The bearings are mounted on the magnetic needle, the aluminum frame, the plastic frame and the squirrel cage. If they are mounted on the needle holder, they can be rotated flexible .. Lightweight and portable design, convenient for storage and carrying, ideal for classroom teaching projects. This instrument describes the type of the rotating magnetic field and the principle of a three-phase induction motor .. Incredible tool for physical laboratory equipment or as a decoration in your laboratory that make the learning of physical experiments efficiently .. Well suited for use in schools, educational displays and collectibles. A great addition to your laboratory equipment.