Building insulation materials weak and brittle. Before its risks were recognized, it was used because it was a cheap, effective insulator with a high R-value and its open-cell structure was a good acoustic insulator. Though it absorbed moisture easily, it regained effectiveness as an insulator when dried. Asbestos once found common use as an insulation material in homes and buildings because it is fireproof, a good thermal and electrical insulator, and resistant to chemical attack and wear. It has been found that asbestos can cause cancer when in friable form (that is, when likely to release fibers into the air - when broken,
Slot insulation Slot insulation Slot insulation is the common name for shielding material used for the rotor inside a power generator. The slot insulation process for electric motors provides a barrier between the copper wirings and the steel lamination for all stator, armature and rotor products. This shielding material separates the rotor's electrically conductive winding from its body. Due to their operating environment, slot insulation must be capable of withstanding high temperatures. In the 1970s, slot insulation materials often had a Class F temperature rating (an operational range up to 155 °C). Today, there are commercially available slot insulation materials with a