1-10 General Information BE1-67Current Sensing Input(s)The unit is designed to operate from the secondary of a standard current transformer rated at 5 amperes. Theunit has a pickup adjustment range covering 0.5 to 12 amperes. The maximum continuous current rating ofeach input is 20 amperes.The one-second current rating of each input is 50 times tap or 500 amperes, whichever is less. Ratings at lessthan one second are calculated as follows:where I = Maximum currentT = Time that current flows (in seconds)Current Sensing BurdenLess than 0.01 ohm per input.Time Overcurrent PickupRangePickup of the time overcurrent elements is continuously adjustable over theentire range of 0.5 to 12 amperes.(See Table 1-3.) This is accomplished through the selection of external connections (LOW RANGE 0.5 to 4.0amperes; HIGH RANGE 1.5 to 12 amperes), a TAP selector switch and TAP CAL adjustment.A TAP RANGE plate is provided on the front panel to define the external connections and the range ofadjustment available when the unit is installed in the protection panel.Table 1-3. Sensing Input Ranges And ConnectionsTAP RangePlate orPickupTAP Selector Current SensingTerminalsA B C D E F G H I J NA NB NCSingle-PhaseHigh 2.25 3.00 4.50 5.25 6.75 7.50 9.00 9.75 11.2512.008,7 ----- -----Low 0.75 1.00 1.50 1.75 2.25 2.50 3.00 3.25 3.75 4.00 9,7 ----- -----Three-PhaseHigh 2.25 3.00 4.50 5.25 6.75 7.50 9.00 9.75 11.2512.008,7 14,15 17,18Low 0.75 1.00 1.50 1.75 2.25 2.50 3.00 3.25 3.75 4.00 9,7 13,15 16,18Pickup AccuracyThe accuracy of the pickup setting established by the TAP selector switch when the TAP CAL adjustment isfully clockwise, is ±5%. The TAP CAL adjustment allows the relay to be set anywhere between the valueestablished by the TAP selector switch position and the next lower setting position.The setting of the relay is repeatable within ±2%.Dropout RatioBetter than 95% of the established pickup level.