ESB Three-Phase Unbalance Detector
ESB Series
Real-time monitoring of three-phase unbalance and zero-sequence current, warning grid-unbalance risks and reducing line losses and equipment wear.
Product Overview
The ESB Three-Phase Unbalance Monitor is a smart monitoring terminal dedicated to in-depth diagnosis of unbalance in low-voltage three-phase distribution systems. The product dynamically calculates in real time the zero-sequence voltage unbalance, negative-sequence voltage unbalance, zero-sequence current unbalance and negative-sequence current unbalance, and provides key indicators such as the phase angle and voltage difference of each phase line. The product exclusively decomposes positive-sequence, negative-sequence and zero-sequence components to precisely locate the root cause of grid unbalance. With its unique vector calculation model, it directly provides 130+ monitoring items covering 6 major categories and 17 parameters - voltage, current, power, energy, power factor, phase angle, unbalance and frequency - equivalent to the combined functions of 5 instruments.
Core Application Scenarios
Three-phase unbalance monitoring and management of low-voltage distribution cabinets. Balanced management of precision power distribution in data centers. Power quality diagnosis and optimization of industrial production lines. Smart power distribution operation & maintenance of commercial buildings. Product Features
Data Generated
Product Features
In-Depth Unbalance Diagnosis
Exclusively monitors zero-sequence and negative-sequence voltage/current unbalance, decomposes positive/negative/zero-sequence components, and precisely locates which phase is abnormal.
130+ Parameters in One Meter
17 parameters in 6 major categories: voltage/current/power/energy/power factor/phase angle/unbalance/frequency, equivalent to the combined functions of 5 instruments.
Industry-Leading Accuracy
Voltage and current measurement accuracy up to class 0.2, unbalance measurement error <2%, 10 times stricter than the national standard, frequency accuracy 0.01Hz.
Multi-Level Intelligent Alarm Linkage
Supports 8 alarm types: overvoltage/undervoltage/overcurrent/over-power/voltage unbalance/current unbalance/undercurrent/under-power, with “AND/OR” logic programming - alarms immediately when limits are exceeded with automatic linkage.
HD OLED Display
The OLED screen displays key parameters such as three-phase voltage and current in real time, with a unique unbalance analysis interface that turns abstract problems into concrete values.
Remote Calibration & Open Data
Supports remote software calibration of current/voltage/power gain; 200+ readable/writable registers are fully transparent, supporting deep secondary development. Selection Guide
System Topology
Selection Guide
Model Naming Rules
ESB - 1 2 1 1 1 - R: 1 Power: 1=DC 5V / 2=AC 220V; 2 Display: 1=LED digital display / 2=OLED screen; 3 Wiring: 1=three-phase four-wire; 4 Current: 1=5A / 2=100A / 3=400A / 4=600A; 5 Input and Output: 1=1 relay output + 2 digital inputs; 6 Communication: R=RS485. Model / Power supply / Display / Current rating / Voltage rating / Digital inputs / Relay output / RS485 Modbus: ESB-12111-R DC 5V OLED 3×5A 3×220/380V 2 channels 1 channel supported; ESB-12121-R DC 5V OLED 3×100A 3×220/380V 2 channels 1 channel supported; ESB-12131-R DC 5V OLED 3×400A 3×220/380V 2 channels 1 channel supported; ESB-12141-R DC 5V OLED 3×600A 3×220/380V 2 channels 1 channel supported; ESB-22111-R AC 220V OLED 3×200A 3×220/380V 2 channels 1 channel supported; ESB-22121-R AC 220V OLED 3×1000A 3×220/380V 2 channels 1 channel supported; ESB-22131-R AC 220V OLED 3×400A 3×220/380V 2 channels 1 channel supported; ESB-22141-R AC 220V OLED 3×600A 3×220/380V 2 channels 1 channel supported. * Other electrical parameters include frequency, power, power factor, etc. For other ranges or communication configurations, please contact sales for a customized solution. Technical Parameters
| Model | Power Supply / Display / Current Rating / Voltage Rating / Digital Inputs / Relay Output / RS485 Modbus |
| ESB-12111-R | DC 5V / OLED / 3×5A / 3×220/380V / 2 channels / 1 channel / Supported |
| ESB-12121-R | DC 5V / OLED / 3×100A / 3×220/380V / 2 channels / 1 channel / Supported |
| ESB-12131-R | DC 5V / OLED / 3×400A / 3×220/380V / 2 channels / 1 channel / Supported |
| ESB-12141-R | DC 5V / OLED / 3×600A / 3×220/380V / 2 channels / 1 channel / Supported |
| ESB-22111-R | AC 220V / OLED / 3×200A / 3×220/380V / 2 channels / 1 channel / Supported |
| ESB-22121-R | AC 220V / OLED / 3×1000A / 3×220/380V / 2 channels / 1 channel / Supported |
| ESB-22131-R | AC 220V / OLED / 3×400A / 3×220/380V / 2 channels / 1 channel / Supported |
| ESB-22141-R | AC 220V / OLED / 3×600A / 3×220/380V / 2 channels / 1 channel / Supported |
Technical Parameters
Basic Parameters
Operating voltage DC 4.75~5.25V (5V model) / AC 180~250V (220V model); power consumption ≤ 2W; operating temperature -20℃ ~ 60℃; operating humidity < 95%; product weight 150g; dimensions 36 × 110 × 69mm (L×W×H); housing material thermoplastic material UL94V0; protection rating IP20; mounting standard 35mm DIN rail; display OLED; communication RS485; protocol Modbus protocol
| Operating Voltage | DC 4.75~5.25V (5V model) / AC 180~250V (220V model) |
| Power Consumption | ≤ 2W |
| Operating Temperature | -20℃ ~ 60℃ |
| Operating Humidity | < 95% |
| Product Weight | 150g |
| Dimensions | 36 × 110 × 69mm (L×W×H) |
| Housing Material | Thermoplastic material UL94V0 |
| Protection Rating | IP20 |
| Mounting | Standard 35mm DIN rail |
| Display | OLED |
| Communication | RS485 |
| Communication Protocol | Modbus protocol |
Monitoring Functions
Voltage (AC): rated 220V/380V; overload 1.2x rated continuous, 2x rated for 1 second; accuracy class 0.5/0.2S. Current (AC): rated 5A, 100A, 400A, 600A; overload 1.2x rated continuous, 2x rated for 1 second; accuracy class 0.5/0.2S. Frequency 45~65Hz, accuracy 0.01Hz. Active energy: accuracy class 1. Reactive energy: accuracy class 2. Three-phase unbalance: zero-sequence/negative-sequence voltage/current unbalance, unbalance measurement error <2%. Digital inputs: dry contact input, built-in power, 2 channels. Digital output: relay output, contact rating AC250V/3A, DC30V/3A, normally open relay contact. Installation Instructions
| Voltage (AC) | Rated 220V/380V; overload 1.2x rated continuous, 2x rated for 1 second; accuracy class 0.5/0.2S |
| Current (AC) | Rated 5A, 100A, 400A, 600A; overload 1.2x rated continuous, 2x rated for 1 second; accuracy class 0.5/0.2S |
| Frequency | 45~65Hz, accuracy 0.01Hz |
| Active Energy | Accuracy class 1 |
| Reactive Energy | Accuracy class 2 |
| Three-Phase Unbalance | Zero-sequence/negative-sequence voltage/current unbalance, unbalance measurement error <2% |
| Digital Inputs | Dry contact input, built-in power, 2 channels |
| Digital Output | Relay output, contact rating AC250V/3A, DC30V/3A, normally open relay contact |
Installation Instructions
a
Mounting Dimensions
36mm width, 110mm height, 69mm depth, 35mm standard DIN rail b
Sensor Description
The product uses external three-phase current transformers, with different rated values corresponding to different aperture sizes. The split-core design enables installation without powering off; dedicated high-precision sensors combined with a patented smart locking design ensure high stability in complex environments. 5A aperture 16mm; 100A aperture 24mm; 200A aperture 36mm; 400A aperture 36mm; 600A aperture 36mm; 1000A aperture 52mm. Rated value / Current ratio / Aperture: 5A - 5A/0.33V - 16mm; 100A - 100A/0.33V - 24mm; 200A - 200A/0.33V - 36mm; 400A - 400A/0.33V - 36mm; 600A - 600A/0.33V - 36mm; 1000A - 1000A/0.33V - 52mm c
| Rated Value | Current Ratio / Aperture |
| 5A | 5A / 0.33V / 16mm |
| 100A | 100A / 0.33V / 24mm |
| 200A | 200A / 0.33V / 36mm |
| 400A | 400A / 0.33V / 36mm |
| 600A | 600A / 0.33V / 36mm |
| 1000A | 1000A / 0.33V / 52mm |
Interface Description
Wiring definitions: Power: 220V - L1 live wire, N neutral wire; 5V - 5V positive, GND 0V (choose one). RS485 communication: A - RS485 A terminal; B - RS485 B terminal. DI inputs: DI1/DI2 - digital inputs, connect the other end to GND, direction-free. DO outputs: DO1/DO1' - relay outputs, direction-free. Current inputs: IA+/IA-, IB+/IB-, IC+/IC- - three-phase current positive and negative terminals. Voltage inputs: L1/L2/L3 - three-phase voltage; N - neutral wire. Note: Only one of the 220V AC input and 5V DC power input can be used; do not connect both simultaneously.
| Power | 220V: L1 live wire, N neutral wire; 5V: 5V positive, GND 0V (choose one) |
| RS485 Communication | A: RS485 A terminal; B: RS485 B terminal |
| DI Inputs | DI1/DI2: digital inputs, connect the other end to GND, direction-free |
| DO Outputs | DO1/DO1': relay outputs, direction-free |
| Current Inputs | IA+/IA-, IB+/IB-, IC+/IC-: three-phase current positive and negative terminals |
| Voltage Inputs | L1/L2/L3: three-phase voltage; N: neutral wire |
Key Points
Definition: The ESB Three-Phase Unbalance Monitor is FEXLINK's electrical safety device dedicated to three-phase voltage/current unbalance monitoring. Core capabilities: Real-time monitoring of three-phase voltage and current amplitude and phase, calculation of unbalance, threshold-crossing alarms, supporting RS485 upload. Applicable scenarios: Suitable for distribution monitoring of scenarios sensitive to three-phase balance, such as industrial motors, UPS and precision equipment. Related products: ESA electrical safety monitoring terminal, ESE power quality monitor, SFA multi-element measurement & control unit.
FAQ
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Learn MoreESB Three-Phase Unbalance Detector Application Scenarios
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