General information on current-limiting fuse-links. The main characteristics of the CNC fuse-links. Construction. Operating.

Transcription

1 General information on current-limiting fuse-links The high-voltage back-up current-limiting fuse-links are designed for protection of systems which include transformers, against the destructive results of short-circuits and overloads, by limiting the thermal and electrodynamic effects of the short-circuit currents. The fuse-links are complying with the industry standards - IEC :2002, DIN and IEC and can be used both in outdoor and indoor applications. The main characteristics of the CNC fuse-links High breaking capacity up to 50 ka imitation of the short-circuit currents at low levels ow power dissipation more energy savings and less heating Reliable interruption of the critical currents Minimum breaking current is relatively low, starting from 3xIn ow switching voltage lower than 60 kv ow level of the cut-off current Unlimited lifetime due to the usage of pure silver melting element Same design for both indoor and outdoor usage Reliable proofing against humidity penetration of the fuse-link interior Highly qualitative raw materials and components. Construction The melting elements, consisting of pure-silver wire or strip, having variable sections, are precisely wounded on a ceramic carrier, ending with copper terminal parts. Inside the cylindrical cavity of the carrier is a helical wire with the role of activating the striking system. The striker is used to indicate the blown of the fuse-link and it also can activate other systems. There are also models without striker. The carrier system is introduced in a ceramic tube, sealed at ends with protective caps of nickel-plated copper, which are also acting as contacts when mounting in the basement. The inside space of the tube is filled with material for extinguishing electrical arcs, made of quartz sand with tight-controlled purity and granularity. Inside the fuse-link tube all the contacts are made through spot welding. The cooper caps are mechanically attached to the ends of the tube and proofed against humidity penetration through the use of O-shaped seals of high-temperature resistant rubber. The caps, which are the contact parts of the fuse-link, are of two types, according to specifications of DIN and IEC : Diameter of 45 mm (series: EA, EPA, EMA, EMPA) Diameter of 56 mm (series: EB, EPB, EMB, EMPB) Operating When the current is between the minimal breaking and the nominal breaking values the fuse element melts and evaporates, appearing the electrical arc. The arc is cooled and extinguished by the extinguishing element of the fuse-link, thus ensuring the protection of the main circuit against damages. Product series 1 Contact Diameter Tube Diameter With Striker Without Striker 45 mm 45 mm EPA EA 75 mm EMPA EMA 56 mm 45 mm EPB EB 75 mm EMPB EMB

2 Technical data Product Code Rated Voltage Un (kv) Rated Current In Rated Breaking Capacity I1 (ka) Minim Breaking Current I3 Power Dissipation Cold Resistance ength Diameter Weight (W) (mω) (mm) (mm) (kg) E(P)A/B-7,2-2,5 7,2 2, , ,1 E(P)A/B-7,2-4 7, , ,1 E(P)A/B-7,2-6,3 7,2 6, , ,1 E(P)A/B-7,2-10 7, , ,1 E(P)A/B-7,2-16 7, , ,1 E(P)A/B-7,2-25 7, ,1 EM(P)A/B-7,2-31,5 7,2 31, ,6 17, ,3 EM(P)A/B-7,2-40 7, , ,3 EM(P)A/B-7,2-50 7, ,7 9, ,3 EM(P)A/B-7,2-63 7, ,9 5, ,3 EM(P)A/B-7,2-80 7, ,3 E(P)A/B-12-2,5 12 2, ,6 E(P)A/B , ,6 E(P)A/B-12-6,3 12 6, , ,6 E(P)A/B , ,6 E(P)A/B , ,6 E(P)A/B ,6 EM(P)A/B-12-31, , ,6 28, ,9 EM(P)A/B ,6 22, ,9 EM(P)A/B ,2 15, ,9 EM(P)A/B ,9 8, ,9 EM(P)A/B ,5 6, ,9 E(P)A/B--2,5 2,5 31,5 8 19, ,8 E(P)A/B , , ,8 E(P)A/B--6,3 6,3 31, , ,8 E(P)A/B , , ,8 E(P)A/B , , ,8 E(P)A/B , , ,8 EM(P)A/B--31,5 31,5 31, ,1 54,9 75 4,5 EM(P)A/B , ,1 43,9 75 4,5 EM(P)A/B , ,5 30,7 75 4,5 EM(P)A/B , , ,5 EM(P)A/B , ,2 12,8 75 4,5 2

3 Time-current characteristic and cut-off current diagram Current (Aef) Current (Aef) Cut-off current Cut-off current Pre-arcing Time (s) Pre-arcing Time (s) Prospective short-circuit current (Akef) Prospective short-circuit current (Akef) The time-current specifications are for a temperature of O C of the surrounding environment. If the fuselink is to be used in closed environments with other sources of heat, the user should contact the manufacturer for choosing the right models of fuse-link. 3

4 Dimensions EPA, EPB U n [kv] 7,2 12 [mm] U n [kv] 7,2 12 [mm]

5 Dimensions EMPA, EMPB U n [kv] [mm] 7, U n [kv] 7,2 12 [mm]

6 How to select the fuse-link model According to the specifications of IEC 787 it is recommended the usage of the following fuse-links depending on the rated power of the transformers to be protected. Un Pn In Primary Short-circuit Voltage Connection Rate Current of the Fuse-link Group (KV) (KVA) (%) In (min) ,72 4 Yzn ,15 4 Yzn-5 4 6, ,81 4 Yzn-5 6, ,88 4 Yzn ,61 4 Yzn ,21 6 Dyn ,5 6 Dyn ,18 6 Dyn-5 31, ,8 6 Dyn ,1 6 Dyn ,44 4 Yzn-5 6, ,31 4 Yzn ,63 4 Yzn ,76 4 Yzn ,23 4 Yzn , ,43 6 Dyn-5 31, ,11 6 Dyn ,37 6 Dyn ,6 6 Dyn ,4 4 Yzn-5 6, ,85 4 Yzn ,06 4 Yzn ,62 4 Yzn , ,39 4 Yzn-5 31, ,05 6 Dyn ,5 6 Dyn ,6 6 Dyn ,2 6 Dyn ,9 6 Dyn In (max) Operation and maintenance requirements For indoor usage the fuse-links could be mounted either horizontally or vertically. For outdoor applications the fuse-links should be mounted only vertically with the strike system downwards. Replacement of the blown fuse-links should be done only complying to the requirements of the work safety techniques and only by personnel trained and qualified for working with high-voltage installations. The operations are forbidden if current is flowing in the circuit. The blown fuse-links should be replaced only with new ones. In case of tri-phases circuitry, after burning one fuse-link the fuses for all phases should be replaced. It is recommended to examine periodically the status of the protective coverings of the fuse-links contacts. 6

7 Ordering information Un (kv) In Diameter of Contact 45 mm 56 mm With Striker Without Striker With Striker Without Striker 2,5 EPA--2,5 EA--2,5 EPB--2,5 EB--2,5 4 EPA--4 EA--4 EPB--4 EB--4 6,3 EPA--6,3 EA--6,3 EPB--6,3 EB--6,3 10 EPA--10 EA--10 EPB--10 EB EPA--16 EA--16 EPB--16 EB EPA--25 EA--25 EPB--25 EB ,5 EMPA--31,5 EMA--31,5 EMPB--31,5 EMB--31,5 40 EMPA--40 EMA--40 EMPB--40 EMB EMPA--50 EMA--50 EMPB--50 EMB EMPA--63 EMA--63 EMPB--63 EMB EMPA--80 EMA--80 EMPB--80 EMB ,5 EPA-12-2,5 EA-12-2,5 EPB-12-2,5 EB-12-2, EPA-12-4 EA-12-4 EPB-12-4 EB ,3 EPA-12-6,3 EA-12-6,3 EPB-12-6,3 EB-12-6, EPA EA EPB EB EPA EA EPB EB EPA EA EPB EB ,5 EMPA-12-31,5 EMA-12-31,5 EMPB-12-31,5 EMB-12-31, EMPA EMA EMPB EMB EMPA EMA EMPB EMB EMPA EMA EMPB EMB EMPA EMA EMPB EMB ,2 2,5 EPA-7,2-2,5 EA-7,2-2,5 EPB-7,2-2,5 EB-7,2-2,5 7,2 4 EPA-7,2-4 EA-7,2-4 EPB-7,2-4 EB-7,2-4 7,2 6,3 EPA-7,2-6,3 EA-7,2-6,3 EPB-7,2-6,3 EB-7,2-6,3 7,2 10 EPA-7,2-10 EA-7,2-10 EPB-7,2-10 EB-7,2-10 7,2 16 EPA-7,2-16 EA-7,2-16 EPB-7,2-16 EB-7,2-16 7,2 25 EPA-7,2-25 EA-7,2-25 EPB-7,2-25 EB-7,2-25 7,2 31,5 EMPA-7,2-31,5 EMA-7,2-31,5 EMPB-7,2-31,5 EMB-7,2-31,5 7,2 40 EMPA-7,2-40 EMA-7,2-40 EMPB-7,2-40 EMB-7,2-40 7,2 50 EMPA-7,2-50 EMA-7,2-50 EMPB-7,2-50 EMB-7,2-50 7,2 63 EMPA-7,2-63 EMA-7,2-63 EMPB-7,2-63 EMB-7,2-63 7,2 80 EMPA-7,2-80 EMA-7,2-80 EMPB-7,2-80 EMB-7,2-80 EXIMPROD GRUP td BUZAU, Bistritei street, number ROMANIA Phone Fax office@eximprod.ro 7