How to find the right Current Transducers AI guide
Written by an AI model from its trained knowledge.
What the AI looks for in Current Transducers
- AC, DC, or both
- Current transformers measure AC only. Measuring DC or mixed signals requires a Hall-effect or fluxgate transducer. A plain CT gives no output on DC current.
- True RMS for distorted loads
- Choose true-RMS output for VFDs, switch-mode supplies or SCR-controlled loads. Average-responding units are fine only for clean sine waves. Average-responding units under-read or over-read badly on non-sinusoidal current.
- Split-core vs solid-core
- Split-core fits existing conductors without disconnecting them. Solid-core is usually more accurate and cheaper but needs the conductor threaded through. Retrofits almost always need split-core, while new panels can use solid-core.
- Aperture and range
- The window must fit the conductor plus insulation. The rated range should sit just above the expected maximum current. Oversized ranges lose low-end accuracy, and undersized ranges saturate.
- Secondary safety on 5 A CTs
- Never open-circuit the secondary of a 5 A-output CT while primary current flows. Short it or use a shorting block. An open secondary can develop dangerous voltages and damage the CT. Units with built-in burden or voltage/mA output avoid this.
- Bandwidth
- Check the bandwidth spec when the load includes drive output or harmonics, not just line frequency. Low-bandwidth sensors miss the harmonic content that matters on drive circuits.
Brands that matter
- LEM: Reference brand for open- and closed-loop Hall-effect current transducers.
- NK Technologies: Industrial AC/DC current transducers and current switches with analog outputs.
- CR Magnetics: Current transformers and current transducers for industrial and energy metering.
- Honeywell: Hall-effect current sensors for board and panel use.
- Allegro MicroSystems: Hall-effect current sensor ICs for PCB-level designs, not panel installs.
- Phoenix Contact: DIN-rail current measuring transducers with standard analog outputs.
What to avoid
- Average-responding transducers on VFD outputs.
- Open-circuiting a 5 A CT secondary under load.
- Hobby Hall-effect breakout boards on mains without proper isolation and enclosure.
Questions
Is a current transducer the same as a current transformer?
No. A current transformer outputs a scaled AC current, typically 5 A, 1 A or a mV signal. A current transducer conditions the measurement into a standard signal such as 4-20 mA or 0-10 V, and Hall-effect types also measure DC.