec calc™ software does in order to get as close as possible to the real phenomenon. The accurate calculation of the let-through energy must, therefore, integrate a chronological cumulation of the energies produced by each source. be the easiest way to reduce your households elec- tricity bill and perhaps help the.
Ngày gi bài: S lt c: 393 ây là mt phn mm nh gn và min phí hoàn toàn, giúp các bn thit k v mch in mt cách nhanh chóng. The protections associated with these different sources may not react at the same time to the short circuit current that they generate. Bob has a stereo that operates at 120 V, using 2.5 A of current. Solve Elec 2.5 Phn mm v s mch in trong Vt lý. Multiple sources: a fault can be supplied by several sources, each contributing to the short circuit current. surface on which zinc has been deposited by the process of hot dipping or elec. It is then advisable to calculate an equivalent thermal current which replaces in the formulas the current Ik.Įlec calc™ takes into account the influence of this continuous component when the standard used requires it. It depends on the disconnection time and the value of the X / R ratio of the circuit at the fault point. The influence of this continuous component is especially noticeable when the point of fault is close to the sources. If we want to be more accurate, we must take into account the DC component of the fault current. Taking into account the DC component: in the formulas mentioned above, we have considered that the value of Ik is the RMS value of the AC component of the prospective fault current. It is this limited value which must be compared with the admissible thermal stress of the conductors.
The limitation performance of a circuit-breaker is given by the manufacturer in the form of limitation curves: Use of limiting circuit-breakers: certain ranges of equipment are designed to prevent the establishment of fault current, by letting only a current of limited intensity. It is, therefore, necessary to check the cable withstand for all types of short circuit current. Note that in the event of fuse protection, the maximum energy can take place during the minimum short circuit because the melting time may be longer. AP 2.5 a Redraw the circuit with all of the voltages and currents labeled. There is, therefore, a natural limitation of the let-through energy. AP 1.2 To solve this problem we use a product of ratios to change units from. Use of fuses: the melting time of a fuse is generally much shorter than the operating time of a circuit breaker for high short circuit currents. However, other possibilities can overcome this increase in section. In the event of a thermal stress problem, it is always possible to oversize the cross-section of the conductors, thus increasing their admissible thermal stress.
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