New Industrial Servo Motor Yaskawa 1300W 10.7A SGMG-13AWA-YR12 Servo Motor In Box

Rotor: Use a small soda bottle (b/c of weight) as rotor body. Form three identical aluminum sheet metal panels to approximately match the radius of curvature of the bottle. A sheet thickness between about 1/4mm and 1/2mm should be fine. You may do this by rolling the sheet metal over a solid cylindrical object that resembles the bottle. Near one of their edges, fold the panels up in a way that the panels have about 5mm wide lips away from the bottle. Slide paper clips over the lips and bend them to allow you to fine-tune the spark gaps. Round off all corners to avoid unwanted discharge. Glue the panels on the bottle in a symmetric fashion (see sketch above and pictures below).

Bearings: Low friction is essential to make this device work. You may use a steel rod (like a welding rod), shape its end into a sharp tip, and push it through the bottle along its symmetry axis. The bottom bearing, which will carry the rotor’s weight, should be some sort of needle bearing consisting of the tip and some receptacle with a conical indent (see picture). Setscrews with conical intents machined into their ends work well for that. The upper bearing only picks up small transverse forces. It is sufficient to just have the axle pass through a hole drilled in a piece of aluminum of about 1mm thickness (see picture). While you are looking for a fairly tight fit, it is more important that you don’t feel any friction when rotating the rotor with your fingers. Both bearings can be oiled as needed. Ball bearings don’t work too well. [Note: If you do try ball Left: One of the three panels mounted on the rotor bottle. Top: Paper clip used to fineadjust the spark gaps. Right: One of the two stator panels. Page 5 bearings, make sure you find a type that doesn’t stick when the load approaches zero. Oiling ball bearings will typically make matters worse.]