Basler Electric BE3-81O User Manual
Instructions

www.basler.com
+1 618.654.2341 (USA)
Model
BE3-81O, BE3-81U,
and BE3-81O/U
INTRODUCTION
BE3 frequency relays provide frequency monitoring and
protection in both single- and three-phase systems. They
are used in applications such as utility mains failure,
regulation of power supplies, and to protect generators
against over or underspeed. Underfrequency,
overfrequency, and combined under/overfrequency units are
available. BE3 frequency relays operate when the
adjustable trip point is reached. A reset control is provided
with an adjustment of 0.3 to 3.0% on 50 or 60 hertz units
and 3 to 30% on 400 hertz units. Reset ensures that the
measured parameter returns to the percent set above or
below the trip point before the relay returns to the original
state. On overfrequency units, the output relay energizes
when the input signal exceeds the trip point. On
underfrequency units, the output relay de-energizes when
the input signal goes below the trip point. A red LED
indicates the state of the relay. A green LED indicates the
condition of the power supply.
SPECIFICATIONS
Operating Power
All units are self powered.
Nominal Voltage:
120 Vac, 240 Vac, 380 Vac,
or 480 Vac
Frequency:
50 Hz, 60 Hz, or 400 Hz
Burden:
<2.5 VA per phase
Overload:
1.25 times nominal continuously.
2 times nominal for 3 s.
Setpoint
Over/Underfrequency Set Range
50 Hz Nominal:
Adjustable 40 to 60 Hz
60 Hz Nominal:
Adjustable 50 to 70 Hz
400 Hz Nominal:
Adjustable 360 to 440 Hz
Over/Underfrequency Reset Range
50 Hz Nominal:
Adjustable 0.3 to 3.0 Hz
60 Hz Nominal:
Adjustable 0.3 to 3.0 Hz
400 Hz Nominal:
Adjustable 3.0 to 30 Hz
Setpoint range accuracy is
±3%.
Repeatability
Greater than 0.5% of full span
Operating Time
200 ms typical
Output
Relay Type:
D.P.D.T.
AC Rating:
250 V, 5 A, non-resistive,
1,200 VA
DC Rating:
125 V, 1 A, resistive, 120 W
Mechanical Life:
5 million operations
Temperature
Operating Temperature:
0°C (32°F) to 60°C (140°F)
Functional Temperature: –25°C (–13°F) to 70°C (158°F)
Storage Temperature:
–40°C (–40°F) to 70°C (158°F)
Temperature Coefficient: 0.03% per °C (300 ppm/°C)
Humidity
Relative Humidity:
95% non-condensing
Physical
Mounting:
DIN rail 1.38” by 0.29” (35 mm by
7.5 mm)
Case:
Complies with IEC 529, DIN
40050, BS 5490
Case Material:
Complies with UL 94VO
Weight
Single Function:
0.88 lb (0.4 kg)
Multiple Function:
1.32 lb (0.6 kg)
Size
Single Function:
2.17” wide (55 mm)
Multiple Function:
3.93” wide (100 mm)
Agency
cULus listed to UL 508 and CSA C22.2 No. 14
CE compliant
GOST-R certified per the relevant standards of Gosstandart
of Russia
OPERATION
BE3-81O and BE3-81U frequency relays have two user-
adjustable controls marked SET and RESET. The BE3-
81O/U has four controls: UNDER SET, OVER SET, UNDER
RESET, and OVER RESET. Each SET control adjusts a
relay trip point. An overfrequency trip causes the relay
output to energize when the frequency rises above the SET
threshold. An underfrequency trip causes the relay output to
de-energize when the frequency decreases below the SET
threshold. Refer to the setpoint specifications for
overfrequency and underfrequency adjustment ranges. The
RESET control adjusts the difference between the nominal
input frequency and the reset frequency. An overfrequency
reset occurs when the frequency decreases below the
RESET setting. The overfrequency RESET setting is set as
the percentage above F
nom
where the relay will reset. An
underfrequency reset occurs when the frequency increases
above the RESET setting. The underfrequency RESET
setting is set as the percentage below F
nom
where the relay
will reset. Refer to the setpoint specifications for the
underfrequency and overfrequency RESET setting ranges.
Setting Example
A BE3-81O relay with a nominal input rating of 60 Hz has
the following settings:
•
SET - 65 Hz
•
RESET - 2 Hz
Publication
9321500990
Revision
C
Instructions
Date
04/14
Copyright
2014