Arc immobility and erosion phenomena in low pressure air

Abstract

By u s i n g a n e x p e r i m e n t a l model o f s w i t c h i n g c o n t a c t s i n a demountable a r c chamber t h e i n i t i a l immobility, edge immobility and e l e c t r o d e e r o s i o n o f s w i t c h i n g a r c s under t h e c o n d i t i o n o f low atmospheric p r e s s u r e 0.1 t o 0.048 MPa i n a i r ( c o r r e s p o n d i n g t o t h e atmospheric p r e s s u r e o f 0-6km high above s e a l e v e l ) were e x p e r im e n t a l l y i n v e s t i g a t e d . The r e s u l t s showed t h a t when t h e atmospheric p r e s s u r e r e d u c e s t h e immobility time o f t h e s w i t c h i n g a r c d u r i n g t h e p e r i o d o f a r c i n i t i a t i o n and a t t h e edge o f c o n t a c t s and t h e n t h e amount o f e l e c t r o d e e r o s i o n a r e a l l i n c r e a s i n g . The i n v e s t i g at i o n s a l s o confirmed t h a t t h e immobility time and t h e e l e c t r o d e eros i o n can be g r e a t l y reduced by enhancing t h e opening speed o f t h e moving c o n t a c t .