dasatcopthorne Posted May 28, 2014 Share Posted May 28, 2014 Hi Guys. Another question please. I can ID most components but not this one. I've Googled the numbers on it to no avail. It sit between the transformer output (ac) and the output screw terminal. The two windings are linked to give 24v ac. I want to rewire this tranny to give 2 x 12v and ad bridge rectifiers to give dc at the terminals. So when I cut the link between the two separate windings, will I need another of these in the second output please? Thanks in advance. Dave Smith Link to post Share on other sites More sharing options...
smokebox Posted May 28, 2014 Share Posted May 28, 2014 A photo would be helpful Link to post Share on other sites More sharing options...
Brian Posted May 28, 2014 Share Posted May 28, 2014 Much of the time a device in series between transformer winding and the output terminal will be an overload cut-out of some sorts to protect the winding of the transformer from excessive current beyond its rating. These can be a fuse, thermal cut-out which is self resetting or can be a manual reset type or a bi metal strip fitted with a simple contact that opens when the strip heats. Transformers can be protected by a self resetting circuit breaker device like this example, wired into one lead from the winding.... http://www.maplin.co.uk/search?text=Circuit+breaker&x=23&y=9 Similar from Rapid.... http://m.rapidonline.com/ProductSearch/ModuleDetails?ModuleCode=64695 You will need to ensure, if used, the chosen circuit breaker current is correct for the transformer. Edit to add Rapid link. Link to post Share on other sites More sharing options...
dasatcopthorne Posted May 28, 2014 Author Share Posted May 28, 2014 Don't know where this disappeared to from the first post, so here another try. Cheers Dave Link to post Share on other sites More sharing options...
RMweb Premium mezzoman253 Posted May 28, 2014 RMweb Premium Share Posted May 28, 2014 It's a voltage dependant resistor (VDR) sometimes known as a varistor, see http://www.resistorguide.com/varistor/ for details. HTH Rob Link to post Share on other sites More sharing options...
Crosland Posted May 28, 2014 Share Posted May 28, 2014 It's a voltage dependant resistor (VDR) sometimes known as a varistor, see http://www.resistorguide.com/varistor/ for details. HTH Rob Not so fast. If it's connected across (in parallel with) the output then it is a varistor for surge suppression. If it connected in series with one of the output leads then it is a "polyfuse" http://en.wikipedia.org/wiki/Resettable_fuse for overload protection. Andrew Link to post Share on other sites More sharing options...
Gordon H Posted May 30, 2014 Share Posted May 30, 2014 The 'RX' that can be seen in the part number indicates to me that it is indeed a Polyswitch fuse, probably one of the Raychem/Tyco range. The letters/numbers after the 'RX' give you the ratings. Link to post Share on other sites More sharing options...
dasatcopthorne Posted June 2, 2014 Author Share Posted June 2, 2014 Thanks guys for you help on this. Cheers Dave Link to post Share on other sites More sharing options...
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