aiptasia
Well-Known Member
I'm working on a DIY stir plate using a small PC fan and a 3-12 watt adjustable wall wort. I have the fan mounted to a project box by four #6 screws with bolts and washers with a rubber grommet on each screw to serve as a shock absorber and a rattle baffle.
I'm using a 2" stir bar and button sized metallic rare earth magnets. I've got two super glued to a pog (circular cardboard circle) and the pog glued to the fan blade in the center of the fan. Each magnet is on opposite sides of the pog to attract the ends of the stir bar. I've repeatedly assembled the stir plate with the magnets in place. Everything seems fine until I plug the unit in. The stir bar seats properly on both poles until I apply the power.
When I plug in the unit, the 2" stir bar goes whizzing off in random directions. Again, it seats just fine over the magnets when it's assembled, but the moment the unit is plugged in, the magnets somehow change polarity and the stir bar gets flung. When I disassemble the unit and test the magnets with the stir bar directly, the poles repel instead of attract, even though they were mounted and glued correctly before the power was applied.
I'm not quite sure what's going on to reverse the polarity or what to do to fix the problem.
I'm using a 2" stir bar and button sized metallic rare earth magnets. I've got two super glued to a pog (circular cardboard circle) and the pog glued to the fan blade in the center of the fan. Each magnet is on opposite sides of the pog to attract the ends of the stir bar. I've repeatedly assembled the stir plate with the magnets in place. Everything seems fine until I plug the unit in. The stir bar seats properly on both poles until I apply the power.
When I plug in the unit, the 2" stir bar goes whizzing off in random directions. Again, it seats just fine over the magnets when it's assembled, but the moment the unit is plugged in, the magnets somehow change polarity and the stir bar gets flung. When I disassemble the unit and test the magnets with the stir bar directly, the poles repel instead of attract, even though they were mounted and glued correctly before the power was applied.
I'm not quite sure what's going on to reverse the polarity or what to do to fix the problem.