Basler Electric BE1-87B - Manual (Page 41)

Power LED
This indicator lights when nominal operating power is applied to the relay at terminals 15 and 16.
Alarm Voltage Control and CT OV LED
The Alarm Voltage rotary select switch allows for a setting range of 10% through 80% of the Pickup
Voltage in 10% increments. The Alarm Voltage element detects unbalance voltages across the sensing
inputs of the relay (Terminals 5 and 7, Single-Phase Units). If the unbalance voltage exceeds the Voltage
Alarm Setting (10 to 80 % of Pickup Voltage), the Alarm Output Contact closes (Terminals 13 and 14),
and the CT OV LED lights. When the voltage input falls below the Alarm setting, the Alarm Relay drops
out and the CT OV LED turns OFF. The response time of the alarm contacts and the LED is intentionally
slow to prevent nuisance alarms.
Example
With the Alarm Voltage setting at 10% and a Pickup Voltage setting of 150 volts, the Alarm output
contacts will close when the input voltage exceeds 15 volts (0.1 X 150).
Pickup Voltage Control
This rotary control allows for a pickup voltage setting range of 50 to 400 volts rms in 50-volt increments.
This sets the voltage at which the back-to-back internal SCRs trigger. The SCRs are triggered when the
input voltage exceeds twice the setting of the Pickup Voltage switch to allow for a fully offset voltage
signal. Refer to Table 1-2 in Section 1 for input impedance values while not triggered.
Example
With the pickup voltage set at 150 volts rms, the input SCRs will trigger when the input voltage is
increased to 300 volts rms (calibration and routine maintenance tests) or when the instantaneous voltage
exceeds 2.83 times the rms pickup voltage (fully offset, peak value). Refer to Section 2, Operating
Principles for more information.
Pickup Current Control
This rotary control allows for a pickup current setting of 0.25 to 2.50 amperes rms in 0.25 ampere
increments. This setting determines the level of current into the sensing input (Terminals 5 and 7) that
causes the two trip output contacts to close and the Trip LED to light. Note that relay operation is based
on the instantaneous peak value of the sinusoidal current detected at the sensing input. Refer to Table 1-
2 in Section 1 for input impedance values while triggered.
Example
When the Pickup Current Control is set at 1 amperes rms, output contact closure occurs when the current
sensing element detects an instantaneous current value of 1.414 amperes.
When the input current falls back below this setting, the output contacts open, but the Trip LED remains lit
until the Reset button is pressed. The Trip LED maintains correct status indication even if power is lost
and then restored.
Pickup Current Trip LED
This indicator lights when the level of current flowing through the relay sensing input exceeds the setting
of the Pickup Current Control. The Pickup Current Trip LED remains lit until the Reset button is pressed.
LED status is maintained when the relay is de-energized. When operating power is re-applied, the LED
lights and remains lit until the Reset button is pressed.
Reset Pushbutton
Pressing the Reset button turns off the Pickup Current Trip LED.
Trip Test Pushbutton
The Trip Test pushbutton is recessed behind the front panel and is accessed through a small opening. It
is actuated by using a nonconductive tool small enough to fit through the front panel. It is used to simulate
a trip condition, to verify operation of both output trip contacts, and to verify that the trip LED lights. Upon
releasing this pushbutton, the output trip contacts open but the Trip LED remains lit. The test operator
must depress the reset switch to clear the Trip LED.
9282300990 Rev P BE1-87B Human-Machine Interface 3-3