Crane use and maintenance: After crane factory, the general provisions of 60 hours of run-in period (some called a walk-in period), which is based on the technical characteristics of the crane manufacturing plant early use regulations. Run-in period is to ensure the normal operation of the crane 90 tons crane, reducing the failure rate and prolong an important part of their life. Crane safety devices: the height limit device. After starting to rise to a predetermined height hook 90 t crane company, touch a weight limit, open limit switch, 'had about' indicator lights that light crane 90 t much money, and cut off the hook lifting, arm stretched out , crane and other movements of volts to ensure safe operation. Then just manipulating hook dropped 90 tons Tadano crane, boom boom retracted or lifted up (ie safe side operation), etc. When the handle so that the limit weight lifting constraints, normal operation is restored.