Abstract: A transportable testing arrangement comprising a testing area configured to receive an electric component to be tested, a removable hood configured to cover the testing area, testing equipment for testing the electric component, a base on which the testing area, the removable hood and at least part of the testing equipment are mounted and a frame on which the base is mounted. The base is mounted on the frame by one or more suspension elements configured to enable movement of the base in relation to the frame, and wherein the base is further configured to be locked in relation to the frame by one or more locking elements to prevent movement of the base in relation to the frame.

Abstract: The operation of a centrifugal pump which pumps a liquid or suspension (e.g. 8-12 percent consistency) containing gas is controlled to minimize pump power consumption, or to vary the pump flow rate. The suspension is rotated within the pump so that a gas bubble is created at a central part of the pump, and gas is discharged from the gas bubble, at a gas discharge pressure. The differential pressure between the suspension inlet and the gas discharge is determined, and the head and/or discharge flow rate of the pump are controlled by controlling the differential pressure so determined. The discharge flow rate may be maintained constant utilizing a control valve and flow meter in the pump discharge line, in which case controlling the discharge of gas from the gas bubble controls the head, and minimizes power consumption for a given flow rate. Alternatively the flow rate is controlled by controlling the gas discharge, with no control valve in the pump discharge line being provided.