Aboutcleggsan Expertise All technical areas of Electronics Engineering.
Experience BSEE, MBA, Design, R&D, University Research.
Senior Life Member of IEEE. Life Fellow of AES.
Organizations IEEE, Consumer Electronics Society, Audio Engineering Society.
Broad teaching experience; work experience mostly in consumer electronics and conversion from analog to digital technologies. Pioneer in digital audio at all levels.
Question I am trying to get a solid grasp on how to accurately determine the maximum current draw I can get on the HV winding of a given transformer. I'm going to phrase this question somewhat indirectly in the context of a known circuit application. The transformer in question is rated at 250-0-250 @60ma. In the circuit it supplies there is @325 VDC across a 1K dropping resistor. Solving for current gives me 325ma. Why does this not burn up the HV transformer winding? I must be either missing some critical info on how to get the maximum current rating from the full load specs(250-0-250 @60ma) or making an error in my calculation. From the full load specs, how do I determine the max current draw for this particular transformer? Thanks
Without knowing the circuit (schematic diagram) I cannot give you a very specific answer, but let me make a few generic comments which may lead to sufficient answer.
BTW what do you mean by HV winding? You state the transformer in question is 250-0-250; is that the primary side or the secondary side? Is it a toriod coil or iron core EI lam transformer? Are you bridge rectifying, half wave or full wave? These are questions to know so I can determine what is going on to get a 325 dc?
And, let us not confuse ratings with maximum. Even though you give 60ma as the rating for the transformer in question, that does not mean you are limited to that amount; you could be running it overload condition which will, over time, overheat the transformer and eventually cause a burnout, but it will produce extra current until it fails. The 325vdc across the power resistor dissipates 105 watts. That is a very hot resistor, by the way. So, the input must be at least 105 watts (can't create energy).
The theory says either you are running the transformer way over it ratings or you have miscalculated the load. Ohms law and power conservation must be maintained. Can't create energy in a passive circuit.
Can you send a schematic or explain to me what the circuit is doing: Drive supply, transformer connections, rectifier configuration and filtering being used. Then I can envision what you are doing. You can attach a drawing with your next email.
)