Basler Electric BE1-59N - Manual (Page 20)

The definite time delay is adjustable from 00.1 to 99.9 seconds in 0.1-second increments. Front panel
mounted switches determine the delay. Position 00.0 is instantaneous.
INVERSE TIME DELAY (OPTIONAL)
The inverse time delay circuit is identical to the definite time delay circuit except that a voltage-controlled
oscillator (VCO) is substituted for the clock signal. The VCO, in turn, is controlled by a voltage derived
from the sensed input. Because the frequency of the oscillator is kept proportional to the sensed input
voltage, the desired inverse time delay is produced.
The inverse time characteristic curve switch is adjustable from 01 to 99 in 01 increments. Each position
corresponds to a specific curve setting except 00, which is instantaneous. Refer to Figure 1-2 to see the
inverse time characteristic curve.
REFERENCE VOLTAGE CIRCUIT
A constant voltage source provides a reference voltage to the potentiometers on the front panel. The
potentiometers, in turn, provide reference voltages to all the comparator circuits and establish the
threshold for each circuit.
UNDERVOLTAGE ELEMENT (OPTIONAL)
Undervoltage Operation
The undervoltage option is sensitive to the third harmonic voltage (150 Hz or 180 hertz) at generator
neutral, and provides 40 dB rejection of the fundamental frequency (50 or 60 hertz). The undervoltage
measuring element determines within five cycles if the third harmonic voltage is less than or greater than
the reference setting. If the measured third harmonic voltage is less than the reference setting, the
undervoltage pickup LED will illuminate, and the delay timer is triggered. When the timer completes its
cycle, a signal is generated to energize the undervoltage output relay and, if selected, the undervoltage
auxiliary relay. However, if the voltage level swings above the reference setting before the delay timer has
cycled, the output contacts reset within 7.0 cycles.
In the event that both trip conditions (undervoltage and overvoltage) are present, the undervoltage
response is inhibited.
The third harmonic pickup setting (i.e., UNDERVOLTAGE PICKUP) is a front panel mounted
potentiometer, continuously adjustable on the high range from 0.5 to 12 Vac (sensing input range 1, 2, 5,
or 6) or 1.0 to 24 Vac (Sensing input range 3, 4, 7, or 8). On the low range, it is adjustable from 0.1 to 2.5
Vac (sensing input range 1, 2, 5, or 6) or 0.2 to 5.0 Vac (Sensing input range 3, 4, 7, or 8). The time
delays available are instantaneous, definite, or inverse time. (Instantaneous is defined as no intentional
time delay. The timing circuits are analogous to those previously described.)
Undervoltage Inhibit
When the undervoltage measuring element is selected, an undervoltage inhibit circuit is included to
monitor the generator terminal voltage. This circuit inhibits operation of the 150/180 hertz measuring
element if the generator terminal voltage is less than the undervoltage inhibit setting. The panel mounted
undervoltage inhibit potentiometer is continuously adjustable from 40 to 120 Vac for 100/120 Vac sensing
input, and 80 to 240 Vac for the 200/240 Vac input.
OUTPUTS
Defined by the style number, the output relays may have either a normally open (NO) or normally closed
(NC) configuration. The normally open output contacts option is required when current operated targets
are desired.
In addition, auxiliary output contacts (1 for Over, 1 for Under) may be provided which are specified by
style number as NO or NC.
PUSH-TO-ENERGIZE OUTPUT PUSHBUTTONS
Small pushbutton switches may be provided as an option to allow testing the primary output contacts and
(if present) the auxiliary output contact. To prevent accidental operation, the pushbuttons are recessed
3-2 BE1-59N Functional Description 9171400990 Rev K