Drying out is contraindicated if physical insulation damage (like burning or short-circuiting) is present.

The process must be gradual to prevent internal thermal stress on winding components.

Monitoring the $IR$ value at periodic intervals (e.g., every hour) is mandatory during the heating phase.

The machine should be clean and dust-free before initiating the drying process.

Restores insulation life without expensive rewinding

Cost-effective maintenance for machines stored in damp environments

Time-consuming process requiring continuous monitoring

Risk of thermal damage if temperature limits are exceeded

Machines stored in humid conditions for extended periods

Commissioning of large motors after long transit/storage cycles

The insulation resistance test is typically performed using a Megger.

Option C is insufficient because physical damage makes drying out useless; repair is required in such cases.

Option B is incorrect because drying is event-driven based on $IR$ measurements, not purely time-driven.