The Hall Effect Sensor (HES) can be used to replace conventional current transformers and is particularly useful for normal CTs ratings between 10 to 150Amps. The HES provides 3-phase current measurement to the relay. It is often used for high-density tiers starters where the physical fitment of a conventional ring type CT is simply to large for the starter cubicle or tray.
Where a relay specification would be normally MV2-1A, the secondary CT rating of the product description is replaced with HES to indicate connection tot his type of sensor, i.e. MV2-HES
The types of the HES exist, this doesn’t affect the physical size of the module but does determine the placement of the internal iron cores.
For example, if the HES is required for a motor of FLC 38A, it would be appropriate to calibrate the HES to either 40 or 45A.
The CT Primary setting of the relay would then be 40 or 45 to match that of the HES rating with the FLC setting at 38A.
The HES is connected to the relay via a 1metre 10 way ribbon lead allowing the HES to be installed in close proximity to the primary circuit connections (or at the rear of the withdrawable starter tray) and the relay, which is door mounted to be installed within the LV compartment (or at the front of the withdrawable starter tray).
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