The design, confirmation and use of a compact Current Coil set for clampmeter calibration

There are a growing number of current clamp meters and current clamp accessory devices appearing in the calibration workload capable of measuring currents up to 1000 Amps AC and DC. In the past users have attempted to make their own current coils to enable calibration sources with 10A outputs to provide stimuli adequate to calibrate these devices close to their full scale values, often without success. A compact current coil set was introduced as an accessory to a recent new 'universal' calibrator product to provide accurate sourcing of currents up to 1000A for clamp devices. This paper discusses error sources and constraints on practical current coil design, describes measurements made to confirm performance of examples of the final design, and discusses how to avoid misleading results when using such current coils in practice.