21. In 1942, David J . Kelman patented a toroidal metal scouring pad. 22. For this, also toroidal winding machines with special magazines can be used. 23. The electronics provide two constant current sources to generate the toroidal magnetic fields. 24. As a consequence, toroidal transformers rated more than a few kVA are uncommon. 25. Toroidal roller bearings were introduced in 1995 by SKF as " CARB bearings ".26. They have solved numerous problems which exhibit circular cylindrical symmetry employing the toroidal functions. 27. Thus a toroidal inductor / transformer, radiates less electromagnetic interference ( EMI ). 28. With Tihiro Ohkawa he invented toroidal devices for containing the plasma with magnetic fields. 29. This corresponds to a negative toroidal energy density symmetric to the x-axis. 30. It was housed in the service module and had two toroidal tanks for pressurization.
