beach_boy90 Posted March 24, 2011 Report Share Posted March 24, 2011 Okay so I built a power supply from an old MOT for my car stereo so i could use it in my room. My question is, is why does the core get really hot after like 10 minutes of use. The primary and secondary windings remain cool to the touch, but the core itself becomes really hot after more than just a few minute of use. What could be causing this? Quote Link to comment Share on other sites More sharing options...
audioguru Posted March 24, 2011 Report Share Posted March 24, 2011 The core is supposed to be laminated in many layers and the layers must be insulated from each other with enamel paint or something.Maybe you scratched the laminations and caused them to be shorted together. Then eddy current flow in them and cause heating.A microwave oven transformer is made as cheap as is possible. Since they never operate continuously then they do not have enough windings on their primary. Quote Link to comment Share on other sites More sharing options...
Hero999 Posted March 24, 2011 Report Share Posted March 24, 2011 Does it vibrate and make a loud humming sound? It could be because you've not secured the laminations and the vibration increases the heating. Quote Link to comment Share on other sites More sharing options...
beach_boy90 Posted April 1, 2011 Author Report Share Posted April 1, 2011 No...it's actually really quiet...I can't hear it if its on the floor and I stand up... Quote Link to comment Share on other sites More sharing options...
Hero999 Posted April 2, 2011 Report Share Posted April 2, 2011 Are you sure you don't have a shorted turn?Did you touch the primary? You should leave it as is.Does it get hot off load?Measure the primary and secondary current.Is there DC in the secondary? You should always use a full wave rectifier with a transformer powering a high power circuit, never a single diode or a voltage doubler to get a bipolar output.Please post the schematic. Quote Link to comment Share on other sites More sharing options...
beach_boy90 Posted April 4, 2011 Author Report Share Posted April 4, 2011 No there isn't a shortI never messed with itI recently blew the fuse in my meter and I haven't been able to get a new one so I can't measure currentand I used a full wave bridge and a 14,000 uF capacitor to help filter it a bit, though I honk it's too low of a value to due any real good... Quote Link to comment Share on other sites More sharing options...
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