Electric (battery or mains-fed), permanent, and electro-permanent magnets.
Arthur leaned back, rubbing his temples. He felt the weight of the structure outside. The opera house was a masterpiece of glass and steel, but masterpieces were held together by the mundane details of documents like this. BS EN 13155 was the code that defined the safety of cranes—specifically the non-fixed load lifting attachments. It dictated the proof forces, the testing methods, and the manufacturing tolerances. Without it, they were flying blind. Bs En 13155 Pdf Free Download