The dangers of dry running
As with any spherical motor, the D5 and DDC product ranges are not designed to be ‘dry run’ or run without liquid in the pump housing.
Due to the bearing and rotor assembly design, fluid from the application or process is required to maintain lubrication between the spherical bearing ball and the rotating rotor/impeller unit. If there is no fluid present and the pump is operated in a ‘dry run’ situation, overheating can occur quickly.
As detailed in the images below, overheating can cause the carbon bearing cap to change its location, which will cause the rotor to spin off center – causing the rotor to come into contact and wear against the inside of the motor housing. If you see conditions like this inside your pump, please investigate if it has been dry run, as this is not covered by the manufacturer.