Electrodynamic Vibration Systems
An Electrodynamic Vibration System generates controlled vibrations to simulate real life conditions in a laboratory environment. For any object meant to operate dynamically in its environment, vibration testing is a useful tool. These systems allow us to precisely re-create, accelerate, and manipulate the vibration an object will experience in its entire lifespan, inside a laboratory. This helps in identifying and isolating weakness of an object is areas such as mechanical design, metallurgy, mounting, heat or chemical treatment, welding, bolting, assembling, etc.
There are five major components that make an Electrodynamic Vibration System:
Electrodynamic Shaker
An Electrodynamic Shaker converts electrical energy from the Power Amplifier to mechanical vibrations using the principles of electromagnetism as described by Maxwell’s Right Hand Rule and Fleming’s Left Hand Rule. Sdyn has established state of the art infrastructure and realised the technology to design and manufacture any rating of Air or Water Cooled Electrodynamic Shakers. All our Shakers have two separate coils, stationary or Field Coil and dynamic or Armature Coil. When DC current is passed through the Field Coils, it generates a magnetic field as per Maxwell’s Right Hand Rule which magnetises the iron of the Shaker. Sdyn uses two Field Coils with opposing direction of current flow. This architecture adds the flux in shaker’s centre and subtracts it outside the shaker, helping reduce leakage of flux.
The construction of a Shaker ensures that poles created due to magnetism are perpendicular to the direction of current flowing in the Armature Coil. As per Fleming’s Left Hand Rule, the current flowing inside the Armature Coil interacts with the magnetic field lines, causing the armature to move. Changing the direction of the current flowing inside the Armature Coil changes the direction of motion of the Armature.
To realise true sinusoidal motion, the Armature is freely suspended using Rocker based Suspension with nearly negligible axial stiffness and very high cross axial stiffness. Centre is maintained with the help of pneumatics pressure and DC bias to allow for equal movement of the Armature in positive and negative direction.
Shaker body and base are mounted on air bellows and rubber pads which completely isolate all vibrations above 5Hz. For operation below 5Hz, option to lockout the shaker body isolation is provided but Sdyn recommends fixed body shaker mounted on seismic blocks to counter the reaction mass. All Shakers are trunnion mounted to allow operation in horizontal axis and to assist service engineers in maintenance procedures. Rotation can be manual or automatic as per customer preference.
Power Amplifier
Sdyn’s Power Amplifiers use compact and extremely efficient Power Modules to multiply the small voltage signal from the Vibration Controller by a fixed gain and deliver it to the Electrodynamic Shaker with the least amount of distortion and noise. Our DSA series Power Amplifier uses solid-state power devices in a Class-D – Full Bridge configuration. They are Pulse Width Modulated (PWM) at a very high frequency to deliver a wide frequency range starting from DC. Final output is differential and directly compatible with any Electrodynamic Shaker of any make in the world. Modular construction makes these Power Modules easy to handle and active current sharing ensures safe operation when connected in parallel to increase current rating. Integral air cooling ensures continuous duty cycle without sacrificing performance at peak temperature and humidity.
These Power Amplifiers are compatible with any make of Electrodynamic Shakers due to their extremely low output impedance and are fully configurable by the password protected Manufacturer’s Interface at customer site. This interface allows the user to change the state and status of any protection, making our Power Amplifier the ideal choice for Replacement Power Amplifiers.
Assembled in industry standard 19” racks, all modules of our Power Amplifier are rack mountable. Removing and installing modules is made easy via guide rails on which every module is designed to slide. Designed to meet international design and safety standards, every section of our Power Amplifier is feature rich and contains a host of protections for operational safety, flexible integration, and easy serviceability.
Head Expander
A Head Expander is bolted to the Armature head for increasing the platform size in the vertical orientation for testing in Z axis. A Head Expander can be Non-Guided or Guided of Square or Circular shape.
Horizontal Slip Table
A Horizontal Slip Table is a frictionless platform used for vibration testing in X and Y axis. The Electrodynamic Shaker turns from its vertical orientation to a horizontal orientation to couple with a Horizontal Slip Table.
Vibration Controller
A Vibration Controller allows the user to create a test profile on a PC and generates a signal in real time to match the test profile. An Accelerometer on the Electrodynamic Shaker provides feedback to keep the system under closed-loop control.