Basler Electric BE1-40Q - Manual (Page 19)

sensing current is present. The effect of this switch, in conjunction with the TAP switch, is shown in the
Specifications, Table 1-1, and on the front panel tap range chart.
TAP SWITCH
The front panel TAP switch selects the pickup setting (in single-phase vars), depending on the position of
the HI/LOW RANGE switch, as shown in Table 1-1. The TAP switch selects the resistive burden value
that is placed across the output of the internal sensing input CT. The resistive burden establishes the
scaling of the internal signal that represents the input current value.
TRANSDUCER
The transducer consists of a multiplier and integrator. The multiplier and associated control circuits
produce an output that is representative of the product of the scaled current input and the scaled, phase-
shifted voltage input signal. The output waveform of the multiplier is an instantaneous value; therefore,
the output is integrated to develop a signal that represents the average var value. The integrator
response time is a function of the pickup multiple, as shown in Section 1, Specifications.
COMPARATOR
The signal representing the single-phase var value is compared with the pickup reference. When the
reference value is exceeded, the PICKUP LED indicator is illuminated and timing is initiated.
TIMING
A definite time delay is initiated when the monitored var level exceeds the pickup reference. A calibrated
frequency generating circuit, in conjunction with counter circuits and the front panel TIME DELAY
thumbwheel switches, establishes the definite time delay interval.
Time delay is adjustable from 0.1 to 9.9 seconds in 0.1-second intervals. A setting of 00 enables
instantaneous (no intentional time delay) operation. Timing is instantaneously reset if the var level
reduces to less than the pickup setting.
For a complete description of timing accuracy, refer to Specifications in Section 1.
OUTPUTS
Defined by the style number, the output relay may have either a normally open (NO) or normally closed
(NC) configuration. The normally open output contact option is required when a current operated target is
desired.
In addition, an auxiliary output contact may be provided which is specified by style number as NO, NC, or
SPDT. If an auxiliary contact is provided, then the power supply status output is not available.
PUSH-TO-ENERGIZE OUTPUT PUSHBUTTON
A small pushbutton switch may be provided as an option to allow testing the primary output contact and (if
present) the auxiliary output contact. To prevent accidental operation, the pushbutton is recessed behind
the front panel and is depressed by inserting a thin, non-conducting rod through an access hole in the
front panel.
POWER SUPPLY STATUS OUTPUT
The power supply status relay has a set of normally closed contacts and energizes when operating power
is applied to the BE1-40Q. If relay operating power is lost or either side of the power supply output
(+12 Vdc or –12 Vdc) fails, the power supply status relay de-energizes and opens the power supply
status output contacts.
POWER SUPPLY
Operating power for the relay circuitry is supplied by a wide range, electrically isolated, low-burden power
supply. Power supply operating power is not polarity sensitive. The front panel power LED and power
supply status output indicate when the power supply is operating. Power supply specifications are listed in
Table 1-1.
9171500990 Rev N BE1-40Q Functional Description 3-3