Bender IRDH265-2

Core Function Features

1. Adaptive Measuring Pulse (AMP) patented measurement technology, stable detection under high system distributed leakage capacitance
2. Two independent adjustable insulation resistance alarm thresholds (Alarm 1 pre-warning, Alarm 2 critical fault)
3. Two sets of isolated changeover relay alarm outputs, drive local buzzer and remote fault notification
4. Built-in LCD digital display, real-time display measured insulation resistance value and system operating voltage
5. Adjustable alarm response delay time to eliminate transient interference false alarms
6. On-board historical fault memory with time stamp, store recent insulation fault records for review
7. Galvanically isolated RS485 BMS communication bus, networking multiple monitors to central SCADA system
8. 0–20mA analog output proportional to insulation resistance value for DCS continuous monitoring
9. Hardware self-test function, one-button automatic calibration to guarantee measurement accuracy long-term
10. Multi-layer electrical safety isolation between measured power circuit and internal measurement circuit

Technical Performance Parameters

• Applicable Power System: 3AC / single-phase AC / DC unearthed IT systems
• Rated Monitoring Voltage: AC 0~793V (50–400Hz), DC 0~650V
• Insulation Resistance Measuring Range: 1kΩ ~ 10MΩ continuous adjustable alarm threshold
• Max Tolerable System Leakage Capacitance: ≤ 300µF
• Power Supply: AC 88–264V / DC 77–286V wide range universal power input
• Analog Output: 4–20mA proportional insulation resistance signal
• Communication Interface: Isolated RS485 Bender Measuring Device Interface (BMS)
• Operating Temperature: -20°C ~ +55°C
• Storage Temperature: -40°C ~ +70°C
• Protection Class: IP20 DIN rail mounting housing

Material & Structural Characteristics

• Housing: Flame-retardant black plastic DIN rail shell, UL94 V0 fire resistance grade
• Circuit Board: Multi-layer PCB with partial conformal coating for high-humidity environments
• Front Panel: Transparent dust-proof LCD display window, physical parameter setting buttons
• Terminal Blocks: Screw spring safety terminals, clearly labeled power and measurement circuit terminals
• Mounting: Standard 35mm DIN rail mounting
• Dimensions: 105mm × 90mm × 62mm
• Net Weight: 0.48kg

Working Principle

1. AMP adaptive pulse measurement circuit injects low-amplitude test pulse signal into unearthed IT power system
2. Collect return pulse signal attenuation amplitude to calculate insulation resistance between live conductors and earth
3. Internal microcontroller compares measured resistance value with two user-set alarm thresholds
4. When resistance drops below Alarm 1 value, first-stage pre-warning relay actuates; below Alarm 2 critical value, second-stage fault relay outputs interlock signal
5. Real-time insulation resistance value converted to 4–20mA analog signal and RS485 digital data upload to upper monitoring system
6. All fault events automatically stored in non-volatile memory with real-time clock time stamp for post-fault troubleshooting

Installation Requirements

1. Install inside IT power distribution cabinet on standard 35mm DIN rail, lock with rail fixing clip
2. Connect measurement terminals directly to ungrounded live busbars of IT power system, strictly follow wiring sequence marked on housing
3. Separate high-voltage measurement circuit wiring and low-voltage communication wiring into different trunking
4. Cabinet protective earth terminal must reliably connect to factory PE earth busbar
5. Do not install near high-power frequency converters which generate strong pulse interference; add filter module if measurement jitter occurs

Application Scenarios

• Hospital operating room, ICU medical isolated IT power supply system insulation monitoring
• Shipboard marine ungrounded power distribution system safety monitoring
• Underground mining explosion-proof equipment IT power system protection
• Industrial variable frequency drive, UPS ungrounded DC power cabinet insulation monitoring
• Battery energy storage system DC IT power cabinet insulation fault early warning

Operation & Maintenance Notes

1. Execute automatic hardware self-calibration function after initial installation and every 12 months
2. Do not connect instrument to grounded TN/TT power distribution systems; permanent circuit damage will occur
3. Check all measurement terminal screw tightness quarterly; loose wiring causes inaccurate resistance measurement
4. When multiple IRDH series monitors network via BMS bus, terminate bus two ends with 120Ω matching resistors
5. Clean front panel LCD window regularly to avoid dust covering affecting resistance value reading