Isolation Amplifiers for Shunt Applications

Product Announcement from Knick Elektronische Messgeraete GmbH & Co. KG

Isolation Amplifiers for Shunt Applications-Image

VariTrans® P 41000 D1

High voltage isolator Input +/- 50mV ... 100V Isolation test voltage up to 15kV Working voltage up to 3600V AC/DC Power supply 20 ... 253V AC/DC 3 port galvanic isolation Excellent for shunt measurement applications

The Task

In high-voltage systems unipolar or bipolar voltage signals ranging from 60mV to 100 V, e. g. voltages across shunt resistors, must be galvanically isolated and converted to standard ±20 mA, ±10 V or 4 ... 20 mA output signals.

The Problems

In the case of insufficient insulation the high voltages and rough operating conditions may impair the galvanic isolation. This can result in false signals or even personal injury or damage to the equipment. These risks have to be securely eliminated in the long term through isolation amplifiers that are specially suited for high-voltage applications.

The Solution

The Varitrans® P 41000 isolation amplifier series has been specially conceived for measurements of bipolar voltages from millivolts to volts. They reliably isolate high potentials at the input circuit.

The isolation unit is designed to permanently withstand potential differences up to 3600 V AC/DC and transient overvoltages up to 20 kV. Protection against dangerous currents is achieved through protective separation to EN 61140 from input to output and power supply.

The Housing

For the Varitrans® P 41000 high-voltage isolation amplifiers a new 22.5 mm wide modular housing is used. It can be fixed on a standard DIN rail. The front panels of the adjustable models provide a rotary decoding switch for selecting the ranges.

The Advantages

The Varitrans® P 41000 are available for any input voltages from ±60 mV to ±100 V. At the output analog unipolar or bipolar (standard) signals are available: ±20 mA, ±10 V or 4 ... 20 mA. 16 input/output signal combinations can be conveniently selected using a rotary coding switch on the device front. Tedious adjustments using screwdriver, calibrator, and multimeter are not necessary. Drift problems due to instable trimming components (e. g. potentiometers) are avoided. Thanks to the easy range selection the devices can be flexibly suited to the individual needs of the application. Up to 16 customized signal combinations can be implemented in one device.

The integrated 20 to 253 V AC/DC broad-range power supply offers highest flexibility. It ensures problem-free operation with every AC or DC supply voltage utilized world-wide. Even instable power supply systems do not cause a problem. Installation is safe and easy: Erroneous connection of mains supply is practically impossible. Expensive standstill times and repair work during the commissioning are prevented.

Vacuum encapsulation provides maximum long-term protection against aggressive environmental influences, shock and vibrations andensures the high disruptive strength required for working voltages up to 3600 V AC/DC. The isolation unit meets the safety requirements of EN 61010-1 and EN 50124-1 (railway applications: insulation coordination).

The Technology

In this product line Knick utilizes the new TransShield® technology which enables the construction of very compact and low-leakage high-voltage transformers. Due to the resulting space savings a just 22.5 mm modular housing is sufficient for input voltages up to 3600 V AC/DC.

To guarantee the specified isolation capabilities, the devices are subjected to routine testing with 15 kV AC (fixed-range models) or 10 kV AC (switchable models) on a 100% basis.

Circuit design and device construction ensure excellent transmission characteristics, which become manifest in zero stability, linearity, long-term stability, frequency response and immunity to interference. A cut-off frequency >5 kHz and rise time <0.1 ms guarantee distortion-free signal conversion. The output signal follows fast changes in the input signal almost without delay.

CLICK HERE to view specifications, drawings, schematics, and more information about shunt measurement devices.