Abstract: A method for moving a carriage of a crane a short distance while simultaneously damping the oscillation of its load. The method includes: determining the period of oscillation T of the load; moving the carriage a first displacement from an initial position to a desired final position; moving said carriage a second displacement from the desired final position back to said initial position, a time T/6 after said first displacement; and repeating the first displacement to provide a third displacement from the initial position back to said desired final position, a time T/6 after said second displacement; while causing load oscillations to be damped.

Abstract: An apparatus and method of controlling a load oscillation dampener for a crane from which a load is suspended by a hoisting rope attached to a carriage driven by a motor controlled by a motion controller. A first direction signal corresponding to a first direction is applied to the motion controller for initiating motion of the carriage in the first direction and it is determined whether a second direction signal corresponding to a second direction is applied to the motion controller while the carriage is traveling in the first direction, the second direction being opposite the first direction. If the second direction signal was detected, the load oscillation dampener is deactivated to prevent uncontrolled motion of the carriage, and if the second direction signal was not detected, the load oscillation dampener is allowed to cause motion of the carriage to damp load oscillations.

Abstract: An apparatus and method of controlling a load oscillation dampener for a crane from which a load is suspended by a hoisting rope attached to a carriage which is driven by a motor controlled by a motion controller. A motion command having a duration is applied to the motion controller, the carriage is moved in response to the motion command, and it is determined whether the duration of the motion command is greater than a given time interval. If the duration of the motion command was less than the given time interval, the load oscillation dampener is deactivated to prevent uncontrolled motion of the carriage, and if the duration of the motion command was greater than the given time interval, the load oscillation dampener is allowed to cause motion of the carriage to damp load oscillation.

Abstract: A method of deactivating an electronic load oscillation dampener on a crane when the crane is reverse plugged is present. Thus allowing the crane to stop faster in emergency situations.

Abstract: A method of automatically deactivating an electronic load oscillation dampener on a crane is presented. In the method, an inching time interval K is determined. In response to motion commands from the crane operator, carriage motion is initiated under the control of the load oscillation dampener so that load swing will be minimized. At the moment motion commands are removed, it is determined whether the time K has expired since the initiation of carriage motion. If the time K has expired, then the load oscillation dampener is deactivated allowing faster and more intuitive response of the crane to operator commands, including a rapid deceleration to a stop. If the time K has not expired, then the load oscillation dampener is kept active, causing load oscillations to be damped for the remainder of the run.

Abstract: A voltage switching arrangement for an electrical power control system including a plurality of switches for connecting and disconnecting voltage from the input to a power transfer network which provides power for a load. A time delay circuit prevents the voltage connected to the input to the power transfer network from being disconnected for a predetermined time period after the control system has been turned off. The power transfer network switches from an on-mode to the off-mode during said time delay period. The voltage connecting switches include an electromechanical DC relay, and the time delay circuit includes a capacitor cooperating with the relay to maintain the relay energized for the time delay period after the control system has been turned off. Safeguards are provided to prevent simultaneous connection of voltage in the forward and reverse directions to the input of the power transfer network.