bepone wrote: ↑Sun Mar 24, 2024 7:33 am
There is no half turn in transformer heater winding
For heaters you need to make very low number of the turns, and all the time you start and finish the turn on the same place..also is easy to make 3.15-0-3.15 , you are winding actually full number very close to the voltage (not to decimal point) actually it is 3.3-0-3.3 if you count losses with full current draw..
And there are in the same line, and winding geometry is the same, so it is the voltage..
I can see that you just didn't understand what I wrote. Try reading it again. If you want me to re-write it in simpler language, I will give that a go. Other than not understanding my post, I can't see why you would try to say say back to me what I said, and try to imply that it's wrong, but when you say it, it's right. That's just weird.
You got the first part right - as I said originally, it's a low number of turns. But you missed several of the points on turns, or perhaps misinterpreted what I wrote.
I have both made the mistake myself and seen others make the mistake of not starting and finishing a full turn. In an E-I winding, it's possible to go through one window and not the other. This causes an unbalanced flux on the core. It is possible to take a center tap out halfway around the core and not unbalance the magnetic flux in the special case of both sections of the winding being equally loaded and low current in the tap without unbalancing the core flux. As I pointed out, there are reasons not to do this.
You missed the point on volts per turn. Volts per turn is fixed. With a low number of turns, you practically only have the option to get the closest number - I kind of think that's what you're trying to say here. In fact, if you actually read what I wrote, I went through an example of picking the nearest higher number of turns, and referenced the losses due to high current.
You are also skipping over the possibility of the winder making a mistake and simply putting one more turn on one of the halves of the heater winding. This can't happen with bifiar winding - which no one does for heaters - but it can, and has happened with two separate windings wound one after the other to make a "center tapped" winding. It doesn't happen much any more with commercial power transformers wound on automated equipment, but it can and does happen on hand wound stuff, including commercial transformers from back in the days when the winding machines were manually controlled. I have both measured what is probably a one-turn error in commercial transformers, and accidentally made the mistake myself when I was learning to wind them.
But all of this doesnt matter because minimum hum is not on the half
Hmmm. Are you trying to say that minimum hum is >never< when the heaters are exactly balanced, or just trying to start an argument?
Hum comes from lots of causes, as you should know. Even with pure DC heaters, there is still hum. I pointed out why an adjuster pot lets you use offset heater hum to cancel out hum from other sources to some extent. Did you not read that part of my post, or not understand it?