4-15
4.1.4 Uniform Step Test
FIGURE 31: Step Test I.D. Screen
Enter an alphanumeric test identification (or leave blank) and press enter.
The step test is used to establish trend curves. During the step test, the voltage is raised in discrete steps to a
final level. The voltage, current, and resistance are recorded in discrete intervals. Performing step tests over
the lifetime of the equipment provides a useful tool for predictive maintenance.
FIGURE 32: Uniform Step Test Setup Screen
At the Uniform Step Test Setup Screen (Figure 32), enter test duration in minutes (1-60), the final voltage and
the number of steps to take to reach that final voltage (MAX=20). Press Enter to cycle through the
Temperature Compensation Screen (Figure 33).
FIGURE 33: Temperature Compensation Setup Screen
At the Temperature Compensation Setup Screen (Figure 33), the operator can choose to activate the internal
buzzer to sound during the test. Inputs are Y for buzzer on and N for buzzer off. Users can then define a
base temperature to correct resistance measurements to, as well as the actual temperature of the test object.
These fields must be completed, as leaving them blank does not bypass the temperature compensation
function of the unit. It is recommended not to correct to a temperature more than ± 20°C from the test
objects temperature, as this could cause significant error in the resistance reading. Once the Temperature
Compensation screen is filled out, press Enter to bring up the HV Waiting Screen.
SPECIAL NOTE ON TEMPERATURE EFFECTS:
Even the best insulation has a small amount of resistive leakage current. With ageing and deteriorating of
some insulation system (motors, transformers and paper oil insulated cables), this leakage current will
increase, which can aid in assessing the quality and remaining lifetime of the insulation system. In order to
achieve the most consistent results it is important to correct the test object temperature to a standard
