What is the acceptable comparison ratio for temperature corrected winding-resistance values obtained during testing?

The acceptable comparison ratio for temperature-corrected winding-resistance values during testing typically allows for a variation of within two percent. This standard is rooted in the need for accuracy when assessing the condition of electrical equipment, particularly motors and transformers.

Maintaining a two percent threshold ensures that any deviations in winding resistance due to temperature fluctuations are minimal, which is critical for ensuring efficient operation and effective troubleshooting. Winding resistance may change with temperature, and the corrections applied are meant to reflect true operational conditions.

If the ratio were set higher than two percent, it might lead to significant misunderstandings about the equipment's health, possibly resulting in unnecessary maintenance or overlooking issues that could lead to failure. Therefore, a limit of two percent is considered a reliable benchmark for ensuring fidelity in the testing results.