In these cases, metal saturates the refractory lining between the loop and the bushing.
However, when the bushing contains an uncooled joint that incorporates a transite T-bar for the electrical isolation, the thermal gradient in the bushing joint area is adversely altered.
In this method, the bushing is fitted with Type K thermocouples.
As pointed out last month in Part 1 of this two-part series, 95% of inductor runouts occur at the bushing joint insulator.
By installing thermocouples in the refractory, the temperature gradient between the bushing and the saturation network can be monitored.