Basler BE1-51C, Instruction Manual

Page: 31 / 66

BE1-51C Operation By Front Panel
4-4
Neutral current instantaneous trip values are similarly entered (as multiples of the Neutral TAP setting) into
registers nin1 and nin2 for the INST 1 and INST 2 contacts.
Selecting the Time Overcurrent Characteristic
The timing curve registers (11th and 12th in the sequence of Table 4-1) may contain any of 8 codes, b1
through b8, representing the curve types listed in Table 4-2. Refer to Figures 1-2 through 1-9 for graphic
representations of these curves.
Table 4-2. Available Characteristics
Number Time Overcurrent Characteristic Figure
b1 Short Inverse 1-2
b2 Long Inverse Time 1-3
b3 Definite Time 1-4
b4 Moderately Inverse Time 1-5
b5 Inverse Time 1-6
b6 Very Inverse Time 1-7
b7 Extremely Inverse Time 1-8
b8 I
2
T 1-9
Selecting the CT Ratios
Registers 13 through 16 (Table 4-1) provide a multiplier that allows the microprocessor to match the relay
response to the turns ratio of the system CTs. The relative turns ratio of the CTs is expressed as a fraction
whose numerator is 5.
Current Sensing Range
The 17th and 18th registers in the sequence (of Table 4-1) display the current sensing range to which the
relay is configured (either HI or LO) in accordance with the style chart. This is a factory setting.
Demand Period
Register 19 (Table 4-1) indicates the number of minutes in a demand period. This figure is used to calculate
the demand current. For further information, look under Instrumentation Display, page 4-5.
DATA MODE
Defined
The data mode provides the normal display of real time data for an operating relay. When in this mode, all
the read-only registers which are accessible from the front panel (Table 4-3) may be viewed by stepping the
MODE switch, or by automatic scrolling (described below).