A procedure defining a balancing strategy includes: providing a computer model which predicts the vibration amplitude at a given axial position along the spool when the spool is rotated at a given rotational speed; using the model to predict respective vibration amplitudes at the given axial position for different axial positions of a unit unbalance applied to the spool; plotting the predicted vibration amplitudes as data points on a graph of vibration amplitude against axial position of the applied unit unbalance; using the graph to identify axial positions which are more or less likely to contribute to flexing of the spool at the given rotational speed when mass is added or removed from the first rotor module to reduce imbalances at the axial positions; and defining a balancing strategy based on the identification.

A procedure defining a balancing strategy includes: providing a computer model which predicts the vibration amplitude at a given axial position along the spool when the spool is rotated at a given rotational speed; using the model to predict respective vibration amplitudes at the given axial position for different axial positions of a unit unbalance applied to the spool; plotting the predicted vibration amplitudes as data points on a graph of vibration amplitude against axial position of the applied unit unbalance; using the graph to identify axial positions which are more or less likely to contribute to flexing of the spool at the given rotational speed when mass is added or removed from the first rotor module to reduce imbalances at the axial positions; and defining a balancing strategy based on the identification.

Provided is a method to acquire the unbalance of a rotor and a balancing machine, in which, the method to acquire the unbalance of a rotor includes the following procedures: install angle sensor at first position on balancing machine, measure the unbalance of rotor, first unbalance in measuring plane 1 and first unbalance in measuring plane 2 can be measured. Move angle sensor on balancing machine from first position to second position, measure the unbalance of the rotor again, second unbalance in measuring plane 1 and second unbalance in measuring plane 2 can be measured. In the above mentioned two measurements, the unbalance amount of rotor has no change, but the unbalance angle relative to angle reference point on rotor is changed by an angle which equals the angle of the sensor being moved.

Provided is a method to acquire the unbalance of a rotor and a balancing machine, in which, the method to acquire the unbalance of a rotor includes the following procedures: install angle sensor at first position on balancing machine, measure the unbalance of rotor, first unbalance in measuring plane 1 and first unbalance in measuring plane 2 can be measured. Move angle sensor on balancing machine from first position to second position, measure the unbalance of the rotor again, second unbalance in measuring plane 1 and second unbalance in measuring plane 2 can be measured. In the above mentioned two measurements, the unbalance amount of rotor has no change, but the unbalance angle relative to angle reference point on rotor is changed by an angle which equals the angle of the sensor being moved.

A rotor balancing method for a gas turbine having a rotor with a first correction plane and a second correction plane, wherein a first balancing weight is attached to the first correction plane. The method includes performing a first influence run wherein first balancing weight remains fitted for the subsequent second influence run; fitting a first calibration weight to the second correction plane using a reference influence vector; performing a second influence run; removing the first calibration weight from the rotor and calculating an influence vector of the second correction plane using a first set of vibration measurements and a second set of vibration measurements taken during the first influence run and the second influence run, respectively; and carrying out balancing of the rotor by fitting a final balancing weight to the first correction plane and a second balancing weight to the second correction plane using the calculated influence vectors.

A rotor has a rotor body having: a flange with a circumferential array of discontiguous apertures; and a surface spaced apart from the flange. One or more rotor balance weight assemblies each have a weight and a fastener. The weight has: a passageway having a first end and a second end; an internal thread along the passageway; and a boss at the first end of the passageway. The boss is in a respective one of the apertures. The fastener has: a shank having a first end and a second end and an external thread engaged to the passageway internal thread; an engagement feature at the shank first end for engagement by a tool to turn the fastener; and a head at the second end contacts the surface.

A rotor has a rotor body having: a flange with a circumferential array of discontiguous apertures; and a surface spaced apart from the flange. One or more rotor balance weight assemblies each have a weight and a fastener. The weight has: a passageway having a first end and a second end; an internal thread along the passageway; and a boss at the first end of the passageway. The boss is in a respective one of the apertures. The fastener has: a shank having a first end and a second end and an external thread engaged to the passageway internal thread; an engagement feature at the shank first end for engagement by a tool to turn the fastener; and a head at the second end contacts the surface.

A method of testing a sensing device with a sensing mass includes accelerating the sensing device along a circular path about a central axis. The sensing mass of the sensing device may be movable relative to the central axis. The method includes determining a position of the sensing mass of the sensing device via a sensor and shifting the sensing device radially relative to the central axis based at least in part on the position of the sensing mass during acceleration.

A method of testing a sensing device with a sensing mass includes accelerating the sensing device along a circular path about a central axis. The sensing mass of the sensing device may be movable relative to the central axis. The method includes determining a position of the sensing mass of the sensing device via a sensor and shifting the sensing device radially relative to the central axis based at least in part on the position of the sensing mass during acceleration.

A balance of a timepiece including an adjustment face provided with at least one recess provided for receiving a projected material for an implementation of an adjustment of the rate of the timepiece notably by the modification of the inertia and of the unbalance of the balance, the recess including an opening and a back notably a solid back or a back fully or partially forming an orifice, the back being at most partially visible from a position defined above the opening notably on a central axis of the opening.