Basler BE1-51/27R User manual

INSTRUCTION MANUAL
FOR
TIME OVERCURRENT RELAY
WITH VOLTAGE RESTRAINT
BE1-51/27R
Publication: 9137200999
Revision: D 07/10

9137200999 Rev D BE1-51/27R Introduction i
INTRODUCTION
This instruction manual provides information about the operation and installation of the BE1-51/27R Time
Overcurrent Relay with Voltage Restraint. To accomplish this, the following information is provided:
General Information and Specifications
Controls and Indicators
Functional Description
Installation
Tests and Adjustments
WARNING!
To avoid personal injury or equipment damage, only qualified personnel should
perform the procedures in this manual.
NOTE
Be sure that the BE1-51/27R is hard-wired to earth ground with no smaller than
12 AWG copper wire attached to the ground terminal on the rear of the unit case.
When the BE1-51/27R is configured in a system with other devices, it is
recommended to use a separate lead to the ground bus from each unit.

ii BE1-51/27R Introduction 9137200999 Rev D
First Printing: September 1993
Printed in USA
Copyright ©1993-2010 Basler Electric, Highland Illinois 62249 USA
All Rights Reserved
July 2010
It is not the intention of this manual to cover all details and variations in equipment, nor does this manual
provide data for every possible contingency regarding installation or operation. The availability and design
of all features and options are subject to modification without notice. Should further information be
required, contact Basler Electric.
BASLER ELECTRIC
ROUTE 143, BOX 269
HIGHLAND IL 62249 USA
http://www.basler.com, [email protected]
PHONE [phone] FAX [phone]
CONFIDENTIAL INFORMATION
of Basler Electric, Highland Illinois, USA. It is loaned for confidential use, subject
to return on request, and with the mutual understanding that it will not be used in
any manner detrimental to the interest of Basler Electric.

9137200999 Rev D BE1-51/27R Introduction iii
REVISION HISTORY
The following information provides a historical summary of the changes made to the BE1-51/27R
instruction manual (9137200999). Revisions are listed in reverse chronological order.
Manual
Revision and Date Change
D, 07/10 Replaced cover drawing and Figure 2-1. (New front panel switches
and graphics.)
C, 08/07 Moved content of Section 6, Maintenance to Section 4.
Move Time Curve Graphs from Section 1 to Appendix A.
Updated front panel illustrations to show laser graphics.
Added manual part number and revision to all footers.
Updated manual to current style used.
Updated power supply burden data in Section 1.
Updated Target Indicator description in Section 3.
B, 05/05 Added new information on wide range power supplies.
Added new information on case covers.
Changed Specifications, Accuracy, Page 1-10 and Isolation, Page 1-
11.
Corrected Figure 1-51 and Table 2-4.
Deleted Figures 4-8 and 4-9, and references to the Service Manual
(obsolete) in the Introduction and Section 6.
A, 09/03 Enhanced the description of the B and C curves in Section 1.
Changes Specifications: Time Overcurrent Pickup Accuracy; Time
Overcurrent Dropout Ratio, and Isolation.
Added formula for pickup current and Chart 1-1, Instantaneous
Response Time.
Corrected Table 1-3, Figure 1-49, and Tables 2-2 and 2-4.
Corrected Figures 5-1 through 5-6 and Test Procedures to reflect
changes in the Specifications.
Added Section 7, Changes.
—, 09/93 Initial release

iv BE1-51/27R Introduction 9137200999 Rev D
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9137200999 Rev D BE1-51/27R Introduction v
CONTENTS
SECTION 1 •GENERAL INFORMATION ................................................................................................ 1-1
SECTION 2 •CONTROLS AND INDICATORS........................................................................................ 2-1
SECTION 3 •FUNCTIONAL DESCRIPTION ........................................................................................... 3-1
SECTION 4 •INSTALLATION .................................................................................................................. 4-1
SECTION 5 •TESTS AND ADJUSTMENTS............................................................................................ 5-1
APPENDIX A •TIME OVERCURRENT CHARACTERISTIC CURVES................................................... A-1

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9137200999 Rev D BE1-51/27R General Information i
SECTION 1 ●GENERAL INFORMATION
TABLE OF CONTENTS
SECTION 1 ●GENERAL INFORMATION ................................................................................................ 1-1
DESCRIPTION....................................................................................................................................... 1-1
APPLICATION ....................................................................................................................................... 1-1
Backup Protection .............................................................................................................................. 1-1
Residually Connected ........................................................................................................................ 1-1
Operating Characteristics at Reduced Voltages ................................................................................ 1-2
STANDARD FEATURES ....................................................................................................................... 1-3
Time Overcurrent Functions............................................................................................................... 1-3
Non-Integrating Timing....................................................................................................................... 1-4
Integrating Timing............................................................................................................................... 1-5
Built-In Test ........................................................................................................................................ 1-5
OPTIONS ............................................................................................................................................... 1-5
Timing................................................................................................................................................. 1-5
Sensing Input Type ............................................................................................................................ 1-5
Sensing Input Range.......................................................................................................................... 1-5
Power Supply ..................................................................................................................................... 1-5
Targets ............................................................................................................................................... 1-6
Outputs ............................................................................................................................................... 1-6
Instantaneous Outputs ....................................................................................................................... 1-6
Packaging........................................................................................................................................... 1-6
MODEL AND STYLE NUMBER DESCRIPTION................................................................................... 1-6
SPECIFICATIONS ................................................................................................................................. 1-7
Voltage Sensing Inputs ...................................................................................................................... 1-8
Sensing Input Burden......................................................................................................................... 1-8
Sensing Input Rating .......................................................................................................................... 1-8
Time Overcurrent Pickup Selection Range ........................................................................................ 1-8
Time Overcurrent Pickup Accuracy.................................................................................................... 1-8
Time Overcurrent Dropout Ratio ........................................................................................................ 1-8
Instantaneous Overcurrent Pickup Range ......................................................................................... 1-8
Instantaneous Overcurrent Measuring Accuracy ............................................................................... 1-8
Instantaneous Overcurrent Dropout Ratio ......................................................................................... 1-8
Instantaneous Response.................................................................................................................... 1-8
Time Delay Accuracy ......................................................................................................................... 1-9
Output Circuits.................................................................................................................................... 1-9
Target Indicators ................................................................................................................................ 1-9
Power Supply ..................................................................................................................................... 1-9
Radio Frequency Interference (RFI) ................................................................................................ 1-10
Isolation ............................................................................................................................................ 1-10
Surge Withstand Capability .............................................................................................................. 1-10
UL Recognized ................................................................................................................................. 1-10
GOST-R............................................................................................................................................ 1-10
Operating Temperature .................................................................................................................... 1-10
Storage Temperature ....................................................................................................................... 1-10
Shock................................................................................................................................................ 1-10
Vibration ........................................................................................................................................... 1-10
Weight .............................................................................................................................................. 1-10
Case Size ......................................................................................................................................... 1-10
Figures
Figure 1-1. Style Number Identification Chart ........................................................................................... 1-7
Figure 1-2. Typical Instantaneous Response Time................................................................................... 1-9

ii BE1-51/27R General Information 9137200999 Rev D
Tables
Table 1-1. Timing, Characteristic Curve B4, with BE1-51/27R at 100% and 50% Voltages..................... 1-2
Table 1-2. Timing, Curve B4, BE1-51/27R at 25% Voltage (00 to 10 Time Dial Settings) ....................... 1-2
Table 1-3. Timing, Curve B4, BE1-51/27R at 25% Voltage (20 to 99 Time Dial Settings) ....................... 1-3
Table 1-4. Power Supply Specifications .................................................................................................... 1-9

9137200999 Rev D BE1-51/27R General Information 1-1
SECTION 1 ●GENERAL INFORMATION
DESCRIPTION
BE1-51/27R Time Overcurrent Relays are microprocessor-based devices that provide voltage restraint of
the phase time overcurrent function. With voltage restraint, the current pickup decreases proportionately
with decreasing voltage over the rated voltage range. Instantaneous overcurrent element(s) and the
neutral time overcurrent element, when supplied, operate independently of the voltage restraint function.
Each relay is available with one, three, or four time overcurrent elements.
APPLICATION
Voltage restraint provides an added means of discriminating between load and fault conditions. This
allows the time overcurrent pickup to be set below the maximum load (or swing) current. This feature
permits the relay to provide dual protection on a generator. For example, either backing up the differential
protection for generator faults and/or backing up other relays external to the generator zone. As a back-
up function, it must be set with a relatively long delay. Prior to relay time-out, the synchronous impedance
of the generator may be limiting fault current to a level comparable to rated. If the regulator is not in
service to boost excitation, the steady-state fault current, even for a fault on the machine terminals, will
usually be less than rated. The relay pickup must be below generator rated current to insure dependable
operation.
Backup Protection
This relay is useful for generator time overcurrent back-up protection for other relaying external to the
system. It also provides primary (first line) phase fault protection for small generators not equipped with
differential protection.
Phase overcurrent units should be supplied on all three phases. Either three single-phase relays or one
three-phase relay when the objective is to protect for phase-phase faults on the other side of a delta-wye
power transformer. Currents at the relay for a three-phase fault are in the proportions of 2:1:1 in the three
phases, so only one phase sees the higher current level. For this application, each phase time-
overcurrent element should be restrained by the phase-to-ground voltage on its phase, rather than by the
phase-phase voltage.
Following fault inception, current varies continuously as the field current decays. In addition, for other than
a bolted fault on the terminals of a generator, the voltage will not be zero and will vary with time as the
fault current decays. If the restraint voltage is between 25 and 100 percent, the time overcurrent element
pickup will also vary with the time because of the changing voltage. Because the pickup varies with time,
the multiples of pickup, and therefore the timing, will also change. These factors must be considered
when coordinating with external protective devices. Section 4 of this manual provides additional
coordination information in the paragraphs on setting the relay.
Instantaneous overcurrent elements would not ordinarily be used for a generator back-up function. They
would not have acceptable operation for faults external to the generator zone.
Because the phase time-overcurrent pickup will be less than the maximum non-fault current, the relay can
misoperate if the voltage signal is interrupted (e.g., a blown voltage transformer fuse). Where two sources
of signal voltage are available, the BE1-60 Voltage Balance relay can prevent such a misoperation. This
relay compares the output of two signal sources to detect an anomaly in one of these sources and block
the operation of those devices connected to that signal source.
Residually Connected
A neutral (ground) overcurrent element can be applied and connected residually to a set of three current
transformers on solidly grounded applications or on impedance grounded systems that provide ground
fault current approximating rated current level. The neutral element can also be connected to a 10/1
ampere, zero-sequence window current transformer to provide protection on systems producing a
minimum of about 20 amperes primary current. Still another alternative would be connecting this device to
a current transformer in the neutral of a generator.

1-2 BE1-51/27R General Information 9137200999 Rev D
Operating Characteristics at Reduced Voltages
BE1-51/27R relays adjust the operating parameters based on system voltage. The sensitivity of the relay
is increased as the system voltage drops. This provides a means of discriminating between load and fault
conditions.
A decrease of the sensed voltage to a point between 100 percent and 25 percent of nominal results in a
proportional decrease in the time overcurrent pickup point. Thus, at 50 percent nominal voltage, the time
overcurrent relay will pickup at 50 percent of the setting (TAP + Calibration). At voltages above 100
percent nominal, the pickup will be the same as the setting. At voltages below 25 percent of nominal, the
pickup will be 25 percent of the setting. Note that the BE1-51/27R is designed to trip at currents less than
the setting if the voltage is depressed.
The timing characteristics of the BE1-51/27R continue to operate on multiples of pickup basis. Pickup
refers not to the setting, but to the operating point as adjusted for voltage. Thus, with a setting of 5.0
amperes, and system voltage of 50 percent, a current of 5.0 amperes represents 2 times pickup. For a
given fault current magnitude, the relay will trip faster at reduced voltage, because the multiples of pickup
increases.
Table 1-1 shows the timing characteristics at normal and reduced voltages. The curve is B4 and the time
dial is five. The pickup is five amperes. Tables 1-2 and 1-3 show the timing characteristics for multiples of
setting as it relates to multiples of pickup with the BE1-51/27R at 25 percent voltage.
Table 1-1. Timing, Characteristic Curve B4, with BE1-51/27R at 100% and 50% Voltages
Fault
Current
System
Voltage
Effective
Pickup
Multiples of
Pickup
Approximate Trip
Time
4.25 A 100% 5.0 A <1.0 No Trip
4.25 A 50% 2.5 A 1.7 1.499 s
4.25 A 0% 1.25 A 3.4 0.507 s
7.50 A 100% 5.0 A 1.5 1.873 s
7.50 A 50% 2.5 A 3.0 0.772 s
7.50 A 0% 1.25 A 6.0 0.474 s
15.00 A 100% 5.0 A 3.0 0.772 s
15.00 A 50% 2.5 A 6.0 0.474 s
15.00 A 0% 1.25 A 12.0 0.355 s
Table 1-2. Timing, Curve B4, BE1-51/27R at 25% Voltage (00 to 10 Time Dial Settings)
Multiple of
Setting
Multiple of
Pickup
Time Dial Setting (Seconds)
00 01 02 03 05 07 10
0.38 1.50 0.604 0.856 1.111 1.370 1.873 2.384 3.142
0.43 1.70 0.480 0.688 0.899 1.104 1.499 1.930 2.504
0.50 2.00 0.382 0.539 0.705 0.866 1.194 1.517 1.994
0.55 2.20 0.344 0.484 0.633 0.775 1.063 1.349 1.780
0.63 2.50 0.300 0.419 0.548 0.663 0.918 1.168 1.542
0.68 2.70 0.278 0.387 0.508 0.620 0.850 1.073 1.420
0.75 3.00 0.250 0.354 0.461 0.561 0.772 0.977 1.284
0.88 3.50 0.218 0.308 0.403 0.494 0.672 0.855 1.127
1.00 4.00 0.202 0.281 0.360 0.445 0.602 0.772 1.016
1.13 4.50 0.186 0.261 0.334 0.410 0.557 0.709 0.936
1.25 5.00 0.176 0.243 0.308 0.377 0.506 0.649 0.831
1.50 6.00 0.159 0.220 0.285 0.347 0.474 0.599 0.790

9137200999 Rev D BE1-51/27R General Information 1-3
Multiple of
Setting
Multiple of
Pickup
Time Dial Setting (Seconds)
00 01 02 03 05 07 10
1.75 7.00 0.151 0.204 0.263 0.320 0.435 0.553 0.727
2.00 8.00 0.142 0.191 0.246 0.300 0.412 0.520 0.683
2.25 9.00 0.136 0.185 0.240 0.290 0.939 0.499 0.654
2.50 10.00 0.130 0.180 0.227 0.277 0.372 0.477 0.622
3.00 12.00 0.123 0.170 0.215 0.262 0.355 0.453 0.593
3.50 14.00 0.118 0.163 0.208 0.250 0.341 0.433 0.566
4.00 16.00 0.117 0.159 0.201 0.243 0.329 0.420 0.548
4.50 18.00 0.112 0.153 0.195 0.237 0.322 0.406 0.537
5.00 20.00 0.111 0.154 0.188 0.231 0.316 0.400 0.526
Table 1-3. Timing, Curve B4, BE1-51/27R at 25% Voltage (20 to 99 Time Dial Settings)
Multiple of
Setting
Multiple of
Pickup
Time Dial Setting (Seconds)
20 30 40 50 60 80 99
0.38 1.50 5.671 8.222 10.788 13.344 15.919 20.918 25.707
0.43 1.70 4.533 6.556 8.527 10.662 12.694 16.698 20.464
0.50 2.00 3.593 5.207 6.808 8.407 9.986 13.164 16.276
0.55 2.20 3.198 4.636 6.041 7.482 8.906 11.694 14.486
0.63 2.50 2.766 4.003 5.218 6.454 7.682 10.146 12.453
0.68 2.70 2.569 3.720 4.848 5.986 7.130 9.381 11.557
0.75 3.00 2.322 3.358 4.372 5.409 6.434 8.489 10.454
0.88 3.50 2.026 2.931 3.829 4.726 5.627 7.406 9.120
1.00 4.00 1.833 2.647 3.450 4.258 5.076 6.688 8.214
1.13 4.50 1.691 2.438 3.188 3.932 4.673 6.166 7.597
1.25 5.00 1.464 2.117 2.749 3.380 4.022 5.303 6.513
1.50 6.00 1.424 2.060 2.688 3.314 3.949 5.200 6.396
1.75 7.00 1.318 1.897 2.479 3.060 3.644 4.802 5.899
2.00 8.00 1.234 1.792 2.329 2.884 3.430 4.518 5.561
2.25 9.00 1.184 1.704 2.229 2.748 3.273 4.298 5.290
2.50 10.00 1.120 1.604 2.093 2.589 3.070 4.053 4.977
3.00 12.00 1.073 1.551 2.018 2.498 2.971 3.917 4.817
3.50 14.00 1.028 1.481 1.928 2.390 2.841 3.741 4.603
4.00 16.00 0.989 1.430 1.866 2.304 2.741 3.610 4.443
4.50 18.00 0.958 1.392 1.818 2.243 2.667 3.514 4.328
5.00 20.00 0.944 1.372 1.786 2.200 2.619 3.454 4.252
STANDARD FEATURES
Time Overcurrent Functions
Time overcurrent elements pick up over a range of 0.1 to 0.8 amperes, 0.3 to 2.4 amperes, 0.5 to 4.0
amperes, 1.5 to 12.0 amperes, 0.1 to 2.4 amperes, or 0.5 to 12.0 amperes and provide an adjustable time
delay that is proportional to the overcurrent. Time delay is initiated when the sensed current exceeds the
pickup point. When the current drops below the pickup point, the timing circuit is reset immediately. At
reset, the output contacts, if operated, are restored to normal.

1-4 BE1-51/27R General Information 9137200999 Rev D
Adjustment of the overcurrent pickup point is provided by controls on the relay front panel. Time delay is a
function of the characteristic curve that has been selected. Time delay is settable from 00 to 99 on the
TIME DIAL thumbwheel switch located on the front panel. Curve type is selected either as an option or, in
some models, is switch selectable.
Sixty-nine characteristic curves and three timing options are available. They are:
Characteristic curves:
•Seven inverse time
•Nine I2t
•Seven inverse time with extended timing range
•Nine I2t with extended timing range
•Five British Standard 142 (E curves)
•Seven integrating inverse time
•Nine integrating I2t
•Seven integrating inverse time with extended timing range
•Nine integrating I2t with extended timing range
Timing option Z1 (switch selectable - 16 position) B and C curves:
•Seven inverse time
•Nine I2t
Timing option Z1 with option 2-D or 2-E (switch selectable - 16 position) B and C curves:
•Seven inverse time with extended timing range
•Nine I2t with extended timing range
Timing option Z2 (switch selectable - 16 position) B and E (British Standard 142) curves:
•Seven inverse time
•One I2t
•Five British Standard (BS) 142 (E curves)
Timing option Z2 with option 2-D or 2-E (switch selectable - 16 position) B and E (BS142) curves:
•Seven inverse time with extended timing range
•One I2t with extended timing range
•Five British Standard 142 (E curves)
Timing option Z3 (switch selectable - 16 position) integrating B and C curves:
•Seven integrating inverse time
•Nine integrating I2t
Timing option Z3 with option 2-D or 2-E (switch selectable - 16 position) integrating extended B and C
curves:
•Seven integrating inverse time with extended timing range
•Nine integrating I2t with extended timing range
Characteristic curves are shown by the graphs in Appendix A, Time Overcurrent Characteristic Curves.
Note that each graph (i.e. function) consists of a set of representative curves. Each curve (as well as any
between-curve interpolation) is selectable by the front panel TIME DIAL using a two-digit destination from
00 to 99. Because of space limitations, each graph shows only 14 of the 100 possible selections.
Non-Integrating Timing
Timing options Z1 and Z2 and the characteristic curves available with those options use non-integrating
timing. Non-integrating timing is accomplished by timing at a gate that is not solely dependent on the
magnitude of the applied multiple of pickup current. The time-out value is calculated based on the type of
time curve characteristic selected, time dial setting, and the magnitude of the applied multiple of pickup
current. The time-out value is continuously updated during the timing cycle. When pickup is exceeded, a
timer is initiated. When the timer elapsed time exceeds the calculated time-out value, a time trip output
signal is generated.
This type of non-integrating time delay characteristic exhibits a dynamic characteristic that is immediately
responsive to changes of the applied multiple of pickup current.

9137200999 Rev D BE1-51/27R General Information 1-5
Integrating Timing
Timing option Z3 and the characteristic curves available for that option uses integrating timing. Integrating
timing is accomplished by summing time increments that are based on the magnitude of the applied
multiple of pickup current, the time curve characteristic selected, and the time dial value. These time
increments are summed until a predetermined value is exceeded, then a time trip output signal is
generated.
This type of integrating time delay characteristic simulates the operating characteristics of an
electromechanical overcurrent relay.
Built-In Test
A built-in test (BIT) switch mounted on the Logic Board provides diagnostic troubleshooting and
calibration.
OPTIONS
Timing
An extended timing option multiplies by approximately 5.7, the standard time delays. The resulting curves
are shown following the standard curves in Appendix A - e.g., Figure A-1 is timing type B1 and Figure A-2
is the timing type B1 with extended timing range.
When timing option Z1, Z2, or Z3 is specified, a printed circuit board mounted selector switch allows a
choice of up to sixteen different time overcurrent functions. Timing option Z1 or Z3 may be further
specified as standard or extended time, depending upon option 2 selection.
Sensing Input Type
When single-phase, two-phase-and-neutral, three-phase, or three-phase-and-neutral sensing has been
specified, the front panel TAP selector and the front panel TAP CAL control set the pickup point for all
phases. An independent front panel TAP (NEUTRAL) selector and front panel CAL (NEUTRAL) control
set the neutral pickup point. In addition, for three-phase-and-neutral sensing units, one of the seven
sensing input range combinations must be specified.
Relay circuits provide a voltage restraint circuit that varies the selected time overcurrent pickup point
proportional to the monitored voltage. As the monitored voltage varies between 100 percent and 25
percent of nominal, the pickup point for each phase varies between 100 percent and 25 percent. Nominal
voltage is 100 Vac for 50-hertz systems and 120 Vac for 60-hertz systems. Neutral time overcurrent
elements are not restrained. Three-phase voltages are measured phase-to-phase for three wire
connections and phase-to-neutral for four wire connections.
Sensing Input Range
For three-phase-and-neutral sensing units, input ranges are:
•0.5 to 4.0 amperes (phase and neutral)
•1.5 to 12 amperes (phase) and 0.5 to 4.0 amperes (neutral)
•0.5 to 4 amperes (phase) and 1.5 to 12 amperes (neutral)
•1.5 to 12 amperes (phase and neutral)
•0.1 to 0.8 amperes (phase and neutral)
•0.3 to 2.4 amperes (phase) and 0.1 to 0.8 amperes (neutral)
•0.3 to 2.4 amperes (phase and neutral)
For all other units, two ranges are available. They are 0.5 to 12 amperes and 0.1 to 2.4 amperes.
Power Supply
Five power supply options are available. They are:
•24 Vdc
•48 Vdc
•125 Vdc and 100/125 Vac
•48 Vdc or 125 Vdc and 100/125 Vac
•250 Vdc and 240 Vac

1-6 BE1-51/27R General Information 9137200999 Rev D
Targets
Single-phase relays have two function targets that indicate when the time delay or instantaneous
element(s) have operated. On multiple phase relays, additional targets indicate which phase or neutral
element(s) operated.
Function targets may be specified as either internally operated or current operated by a minimum of 0.2
amperes through the output trip circuit. When current operated, the output circuit must be limited to 30
amperes for 0.2 seconds, 7 amperes for 2 minutes, and 3 amperes continuously.
Outputs
Optional normally opened, normally closed, or SPDT auxiliary output contacts may be selected. Contacts
actuate when the output relay is energized. Internally operated front panel mounted targets, and front
panel targets operated by the dc current in the output circuit are available for the time overcurrent and
instantaneous overcurrent functions. Optional front panel mounted PUSH-TO-ENERGIZE-OUTPUT
pushbuttons allow direct actuation of each output relay for external circuit testing.
Instantaneous Outputs
One or two instantaneous overcurrent outputs are optionally available. Each is adjustable up to 40 times
the time overcurrent pickup point. When the sensed current exceeds the instantaneous overcurrent
pickup point, an output relay is energized. An independent front panel control (INST 1 or INST 2) adjusts
the pickup point for each optional output. If more than one phase is applied to the relay, the instantaneous
pickup point will be the same for all phases. If neutral current is sensed, a front panel INST 1 (NEUTRAL)
provides adjustment of the neutral pickup point. Instantaneous overcurrent elements are not voltage
controlled.
Packaging
Each relay is mounted in a drawout cradle and enclosed in a standard utility style case with either semi-
flush or projection mounting (depending upon case style selected). An available test plug (Basler Electric
part number 10095) allows the relay to be tested in place without disturbing external control circuit wiring.
MODEL AND STYLE NUMBER DESCRIPTION
BE1-51/27R Time Overcurrent Relay electrical characteristics and operational features are defined by a
combination of letters and numbers that make up its style number. The model number, together with the
style number, describes the options included in a specific device, and appears on the front panel, drawout
cradle, and inside the case assembly. Upon receipt of a relay, be sure to check the style number against
the requisition and the packing list to ensure that they agree.
Style Number Identification Chart (Figure 1-1) illustrates the manner in which the relay style number is
determined. For example, if the style number were U3E-Z1P-B1C1F, the device would have the following
characteristics:
U- Three-Phase-and-Neutral sensing, 3-phase, 4-wire voltage restraint
3- Sensing input range of 1.5 to 12.0 amperes for phase and 0.5 to 4.0 amperes for neutral
E- Normally open outputs
Z1 - Switch selectable time curves
P- Operating power derived from 125 Vdc or 120 Vac
B- Current operated targets
1- One instantaneous element
C- Push-to-energize outputs
1- Normally open auxiliary timed output relay
F- Semi-flush mounting

9137200999 Rev D BE1-51/27R General Information 1-7
Figure 1-1. Style Number Identification Chart
SPECIFICATIONS
BE1-51/27R Time Overcurrent Relays electrical and physical specifications are as follows:

1-8 BE1-51/27R General Information 9137200999 Rev D
Voltage Sensing Inputs
Rated for 160 Vac continuous at 40 to 70 Hz (nominal frequency 50 or 60 Hz) with a maximum burden of
1 VA.
Sensing Input Burden
Less than 0.1 ohms per phase or neutral.
Sensing Input Rating
The maximum continuous rating is 20 A, 1 second current rating is 50X (times) the maximum tap current
selected, or 500 A, whichever is less. For ratings other than those specified by the time curves, the rating
is calculated as follows:
Tless)is(whicheverA500ortapx50
I=
Where: I = Maximum current
T = Time that current flows (in seconds)
Time Overcurrent Pickup Selection Range
Continuously adjustable over the current sensing input ranges specified in the Style Chart (Figure 1-1).
Time Overcurrent Pickup Accuracy
±5% of front panel tap selector setting with TAP CAL control fully CW or ±7% of minimum tap, whichever
is greater.
Voltages ≥Nominal
±10% of calculated pickup value or ±7% of the minimum tap, whichever is greater.
Voltages <Nominal
To find the effective multiple of pickup current use the formula:
V
V
II
M
N
t
×=
Where: M = Multiple of tap value current
I = Applied current level
IT= Tap value
VN= Nominal voltage
V = Applied voltage level
Time Overcurrent Dropout Ratio
Better than 92% of pickup level.
Instantaneous Overcurrent Pickup Range
Continuously adjustable over the range of 1 to 40 times the time overcurrent pickup setting.
Instantaneous Overcurrent Measuring Accuracy
±2% of pickup setting.
Instantaneous Overcurrent Dropout Ratio
Better than 98% of pickup level.
Instantaneous Response
Figure 1-2 shows the typical response for the instantaneous pickup element.

9137200999 Rev D BE1-51/27R General Information 1-9
Figure 1-2. Typical Instantaneous Response Time
Time Delay Accuracy
±5% of the characteristic curve (Figures A-1 through A-69) for any combination of the front panel TIME
DIAL setting and the front panel TAP/TAP CAL overcurrent pickup setting. When evaluating time delay
accuracy, time overcurrent pickup accuracy also needs to be considered.
Repeatability is within ±2% of setting at 25°C.
Output Circuits
120 Vac: Make, break, and carry 7 Aac continuously
Resistive Ratings
250 Vdc: Make and carry 30 Adc for 0.2 s, carry 7 Adc continuously, and break 0.3 Adc
500 Vdc: Make and carry 15 Adc for 0.2 s, carry 7 Adc continuously, and break 0.3 Adc
120 Vac, 125 Vdc, 250 Vdc: Break 0.3 A (L/R = 0.04)
Inductive Ratings
Target Indicators
Function targets may be specified as either internally operated or current operated by a minimum of 0.2
amperes through the output trip circuit. When current operated, the output circuit must be limited to 30
amperes for 0.2 seconds, 7 amperes for 2 minutes, and 3 amperes continuously.
Power Supply
Power for the internal circuitry may be derived from a variety of ac or dc external power sources as
indicated in Table 1-4.
Table 1-4. Power Supply Specifications
Type Input Voltage Burden at Nominal
Nominal Range
O (mid range) 48 Vdc 24 to 150 Vdc 1.6 W
P (mid range) 125 Vdc
120 Vac 24 to 150 Vdc 90 to 132 Vac 1.9 W 8.9 VA
R (low range) 24 Vdc 12 to 32 Vdc ∗1.7 W
S (mid range) 48 Vdc
125 Vdc 24 to 150 Vdc 24 to 150 Vdc 1.6 W 1.9 W
T (high range) 250 Vdc
240 Vac 68 to 280 Vdc 90 to 270 Vac 2.1 W 14.2 VA
∗Type R power supply may require 14 Vdc to begin operation. Once operating, the voltage may be
reduced to 12 Vdc.

1-10 BE1-51/27R General Information 9137200999 Rev D
Radio Frequency Interference (RFI)
Field-tested using a five-watt, hand-held transceiver operating at random frequencies centered around
144 MHz and 440 MHz, with the antenna located six inches from the relay in both horizontal and vertical
planes.
Isolation
In accordance with IEC 255-5 and ANSI/IEEE C37.90, one-minute dielectric (high potential) tests as
follows:
All circuits to ground: 2,828 Vdc
Input to output circuits: 2,000 Vac or 2,828 Vdc
Surge Withstand Capability
Qualified to ANSI/IEEE C37.90.1-1989, Standard Surge Withstand Capability (SWC) Tests for Protective
Relays and Relay Systems.
UL Recognized
UL recognized per Standard 508, UL File No. E97033. Note: Output contacts are not UL recognized for
voltages greater than 250 volts and input power supply voltages greater than 150 volts.
GOST-R
Gost-R certified per the relevant standards of Gosstandart of Russia.
Operating Temperature
The operating temperature range is from −40°C (−40°F) to +70°C (+158°F).
Storage Temperature
The storage temperature range is from −65°C (−85°F) to +100°C (+212°F).
Shock
In standard tests, the relay has withstood 15 g in each of three mutually perpendicular planes without
structural damage or degradation of performance.
Vibration
In standard tests, the relay has withstood 2 g in each of three mutually perpendicular planes, swept over
the range of 10 to 500 Hz for six sweeps, 15 minutes each sweep without structural damage or
degradation of performance.
Weight
Single-Phase: 13.0 lbs. (5.90 kg)
Two-Phase and Neutral: 14.0 lbs. (6.35 kg)
Three-Phase: 14.0 lbs. (6.35 kg)
Three-Phase and Neutral: 14.4 lbs. (6.53 kg)
Case Size
S1 (Refer to Section 4 for case dimensions.)