Required power is a measurement of how much effort it takes to move our lubricity testing machine. A higher required power rating in indicative of increased resistance/friction of the moving components. A lower required power rating means the oil is providing good lubrication between moving components.
The require power rating is recorded as the difference in power between unloaded and loaded. Loaded power is recorded first, while the machine is actively engaged in rotating against the cylinder while being lubricated by the oil mixture. Unloaded power is recorded immediately after, at each recoding interval, with the cylinder making no contact. Measure the power in a differential like this allows us to to rule out any minor differences in how the base unloaded power may affect the loaded power rating.
As an example, if the loaded power consumption is 450 Watt/hr, and the unloaded power consumption is 420 Watt/hr, the "Required Power" would be 30 Watt/hr.