General
Rated current	200 A AC

The MN89 clamp from Chauvin Arnoux is an amperometric current transformer for measuring alternating currents up to 200 A AC. It serves as an accessory for multimeters or power analysers that are not sufficiently sensitive in the AC current or AC voltage ranges. The clamp generates a proportional DC voltage signal at the output, which can be directly read on a suitable measuring instrument. The compact and ergonomic design enables measurements in hard-to-reach locations, with cables up to a maximum diameter of 20 mm being enclosed. The clamp is approved for use in installations up to safety category CAT III 600 V or CAT IV 300 V.

Applications

The MN89 clamp is suitable for measuring alternating currents in electrical installations, particularly in industrial, commercial, and electrical installation environments. It is frequently used in the maintenance, servicing, and diagnosis of power supply systems, where precise current measurement without direct contact with the conductor is required. The maximum jaw opening of 20 mm makes it especially suitable for cables in switchgear, distributors, or machines that cannot be fully exposed.

Functions and Equipment in Detail

The MN89 clamp converts alternating current in the cable into a proportional DC voltage signal. The ratio between output signal and input current is 100 mV DC per ampere AC. This signal is transmitted via a cable with an insulated plug (diameter 4 mm). The output voltage can thus be directly measured on a multimeter in the DC voltage range. The clamp is designed for use in installations up to CAT III 600 V or CAT IV 300 V, enabling safe measurement in electrical systems with the corresponding voltage class.

Technology Explained Simply

The MN89 clamp current transformer operates on the principle of inductive current measurement. When an electrical conductor carrying alternating current is passed through the clamp, the current generates a magnetic field that induces a voltage in the clamp. This induced voltage is converted into a DC voltage signal proportional to the measured current. The conversion takes place internally in the device, so the measuring instrument only needs to read the DC voltage signal. The output voltage of 100 mV per ampere allows for easy scaling and measurement, even with standard multimeters that do not have special current measurement functions.

Compatibility and Accessories

The MN89 clamp is designed for use with multimeters and power analysers that can measure in the DC voltage range. The output voltage is directly readable when the measuring instrument is set to an appropriate voltage range (e.g. 200 mV or 2 V DC). The clamp is not designed for direct connection to AC measurement ranges, as it generates a DC voltage signal. Connection is made via the supplied cable with an insulated plug (Ø 4 mm), which is connected to the measuring instrument.

Mounting and Installation

The clamp is simply placed around the cable to be measured, ensuring that the maximum diameter of 20 mm is not exceeded. The clamp opens by pressing a lever mechanism, allowing the cable to be inserted. After closing the clamp, measurement is immediately possible. No additional mounting or installation measures are required. The clamp is suitable for use in electrical installations up to CAT III 600 V or CAT IV 300 V, with safety regulations for the respective installation to be observed.

Advantages in Operation

The MN89 clamp enables contactless current measurement, thereby reducing the risk of short circuits or electric shocks. The compact design and ergonomic shape facilitate handling, especially in tight or hard-to-reach areas. The conversion into a DC voltage signal extends compatibility with standard measuring instruments that do not have special current measurement functions. The clamp is approved for use in installations up to CAT III 600 V or CAT IV 300 V, ensuring safe measurement in a wide range of applications. The output voltage of 100 mV per ampere allows for simple and precise scaling of measurement values.

The MN89 clamp is a reliable measuring aid for current measurement in electrical installations. It combines functionality, safety, and compatibility with standard measuring instruments, making it versatile in practical use. The clamp is not designed for direct connection to AC measurement ranges, but generates a DC voltage signal that must be read on a DC voltage measurement range. The maximum jaw opening of 20 mm and approval for CAT III 600 V or CAT IV 300 V make it particularly suitable for use in industrial and commercial installations.