Modal 50A Exciter System

The #1 Selling Modal Exciter System Worldwide

Modal 50 Exciter

“The Modal 50A exciter system, along with MB’s modal test expertise, have revolutionized modal testing!” This exciter was designed by a team of world-respected modal testers, including University of Cincinnati Structural Dynamic Research Center (SDRC) professors, to eliminate problems encountered when using traditional shakers for modal tests. The Modal 50A exciter system slashes test setup time to a minimum! Conveniences in fixturing and setup, like the clearance hole through the armature and shaker and a collet chuck for gripping a threadless stinger make easy the attachment of the Modal 50A exciter system to a test structure. Fifty pounds of dynamic force from an Exciter weighing little more than 50 lbs makes it portable and easy to setup by one person.

MB Dynamics’ Unique Qualifications in Dynamic Testing

MB’s three principals (all of whom are University of Cincinnati SDRC alumni) have over seven decades of combined experience in dynamic testing performed across North America, Europe and Asia Pacific. Even today, these experienced test industry veterans help hundreds of customers to achieve good modal data, faster, by properly applying the right excitation source, and thereby solving real-world dynamic testing challenges at all experience levels, and across all industries! Choosing an MB Dynamics Modal 50A exciter system allows an end-user to gain instant, unprecedented access to MB’s own wealth of applications experience that remains unsurpassed in the market today. So, whether your needs call for custom-tailored modal testing solutions; on-site or virtual tests engineering consulting; in-house or virtual modal theory seminars and webinars, applications engineering support, tutorials on modal excitation best practices; or, practical hints for acquiring valid modal data, you’ll get it all with MB Dynamics.

Modal 50A Applications

Modal Exciter Application

The Modal 50A (and multiples thereof) is ideal for exciting structures smaller than say, a full-size automobile. Total vehicle modal tests on any larger test article (truck, jet, even a space shuttle) require multiple Modal 50A’s or the Modal 250A.

Requirements for the modal testing of structures calls for an exciter that is highly portable, easy to setup and operate. The lightweight, compact Modal 50A exciter system was designed with these needs in mind. A center bore extending through the armature, housing, trunnion base, and inertial masses allows for a stinger to be easily positioned along its axis. It may then be placed as close to the test article as desired and the chuck tightened down to firmly grip the stinger. The stinger does not need to be cut-off, thus retaining its flexibility for future use in different orientations and applications.

The ideal stinger would be infinitely stiff in the axial direction and have no bending stiffness. Since this is not possible, it can be approached with a pre-loaded thin wire. Replacing the 1/8″ stinger with piano wire is easy by simply changing one of the collets provided in the Accessory Kit. Once installed, the wire can be pre-loaded using a bungee cord and a small block pulley. An oscillatory force of 50 pounds keeps tension in the stinger while delivering peak dynamic force. This virtually eliminates measurement errors due to bending moments and side loads that can result when using compression loading of traditional stingers.

Why Choose the Modal 50A Exciter System?

Ease of Installation

  • Clearance hole through armature and shaker allows unlimited positioning along the stinger axis
  • Collet chuck, with clearance hole through armature and shaker, provides easy attachment of “one size fits all” stinger
  • ‘Piano wire’ minimizes cross-axis measurement errors; allows large static force to be applied without derating 50 lb dynamic force
  • Quick disconnect turnbuckles for adjustable suspension and easy, 6 DoF positioning
  • Lightweight shaker, easy-mount inertial masses/accessories allows for one-person setup and portability in remote locations
  • Trunnion base with two hand-knobs and three screw feet adjust to virtually any excitation angle
  • Quick connect/disconnect of additional mass supplies large inertial restraint for low- frequency testing

Universal Operation

  • Eliminates the need for 2 lbf or 6″ stroke shakers!
  • 1″ stroke – sufficient for flexible structures and low frequency “suspended shaker” tests (Optional: 30 mm pk-pk)
  • 50 pounds dynamic force – enough for large test articles such as mid- to full-size automobile
  • Lightweight armature (≤0.33 lbs.) enables testing small items
  • Broad usable frequency range (DC to 5000 Hz) handles almost every modal survey
  • Ideal for multi-shaker random, single-point random, multi-point sine dwell, and even burst random

Superior Accuracy with Fewer Errors

  • The ‘current mode’ of MB Dynamics Model MB500VI amplifier virtually eliminates mass loading on very small test items
  • Lightweight armature minimizes mass loading, dramatically reducing force drop-off at test specimen resonances
  • Low armature axial suspension stiffness (<15 lbs/in) ensures that shaker dynamics are decoupled from test specimen
  • Ultra-thin stinger decouples force inputs in all directions except the driven axis – avoids “cross axis” errors in force measurement
  • Applies/maintains pre-loaded tension to the stinger, eliminating buckling problems, resulting in superior forcing function!

The Modal 50A exciter system accessory kit includes chucks, turnbuckles, nuts, bolts, bolt-on masses, wrenches for bolt-on masses, stingers, user’s manual, and extra storage for stingers and load cells.

System Specifications:

  • Stroke: 1″ pk-pk (continuous)(optional MODAL 50ALS: 30 mm pk-pk) 1.1″ between stops
  • Force Output: Convection Cooling – 25 pounds (pk); Shop Air by User – 50 pounds (pk); Portable Cooling – 50 pounds (pk) optional
  • Stinger Attachments: Chuck and collets handle stinger sizes from 0.020″ to 0.12″ (0.5 to 3.0 mm)
  • Shaker Attachments (mounting): Floor: adjustable trunnion base & screw feet; Suspended: multiple turnbuckles
  • Test Specimen Static Pre-Load: Capable of tensioning stinger in excess of 50 lbs.
  • Weight: 55 lbs. (shaker w/trunnion base)
  • Bounce Mode of ‘Large Inertial Configuration’ on Armature Suspension: Approximately 1 Hz
  • Dimensions: 11 ½” H (to top of collet chuck with feet retracted) 7 ½” x 9 ¼” footprint
  • Drive Cable Length: 30′ standard (100′ cable optional)
  • Optional Accessory:  Lateral Excitation Stand

Download MB Dynamics MODAL 50A Datasheet (Rev 09/2021)

For more information or quotes on the MB Dynamics Modal 50A exciter system, please fill out the “Request Information” form on this page, visit our contact page, or call us at +1-216-292-5850.

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