The TOR-5 removes moisture from the oil by a sorption-based drying method using zeolite-filled adsorber cartridges. Oil is continuously circulated through the sorbent, where dissolved water is physically adsorbed onto the zeolite surface. There is no heating or vacuum involved in the standard configuration, which makes the process safe for energized transformers. The key idea is long-term stabilization: by keeping oil moisture low, the system gradually draws water out of the paper insulation through equilibrium, reducing overall insulation moisture over time.