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Forum Index : Electronics : Inductor Saturation Tester Ver 2
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| Solar Mike Guru  Joined: 08/02/2015 Location: New ZealandPosts: 1138 |
Well its 2022, more circuits; Decided to upgrade my old 3yr Inductance Saturation tester Link as it was a bit of a dogs breakfast using a single layer pcb with bad earthing and sometimes burning out its current sensor resistor. So here is ver 2, better designed and hopefully easier to use. Circuit is basically an H-Bridge driving the test inductor with a 50% duty square wave of variable frequency and voltage altered by the 10-30v PSU. Schottky rectifiers are used in the Bridge to return power back to the PSU storage capacitor when the mosfets turn off. The low esr cap I'm using came out of an old computer supply, some 160,000uf at 30V and 40 odd amps of ripple. Have used the same voltage controlled oscillator using a CD4046B phase locked loop chip, to produce a 50% duty variable frequency square wave drive output. Everything now runs off the one variable 30v 5A supply, the old circuit required an extra 12v rail from a plug pack for the control electronics. Original mosfet drivers have been upgraded to 4A isolated types to better isolate the high current switching noise from the control part. Now sensing the inductor choke current with an isolated 50amp current sensor chip rather than a 0.01R 5w precision resistor; If I wasn't careful the resistor would burn out. Star connections used for the 0v signals to keep noise level down, hopefully less noise on the scope probe.   Will load the PCB shortly... Cheers Mike |
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| Solar Mike Guru Joined: 08/02/2015 Location: New ZealandPosts: 1138 |
PCB 141 x 150mm, bolts on top of the huge capacitor attached by its 5mm terminal bolts. The mosfets and rectifiers bolt to the L shaped finned heat sink sitting on top of the pcb.   Gerbers: GerbersV2.zip Cheers Mike |
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