LEM current transducer Lf505-s/SP27 LEM CT Lf505-s/sp13 LEM CT Lf305-s/sp11 LEM CT Lf1005-s/SP16 LEM CT Lf1005-s/SP36 LEM CT Lf1005-s/sp31 LEM CT LAH100P LEM Swiss CT Has600s LEM CT Has400s LEM CT LEM current transducer Swiss