LEM sensor measures ±1,500A for automotive battery

CAB 1500 is an automotive grade open-loop flux-gate transducer, aimed at compliance with ISO 26262 ASIL C functional safety.

Range is ±1.5kA and the sensor is compatible with 800V applications to IEC 60664-1.

Galvanic isolation is up to 2.5kV, and total error over -40 to +85° is 0.5%, according to LEM, with up to 0.1% resolution.

Power is needed at 12V (8 – 16V), and interfacing is over CAN bus (Configurable ID, configurable speed, Tyco AMP 1473672-1 connector).

The size is 71 x 53 x 21mm (plus mounting bosses), and there are two versions, one for mounting on bus bars (shown) and the other on panels. Other options are 4.8kΩ or 120Ω bus termination, and an inverted output signal.

The aperture is D-shaped – just over 24mm in diameter with a segment blocked off.

Flux gate?

LEM explains flux gate:

A low-frequency flux gate transducer is made of a wound core which saturates under low induction. A current chopper switches the winding’s current to saturate the magnetic core alternatively at ±Bmax with a fixed frequency.
Fluxgate transducers use the change of the saturation’s point symmetry to measure the primary current.
Due to the principle of switching the current, all offsets (electric and magnetic) are cancelled.

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