I need to heat a 5U4G but I don't have a 5V winding, so will need a small separate 5V filament xformer. Would these Triad flatpack dual 5V secondary transformers have enough isolation for the HV?
https://www.farnell.com/datasheets/2279132.pdf
5U4G wants 3 Amps, this little xformer can do 4.8 A @ 5V with dual secondaries in parallel. So the current is covered, I just need confirmation that the HV will be ok here. Is the "hipot test" the measurement I'd be interested in to determine the safety factor one needs in a 5U4 rectifying 280-0-280.
https://www.farnell.com/datasheets/2279132.pdf
5U4G wants 3 Amps, this little xformer can do 4.8 A @ 5V with dual secondaries in parallel. So the current is covered, I just need confirmation that the HV will be ok here. Is the "hipot test" the measurement I'd be interested in to determine the safety factor one needs in a 5U4 rectifying 280-0-280.
IMO it would be fine, likely better insulated than the 5V winding from an older transformer. Be sure and check the voltage under load - heater windings are always high in my experience.
5U4G wants 15VA power, the transformer has 24VA (continuos).
IMO better choice -at least- any 30VA transformer, else the transformer would be warming up (the flat pack construction not the best in this regard).
IMO better choice -at least- any 30VA transformer, else the transformer would be warming up (the flat pack construction not the best in this regard).
The datasheet gives the breakdown voltages.
These products are 100% hipot tested with an insulation of 2000V between primary and secondary windings and 1500V between the primary / secondary windings and the core.
These products are 100% hipot tested with an insulation of 2000V between primary and secondary windings and 1500V between the primary / secondary windings and the core.
While I think that drawing 15VA from a 24VA transformer is not problematic (62.5% of rated output), if there was any concern the OP could just clip-lead one up on the bench and run a 6 hour test to see how the transformer holds up.
Thanks, Ill get it. The four windings are on separate bobbins with these so there is that level of separation too. And they are easy to fit somewhere. Hammond makes the identical line of transformers too, Triad seems to be having a little supply chain issue;
Let us know how it works out. BTW, if you do need to knock down the voltage, put a resistor in the primary, not the secondary. The resistor value will be easier to find (not sub-one-Ohm), and the transformer won't be passing power that just gets wasted in a secondary resistor.
Wow thanks, more often we see people trimming the secondary, but it makes perfect sense to do it on the primary. My home always seems to be 123V occasionally dipping to 122 rarely going lower than that or more than 123.5. When I light up the 5U4 I'll see how much over 5V it settles at and adjust the primary.