ELECTRO-SEIS® Long Stroke Shakers

The APS Dynamics series of ELECTRO-SEIS shakers are force generators specifically designed to be used alone or in arrays for modal excitation of various structures. They find use in forced excitation of complex structures such as floors, bridges, aircraft, spacecraft and automobiles.

Applications

• Determination of natural mode frequencies, shapes damping ratios, and stress distributions
  
• Excitation for transmissibility measurement
  
• Seismic simulation for components

Features

• Generate sinewave, swept sinewave, random or impulse force waveforms, fully adjustable at source.
  
•  Test set-up flexibility - operate in fixed body, free body, and free armature - reaction mass modes.
  
•  Optimized to deliver power to resonant load with minimum shaker weight and drive power
  
•  Adjustable armature re-centering for horizontal and vertical operation or other required pre-loads
  
•  Rugged armature with linear guidance system carries full weight of body
  
•  One or two man portability
  
•  Optional Air Bearings, Lightweight Armature and Extended Stroke

Description and Characteristics

The APS Dynamics series of ELECTRO-SEIS shakers have been optimized for driving structures at their natural resonance frequencies. These are electrodynamic force generators, the outputs of which are directly proportional to the instantaneous value of the applied current, independent of frequency and load response. They can deliver random or transient as well as sinusoidal waveforms of force to the load. The ample armature stroke allows driving antinodes of large structures at low frequencies and permits rated force at low frequencies when operating in a free body mode.
 The units employ permanent magnets and are configured such that the armature coil remains in a uniform magnetic field over the entire stroke range - assuring force linearity. The enclosed, self-cooled construction provides safety and minimum maintenance.

 A low frequency amplifier, such as the APS Dynamics DUAL-MODE Power Amplifier, is required to provide armature drive power.

Standard Configurations

ELECTRO-SEIS Shakers are available in two basics sizes - Model 113, with system force ratings from 20 to 40 pounds,

Model 400, with system force ratings of 70 to 100 pounds.

Optional Configurations

Model 113-AB
Air lubricated bearings replace the linear ball bearings used in the basic ELECTRO-SEIS armature guidance system. In addition, an air distribution system and base tie-down are provided.

 The Air Bearing configuration extends the application of the basic Model 113 to include the calibration and evaluation of accelerometers and other motion transducers in the seismic frequency range.

 Model 113-LA Lightweight Armature and Model 113-AB-LA Air Bearing-Lightweight Armature
 The body of the ELECTRO-SEIS Shaker is retained but the armature and guidance system are replaced with elements offering substantial weight reduction. The drive coil is lightened - with corresponding reduction in maximum force.

 Model 113-AB-ES Air Bearing - Extended Stroke
 The body of the basic Model 113 is extended to accommodate a longer stroke. The lightweight armature feature of the 113-AB-LA version is retained. The Lightweight Armature is a desirable feature when using the shaker for exciting structures having low modal mass.

 Model 113-LZ Low Impedance Coil
 All features of the basic ELECTRO-SEIS Shaker are retained. The drive coil is wound in a manner which allows series or parallel connection, offering the user the choice of standard or low impedance. This option may be required if the shaker is to be used with an amplifier from other manufacturers.

 Model 113-HF High Force Coil
 All features of the basic ELECTRO-SEIS Shaker are retained as in the Model 113-LZ. The drive coil is provided to match the Model 124 DUAL-MODE Power Amplifier for 40% increase in force with a 50% duty cycle (1/2 hr cycle).
 

Specifications

Model 113

Model 400

Maximum Force, Vector

30 lb, 133 N

100 lb, 445 N

Maximum Stroke, p-p

6.25 in, 158 mm

6.25 in, 158 mm

Armature Weight

4.9 lb, 2.2 kg

6.1 lb, 2.8 kg

Matching Power Amplifiers

Sinewave

114, 124

124, 144

Random

114-EP, 124-EP

124-EP