12-12-2021, 08:57 AM
But before I go any further I could do with understanding why the line scan is double the voltages of the DC tests? Is this because of back EMF? If you shove current through a coil of wire, it creates a magnetic force, stop the current,the magnetic field collapses creating a voltage. That's why we have to put diodes on relays and OPT's have to be rated for higher than HT. Hope I got that right and it's what you meant.
Re, building tfmr's, a lot of the tomes on the subject are heavy going but there's a few tricks to sidestep the maths. To find out if you have enough turns on a primary, use a lightbulb in series with your winding. I use my variac, lamp limiter combo to test tfmr's. For toroids to find number of turns divide 42 by area of core, don't know if this works for EI and for other frequencies. It might be that you could use that "formula" and double NT for half the frequency?
This video explains some of the mysteries of tfmr's - https://www.youtube.com/watch?v=4UFKl9fULkA This page is useful - https://engineerexperiences.com/design-c...tions.html and this one - http://dicks-website.eu/coilcalculator/index.html
Good luck, Andy.
Re, building tfmr's, a lot of the tomes on the subject are heavy going but there's a few tricks to sidestep the maths. To find out if you have enough turns on a primary, use a lightbulb in series with your winding. I use my variac, lamp limiter combo to test tfmr's. For toroids to find number of turns divide 42 by area of core, don't know if this works for EI and for other frequencies. It might be that you could use that "formula" and double NT for half the frequency?
This video explains some of the mysteries of tfmr's - https://www.youtube.com/watch?v=4UFKl9fULkA This page is useful - https://engineerexperiences.com/design-c...tions.html and this one - http://dicks-website.eu/coilcalculator/index.html
Good luck, Andy.
