Overview
The ARD3M series is Acrel’s intelligent motor protector designed for low-voltage motor circuits up to 660V. Featuring a split structure (main unit + display unit + CTs + communication module), it integrates protection, measurement, control, communication, and maintenance functions. Comprehensive protection ensures safe motor operation, programmable logic supports multiple control modes, and various communication modules are available for fieldbus adaptation. With full-wave/fundamental parameter measurement, 2nd~63rd harmonic analysis, event logging and waveform export, it serves as the core terminal for digital motor management systems.
Highlight
Highly Integrated
- Replaces thermal relays, meters, etc. Simplifies circuits and wiring.
Comprehensive Protection
- 20+ functions, fully configurable thresholds/delays/stages.
Smart O&M
- USB export of waveforms/events, WiFi monitoring, full lifecycle traceability.
Flexible Programming
- Fully programmable DI/DO, logic diagram, multi-protocol from serial bus to industrial Ethernet.
Focus Areas
Overload, stall, tE time protection for large motors, preventing burn-out.
Underload protection for pumps, runtime alarm, predictive maintenance.
Reversing & two-speed control, suitable for frequent start/stop.
Ex motor tE time protection, leakage/ground fault protection for hazardous areas.
PROFINET/Ethernet access to PLC/DCS for motor energy monitoring & remote diagnosis.
Specification
| Item | Parameter |
| Auxiliary Power | AC85~265V / DC100~300V（默认），可选 AC/DC100~415V |
| Motor Rated Voltage | AC220V / 380V / 660V，50/60Hz |
| Motor Rated Current | 0.1~800A（外置CT，最大5000A） |
| Digital Input | 10路，干节点（可选湿节点 DC110V/DC220V/AC220V） |
| Relay Output | 6路，AC250V / 10A（阻性） |
| Analog Output | 可选 1路或2路 DC4~20mA |
| Standard Communication | 2路 MODBUS RTU（RS485） |
| Optional Communication | PROFIBUS DP V1（1/2路）、PROFINET、以太网（MODBUS TCP） |
| Mounting | 35mm 导轨 |
| Operating Temp | -10℃ ～ +55℃ |
| Storage Temp | -25℃ ～ +70℃ |
| Protection Rating | 主体 IP20，显示模块（面板安装）IP65 |
| Pollution Degree | 3 |
| Installation Category | III |
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Display Unit
| Model | Type | H×W×D (mm) | 开孔尺寸 (mm) | Features |
| 60L1 | 黑白点阵液晶 | 98×60×? | 92×55 | 中英文菜单，按键操作 |
| 60L2 | 彩色点阵液晶 | 98×60×? | 92×55 | 彩色界面，可选WiFi监控 |
CT Specifications
| Protector Current Range | Applicable Motor Current (A) | Power Range (kW) | Turns | Secondary Wire |
| 1A | 0.1~5 | 0.12~2.2 | 支持5圈 | 1m±10cm（可选3m/5m） |
| 5A | 0.5~5 | 0.55~2.2 | 1圈 | 1m±10cm（可选3m/5m） |
| 25A | 6.3~25 | 3~11 | 1圈 | 1m±10cm（可选3m/5m） |
| 100A | 25~100 | 15~45 | 1圈 | 1m±10cm（可选3m/5m） |
| 250A | 63~250 | 55~132 | 1圈 | 无，配3只 |
| 800A | 250~800 | 160~250 | 1圈 | 无，配3只 |
Function
| Protection Function | Standard | Optional |
| Definite-time overload | √ | |
| Inverse-time overload | √ | |
| Start timeout | √ | |
| Phase loss | √ | |
| Voltage unbalance | √ | |
| Current unbalance | √ | |
| Stall | √ | |
| Jam | √ | |
| Underload | √ | |
| External fault | √ | |
| Temp. protection | √ | |
| Ground fault (residual) | √ | |
| Leakage | √ | |
| Phase sequence | √ | |
| Undervoltage | √ | |
| Overvoltage | √ | |
| Underpower | √ | |
| Overpower | √ | |
| tE time (Ex motor) | √ | |
| Overflow | √ | |
| Start count alarm | √ | |
| Runtime alarm | √ | |
| Fault count alarm | √ |
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| Control Mode | Standard | Optional |
| Protection mode | √ | |
| Manual mode | √ | |
| Two-step mode | √ | |
| Two-speed mode | √ | |
| Star-delta | √ | |
| Auto-transformer | √ | |
| Anti-sag restart | √ |
| Measurement/Logging | Standard | Optional |
| U/I | √ | |
| P/Q/S | √ | |
| PF, F | √ | |
| EP/EQ | √ | |
| 2nd~63rd harmonics | √ | |
| Fault waveform | √ | |
| Events log | √ | |
| Trend log | √ |
Core Monitoring & Protection Functions
- Monitoring: 3-phase current/voltage (fundamental+full-wave), line voltage, zero/pos/neg sequence components, unbalance, P/Q/S, PF, F, energy, leakage current, 2nd~63rd harmonics (V/I), PTC/NTC resistance, thermal capacity, insulation resistance.
- Protection/Alarm: Inverse-time overload, definite-time overload, stall, jam, underload, phase loss, current unbalance, voltage unbalance, over/under voltage, phase sequence, over/under power, short circuit, overflow, ground fault, leakage, PTC/NTC temp, external fault, start timeout, tE time, start count, runtime, fault count.
- Control: Local start/stop (LCD keys/DI), remote control via communication, programmable logic, anti-sag restart (instant/undervoltage restart), two-speed/star-delta/auto-transformer starting modes.
- Precise Metering: Voltage/current accuracy Class 0.5, active energy Class 1, leakage current Class 1.
Summary
The Acrel ARD3M intelligent motor protector is more than just a protection device; it is a complete sensing-protection-control-communication-maintenance integrated motor management terminal. Through the deep integration of programmable protection settings, logic control and multiple communication protocols, it upgrades traditional passive motor protection to proactive warning, precise metering and predictive maintenance. Whether for standard low-voltage motors or Ex increased-safety motors, ARD3M provides tailor-made protection solutions – an ideal choice for building digital industrial motor management systems.
FAQ
ARD3M natively supports Protection mode (external pushbuttons), Manual mode (LCD/DI direct start/stop), as well as Two-step (star-delta), Two-speed, and Auto-transformer modes (with external contactors). All control modes can be switched via DI or remote communication.
Set “Motor type” to “Ex increased-safety” in protection parameters; the “Trip class” will automatically switch to tEp setting (2~15s). Select the trip class according to the motor nameplate tE time. Under locked-rotor current, the protector will trip according to the tE characteristic curve, ensuring power-off before reaching the temperature limit.
Yes. The two RS485 ports are electrically isolated, with independent address, baud rate and parity settings. They can connect to different host systems simultaneously (e.g., PLC + HMI, DCS + energy management platform) without interference.
Only available with the 60L2 color LCD display unit. After a fault occurs, insert a USB drive into the display’s USB port, enter the “USB Function” menu, select “Export fault waveform”, and a CSV file will be generated – readable in Excel for analysis.
Yes. With optional “SU” anti-sag function, you can configure “instant restart” (0.1~10s after voltage recovery) and “undervoltage restart” (delay restart after voltage drops below set value). Ideal for production lines requiring high power supply continuity.
Both PTC (Positive Temperature Coefficient) and NTC (Negative Temperature Coefficient) thermistors are supported. Select the sensor type in protection parameters, set alarm/trip thresholds and return resistance. Suitable for motor winding and bearing temperature monitoring.
Select the 1A or 5A current version of the protector, use external high-ratio CTs (e.g., 2500/5A), and set the “CT ratio” parameter (1~5000). The primary current can be extended up to 5000A. The displayed values will automatically reflect the actual primary current.
Standard cable length is 1.5m (Ethernet cable), with optional 3m and 5m lengths. For reliable communication, the maximum recommended length is 5m. For longer distances, please use shielded twisted pair and consult our technical team.
Two methods: 1) Via display menu “System parameters” -> “Factory reset”, select “Yes”; 2) Write 0xFFFF to communication address 0x2B (43). After reset, all protection settings and communication parameters will be restored to default; reconfiguration is required.
Yes. With optional Ethernet (MODBUS TCP) or 4G gateway, it can connect to third-party IoT platforms via MQTT protocol. We provide open Modbus register maps and API documentation, and support customized protocol conversion.
