Yokogawa Test & Measurement has introduced the CT500SA and CT200SA, two advanced clamp-on current sensors aimed at electric vehicle (EV) testing scenarios where space limitations prevent threading cables through traditional through-hole sensors. These second-generation models enable accurate current measurement without cutting cables, addressing a key challenge in tightly packed in-vehicle environments.
The sensors feature a compact design, measuring 110 mm wide by 62 mm high and 25 mm deep, with a single-button unlock-and-open mechanism that allows easy one-handed operation. Each unit includes an M4 screw hole and a cable tie slot, enabling secure mounting, which Yokogawa highlights as crucial for improving measurement consistency given the sensitivity to sensor positioning.
Accuracy ratings stand at ±0.1% across a broad temperature range from -40° C to 85° C, refining to ±0.09% plus 0.01% full scale near room temperature. The phase accuracy reaches ±0.1° between 0.1 Hz and 1 kHz, achieving performance comparable to conventional through-hole sensors and surpassing typical clamp-on models, which often struggle with precision due to their design constraints.
The CT500SA supports currents up to 500 A and has a frequency bandwidth of 500 kHz (-3 dB), while the CT200SA covers 200 A with bandwidth extending to 1 MHz (-3 dB). Both models accommodate the high-frequency switching signals found in motor inverter testing and validation, an important aspect for EV powertrain development.
Yokogawa emphasizes that these sensors are designed for modern vehicle architectures where compactness and lightness further restrict access around components, making the larger CT1000S impractical at these current levels. Additionally, the new sensors can connect directly to either power analyzers or waveform measuring instruments without adapters, eliminating the need for sensor swapping and data synchronization during different test phases.
Potential applications include photovoltaic output measurement, HVAC current monitoring, pulse width modulation inverter efficiency testing, and other scenarios requiring both waveform and power analysis. The CT500SA and CT200SA models are scheduled for release in early September 2026, expanding the tools available for accurate current measurement in challenging test environments.