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| Tap on secondary of transformer |
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| stolevole:
I dissasembled transformer with burnt primary and good secondary coil.Secondary is tapped but i cant figure out is it center tap or not and how is it wound.It has three separate wires and it had three wires at output of secondary with two center wires soldered together.Which type of tap that is and how do i rewind it? |
| MarkF:
It sounds like it had two secondaries wired in series. The voltage of each secondary would add in that case. You just need to determine the direction of each winding. Maybe each has a solid color and a striped wire. Picture? |
| MarkF:
If your secondary has two solid color wires and one striped wire, the striped wire will be the center tap. You can also check the resistance. The two wires with the highest resistance will be the outside ends of the coil. The resistance between the third wire to either of the other two should be the same if the center tap is in the middle. |
| stolevole:
If you meant photo of assembled secondary unfortunately i dont have it but heres photo of three coils i unwound i didnt look how they were placed because i thought transformer was unfixable but it turned out its fixable. http://oi65.tinypic.com/j0bq5d.jpg You can see on picture where i cut stranded wires going out of transformer(number 2 and 3).I think number 1 was the wire that had two soldered solid wires coming out of transformer because theres solder on both ends.They arent unwound by any order how they were on transformer.Its taken out of car battery charger if that helps (its probably step down transformer).I think it had two white and one black stranded wire coming out of secondary.Maybe if its impossible to find out how it was before i can solder three wires in series and have untapped transformer?Thank you so much for your help. |
| Ian.M:
Its FUBARed. You don't know the turn counts, and although they can be roughly estimated from winding wire lengths and winding dimensions, I bet you didn't record the dimensions as you unwound each winding and probably don't have a length for the burnt primary. Also reusing salvaged once-wound magnet wire in a power transformer is a very bad idea - you'll never get the turns to lay neatly side by side as they were originally so each winding will take up more core window area, which means you'll probably run out of room to get all the windings back on. Also, the odds of a shorted turn (that will overload and probably burn your new primary) are much much higher as the insulation coating on the wire will be fatigued and probably cracked from the unwinding. Therefore, all you've got that *MAY* be usable is the core and any coil former that was present. so its design your own transformer from scratch time. The salvaged wire may be usable for single layer experimental RF coils, low voltage battery powered electromagnetism experiments etc. where the available energy is limited and the consequences of a coil failure are slight, but IMHO its barely above scrap grade. |
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