Tekniikan ja innovaatiojohtamisen yksikkö, 2018
Sähkö- ja energiatekniikan koulutusohjelma (DI)
Beside new design and better performance, product development of low voltage switches should focus on manufacturing easiness, product quality and possibilities for customer’s variation. The target of this thesis is to study the possibilities and develop a screwless-type cable mounting for small low voltage switches. Thesis is designed to serve as a feasibility study that can be used at the further development project for screwless-type cable mounting.
Study starts by researching existing products using screwless-type cable mounting. Terminal blocks and contactors work as example products that are using screw- and screwless-type cable mounting terminals. After example products, small low voltage switches OT40 and OT80 are presented. The study will also present IEC and UL standards and the requirements they define for small low voltage switches delivered to Europe and North America.
Nominal currents of products focused in thesis set the required cross-sections for cables used in wiring. Cable cross-sections set the required standardized cable mounting tests. Required flexion and pull-out tests for screwless-type cable mounting are firstly performed for terminal block samples. After tests of terminal block samples, protomodels OT40 and OT80 using screwless-type cable mounting are designed. Protomodels are firstly designed with computer and after that also manufactured. Protomodels are tested with the same flexion, pull-out and usability tests than terminal block samples.
Lot of knowledge about possibilities and challenges, when designing screwless-type cable mounting in small low voltage switches are accomplished in this thesis. Protomodels with screwless-type cable mounting will hold cables. But they will not pass all the required tests set by IEC and UL standards. When the challenges in this thesis are solved, screwless-type cable mounting could be possible also in small low voltage switches.
Low voltage switch, screwless cable mounting, standard