US 4,283,957 A · Torsional exciter for a rotating structure

Abstract

An exciter is disclosed for applying a dynamic torsional force to a rotating structure, such as to the shaft of a turbine generator, the axle of a vehicle, or the like, during mechanical testing to determine the mechanical response characteristics, natural modes of vibration, fatigue life, etc., of the structure. The exciter includes a rotary hydraulic actuator having a housing secured to the structure to be tested and a driveshaft which is rotatable relative to the housing as well as an inertial mass mounted on the driveshaft. The exciter also includes a hydraulic power supply for the actuator and an electrohydraulic means comprising a torque setpoint circuit for producing a torque command signal to set the desired amplitude and frequency of oscillation of the inertial mass, a position setpoint circuit for producing a position command signal to set the midpoint of the arc through which the inertial mass oscillates, means for producing a torque feedback signal dependent on the actual dynamic torsional force produced by the oscillating inertial mass, means for producing a position feedback signal dependent on the average angular position of the inertial mass relative to the structure as the inertial mass oscillates and a controller responsive to the command and feedback signals for energizing a servovalve that controls the supply of pressurized fluid to the actuator. The actuator oscillates the inertial mass relative to the structure to be tested in order to produce a controlled dynamic torsional force on the rotating structure.

Claims26

Dependent claims

An exciter for applying torque to a rotating structure, comprising:

a rotary hydraulic actuator including a first element and a second element, said second element being rotatable relative to said first element;
means for securing one of said first and second elements to said rotating structure;
an inertial mass mounted on the other of said first and second elements;
a hydraulic power supply for supplying pressurized fluid;
and
electrohydraulic means for controlling said actuator, said electrohydraulic means including:
(a) a torque setpoint circuit for selectively producing a torque command signal to set a desired amplitude and frequency for torque applied to said rotating structure;
(b) means for producing a torque feedback signal dependent on the actual torque applied to said rotating structure;
(c) a controller responsive to said command and feedback signals for producing a control signal;
and
(d) means interconnecting said hydraulic power supply and actuator and responsive to said control signal for controlling the supply of pressurized fluid to said actuator such that said actuator oscillates said inertial mass with respect to said rotating structure at said desired amplitude and frequency;
whereby a controlled dynamic torsional force is applied to said rotating structure.

9 more elements

An apparatus for mechanically testing a rotating structure to determine the response, natural modes of vibration or fatigue life of the rotating structure in the presence of dynamic torsional excitation, comprising:

a rotary structure to be tested;
a motor;
a drivetrain interconnecting said rotary structure and motor;
said motor being selectively energizable for activating said drivetrain to rotate said rotary structure;
a rotary hydraulic actuator including a housing and a driveshaft, said driveshaft being rotatable relative to said housing;
means for securing said housing to said rotating structure;
an inertial mass mounted on said driveshaft;
a hydraulic power supply for supplying pressurized fluid;
and
electrohydraulic means for controlling said actuator, said electrohydraulic means including:
(a) a torque setpoint circuit for selectively producing a torque command signal to set a desired amplitude and frequency for torque applied to said rotating structure;
(b) means for producing a torque feedback signal dependent on the actual torque applied to said rotating structure;
(c) a controller responsive to said command and feedback signals for producing a control signal;
and
(d) means interconnecting said hydraulic power supply and actuator and responsive to said control signal for controlling the supply of pressurized fluid to said actuator such that said actuator oscillates said inertial mass with respect to said rotating structure at said desired amplitude and frequency;
whereby a controlled dynamic torsional force is applied to said rotating structure.

13 more elements

torsional exciter for a rotating structure, comprising:

a rotary hydraulic actuator including a first element and a second element, said second element being rotatable relative to said first element;
means for securing one of said first and second elements to said rotating structure;
an inertial mass mounted on the other of said first and second elements;
a hydraulic power supply for supplying pressurized fluid;
and
electrohydraulic means for controlling said actuator, said electrohydraulic means including:
(a) means for selectively producing a position command signal correlated to a desired angular position of said inertial mass with respect to said rotating structure;
(b) means for producing a position feedback signal correlated to the actual angular position of said inertial mass with respect to said rotating structure;
(c) a controller responsive to said common and feedback signals for producing a control signal;
and
(d) means interconnecting said hydraulic power supply and actuator and responsive to said control signal for controlling the supply of pressurized fluid to said actuator such that said actuator angularly displaces said inertial mass with respect to said rotating structure;
whereby a torsional force is applied to said rotating structure.

9 more elements

Dependencies are inferred from the claim text.

Torsional exciter for a rotating structure

Life of this patent

Torsional exciter for a rotating structure

Life of this patent

Abstract

Claims26