HiFiFreq
Tele-Meister
I have a PT from some old gear that I parted out . Total of 6 leads .
Two for primary , two for secondary HT @ 500 vac and two for secondary filament @ 6.3vac . No center taps . Had it wired into a single ended circuit with a SS bridge rectifier and it got hot immediately so I shut it down . Checked the circuit and can find no mistakes . Pulled the transformer to test on my bench . On the bench with no load and AC applied to the primaries it works fine . With no AC to the primaries I ohmed out the leads with my meter . I found what I expected with low resistance across the primaries at about 12 ohms , .4 ohms across the filament secondaries and 272 ohms across the HT secondaries . But , when I check with my meter from one leg of the secondary HT to the transformer itself I get roughly half of the resistance . My question ; Is the body of the transformer considered a ground or center tap ? If so is my SS bridge rectifier with it's virtual center tap grounded causing the PT to get hot? Also forgot to mention that when the primaries are connected to AC the secondaries will measure about half when taking voltage readings from one leg to the transformer body . So the 500 volts across the secondaries measures half @250vac when measuring from one leg to the transformer body . The filament leads act this way as well .
Two for primary , two for secondary HT @ 500 vac and two for secondary filament @ 6.3vac . No center taps . Had it wired into a single ended circuit with a SS bridge rectifier and it got hot immediately so I shut it down . Checked the circuit and can find no mistakes . Pulled the transformer to test on my bench . On the bench with no load and AC applied to the primaries it works fine . With no AC to the primaries I ohmed out the leads with my meter . I found what I expected with low resistance across the primaries at about 12 ohms , .4 ohms across the filament secondaries and 272 ohms across the HT secondaries . But , when I check with my meter from one leg of the secondary HT to the transformer itself I get roughly half of the resistance . My question ; Is the body of the transformer considered a ground or center tap ? If so is my SS bridge rectifier with it's virtual center tap grounded causing the PT to get hot? Also forgot to mention that when the primaries are connected to AC the secondaries will measure about half when taking voltage readings from one leg to the transformer body . So the 500 volts across the secondaries measures half @250vac when measuring from one leg to the transformer body . The filament leads act this way as well .
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