9252000899 Rev —
BE1-50/51B-237/-238 General Information
1-1
SECTION 1
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GENERAL INFORMATION
INTRODUCTION
BE1-50/51B-237 and BE1-50/51B-238 protective relays are direct replacements for General Electric, IAC
relays. The BE1-50/51B-237 has a 5-ampere current sensing input. The BE1-50/51B-238 has a 1-ampere
current sensing input. Compatible IAC model numbers are listed in Table 1-1.
Table 1-1. GE IAC Relays Suitable For Direct Replacement
IAC Model Number
Curve Type
12IAC51A
∗∗∗
A
Inverse
12IAC51B
∗∗∗
A
Inverse with Instantaneous
12IAC53A
∗∗∗
A
Very Inverse
12IAC53B
∗∗∗
A
Very Inverse with Instantaneous
12IAC55A
∗∗∗
A
Short Time
12IAC55B
∗∗∗
A
Short Time with Instantaneous
12IAC66A
∗∗
A
Long Time
12IAC66B
∗∗
A
Long Time with Instantaneous
12IAC77A
∗∗∗
A
Extremely Inverse
12IAC77B
∗∗∗
A
Extremely Inverse with Instantaneous
∗
Any digit covering all pickup ranges and 50 Hz or 60 Hz models.
To replace an existing IAC relay, perform the following steps.
1. Select the desired relay settings on your new BE1-50/51B-237 or BE1-50/51B-238 relay.
2. Remove the existing IAC relay.
3. Attach the cover adapter to the existing case.
4. Insert the new relay.
5. Reinstall the existing connection plug.
6. Install the new Basler Electric cover.
BE1-50/51B-237 and BE1-50/51B-238 relays are self-powered, compatible with 50 or 60 Hz power
systems, and have three protection elements: one time overcurrent (51) element and two instantaneous
overcurrent (50) elements. The 51 element offers timing characteristic curves similar to those used by GE
IAC and ABB relays.
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.
In addition, an integrating reset function is available to simulate the disk reset of electromechanical relays.
BE1-50/51B-237 and BE1-50/51B-238 overcurrent relays have the following standard features.
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Independent time and instantaneous elements
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A secure method to manually trip the breaker at the relay front panel
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Direct reading front panel controls
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Minimum pickup setting for safety during installation
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Time characteristics extend to a pickup multiple of 40
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Rugged draw-out construction with steel case
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Gravity latching targets retain indication without power
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Built-in accuracy eliminates internal adjustments
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Minimum transient overreach
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Field selectable characteristic curve selection similar to either GE IAC or ABB type curves
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Field selectable instantaneous or integrating reset
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Field selectable 50 or 60 Hz operation
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Field selectable 0.0 or 0.1 second, fixed, instantaneous delay
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