General
Rated current	1500 A AC
Enclosure dimensions	64 x 150 mm
Maximum jaw opening	90 mm
Maximum cable diameter	64 mm
Influence from adjacent conductors	0,005 A / A AC
Influence due to conductor position	1 % ± 0,1 A

The D31N current transformer from Chauvin Arnoux is a measuring device for accurate detection of alternating currents in voltage and current measurement technology. It is specifically designed for use with thick cables and busbars, where the rectangular shape of the jaw clamps enables secure encirclement of conductors with cross-sections up to 64 mm diameter or 64 x 100 mm for multiple conductors. The magnetic circuits and distributed windings ensure high measurement accuracy at medium and high current levels. The device is part of the "D" model series, which includes current transformers for alternating currents up to 3000 A AC.

Applications

The D31N is suitable for applications in industrial electrical engineering, maintenance and servicing of power supply systems, as well as for measuring load currents in electrical installations. It can be used on cables, busbars, and other conductors with large cross-sections, where direct current measurement with conventional measuring instruments would not be possible. The rectangular shape of the jaw clamps allows precise encirclement even of irregular conductor geometries.

Functions and equipment in detail

The device features three measurement ranges with different transformation ratios: 500/1, 1000/1, and 1500/1. Typical accuracy is ≤ 3 % in the range 1 A to 600 A, 1 % in the range 1 A to 1200 A, and 0.5 % in the range 1 A to 1800 A. This multi-stage design enables improved measurement resolution and accuracy depending on the required measurement range. The output signal is an alternating current delivered via insulated sockets with a diameter of 4 mm. These sockets are equipped with overvoltage protection to safeguard the connected measuring device against damage from high voltages.

Technology explained simply

The current transformer operates on the principle of a current transformer: the current to be measured flows through the jaw, generating a magnetic field in the magnetic core. This induces a proportional current in the secondary circuit, which is delivered via the sockets. The transformation ratios (e.g., 1500/1) mean that a current of 1500 A in the primary circuit generates a current of 1 A in the secondary circuit. Measurement accuracy is ensured by the quality of the magnetic cores and the distributed winding. Measurement is performed in the range of 1 A to 1800 A, with a maximum rated current of 1500 A AC. The bandwidth ranges from 30 Hz to 5 kHz, with the maximum measurable current limited above 1 kHz during continuous operation.

Compatibility and accessories

The D31N can be connected to multimeters, harmonic and power measuring instruments, data acquisition devices, or other instruments that support an alternating current input. As accessories, a set of two adapters (BNC socket / 4 mm plug) is offered, enabling connection to devices with BNC connectors. The output sockets are insulated and provide electrical safety in accordance with IEC 1010-2-032. The operating voltage is 600 V AC, with the devices designed for Category III (600 V) and Category IV (300 V).

Installation and mounting

Installation is carried out by simply opening the jaw clamps, encircling the conductor to be measured, and closing the jaw. The rectangular shape allows secure and stable positioning even on irregular or multiple conductors. The jaw is designed for an operating temperature of -10 °C to +50 °C, with a storage temperature of -25 °C to +80 °C. Mechanical strength is ensured by a drop test of 500 mm and an impact resistance of 100 g according to IEC 68-2-27.

Operational advantages

The D31N offers high measurement accuracy at high currents, safe and easy handling, and integrated overvoltage protection at the output. The rectangular shape of the jaw clamps enables measurement on thick cables and busbars, which is frequently required in industrial electrical engineering. The 4 mm output sockets are universally applicable and compatible with many measuring instruments. Electrical safety in accordance with IEC 1010-2-032 and Category III/IV rating make the device suitable for use in industrial and electrical installations.

Protection rating and environmental conditions

The protection rating is IP20 according to IEC 529, providing protection against contact with fingers and against solid foreign objects larger than 12.5 mm. The device is not designed for outdoor use or in damp environments. The operating temperature ranges from -10 °C to +50 °C, with a storage temperature from -25 °C to +80 °C. The temperature influence on accuracy is less than 0.1 % per 10 °K.

Accessories and alternatives

For use with devices featuring a BNC connector, a set of two adapters (BNC socket / 4 mm plug) is offered. These adapters enable direct connection between the current transformer and BNC-compatible measuring instruments such as oscilloscopes.

Accuracy and standards

Accuracy conforms to IEC 185-26-27, Class 0.5, with a load impedance of < 5 Ω. Measurement is performed in the frequency range of 48 Hz to 1000 Hz. The influence of adjacent conductors is 0.005 A/A AC, and the influence of conductor position within the jaw clamps is 1 % ± 0.1 A. The maximum output voltage with an open secondary winding is electronically limited to 42 V peak. The overload capacity is 3600 A for 5 minutes.

Application safety

The device is designed for use in electrical installations with an operating voltage of 600 V AC (Category III) and 300 V AC (Category IV). The IP20 protection rating safeguards against contact with fingers and solid foreign objects larger than 12.5 mm. The housing materials are self-extinguishing (UL94 V0 for housing, UL94 V2 for jaw clamps).