dc-ac/dc

[devlin maguire]

Hi After reading another post about IR tests a thought occurred to me that I cannot answer, some of the more technically gifted wil,l I am sure know, anyway if you apply dc voltage to a ac to dc transformer what happens? anyone !!
Mac

 

[GrannySmiff]

Booooooooooom.

 

[devlin maguire]

Well if so that would confirm the opinion held by me and others regarding the 250v or 500v ir tests without confirming whats on the circuit, someone said use the 250v test first to see if there is something connected and, if BooM is indeed the result of dc entering a ac/dc tranny then we all best beware, any way joking aside I think I have an old coka cola font light tranny kicking around might stick it onto a dc test and see if it melts
MAc

 

[JulianC]

By transformer I take it you mean a power supply containing a transformer followed by a rectifier circuit to generate the DC. In this case, applying DC to the input will have bugger all effect as nothing will be produced at the secondary side of the transformer. However, unless you can disconnect the transformer you will read a resistance through the primary winding so it will be a case of linking the lives and IR testing them to earth. 250v will certainly be no problem. 500v...hmmm, not sure, depends on the insulation classification of the transformer winding. Probably best not risk it.

 

[devlin maguire]

JC Dc Cheers that was very informative there is lots of things like that I would love to investigate but right now Iam without a workshop to play in
Mac