| Electronics > Beginners |
| Using schematic to calculate transformer windings. |
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| Jwillis:
Just a thought .Have you attempted de-potting the transformer by heating either by boiling in water or in the oven ? Or by soaking in denatured alcohol.I thought I would try these methods but I don't have any transformers that are potted in epoxy. All I have are layered in tape.I know that boiling can separate the glue on the cores . |
| gkmaia:
--- Quote from: andy3055 on October 23, 2019, 03:47:29 am ---"I cannot understand how an input of +100vdc can become a wave with such amplitude... plus negative amplitude." This is a DC switching circuit. Just like in a TV flyback/EHT generation or an SMPS. Does that make any sense? I am not too conversant with it either. --- End quote --- I understand a DC switching circuit uses ferrite at high frequencies and how having more turns on the secondary increases the voltage that flows throughout the magnetic field. This part of the concept is fine. Also how other types of flybacks work with optocouplers which is slightly different to this circuit. What I cannot understand is the oscillation on the primary ITSELF. See the chart bellow I think it may explain what my doubt is better than words. --- Quote from: Jwillis on October 23, 2019, 05:23:16 pm ---Just a thought .Have you attempted de-potting the transformer by heating either by boiling in water or in the oven ? Or by soaking in denatured alcohol.I thought I would try these methods but I don't have any transformers that are potted in epoxy. All I have are layered in tape.I know that boiling can separate the glue on the cores . --- End quote --- I tried all that... plus a heat gun. The only thing I did not try was thinner. Yes indeed I usually use hot water to separate laminates then re-coat them with clear spray. But this transformer is tinkering proof... |
| Ian.M:
If you can get the core out, or are willing to sacrifice it, you could saw the bobbin and HT winding in half to get a cross-section and count turns from the exposed wire ends under a microscope. Some polishing may be required to get a good enough cross-section surface. If its tightly and neatly wound, you can probably settle for counting turns in one layer and multiplying it by the number of layers. It will also show you details of construction like margin tape that will be important to duplicate if you want it to stand up to the EHT without inter-layer arcing. |
| gkmaia:
--- Quote from: Ian.M on October 23, 2019, 08:05:58 pm ---If you can get the core out, or are willing to sacrifice it, you could saw the bobbin and HT winding in half to get a cross-section and count turns from the exposed wire ends under a microscope. Some polishing may be required to get a good enough cross-section surface. If its tightly and neatly wound, you can probably settle for counting turns in one layer and multiplying it by the number of layers. It will also show you details of construction like margin tape that will be important to duplicate if you want it to stand up to the EHT without inter-layer arcing. --- End quote --- I already destroyed the core. Isolating the HV inner layers must be fine to do. But looking at the old one there is no isolation between HV layers, just between windings. |
| T3sl4co1l:
FWIW, you can count on enamel handling, eh, a hundred volts should be fine, a few hundred volts would be questionable without extra e.g. triple insulated wire. If the width of a layer is such that the layer-to-layer voltages are modest like this, you don't need to worry about tape within a winding. Tim |
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