Hopefully? Another 48vdc-240vac Toriod Inverter build.

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poida Guru Joined: 02/02/2017 Location: Australia Posts: 1458	Posted: 09:56pm 16 Jan 2023         KeepIS said   Looking at noise on the Inverter AC out. .. D: The transformer, choke and load are now silent at idle to 300 watts (may test limit) and zero startup noise.   E: Using a choke with "more" inductance causes a slight startup growl and the Toriod starts to get a low frequency growl even at idle.   ..  This will be very interesting to Wiseguy. He has been on a quest to quell this growl sound. I wrote some custom versions of the nanoverter firmware, one that made it into a variac. A pot controlled the PWM width. No feedback. Instant application of pot setting to PWM width. This was great fun to play with, exploring when saturation kicks in and how much at what voltages. I found that I could initiate the growl sounds at will using the pot with rapid increases in voltage. The faster the jump up, the louder the growl. No growl was heard when reducing voltage...