Basler BE1-47N Relay Field Setting and Testing Guide

Practical Guide for Field Application and Setting Test of Basler BE1-47N Voltage Phase Sequence Relay

In industrial power distribution and motor protection systems, voltage asymmetry, phase sequence errors, and phase loss operation are common causes of equipment damage and production interruptions. The BE1-47N voltage phase sequence relay from Basler Electric provides a reliable monitoring and protection solution for such issues. This article combines the actual technical data of this type of relay and systematically sorts out its selection points, installation wiring, panel operation, parameter setting, and verification testing methods from the perspective of on-site application, providing engineering and technical personnel with a directly referenceable practical document.

Product positioning and typical application scenarios of BE1-47N

BE1-47N belongs to voltage phase sequence relays, whose core function is to respond to negative sequence voltage (V2) in three-phase systems. The occurrence of negative sequence voltage often indicates asymmetric faults or incorrect wiring in the system, such as phase loss, reversed phase sequence, severe three-phase load imbalance, etc. This relay not only detects these abnormalities, but also has built-in overvoltage and undervoltage protection functions (optional), allowing it to provide protection in various scenarios.

Typical applications include:

The phase sequence protection and phase loss protection of the motor prevent the motor from starting or running in case of phase sequence error or phase loss;

The voltage and phase sequence verification in the automatic transfer switch (ATS) scheme ensures the correct phase sequence before the backup power supply is connected;

Grid connection or line switching protection for generators, transformers, and synchronous phase-shifting cameras;

Phase sequence and voltage imbalance monitoring of power capacitor banks.

It is worth noting that BE1-47N has high sensitivity in detecting negative sequence voltage and can identify negative sequence voltage components as low as 2%. In industrial power supply systems, a negative sequence voltage of 1% to 2% is within the normal range. Once it significantly increases, it usually indicates abnormal power supply. If not dealt with in a timely manner, it may cause serious production problems.

Key selection points and model code interpretation

The model code of BE1-47N includes key information such as voltage level, frequency, output configuration, timing characteristics, control power supply, target indication mode, and housing form of the equipment. Correctly understanding the model code is the first step in selecting a model.

Model code example: E3FE1PA1R0F

The disassembly is as follows:

E: Three phase line voltage detection method;

3: The rated voltage is 120 Vac and the frequency is 60 Hz;

F: Equipped with two output relays, the contact form is normally open (NO);

E1: Negative sequence voltage protection adopts timed delay characteristics;

P: The auxiliary power supply is 125 Vdc or 120 Vac;

1: Built in 1 internal incentive target indicator;

1: Contains instantaneous undervoltage components;

R: Contains instantaneous overvoltage components;

0: No auxiliary output relay;

F: Semi embedded installation shell.

When selecting, special attention should be paid to whether the voltage level and frequency match the on-site system (such as 120 Vac/60 Hz or 208 Vac/60 Hz), and whether undervoltage and overvoltage protection functions are required. If normally closed contacts or additional signal contacts are required on site, they should also be clearly selected in the model.

Installation method and structural dimensions

BE1-47N adopts S1 type chassis, supporting two installation methods: semi embedded installation and protruding installation. Due to the use of solid-state circuit design, the relay itself does not need to be installed vertically, and the installation angle can be flexibly selected according to the cabinet space.

Key installation dimensions (taking semi embedded as an example):

The size of the panel opening should refer to the panel cutting diagram in the manual;

The depth of the chassis is about 141.3 mm (calculated from the back of the panel);

When installed in a protruding manner, there is an increased demand for rear space.

Special attention should be paid to grounding issues during installation: the relay housing must be reliably connected to the ground through a copper wire of not less than 12 AWG, and it is recommended that each device be independently led to the grounding busbar to avoid interference caused by shared grounding wires.

Precautions for Electrical Connections and Wiring

The wiring of BE1-47N mainly includes voltage detection input, auxiliary power input, output contacts, and status indication contacts.

Voltage detection input:

According to different models, the detection input is divided into 120 Vac, 208 Vac (60 Hz) or 100 Vac, 173 Vac (50 Hz). In typical wiring, the three-phase voltages A, B, and C are respectively connected to the corresponding terminals on the back of the relay. The manual clearly states that the relay is sensitive to phase sequence, and all wiring diagrams and settings are based on ABC positive phase sequence. If the actual phase sequence on site is ACB, the phase sequence needs to be adjusted or the test values need to be recalculated.

Auxiliary power supply:

The power supply types include DC (such as 24 Vdc, 48 Vdc, 125 Vdc, 250 Vdc) and AC (such as 120 Vac, 240 Vac). The power terminals have no polarity requirements, but it is necessary to ensure that the voltage is within the allowable range. When the power is normal, the red LED indicator on the panel lights up.

Output contact:

The main output contact is used for tripping circuits and can be selected as normally open or normally closed. The auxiliary output contact can be used for signal remote transmission or alarm. If a current type target indicator is selected, it is necessary to ensure that the tripping circuit current is not less than 200 mA, otherwise the target indicator may not function properly.

Suggestions for wiring construction:

Unless otherwise specified, the wire diameter should not be less than 14 AWG;

If the output contact is used to drive the external relay coil, it is recommended to parallel reverse diodes at both ends of the coil to suppress EMI interference generated during power failure;

If insulation withstand voltage testing is required, it is necessary to first unplug the connection plug and extract the relay from the chassis to avoid damaging the internal circuit.

Panel controls and operating instructions

The layout of the BE1-47N panel is clear, with operation controls concentrated on the front for easy on-site tuning and status viewing.

The main controls include:

Negative sequence voltage setting dip switch: 16 positions, corresponding to negative sequence voltage setting values of 2% to 32%, with an interval of 2% between each position. The panel is accompanied by a comparison table, indicating the percentage values corresponding to grades A to S.

Undervoltage setting dip switch (optional): The setting range is 2% to 32% below the rated voltage.

Overvoltage setting toggle switch (optional): The setting range is 2% to 32% higher than the rated voltage.

Delay setting dip switch: For timed characteristics, it can be set from 0.1 seconds to 9.9 seconds with a step size of 0.1 seconds; For the inverse time characteristic, the range is set from 01 to 99.

Target reset button: used to manually reset the target indicator that has been activated.

Output test hole: A non-conductive rod can be inserted into the panel hole to manually trigger the output relay for circuit inspection.

Status indication:

Power indicator light: green or red LED, lit up to indicate that the auxiliary power supply is normal.

Pick up indicator lights for negative sequence, undervoltage, and overvoltage protection units: red LED, which lights up when the corresponding power exceeds the set value, indicating a delayed or instantaneous action state.

Target indicator: Electronic locking type red LED, which remains lit when the output relay is activated until manually reset.

Parameter tuning methods and principles

Reasonable setting is a prerequisite for relays to perform protective functions. The following are the principles for setting various protections.

Negative sequence voltage setting:

The negative sequence voltage in normal industrial power supply is usually between 1% and 2%. It is recommended to set the initial setting value to 4%~6% to avoid frequent misoperation caused by normal system imbalance.

If the motor load is heavy, the setting value can be appropriately increased, but should not exceed 10%, otherwise it may not effectively protect the equipment from the impact of phase loss faults.

Undervoltage setting:

Usually set at 80% to 90% of the rated voltage, used to detect significant drops in the supply voltage.

It needs to match the minimum operating voltage allowed by the system to avoid misoperation during brief voltage drops such as motor start-up.

Overvoltage setting:

Generally set to 110%~120% of the rated voltage, used to prevent excessive voltage caused by capacitor bank switching or system faults.

Delay characteristic selection:

Fixed time limit: Suitable for situations with clear requirements for time limits, such as cooperating with subordinate protection.

Inverse time limit: applicable to equipment such as motors or transformers, whose ability to withstand asymmetric voltage rapidly decreases with the increase of negative sequence voltage.

Instantaneous (delay set to 00): Used for severe faults that require immediate action, with an action time of less than 50 milliseconds.

On site testing and functional verification

To ensure reliable operation of the relay after it is put into operation, it is recommended to conduct basic functional tests under on-site conditions. The following testing methods are all from official technical manuals and are suitable for on-site implementation.

7.1 Negative sequence voltage pickup and return value test (single-phase method)

Due to the laboratory level symmetrical component testing requiring three-phase voltage sources and phase measurements, a simplified single-phase method can be used on site:

Set the negative sequence setting switch to K position (corresponding to 20%);

Short circuit the terminals of phases B and C (simulate Vbc=0);

Apply a single-phase voltage between phases A and B/C at the rated frequency;

Calculate according to the formula:

V_AB = V2PU × √3 × VN

VN is the rated phase voltage (such as 120 Vac), and V2PU is the set value (such as 0.2 pu).

For a 120 Vac system, the calculated value is approximately 41.57 Vac. At this time, the negative sequence picking LED should light up.

Slowly decrease the voltage and observe the voltage value when the LED is turned off. The return value should be around 98% of the picked up value, which is approximately 40.7 Vac.

This method can quickly verify whether the negative sequence detection circuit is normal and confirm the accuracy of the setting switch.

7.2 Overvoltage and undervoltage pickup test

Overvoltage test:

Set the overvoltage setting switch to E position (10%);

Apply 1.10 times the rated voltage (such as 132 Vac) between phases B and C;

The overvoltage pickup LED should light up;

Reduce the voltage until the LED goes out, and the return value should be around 98% of the pickup value.

Undervoltage test:

Set the undervoltage setting switch to E position (10%);

Apply 0.90 times the rated voltage (such as 108 Vac) between phases B and C;

The undervoltage pickup LED should light up;

Raise the voltage until the LED turns off, and the return value should be around 102% of the pickup value.

7.3 Fixed time and inverse time delay verification

Time limited verification (taking overvoltage as an example):

Set the delay switch to 33 (i.e. 3.3 seconds);

Set the overvoltage setting to A level (2%);

Apply 1.20 times the rated voltage and start the timer at the same time;

The output contact should close within 3.3 seconds ± 5%.

Inverse time limit verification (taking negative sequence as an example):

Set the negative sequence to B level (4%) and set the delay to 10;

Short circuit phases B and C;

Apply a voltage twice the value of the pickup (refer to the table in the manual);

The measurement of the time from voltage application to contact closure should be consistent with the corresponding value of the inverse time curve provided in the manual (such as 5.96 seconds ± 0.298 seconds).

Maintenance and Storage Suggestions

BE1-47N is a solid-state relay with less daily maintenance workload. It is recommended to conduct a functional test on a regular basis (such as annually) to confirm that all protection parameters and action times meet the requirements. If the relay is stored for a long time as a backup, it should be powered on for 30 minutes every 12 months to maintain the performance of the internal electrolytic capacitor and extend its service life.

If there is an abnormality in the relay, it is not recommended to disassemble and repair it on site. It is necessary to promptly contact Basler Electric technical support for professional repair services.