BENDER ISOMETER ® IRDH375 series Insulation Monitoring Equipment

BENDER ISOMETER ®  IRDH375 series Insulation Monitoring Equipment

Core positioning and adaptation scope of the product

Core purpose: Monitor the insulation resistance of ungrounded main circuits (IT systems), and trigger an alarm when the insulation resistance is lower than the set value

Adaptation system type:

AC system, DC system, AC/DC hybrid system

AC/DC main circuit with rectifier, converter, thyristor controlled DC driver

High leakage capacitance IT system, coupled IT system

Voltage parameters:

Rated voltage: AC/AC-DC 0... 793V, DC 0... 650V

Extended voltage: Suitable for higher voltages such as DC 0... 1760V, 3/N/AC 0... 7200V, etc. through coupling devices

Power supply voltage: AC 88... 264V (42... 460Hz); DC 77... 286V or 19.2... 72V

Core functions and technical features

Measurement technology: using patented AMPPlus measurement method, suitable for high leakage capacitance scenarios in modern power supply systems

Key functions:

Dual adjustable response values: 1k Ω... 10M Ω, supporting two-level distinction between warning and alarm

Automatic adaptation: Automatically adapts to system leakage capacitance (maximum ≤ 500 μ F)

Self monitoring and self testing: continuous self-monitoring+optional automatic self testing, triggering system fault alarm in case of failure

Display and operation: Dual row backlit LCD display, INFO/TEST/RESET/MENU four key operation, supports external k Ω indication

Communication interface: RS-485 interface (ASCII/BMS protocol), transmission distance ≤ 1200m

Alarm output: 2 independent alarm relays (with passive conversion contacts), supporting N/O or N/C modes; System fault relay (N/C mode)

New features added to IRDH375B:

Historical storage: Alarm record storage with real-time clock (including date and timestamp)

Isolation communication: electrically isolated RS-485 interface (BMS protocol)

Coupling system adaptation: Insulation monitoring device disconnect relay, supports coupling IT system multi device collaboration (ensuring single device activation)

Current output: 0 (4)... 20mA analog output

Key performance parameters

Category specific parameters

When the response time R_F=0.5 × R_an and C_e=1 μ F, ≤ 5s

Measurement accuracy 1k Ω... 1M Ω: ± 15% ± 1k Ω; 1k Ω... 10M Ω: ± 15% ± 0.1M Ω

Environmental adaptability working temperature: -10...+55 ℃; Storage temperature: -40...+70 ℃ (regular model)/-25...+70 ℃ (Option-W model)

Protection level: Terminal protection IP30, equipment enclosure IP20

Mechanical specification panel opening 138 × 68mm, weight ≤ 510g, DIN rail installation

Electromagnetic compatibility complies with IEC 61326-2-4 standard, resistant to impact and vibration

4、 Model and ordering information

Model RS-485 interface coupling system adaptation output type power supply voltage order number

IRDH375-435 ASCII not applicable for external k Ω indication (0... 400 μ A) AC 88... 264V/DC 77... 286V B91065000

IRDH375-427 ASCII not applicable for external k Ω indication (0... 400 μ A) DC 19.2... 72V B91065002

IRDH375B-435 BMS is suitable for current output 0 (4)... 20mA AC 88... 264V/DC 77... 286V B91065004

IRDH375B-427 BMS is suitable for current output 0 (4)... 20mA DC 19.2... 72V B91065006

Supporting components

Component type, model, and order number

External k Ω measuring instrument 7204-1421 B986763

External k Ω measuring instrument 9604-1421 B986764

External k Ω measuring instrument 9620-1421 B986841

Coupling device AGH150W-4 B98018006

Coupling device AGH204S-4 B914013

Coupling device AGH520S B913033

IP65 transparent front cover 144x72 B98060005

Key issues

Question: What are the core adaptation scenarios and voltage ranges of the IRDH375 series? How to expand the applicable range of voltage? Answer: Core adaptation for ungrounded AC, AC/DC, and DC systems (IT systems), including UPS, battery systems, switch power supplies, and other equipment containing high leakage capacitors or DC components; The rated adaptation voltage is AC/AC-DC 0... 793V, DC 0... 650V; It can be extended to higher voltage scenarios such as DC 0... 1760V, 3/N/AC 0... 7200V by combining with coupling devices such as AGH150W-4 and AGH520S.

Question: What are the core differences between the IRDH375 and IRDH375B models? What scenarios are the new features applicable to? Answer: The core difference lies in the addition of four advanced features to the IRDH375B: alarm history storage with real-time clock, electrically isolated RS-485 (BMS protocol), disconnect relay adapted to the coupled IT system, 0 (4)... 20mA current output; The new features are suitable for industrial or large-scale building power distribution scenarios that require traceability of alarm records, access to building management systems (BMS), coupled operation of multiple IT systems, and remote transmission of measurement data.

Question: What are the measurement accuracy, response time, and environmental adaptability of the IRDH375 series? In which scenarios is the reliability of the device ensured? Answer: The measurement accuracy is ± 15% ± 1k Ω when it is 1k Ω... 1M Ω, ± 15% ± 0.1M Ω when it is 1k Ω... 10M Ω, and the response time is ≤ 5s (Rf=0.5 × R_an and C_e=1 μ F); Working temperature -10...+55 ℃, storage temperature -40...+70 ℃, shock and vibration resistance, and compliance with EMC standards; These parameters ensure the reliable operation of equipment in complex electrical environments such as industrial plants, data centers, and medical facilities that require high insulation monitoring accuracy and stability.