Informatics Publishing Limited

B. K. Nashine ¹, Rajendra Prasad ¹, Vijay Sharma ¹, B. P. C. Rao ¹

Affiliations
1 Indira Gandhi Centre for Atomic Research, Kalpakkam - 603 102, Tamil Nadu, IN

Abstract

Prototype Fast Breeder Reactor (PFBR) employs induction motors of various power ratings in high temperature ambient and sometimes corrosive atmosphere. Safe operation of the reactor depends on robustness and reliability of induction motors in its critical components. Safety related systems such as shutdown and online inspection systems, utilize induction motors as actuators in their mechanisms. Since external cooling is not permitted in control and inspection motors, special design of motors is required to withstand high temperatures. This paper deals with design, analysis, fabrication and testing of a compact 50 W, three phase induction motor, suitable for operating up to 250 °C ambient with winding temperature withstand capability up to 550°C. The designed motor was analyzed with two dimensional Finite Element Model (FEM) code FEMM to study the torque slip characteristics and magnetic flux density patterns in stator and rotor.

Keywords

Induction motor, high temperature, FEM Analysis, MI cable

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M. Anandaraj ¹, P. Parameswaran ², S. Krishnakumar ¹, T. Ezhilarasi ², V. Thomas Paul ², R. Thirumurugesan ², S. Chandramouli ¹, V. Ramakrishnan ¹, G. Padmakumar ¹, Shaju K. Albert ², B. K. Nashine ¹, V. Prakash ¹, P. Selvaraj ¹

Affiliations
1 Fast Reactor Technology Group, Indira Gandhi Centre for Atomic Research, Kalpakkam, India - 603 102, IN
2 Metallurgy & Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam, India - 603 102, IN

Abstract

One of the spark plug leak detectors employed in high temperature liquid sodium systems had failed to detect a sodium leak and systematic failure analysis was carried out to identify the ischolar_main cause of the failure. Radiography image of the leak port nozzle revealed that the extension wire which was welded with spark plug electrode had snapped. Since the failure originated from the cracks present in the weld, it was decided to standardize the welding procedure of spark plug electrode to extension wire to prevent the possibility of similar failures in future. Three different materials viz, stainless steel, nickel, inconel were chosen as extension wires as well as filler wires to optimize the welding parameters. Microstructural studies in terms of presence of defects, interface integrity between the weld and extension wire as well as that of spark plug electrode were carried out. Based on this, the final choice of welding parameters, material for extension wire and for filler wire to achieve a sound weld was proposed.

Keywords

Spark Plug Detector, Extension Wire, Failure Analysis, Metallography, Welding Procedure Qualification.

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