Toroidal transformer transistor driver for electrical ballast  - Page 1
Forum section: electronics / projects

author: eneuro
author_rank: Super Contributor
timestamp: October 14, 2014, 09:28:21 pm
content: I was very suppriced while was thinking of using something similar in my spot welder project to provide power supply for AC mosfets switch gate driver trigering two 230VAC 25A SCR's in parallel.QuoteQuoteIt is quite new patent published this year AD 2014, but when we look intohttp://en.wikipedia.org/wiki/Transformerthan we can find that more than 120 years ago William Stanley in his patenthttp://www.google.com/patents/US349611also shows transformers withadjustable gap, so when looked there a few years ago it was clear for everyone that when we change this gap and make it smaller transformer core will saturate easier, so simply when found a few day ago thisbrand newpatent I feel a little bit disapointed, why someone gets patent now for something shown more than 100 years ago?Maybe the reason is that language is difficult to understand in the therms of nowadays physics like its name and... lawyers was not able to"Google"this old patent or it expired?QuoteHopefully, probably I found how to easy go around this patent in own applications, since they mention in abstract and claims:QuoteSo, we can use simply a few cores where only a few of them are cut in 100% and rest is not cut at all.This is what I used to do even without knowledge of this new patent, so I do not know it looks like that such simply solution easy makes this"patented invention"published this year... worth $0, while I do not need restrict gap cut to 75% of the effective cross-sectional area while I used not one but many cores in my transformerIt looks like"reinventing a wheel"type patentAnyway, what do you think about such protection by a non-linear response to thevariations of the intensity of the load currentjust by adjusting this transformer core(s) cross-sectional area by creating some kind of cage for magnetic flux?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: October 15, 2014, 03:40:08 am
content: No, you're misunderstanding the purpose. The idea is novel, though unlikely as of the publication date. Similar examples probably date back 50-100 years. As a specific implementation in a limited field, it might still be novel, and therefore patentable.For example, VAC makes precision DC current sensors which utilize the saturation of a thin strip of magnetic core material. The magnetic path loop looks like a large core with low reluctance, with a small section of relatively high reluctance (but not pure air gap). The "reduced cross section" region saturates easily (going from low to very high reluctance). The current sense circuit amounts to a saturation sensor and servo loop.Tim

author: eneuro
author_rank: Super Contributor
timestamp: October 15, 2014, 06:15:28 am
content: Quote from: T3sl4co1l on October 15, 2014, 03:40:08 amNice, so we have another ways to forget about this patent and as one can expect there are many ways to get this non-linear response by changing reluctanceIn my solution I can do it without any complicated manufacturing-just take a few cores of diffrent parameters and design its secondary response.They can be cut or simply E type cores with diffrent gap width, but cut 100% or not cut at all, so no worry when another patent with not up to 75% , but up to 88% of cut gap will be published

author: oldway
author_rank: Super Contributor
timestamp: October 15, 2014, 03:02:34 pm
content: QuoteThis is a wrong practice. Look for a 50A SCR instead !

author: eneuro
author_rank: Super Contributor
timestamp: October 15, 2014, 06:03:58 pm
content: Quote from: oldway on October 15, 2014, 03:02:34 pmI do not need one bigger 50A but to switch AC 230VAC I need two like intriac, so they are in parallel but at given time only one of them conducts like in video in this thread belowMore details and prototype PCB in my last post therePulse spot welder (above 2kVA 230VAC 50Hz mains input power)GDT powered from 5V and step up to 15V can easy turn on those SCR's while I used AC mosfets switch to triger those SCR's, so very small average current needed on GDT secondary to keep those SCR's turned on, while mosfets used in AC mosfet switch has total gate charge about 60nC each so, about 120nC only needed to turn ON those SCR's thanks to AC mosfets switch.