9. Recommendations for use of current transducers

When measuring current with a measurement shunt, care must be taken to reduce the surface area of the current measurement loop to avoid including parasitic inductance. If the resistor is placed far away, a twisted pair reduces the influence of connection inductance and surrounding stray fields. Common-mode current problems can be reduced by using an isolation amplifier (type AD 210 from Analog Device, for example).

Several manufacturers market current transducers based on the measurement of a magnetic field by an induction sensor. They use a flux compensation or open-loop principle for industrial applications: LEM, Honeywell, Allegro, Bell... They are very simple to use. They require a symmetrical or asymmetrical power supply. Output is either current or voltage. In the case of current output, this value is the image of the primary current multiplied by the ratio...