Ruttonsha power semiconductor device, likely a high-power diode or rectifier module.
Manufacturer: Ruttonsha International Rectifier Ltd., an Indian company specializing in semiconductor devices and power equipment.
Specifications: The markings "B 250 C 5000 / 3500" likely refer to its electrical ratings, such as voltage and current capabilities. The specific function is for converting alternating current (AC) to direct current (DC) in industrial applications.
Polarity: The plus (+) and minus (-) signs on the side indicate the polarity of the terminals.
Applications: These components are used in various industrial sectors, including railways, induction furnaces, and power generation systems.