An open configuration is provided for the housing of a particulate material dedusting apparatus through which particulate material passes to be cleaned by air passing through wash decks to separate dirt and debris from the particulate material for discharge from the housing. A control unit activates a motor by setting a rotational speed of a rotational magnetic field of a stator to 600 rpm in the rotation step of 113\xb0 and to 1500 rpm in the rotation step of 263\xb0 so as to prevent the eccentric cam from receiving acceleration of a rotational direction from a pressure lever before a rotational speed of a rotor reaches a first rotational speed. A dielectric portion is coupled to an end portion of the at least one first conductive lead. A pressure compensator is configured to adjust pressure differential between the inner cavity and the external well volume. The transducer is configured such that when necessary the transducer can transmit a signal and receive a signal or signal reflection simultaneously. The external ends of the first and third loops are connected to the first and second access terminals.