The PhaseCap MKK capacitor from Epcos is a compactly designed metallised polypropylene film capacitor with self-healing properties. The current-carrying metal layer of an MKK capacitor is vapour-deposited onto one side of the polypropylene film.
Three electrically-separated partial capacitors are wound concentrically in a single operation onto an insulated metal core tube, which guarantees excellent winding precision. The electrodes are connected by metal spraying (schooping) at the front surface of the winding element. The partial capacitors can be connected in star, delta or series circuits. The compact MKK winding element is housed in a cylindrical aluminium case with a metal lid, press-rolled onto it.
Extended service life more than 100 000 h
After an extended drying period, impregnation (filling the capacitor's case with N2/SF6 mixture) is carried out under high vacuum to reduce moisture at the active element. Finally, the case is hermetically sealed and the gas tightness is inspected in routine tests using a special SF6 leakage tester.This construction method avoids oxidation as well as partial discharges, and ensures that capacitance remains stable over an extended period of time, which is essential especially in filter circuit applications.
Inrush current withstand
Capacitors used in power factor correction systems are frequently switched. The related inrush currents must be handled without affecting the service life. The pulse handling capability of this technology depends mainly on the contact zone areas. Enlargement of the sensible contact zone is of major importance. The manuacturer's patented 'Wave-cut' technique has enabled inrush currents to 300 times rated current and above.
The MKK capacitor offers a triple safety system: Its dry type design means that it is free of liquid impregnating agents, such as oil or PCB, thus eliminating the risk of fire caused by spurting or leaking oil. In ecologically-sensitive applications as well as for insurance aspects the dry-type design is a must; it has self-healing technology; it uses the SIGUT reliable connection technology; and it has an overpressure tear-off fuse that prevents the capacitor from bursting at the end of service life, or due to inadmissible electrical or thermal overloads.
| Tel: | +27 11 458 9000 |
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| www: | www.electrocomp.co.za |
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