Checking 110v Transformer (pat Test?)

[Karin]

got given a 230V-110V site transformer today. probably reasonably old and been sitting in a garage for a while. so thought it'd be an idea to run some tests on it before chucking it into service?

i'm thinking that after an inspection for condition and obvious damage (even inside the case), i should probably check for earth continuity (low resistance ohmmeter?). then insulation resistance between the windings? what would be the way to do that? i'd think i check that between line or neutral on the 230V side and either line on the 110V side?

are there other things you'd do in a PAT test? never really come across it before but can't really think of anything else.
guess i could check the output voltage and voltage to earth..

 

[Pete999]

This any use to you?

 

[Lucien Nunes]

I would test earth continuity from input to output, and using a low current test check that the secondary winding (output) centre-tap is also earthed which it must be in a site tool transformer (although not all kinds of step-down transformer). Then test IR L&N to E as normal at the input. Because we have already proven that the secondary centre-tap is earthed this will check the insulation from primary to secondary as well.

Personally I would flip the top and check that the correct secondary fuses are fitted, if it has them.

 

[Karin]

forgot to get back to this! i did the tests as Lucien suggested (very clear, thanks) and all came back well. popped the lid and it basically looked as in pete's video. no secondary fuses, just that thermal trip. interestingly though i could now see that the 32A socket is clearly a later addition, judging by the drill marks in the resin!

cheers guys!