Description
Overview of Low Voltage Motor Protector
- This series of Low Voltage Motor Protector are low-voltage AC motor protection and control devices independently developed by our company, suitable for motors with rated frequency 50Hz, AC voltage up to 690V and rated current up to 800A.
- Integrated with monitoring, control, protection and communication functions, this motor protective relay provides full-range protection for electric motors.
3 Phase motor protection relay-Features
- Built-in multiple protection functions; users can easily enable/disable protection, set alarm or tripping modes with simple selection.
- Supports various control modes including protection mode, direct start, two-way start, two-speed start and star-delta start. Different control logics can be switched conveniently with high flexibility and universality.
- Equipped with optimized start-up protection, it automatically identifies start-up process and accurately distinguishes starting current from fault current.
- Built-in 4-20mA analog output to realize transmission output of multiple measured variables.
- Stores 8 groups of detailed fault records with complete fault information.
- Supports 8 groups of digital input status records, 8 start records and 8 stop records.
- Adopts Chinese LCD display for intuitive viewing of parameters, data and operating status.
- Equipped with 5 programmable digital inputs and 4 programmable relay outputs.
- Flexible installation and compact dimension, suitable for installation in 1/4 drawer cabinet.
Functions of Digital Motor Protection Relays
Control Mode
| Direct Start | Two-way Start | Two-speed Start |
| Star-Delta Start | Protection Mode | Undervoltage Restart |
| Power-on Auto Start |
Protection Function
| Overload Protection | Locked Rotor Protection | Phase Unbalance Protection |
|---|---|---|
| Phase Loss Protection | Underload Protection | Blockage Protection |
| Short Circuit Protection | Residual Current Protection | Single-phase Earth Protection |
| Overvoltage Protection | Undervoltage Protection | Start Timeout Protection |
| External Fault Protection | tE Time Protection |
Measurement Function
| Three-phase Current | Three-phase Voltage | Frequency |
|---|---|---|
| Active Power | Reactive Power | Power Factor |
| Active Energy | Thermal Capacity | Unbalance Degree |
| Positive & Negative Sequence Current | Residual Current Value |
Management Function
| DI & DO Status | 8 Fault Records | 8 DI State Change Records |
|---|---|---|
| 8 Start Records | 8 Stop Records | Real-time Starting Current |
| Real-time Starting Time | Total Start Times | Total Trip Times |
| Total Running Time | Total Stop Time |
Communication Function
| Modbus-RTU | Profibus-DP |
|---|
Dimensions and Cutout Sizes
Technical Specifications
| Item | Specification |
|---|---|
| Rated Motor Voltage | AC380V or AC660V, 50Hz |
| Rated Motor Current | 0.1A ~ 800A |
| Insulation Resistance | ≥100MΩ |
| Controller Auxiliary Power Supply | |
| Operating Range | AC/DC 80～270V |
| Power Consumption | 5VA |
| Operating Environment | |
| Ambient Temperature | -20℃～+60℃ |
| Relative Humidity | ≤93%RH |
| Storage Temperature | -40℃～70℃ |
| Protection Grade | IP66 |
| Other Requirements | No explosive medium, corrosive gas or conductive medium that damages metal and insulation on site |
| Protection Action Accuracy | |
| Current/Voltage Startup Value | ±1% of set value |
| Thermal Capacity Accumulated Value | ±1% of set value |
| Time Delay Action Time | ＜2s: ±100ms; ≥2s: ±5% of set value |
| Control Relay Output | |
| Contact Capacity | AC250V/5A (resistive), AC250V/3A (AC15) |
| Max Breaking Voltage | AC400V |
| Max Breaking Capacity | 2000VA |
| Signal Relay Output | |
| Contact Capacity | AC250V/3A (resistive), DC30V/3A (resistive) |
| Max Breaking Voltage | AC300V |
| Max Breaking Capacity | 750VA |
| Analog Output | |
| Output Type | DC 4～20mA, RL≤350Ω |
| EMC Electromagnetic Compatibility | |
| Electrostatic Discharge | Severity Level Ⅲ |
| Electrical Fast Transient Burst | Severity Level Ⅲ |
| Surge Immunity | Severity Level Ⅲ |
| Damped Oscillatory Wave Immunity | Severity Level Ⅲ |
| Radiated Radio Frequency Field Immunity | Severity Level Ⅲ |
| Conducted Radio Frequency Immunity | Severity Level Ⅲ |
| Power Frequency Immunity | Class A |
| Conducted Emission Test | 150kHz-30MHz |
| Radiated Emission Test | 30MHz-1000MHz |
| Dielectric Withstand Voltage | |
| Between Power Supply and Input | AC2kV/1min |
| Between Power Supply and Output | AC2kV/1min |
| Between Input and Output | AC2kV/1min |
FAQ
Q：How to Select a Low Voltage Motor Protection Relay？
A:Select low voltage motor protector based on motor power, rated current and startup mode. Match overload, phase loss, overvoltage and earth fault protection functions. Confirm working voltage, installation size and communication protocol, ensure protection accuracy and on-site adaptability
Q：Are low-voltage motor protection relays suitable for three-phase or single-phase systems?
A:Low Voltage Motor Protector features strong versatility. It can be used as three phase motor protection relay or single phase motor protection relay according to actual application demands.
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