Hi folks. I am new to the forum, and my question is not strictly audio but close. I have a power supply I built 30 years ago to power an electromagnet on a home built magnetic drill press. Consisted of a rectifier bridge from a GM car alternator, a 200 mfd motor start capacitor and a 3/8" diameter 9" long steel rod with about a couple hundred turns of 18 ga magnet wire around it as an inductor to help smooth the voltage. The input was direct (fused) from the 120 VAC. It worked fine for years. Then my magnet burned out and I put it aside for a few decades.
I recently found a few spare moments and made a new bigger magnet using a full 10 pound spool of 22ga magnet wire stuffed into a welded cylindrical magnet housing. Has 80 ohms resistance and draws about 2 amps at the 160 v or so DC output from my power supply. Works great generates huge amount of pull.
My problem is the inductor in the power supply is getting quite warm (hot actually) which I do not recall being a problem when used with the old magnet. I don't remember what the old magnet drew, but I know it was a lot less as it was 1/5 the physical size of the current one. The inductor rod buzzes a fair amount, which I don't remember it doing in the former incarnation of my device .
What are the easy solutions - make a bigger inductor - longer? - more turns? - heavier wire? I think the heat is coming from the "induction" action in the core, not resistance in the wire as it is much larger gauge wire than used in the magnet the power supply is driving. One other possible factor is the power supply is now mounted on the drill press itself within a few inches of the magnet so maybe being in the magnetic field of the magnet is having some effect?
Any suggestions would be appreciated. I am not an engineer - I'm a beanie by training and worked as a marketing guy for years, but am moderately handy with simple electronics.
I recently found a few spare moments and made a new bigger magnet using a full 10 pound spool of 22ga magnet wire stuffed into a welded cylindrical magnet housing. Has 80 ohms resistance and draws about 2 amps at the 160 v or so DC output from my power supply. Works great generates huge amount of pull.
My problem is the inductor in the power supply is getting quite warm (hot actually) which I do not recall being a problem when used with the old magnet. I don't remember what the old magnet drew, but I know it was a lot less as it was 1/5 the physical size of the current one. The inductor rod buzzes a fair amount, which I don't remember it doing in the former incarnation of my device .
What are the easy solutions - make a bigger inductor - longer? - more turns? - heavier wire? I think the heat is coming from the "induction" action in the core, not resistance in the wire as it is much larger gauge wire than used in the magnet the power supply is driving. One other possible factor is the power supply is now mounted on the drill press itself within a few inches of the magnet so maybe being in the magnetic field of the magnet is having some effect?
Any suggestions would be appreciated. I am not an engineer - I'm a beanie by training and worked as a marketing guy for years, but am moderately handy with simple electronics.