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BE1-50/51M General Information 1-1

SECTION 1 • GENERAL INFORMATION

DESCRIPTION

BE1-50/51M 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 hertz or 60 hertz power systems. Models are available with fifteen popular time

characteristics and a wide range of pickup settings.

APPLICATION

The 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.

Integrating reset functions are available to simulate the disk reset of electromechanical relays. BE1-50/51M

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.

Magnetic 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 hertz 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. BE1-50/51M

Overcurrent Relays (both horizontal and vertical mounts) must be removed from the case and installed on

a test bench for testing. Shorting contacts are provided for all current inputs when the relay chassis is

removed from the relay case. Figure 1-1 shows the front panel of the BE1-50/51M Overcurrent Relay, in

a C1, horizontal mount case. Figure 1-2 shows the front panel of the BE1-50/51M Overcurrent Relay, in a

C1, vertical mount case. Internally (circuit wise), all relay models are the same and use the same circuit

assemblies.

BE1-50/51M Overcurrent Relays have many advantages over other overcurrent relays. The five primary

advantages are:

Time characteristics are defined by equations and graphs.

Field selectable time characteristics.

Very low burden.

Self powered from the sensed current.

Continuous automatic calibration.

Courtesy of NationalSwitchgear.com

Basler BE1-50/51M-209 Series User Manual

Questions and Answers: