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Insulation resistance decreases as______
Temperature decreases
Temperature increases
Temperature Slowly decreases
Temperature remains same
Temperature increases
Insulation resistance is inversely proportional to temperature due to the increased mobility of charge carriers in insulating materials at higher temperatures. As temperature rises, the thermal agitation of molecules increases, leading to a decrease in the resistivity of the dielectric material.
Insulation resistance is inversely proportional to temperature due to the increased mobility of charge carriers in insulating materials at higher temperatures. As temperature rises, the thermal agitation of molecules increases, leading to a decrease in the resistivity of the dielectric material.
RTтАЛ=R0тАЛeтИТ╬▒T тАФ Resistance-Temperature relationship for dielectrics
╧БTтАЛ=╧Б0тАЛeтИТ╬▒T тАФ Resistivity dependence on temperature
In insulating materials (dielectrics), an increase in temperature provides more kinetic energy to the molecules, facilitating the detachment of electrons and increasing ionic mobility. This reduction in the material's ability to resist current flow is mathematically represented by an exponential decay formula, causing the overall insulation resistance to drop significantly as heat increases.
Insulators exhibit a negative temperature coefficient of resistance.
Higher temperatures facilitate dielectric breakdown and leakage current.
Maintenance tests (like Megger tests) must be temperature-corrected to a reference value (usually 20┬░C or 30┬░C).
Predictive maintenance allows for early fault detection
Prevents catastrophic dielectric failure
Insulation resistance values vary wildly with ambient temperature
Requires temperature correction factors for accurate comparison
Transformer winding insulation monitoring
Cable insulation integrity verification
Electrical motor maintenance
The Megger test is the standard industry practice for measuring insulation resistance.
As a rule of thumb, insulation resistance often halves for every 10┬░C increase in temperature.
B is correct тАФ Insulation resistance decreases as temperature increases because higher temperatures increase charge carrier mobility, thereby reducing the resistivity of the dielectric material.
When performing a Megger test, always record the ambient temperature, as the raw resistance value is meaningless without the corresponding temperature correction factor.