BE1-81 Testing
5-5
Step 23. Again using the 60 hertz 0 TIME curve as an example, the time delay recorded in Step 22
should be 0.135 seconds ±15 percent. Here again, subtract test frequency (57 hertz) from
nominal (60 hertz) to arrive at hertz below pickup (3.0 hertz). Subtract front panel TRIP
FREQUENCY setting (1.00) from hertz below pickup (3.0) to get normalized (2.0) hertz below
pickup point. Move to the left along the 0 TIME curve until the vertical HERTZ BELOW
PICKUP (2 hertz) and curve intersect. Read the corresponding delay on the TRIP TIME
(SECONDS) axis.
Step 24. Progressively decrease test variable oscillator frequency in 1 hertz steps to 46 hertz for the
50 hertz (T2), or to 56 hertz for the 60 hertz (T1). Record the resultant time delays as
provided in the previous steps.
Step 25. Using the delay times recorded in Steps 16, 22, and 24, plot these points on the appropriate
time curve (50 or 60 hertz) for future reference. Connection of these points should be a curve
of the same shape as the desired curve within ±15 percent.
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