Using a Microclamp with a Transconductor

INTRODUCTION

The AYA current clamps are available with either a voltage output or a current output. Mid-size and large current clamps that deliver an output current up to 5 Amperes are of special importance because they can be used to simulate permanently installed current transformers and, therefore, they can be used with portable power analyzers that require such input signals.

The small AYA Microclamps, with a current range of 100 or 200 Amperes, have a very small magnetic field, and, therefore, their output current is limited to one ampere.

For currents below 100 Amperes, AYA Microclamps are available with a voltage output only. Their magnetic field is too small to generate a current output level that can be used with power analyzers without converting the voltage signal to a current signal. This can be done by an AYA transconductor.

WHAT ARE TRANSCONDUCTORS?

The VI-11 and VI3-11 Transconductors are precision amplifiers designed for converting incoming AC or DC voltage signals to AC or DC current outputs. They are intended for use in power line monitoring, power line analysis and calibration of AC or DC current transformers and shunts. For a DC input voltage, the output current has the same polarity as the input. For an AC input voltage, the output current has the same frequency, phase and waveshape as the incoming signal. The transconductors can operate over the range of DC to 10,000 Hz with an accuracy of 0.5% at power line frequencies. Incoming voltages from 0 to 1 Volt AC or DC can be converted to a current output for use in applications that require 0 to 1 Ampere. The output is short-circuit protected. Single and triple-channel units are available.

The transconductors can be driven from any voltage source. For AC or DC current monitoring, the input can be generated from clamp-type current transformers that provide voltage signals. For use with current shunts, input voltage ranges of 50, 100, 200 and 500 mV are optional. For calibration applications, input voltages can be obtained from commercially available AC or DC calibrators.

Single Channel Transconductor

TRANSCONDUCTOR CONVERTS VOLTAGE TO CURRENT

The following drawing shows how a Microclamp can be used with a VI Transconductor to provide an output current when measuring very low currents. A Model M1V-1-1 Microclamp provides a 1 Volt AC output when the measured current is 1 Ampere AC. When this signal is fed to the input of a VI-11 Transconductor, it is converted to 1 Ampere for use with a portable power analyzer. Similarly, a Model M1V-5-1 with a VI-11 can provide a 1 Ampere output when the input is 5 Amperes. Microclamps with range of 0-10, 0-20, 0-25 and 0-50 are also available.

Using a Transconductor with a Microclamp

For a three-phase analyzer, the Model VI3-11 can be used with three Microclamps to provide three currents simultaneously.

For use with current shunts, input voltage ranges of 50, 100, 200 and 500 mV are optional. For calibration applications, input voltages can be obtained from commercially available AC or DC calibrators.