Timeline for Custom wound transformer primary winding appears shorted
Current License: CC BY-SA 3.0
18 events
| when toggle format | what | by | license | comment | |
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| Feb 21, 2014 at 14:16 | vote | accept | secretformula | ||
| Feb 21, 2014 at 14:16 | answer | added | secretformula | timeline score: 1 | |
| Jul 22, 2013 at 14:06 | comment | added | secretformula | I have an inductance of 246mH in the primary | |
| Jul 19, 2013 at 21:20 | comment | added | secretformula | I will try winding it yet again but I have each layer insulated for its neighbor and the odds of a short seem unimaginable. | |
| Jul 19, 2013 at 18:55 | comment | added | Vasiliy | @secretformula, assuming that you plug it in 120V AC RMS, and taking into account DC resistance of 4 Ohm + AC current of 8A, leads to ~11 Ohm of inductor's impedance. Assuming frequency of 60Hz we get ~30mH inductance. I'd say that even air cored inductor of similar dimensions should give more than that. Conclusion: probably you do have a short in your inductor. You could add a big inductor in series, but if you primary is indeed screwed up - you'll (probably) won't get the required functionality | |
| Jul 19, 2013 at 17:18 | comment | added | secretformula | Is there anyway I could add inductance in series with the transformer to get the required impedance? I have no time to go out and buy new core materials which would be needed due to space constraints with this current design. | |
| Jul 19, 2013 at 16:26 | comment | added | Andy aka | @secretformula I'd say (and this is a total generalization) 10H - this is an impedance of 3770 ohms at 60Hz and will "take" (with no secondary load) a current of about 32mA from 120V AC RMS 60Hz. | |
| Jul 19, 2013 at 14:44 | comment | added | secretformula | What would be a more ideal transformer impedance? I thought as the core material I was using had an extremely high saturation I could get by using less windings. I used the following: ` t = V(RMS) / 4.44 / m2 / Hz / T` | |
| Jul 19, 2013 at 14:28 | comment | added | secretformula | 4 ohms and I cant measure the impedance, I dont have a meter, that was the dc resistance. I wasn't aiming at any impedance | |
| Jul 19, 2013 at 14:21 | comment | added | Andy aka | Say the core is 10 uH per turn^2, you'll get a primary inductance of 161mH which at 60Hz is an impedance of 60 ohms. At 120V RMS you'll get 2A. Now I don't know what core you are using but it strikes me that 127 turns may be a little light. | |
| Jul 19, 2013 at 14:19 | comment | added | Vasiliy | 40 Ohm is its actual impedance, or the one you aimed for? | |
| Jul 19, 2013 at 14:04 | comment | added | secretformula | The primary without the secondaries draws 8A. I don't have an RLC meter but it has a resistance of around 4ohms | |
| Jul 19, 2013 at 13:56 | comment | added | Vasiliy | Did you measure the primary with RLC meter before adding secondaries? Did you test the primary without the secondaries? | |
| Jul 19, 2013 at 12:48 | history | edited | secretformula | CC BY-SA 3.0 |
added 704 characters in body
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| Jul 19, 2013 at 12:43 | comment | added | secretformula | Yes they are enamaled, will post more details | |
| Jul 19, 2013 at 12:29 | comment | added | Spoon | Is the wire enamal coated? - I know it seems a silly question... | |
| Jul 19, 2013 at 12:24 | comment | added | Adam Lawrence | Please specify more details; which (and how many) laminations, secondary turns, etc. as well a simple drawing of how you've wired the test circuit. | |
| Jul 19, 2013 at 12:06 | history | asked | secretformula | CC BY-SA 3.0 |