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Implications of Direct and Indirect Heating of Bi-Metallic Strip in MCCBs – Challenges and Solutions


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1 R&D Department, C&S Electric Ltd, Sector-8, Noida – 201301, Uttar Pradesh, India
     

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This describes about the main differences between direct and indirect heating of bi-metals for overload protection for MCCBs. It also explains about analysis of thermal behavior of bimetal strip during both steady-state and transient conditions. To validate the thermal model, experimental tests both in steady-state and transient conditions have been done. The time current characteristics curves for both types of MCCB are plotted for meeting relevant product standards and same is validated with actual tripping time. There is a good correlation between experimental and theoretical results. Direct heating of bi-metal element can help in reduction of electrical stresses and also increases the life span of the power cables. It also outlines the challenges overcome during development and solutions for implementation of direct and indirect heating of bi-metal strips for developing the MCCBs for fulfillment of IEC 60947-2 as well as REC specifications.

Keywords

Bi-Metallic Strip, Characteristics, Circuit Breaker, Deflection, Deformation, Direct Heating, IEC Standards, Indirect Heating, Loads, Magnetic, Overload, Performance, Power Cables, Rated Current, Curves, REC Specifications, Resistance, Short circuit, Temperature, Thermal, Tripping, MCCB.
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  • Implications of Direct and Indirect Heating of Bi-Metallic Strip in MCCBs – Challenges and Solutions

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Authors

Sudhakar Sapuram
R&D Department, C&S Electric Ltd, Sector-8, Noida – 201301, Uttar Pradesh, India
Suresh Srikantaiah
R&D Department, C&S Electric Ltd, Sector-8, Noida – 201301, Uttar Pradesh, India
Amit Kumar Vishnoi
R&D Department, C&S Electric Ltd, Sector-8, Noida – 201301, Uttar Pradesh, India
Siraparapu Satyanarayana
R&D Department, C&S Electric Ltd, Sector-8, Noida – 201301, Uttar Pradesh, India

Abstract


This describes about the main differences between direct and indirect heating of bi-metals for overload protection for MCCBs. It also explains about analysis of thermal behavior of bimetal strip during both steady-state and transient conditions. To validate the thermal model, experimental tests both in steady-state and transient conditions have been done. The time current characteristics curves for both types of MCCB are plotted for meeting relevant product standards and same is validated with actual tripping time. There is a good correlation between experimental and theoretical results. Direct heating of bi-metal element can help in reduction of electrical stresses and also increases the life span of the power cables. It also outlines the challenges overcome during development and solutions for implementation of direct and indirect heating of bi-metal strips for developing the MCCBs for fulfillment of IEC 60947-2 as well as REC specifications.

Keywords


Bi-Metallic Strip, Characteristics, Circuit Breaker, Deflection, Deformation, Direct Heating, IEC Standards, Indirect Heating, Loads, Magnetic, Overload, Performance, Power Cables, Rated Current, Curves, REC Specifications, Resistance, Short circuit, Temperature, Thermal, Tripping, MCCB.

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DOI: https://doi.org/10.33686/pwj.v16i1.152772