Electrodynamic Shaker System

Application

An Electrodynamic Vibration System and an audio system are somewhat similar in the basic principle. In an Electrodynamic Vibration System the Electrodynamic Shaker works like the speakers of an audio system, the Vibration Controller generates the signal that is feed to a Power Amplifier much like an MP3 Player of an audio system. The Power Amplifier’s outputs is proportional to the input signal by a fixed gain. This output of the Power Amplifier matches the input impedance of the speaker in an audio system and Electrodynamic Shaker in an Electrodynamic Vibration System. The main purpose of speaker in an audio system is to drives the diaphragm to create sound whereas the main purpose of Electrodynamic Shaker in an Electrodynamic Vibration System is to create the vibration itself.

The one big difference between the two is that in an Electrodynamic Vibration System, a sensor is placed on the armature of the Electrodynamic Shaker to sense the acceleration and provide a negative feedback to the Vibration Controller so that it may control the vibrations to meet the required test parameters.

The Electrodynamic shaker system is intended to simulate the effects of real life vibrations likely to be experienced by components, sub-assembly and systems during their service life when they are installed in an environment where vibrations are continuously induced during usage. These shakers perform vibration test in accordance with different standards. Its have proven versatility in vibration testing applications, they are designed to cater wide range of vibration testing and analysis.

Premax  offers a choice of force and payloads to suit different test requirements. Due to our technical knowledge and experience in designing and manufacturing high quality and high reliability products, we can also provide tests for different applications.

What kind of testing do we support?

  • Automotive parts and systems 
  • Electronic assembly, computer equipment testing
  • Satellite component testing
  • Product and package testing

The System has major sub systems like Shakers, High Power Amplifiers, and Vibration Controllers.

Shakers

The heavy steel structure body  Of Electrodynamics Shakers are made of high quality materials to make it suitable for longer service life. The Shaker is supported on air springs/ isolators to isolate the vibration to be transferred to the ground thus eliminates the requirement of special foundation and can be installed on any  industrial floor. It have unique feature of higher resonance frequency and high bare table acceleration with required accuracy and reliability.

Complete shaker and external interlocks help protect the system from accidental abuse. Oil film slip table base systems are available for larger and heavier loads or loads with high centers of gravity.

Electrodynamic shaker produces vibration based on the principle of magnetism . It has two separate coils, one is stationary and the other is dynamic. A stationary coil or Field Coil helps in magnetising the iron to produce magnetic field lines and current flowing in the dynamic coil or Armature Coil interacts with these magnetic field lines to produce motion. This principle of magnetism is based on Maxwell’s Right Hand Rule and Fleming’s Left Hand Rule.

Vibration Shaker can test in a vertical or horizontal orientation; utilize a fixture, sliptable, or head expander.


Shaker optional attachment


Head Expanders/ Load Support Platform (for Vertical direction)

The head expanders are designed and fabricated as bolt-on platform for shaker armature to accommodate large size objects during vertical axis vibration testing (Z-axis). In most of the applications, the space on armature top of shaker is a constraint for mounting large fixture and test objects.  In order to increase the working area of an armature, a head expander is used. We offer a varied range of head expanders to meet various testing requirement like accommodating large test articles or multiple test objects at one time.The head expanders are made of Al/ Mg alloy material having casted/ welded structure in circular or square shape to suit different test requirements. For voluminous and overhanging objects, the guided head expanders (Load Support Platform) are preferred which enhances the loading capacity and restricts overturning moments during vibration testing。They are available for any size armature with customised hole pattern as per customer requirement.

Horizontal Slip Tables

Premax offers slip tables in various sizes for coupling with shaker to facilitate horizontal testing. The axis of a shaker’s operation is Z axis. In order to achieve vibrations in X and Y axis, a Horizontal Slip Table  is used. A Horizontal Slip Table is compactly constructed using a precisely machined magnesium alloy tool-plate, which rests on top of the flat marble block.
The size of platform is determined by the dimension of test object and holding fixture. The slip plate surface is precision machined for required flatness. A closed loop hydraulic pump is used to form consistent oil film between slip plate and marble block for friction less motion and bearings ensure true linear guidance over a wide frequency band with high overturning moments.
A consistent oil film is generated on the marble block and in the bearing in order to remove friction, provide dynamic support, control crosstalk and restrain overturning moments. 

The Horizontal Slip Tables provide excellent performance for heavy, tall or eccentric loads. The test object can be rotated by 90° on the table to switch between X and Y axis. It makes the electrodynamic Shaker System is capable of testing objects in all three axis, one at a time.

Power Amplifiers

A Power Amplifier (or digital switching Power Amplifiers)multiplies the output of the Vibration Controller by a fixed gain with great efficiency and feeds it to the Electrodynamic Shaker. Amplify the small electrical signal from the Vibration Controller to a proportionally high voltage and high current output, that is ideal to drive the shaker

The Power Amplifiers  provide very high level of efficiency with superior performance, they are digitally modulated with a high frequency pulse width modulated signal with efficiency of over 92%.The design of the VSA-H Series Power Amplifier  use  MOSFETs or IGBT as their primary switching devices . 

Assembled in industry standard modular 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. Their modular construction makes them easy to handle and arrange for maximum output power with direct coupling to any resistive or inductive load. 
Integral air cooled design ensures continuous duty cycle without sacrificing performance at peak temperature and humidity. It can  keep uninterrupted rated voltage and current even at higher ambient temperature and humidity.

Vibration Controllers

Premax vibration controllers offer the latest technology in digital signal processing and shaker control algorithms providing real time vibration test controller systems for Random, Sine, Shock, Resonance Dwell, Random on Random, as well as extensive data acquisition and analysis.

VT-9008: ED VIBRATION CONTROLLER

VT-9008 series vibration controller is a cutting-edge vibration control product for electro-dynamic shakers, utilizing the latest DSP technology, low noise hardware design, advanced vibration control algorithms, and data transmission protocols. Controls vibration at extremely low frequency (0.1 Hz of sine sweep test) and high frequency (18750 Hz of random vibration test) with sampling frequency up to 48000 Hz. It is compatible with all vibration control types: acceleration, velocity, displacement, force, voltage, and user define。
One end of the ABORT Port is directly connected to the hardware by designers, and the other end can be connected with an external switching line. This allows users at a distance to conveniently and instantly stop a running test.

The control software is based on PC, but the control process is independent from PC to ensure the efficiency of real-time control system, with timely and rapid response to system dynamic changes. Thus it guarantees high performance, powerful features, safety assurance, as well as very easy to use software interfaces.

we are able to customize vibration control test modules to meet your special test needs. A trade-in program is also available if you want to replace old controller and save your budget for upgrading.

VT-8008: MIMO Vibration Controller

Due to the development of technology, the structure of products is becoming more and more complex and sophisticated. A single excitation vibration can not meet the force of some large volume and heavy weight products, or can not more realistically simulate the multi-dimensional vibration environment of the product in the actual work process, resulting in inaccuracy of the experimental results.

VT9008 Controller can control three methods for products with large weight and large volume, slim body structure and precise structure.

1. Multiple synchronous vibration control
For large mechanical structures such as ships and automobiles, a single excitation vibration test cannot meet the space or thrust requirements and cannot be tested. In this case, two or more vibration tables can be tested using VT9008 MIMO Vibration Controller.
2. Multiple asynchronous vibration control
For slender body structures such as rockets, missiles and bridges, using VT9008 to perform multiple asynchronous vibration tests can make the load distribution of the test piece more uniform and reasonable and true, reducing the stress concentration and local under-experiment or over-test caused by a single excitation
3. Multi-axis multi-freedom vibration control
For complex structures such as artificial satellites, using VT9008 for multi-axial multi-degree-of-freedom vibration test can avoid over-test and under-test of the product, and avoid over-test or under-test that cannot be estimated due to single excitation.