Basler Electric BE1-50/51B - Manual (Page 13)

9252000991 Rev R BE1-50/51B General Information 1-1
SECTION 1 • GENERAL INFORMATION
Introduction
BE1-50/51B overcurrent relays are microprocessor based, non-directional phase or ground relays that
monitor the magnitude of a single-phase ac current to provide accurate instantaneous and time
overcurrent protection for 50 or 60 Hz power systems. Models are available with fifteen popular time
characteristics and a wide range of pickup settings.
Features
A wide range of pickup settings and front panel selectable time characteristics permit applications
involving coordination with fuses, reclosers, cold load pickup, motor starting, and fixed time requirements.
Also, an integrating reset function is available to simulate the disk reset of electromechanical relays.
BE1-50/51B overcurrent relays have the following standard features.
• Independent time and instantaneous elements
• A secure method to manually trip the breaker at the relay front panel
• Direct reading front panel controls
• Minimum pickup setting for safety during installation
• Time characteristics extend to a pickup multiple of 40
• Rugged draw-out construction with steel case
• Gravity latching targets retain indication without power
• Built-in accuracy eliminates internal adjustments
• Minimum transient overreach
• Field selectable characteristic curve selection
• Field selectable instantaneous or integrating reset
• Field selectable 50 or 60 Hz operation
• Field selectable fixed instantaneous delay (0.0, 0.1, 0.2, or 0.3 second on 100 series relays and
0.0 or 0.1 second on 200 series relays.).
Individual models are available for 1 ampere and 5 amperes sensing input currents and installed in A1 or
S1 cases. BE1-50/51B overcurrent relays may be tested without removing the relay from the case.
Shorting contacts are provided for all current inputs when the connection plug or relay chassis is removed
from the relay case. Figure 1-1 shows the front panel of the BE1-50/51B overcurrent relay, in an S1 case.
Advantages
BE1-50/51B overcurrent relays have many advantages over other overcurrent relays. The primary
advantages are:
• Time characteristics are defined by equations and graphs
• Field selectable time characteristics
• Very low burden extends the linear range of the CTs
• Self powered from the sensed current
• Continuous automatic calibration