Ragnar and Else Holm electric contacts and arc ignition theory

German émigré scientist Ragnar Holm (with his wife Else, both PhDs, of Saint Marys, Pennsylvania) at Westinghouse wrote *Electric Contacts* (now in its 4th edition) and derived the contact-asperity heating equivalence between the voltage and temperature fields (both Laplace's equation). His table of softening/melting/boiling voltages (Ag at 90 mV softening, 0.41 V melting Cu, 1.1 V melting W, etc.) explains that arc ignition in welding occurs by boiling metal asperities during contact separation at sub-volt voltages — *not* by Paschen breakdown or field emission as welding handbooks still claim. The IEEE Holm Conference is named for him.

Ragnar Holm was an expert on electrical contacts. Ragnar and his wife both had PhDs. [Tom produces a book.] This is the fourth edition of Electric Contacts, Ragnar Holm PhD, in collaboration with Else Holm PhD, both of Saint Marys, Pennsylvania. His wife was Else. They wrote a book but he got all the credit. He went to work for Westinghouse on electrical contacts. He wrote the first definitive book on electrical contacts. Today the IEEE has a Holm conference every year named after Ragnar. This is his book.