MODEL 113 SHAKER - ITLL · CHARACTERISTICS AND PERFORMANCE ... MATCHED RESONANT LOAD . . . . . . ....

INSTRUCTIONINSTRUCTIONINSTRUCTIONINSTRUCTIONINSTRUCTIONMANUALMANUALMANUALMANUALMANUAL

ELECTRO-SEIS®

MODEL 113 SHAKERMODEL 113 SHAKERMODEL 113 SHAKERMODEL 113 SHAKERMODEL 113 SHAKER

Systems for Generating Controlled VibrationSystems for Generating Controlled VibrationSystems for Generating Controlled VibrationSystems for Generating Controlled VibrationSystems for Generating Controlled Vibration

5731 Palmer Way, Suite A, Carlsbad, CA 92008 USA (760) 438-4848 FAX (760) 438-8845 [email protected]

APS

Serial Number

TTTTTable of Contentsable of Contentsable of Contentsable of Contentsable of Contents

iii

SECTION 1: GENERAL INFORMATIONSCOPE . . . . . . . . . . . . . . . . . . . . . . . . . 1-1DESCRIPTION AND PURPOSE . . . . . . . . . . . . . . 1-1CHARACTERISTICS AND PERFORMANCE

PARAMETERS . . . . . . . . . . . . . . . . . . . . 1-2ACCESSORY INFORMATION

AUXILIARY TABLES 0052, 0077 AND 0078 . . . . . . 1-3CRADLE ASSEMBLY 0072 . . . . . . . . . . . . . . 1-3REACTION MASS 0112 . . . . . . . . . . . . . . . . 1-4CARRYING HANDLES AND

TIE-DOWN BARS - 0108 . . . . . . . . . . . . . 1-4

SECTION 2: PREPARATION FOR USEUNPACKING AND PACKING . . . . . . . . . . . . . . . 2-1PREPARATION FOR USE . . . . . . . . . . . . . . . . 2-2SUSPENSION SYSTEM ADJUSTMENT . . . . . . . . . . 2-2ATTACHMENT OF SHAKER TO TEST

STRUCTURES USING THRUST RODS . . . . . . . . 2-4PREPARATION FOR STORAGE OR RESHIPMENT . . . . 2-4ACCESSORY INFORMATION . . . . . . . . . . . . . . . 2-5

AUXILIARY TABLES 0052 & 0077 . . . . . . . . . . . 2-5CRADLE ASSEMBLY 0072 . . . . . . . . . . . . . . 2-6REACTION MASS ASSEMBLY 0112 . . . . . . . . . 2-7CARRYING HANDLES AND LEVELING FEET 0108 . . 2-8

SECTION 3: PRINCIPLES OF OPERATIONTHEORY OF OPERATION . . . . . . . . . . . . . . . . 3-1

FORCE GENERATION . . . . . . . . . . . . . . . . 3-1MAXIMUM FORCE AND CURRENT RATINGS . . . . . 3-1MAXIMUM STROKE . . . . . . . . . . . . . . . . . 3-2MOTIONAL IMPEDANCE . . . . . . . . . . . . . . . 3-2RESONANT LOAD DRIVE REQUIREMENTS . . . . . 3-3MATCHED RESONANT LOAD . . . . . . . . . . . . 3-3

MODES OF OPERATION . . . . . . . . . . . . . . . . . 3-4GENERAL . . . . . . . . . . . . . . . . . . . . . . 3-4FIXED BODY MODE . . . . . . . . . . . . . . . . . 3-4FREE BODY MODE . . . . . . . . . . . . . . . . . 3-4FREE ARMATURE MODE . . . . . . . . . . . . . . 3-5SHAKER TABLE MODE . . . . . . . . . . . . . . . 3-6ENVELOPES OF PERFORMANCE . . . . . . . . . . 3-6

Model 113

NOTES

iv

SECTION 4: MAINTENANCEREPLACEABLE PARTS . . . . . . . . . . . . . . . . . 4-1ORDERING INFORMATION . . . . . . . . . . . . . . . 4-1LISTS OF SERVICE TOOLS AND MATERIALS . . . . . . 4-1INSPECTION AND PREVENTATIVE MAINTENANCE . . . 4-1CLEANING AND PARTS REPLACEMENT PROCEDURE . . 4-2DISASSEMBLY . . . . . . . . . . . . . . . . . . . . . 4-2REASSEMBLY . . . . . . . . . . . . . . . . . . . . . . 4-3ACCESSORY INFORMATION . . . . . . . . . . . . . . . 4-4

INSTALLATION OF BEARING HOUSING CLAMPS . . . 4-4FOR AUXILIARY TABLES 0052, 0077, and 0078 . . 4-5FOR THE CRADLE ASSEMBLY 0072 . . . . . . . 4-6FOR THE REACTION MASS 0112 . . . . . . . . 4-6

REPAIR/REPLACEMENT ACTION . . . . . . . . . . 4-8

SECTION 5: SUPPORT DOCUMENTATION

Table of Contents

Model 113

NOTES

11111General InformationGeneral InformationGeneral InformationGeneral InformationGeneral Information

1-1

SCOPE

This Instruction Manual provides operation and maintenanceinformation for the APS Dynamics Model 113 ELECTRO-SEIS Shaker,including HF and LZ versions, and applicable accessory items. SerialNumber effectivity of this manual is given on the title page.

DESCRIPTION AND PURPOSE

The Model 113 ELECTRO-SEIS Shaker is a long stroke,electrodynamic shaker, designed to be used alone or in arraysfor exciting and studying the dynamic response characteristicsof structures in the seismic frequency range. Its design has beenoptimized specifically for driving structures at their natural resonancefrequencies, delivering maximum power to such resonant loads, withminimum total shaker weight and drive power.

The Model 113 provides modal test excitation of such complexstructures as piping systems, electrical substation structures andapparatus, floors, missiles, aircraft, spacecraft, etc. To accommodatea wide variety of structures and test configurations, the shaker iscapable of operating in four modes: fixed body, free body, freearmature, and shaker table mode. Its thrust axis may be orientedat any angle between vertical and horizontal, with no degradation ofperformance. A linear bearing/shaft system provides high lateral loadcapability and an adjustable, high compliance axial suspensionsystem provides for a variety of load/shaker support configurations.

The unit employs permanent magnets and is configured such thatthe armature coil remains in a uniform magnetic field over the entirestroke range. Drive power for the shaker is obtained from a poweramplifier, such as the APS Dynamics Model 114 or 124.

The shaker can be used with accessory items to extend the areasof application.

1. AUXILIARY TABLES 0052 and 0077 - extend the application ofthe shaker to vibration of such items as components and model

buildings.

Model 113

NOTES2. CRADLE ASSEMBLY 0072 - provides a means of supporting theshaker in a free body mode on a test structure and to introduceforce parallel to a horizontal mounting surface on the structure.

3. REACTION MASS 0112 - allows either horizontal or verticalgenerated force to be applied through the shaker body to ahorizontal surface on which the shaker is placed.

4. CARRYING HANDLES & TIE-DOWN BARS 0108 - providesconvenient portability and tie-downs.

CHARACTERISTICS AND PERFORMANCE PARAMETERS

Frequency Range . . . . . . . . . . . . . . . . . . 0 to 200 Hz

Force Rating 113, 113-LZ (continuous)dc to 0.1 Hz . . . . . . . . . . . . . . . . . . . 21 lb, 94 NAbove 0.1 Hz . . . . . . . . . . . . . . . 30 lb, 133 N peakAbove 20 Hz . . . . . . . . . . . . . . . Refer to figure 3-7

Force Rating 113-HF (50% Duty Cycle - 1/2 hr)dc to 0.1 Hz . . . . . . . . . . . . . . . . 30 lb, 133 N peakAbove 0.1 Hz . . . . . . . . . . . . . . . 42 lb, 186 N peakAbove 20 Hz . . . . . . . . . . . . . . . Refer to figure 3-7

Maximum Stroke . . . . . . . . . . . . . 6.25 in, 158 mm pk-pk

Velocity . . . . . . . . . . . . . . . . . . . . 30 in/s, 762 mm/s

Armature Weight, Typical . . . . . . . . . . . . . 5.0 lb, 2.27 kg(Refer to Section 5 Calibration)

Rated Current, Typical (113) . . . . . . . . . . . . . . . . 3.5 A 113-HF . . . . . . . . . . . . . . . . . . . . . . . . . 8 A

(Refer to Section 5 Calibration)

Load Attachment . . . . . . . Clearance hole for 1/4 in, 6 mm rod

Accelerometer/ComponentAttachment . . . . . . . . . . . 6 each 10-32 threaded holes

Outline and InstallationDimensions . . . . . . . . . . . . . Refer to Figure Section 5

WeightsBody . . . . . . . . . . . . . . . . . . . . . . 78 lb, 35 kgTotal Shaker . . . . . . . . . . . . . . . . . . 83 lb, 38 kg

EnvironmentalOperating Temperature . . . . . . . . . . . 5 to 40 degrees CStorage Temperature . . . . . . . . . . -40 to 85 degrees CHumidity . . . . . . . . . . . . . . . . . 90% RH Maximum

Section 1: General Information

1-2Model 113

NOTES


ACCESSORACCESSORACCESSORACCESSORACCESSORY INFORMAY INFORMAY INFORMAY INFORMAY INFORMATIONTIONTIONTIONTION

AUXILIARY TABLES 0052, 0077 AND 0078

The 0052 and 0077 Auxiliary Tables attach to the armature supportpoints on the shaker and provide mounting platforms for supplyingtransverse and axial base excitation to such test items ascomponents, model structures, accelerometers, accelerographs,and other low frequency instrumentation. Refer to Section 5 forinstallation drawings. The 0078 provides all parts required for eitherconfiguration.

Static and dynamic loads from the table and test item are transferreddirectly to the shaker’s internal guidance and suspension systems.The table and guidance bearing system are rated to support up to50 lb, 23 kg maximum test loads weight. The shaker’s internalsuspension system may be adjusted to center the armature andtable within the stroke range for all orientations.


Armature weight (including four bearinghousing clamps) . . . . . . . . . . . . . . . . 5.5 lb, 2.5 kg

Armature weight including horizontal table(Part Number 0052) . . . . . . . . . . . . . . 11.9 lb, 5.4 kg

Armature weight including vertical table(Part Number 0077) . . . . . . . . . . . . . . 12.8 lb, 5.8 kg

Table Size . . . . . . . . . . . . . . . . . . . . . . . 10 x 10 in254 x 254 mm

Load Attachment Points . . . . . . . . . . 25 on 2.000 in centers(25 mm optional)

Load Attachment Thread Size . . . . . . . 1/4-20 (M6-1 optional)

Maximum Test Load WeightHorizontal . . . . . . . . . . . . . . . . . . . 50 lb, 23 kgVertical . . . . . . . . . . . . . . . . . . . . . 25 lb, 11 kg

CRADLE ASSEMBLY 0072

Part Number 0072 Cradle Assembly is a unit on which the Model 113may be placed to support the shaker via its lower four armaturesupport points. The cradle provides a convenient means of supportingthe shaker in a free body mode on a large test structure to introduceforce parallel to a horizontal mounting surface on the structure.

1-3

Auxiliary Table 0052

Auxiliary Table 0077

Model 113

NOTES

NOTES


Vertical members of the cradle penetrate the slots on the bottomof the shaker. Four Bearing Housing Clamp Blocks provide theattachment points to the armature. When supported on the CradleAssembly, the shaker operates in a free body mode. Refer toSection 5 for installation drawing.


Armature weight including Cradle . . . . . . . . . . 13.9 lb, 6.3 kg

Minimum frequency for 30 lb Force . . . . . . . . . . . . 1.15 Hz

REACTION MASS 0112

Two Reaction Mass Blocks attach to the armature support points onthe shaker and provide sufficient reaction mass to obtain rated forcedown to 2 Hz in a free armature mode. Refer to Section 5 forinstallation drawing.

The Reaction Mass Suspension System may be adjusted to centerthe Armature and Reaction Mass within the stroke range for allorientations of its force axis. Handles provide a convenient meansfor carrying the unit. A handle diagonally interchanged with one ofthe feet extension bars allows horizontal placement of the shakerforce axis.


Armature weight including Reaction Mass . . . . . . 29 lb, 13.2 kg

Minimum frequency for 30 lb Force . . . . . . . . . . . . 1.85 Hz

Total Shaker Weight including Reaction Mass . . . . 103 lb, 47 kg

CARRYING HANDLES AND TIE-DOWN BARS 0108

This kit provides convenient portability and tie-down in both a horizontaland vertical mode. Refer to Section 5 for installation drawing.

1-4Model 113

NOTES

22222Preparation for UsePreparation for UsePreparation for UsePreparation for UsePreparation for Use

2-1

UNPACKING AND HANDLING

The Model 113 ELECTRO-SEIS Shaker is shipped in a heavy duty,corrugated cardboard box. Within the box the unit is secured andprotected by foam blocks. The box and packing material should beretained for shipment of the Model 113 to test sites or for extendedstorage periods.

* CAUTION *

THE MODEL 113 SHAKER CONTAINS A BALANCED MAGNETICCIRCUIT. HOWEVER, THE SMALL STRAY FIELD NEAR THE UNITCAN AFFECT WATCHES AND OTHER DELICATE MECHANISMS.KEEP SUCH OBJECTS AT LEAST A FOOT AWAY FROM THESHAKER.

The unit weighs approximately 83 lb, 38 kg and may be lifted byusing the end frames as hand holds or by installing four eyeboltsin the upper body support points and lifting with a light hoist.

In addition to the basic shaker, the shipping box contains:

1. Instruction manual

2. Optional suspension bands

Four rubber feet are installed on the bottom of the shaker for normalresting on horizontal surfaces. The feet are secured to the end framesof the body by 1/4-20 socket head cap screws. The feet may beremoved if the unit is to be attached to certain accessories or aspecialized mounting fixture. Refer to Section 5, Outline DrawingModel 113.

* CAUTION *

IF FEET ARE REMOVED, BE SURE UNIT DOES NOT REST ONSUSPENSION ADJUSTMENT SLIDE KNOBS. THESE KNOBSPROJECT BELOW THE PLANE OF THE MAGNET STRUCTURE'SLOWER SURFACE.

Model 113

NOTES

Section 2: Preparation for Use

2-2Model 113

PREPARATION FOR USE

The unit is completely assembled when shipped. Light suspensionbands are installed in the shaker, and the suspension system isadjusted to retain the armature against its inner stops. Prior tooperating the unit, adjust the internal suspension for mid-positionof the armature relative to the magnet structure. To accomplish this,loosen the upper suspension knobs and slide in the direction of thedesired armature movement. Retighten the knobs.

Manually displace the armature over its stroke range to verify freeoperation of the bearings and free running of the coil in the magneticair gap.

Attach armature current leads to the terminal located on the loadattachment end of the armature. Specific polarity of the leadattachment is not required unless the unit is part of a multiple channelsystem. The armature leads should be arranged for free “rolling” action.Secure the fixed or connector end of the “pigtail” lead. The shakercable ground wire should be attached to the body of the shaker at thegrounding screw located on the side of the forward end frame. The unitis now ready for operation.

* WARNING *

WHEN OPERATING SHAKER, ENSURE THAT PERSONS,DOMESTIC ANIMALS, AND PROPERTY (OTHER THAN PROPERTYINVOLVED IN TESTING) ARE NOT ADJACENT TO MOVINGARMATURE.

SUSPENSION SYSTEM ADJUSTMENT

The Model 113 Shaker’s internal suspension system uses highstrength silicone bands in several possible arrangements to supportexternal static loads. The bands act in tension between attachmentpoints on the armature and body. The configuration of the suspensionsystem allows the ends of the bands attached to the body to be shiftedalong the axis of the shaker to accommodate different static loads andreturn the armature/body neutral position to the center of the relativestroke range. Always use maximum stretch possible consistent withthe above adjustment. The available range of adjustment is extendedby using different numbers of the light or heavy bands provided with theunit.

The recommended configurations of the suspension bands for othermodes of operation are given in Figure 2-1.

!

2-3


Figure 2-1 Configuration of suspension bands for various modes of operation

Model 113

NOTESIn order to change the band configuration or type, perform the followingsteps:

1. If the bands to be changed are in the lower half of the shaker,place the shaker in a vertical orientation resting on its rearend frame. Place it on its feet in the horizontal orientation forchanging bands in the upper half.

2. Loosen the suspension slide knobs and allow the bands to returnto minimum elongation. When opposing bands are used, theknobs will be in the middle position along the shaker axis.

3. Remove the appropriate corner covers to allow access to theband attachment points. To remove a corner cover, first loosenthe knurled, captive screw at each end, and then slide the coveroutwardly in the end frame channels.

4. Remove the bands from the suspension slide pins first, and thenremove them from the armature pins.

5. To replace the bands, reverse the above procedure, alwayslocating the wide section of the bands over the support pins.Note that the suspension slide may be locked in any positionalong the suspension slide guide with the corner cover removed.When replacing the corner cover, be sure that the Nylon washerunder the knob is not obstructing the cover from sliding into itscorrectly installed position. DO NOT over-tighten the knurled,captive screw.

ATTACHMENT OF SHAKER TO TEST STRUCTURESUSING THRUST RODS

For structural excitation employing the fixed body and free body -pendulously suspended modes, a thrust rod must be provided by theuser to connect the shaker armature to the drive point on the structure.Threaded rod stock is recommended for this purpose. Used in lengthsof several inches or more, it offers a degree of cross-axis complianceto accommodate curvilinear shaker/structure motion and makealignment of the shaker and drive point less critical.

PREPARATION FOR STORAGE OR RESHIPMENT

The shaker is best stored or shipped in its original shipping container,sealed against moisture in a plastic bag. The internal suspensionshould be adjusted to displace the armature to its innermost position.


2-4Model 113

NOTESACCESSORACCESSORACCESSORACCESSORACCESSORY INFORMAY INFORMAY INFORMAY INFORMAY INFORMATIONTIONTIONTIONTION

The relevant Installation Drawings in Section 5, contain lists of allreplaceable parts for the following accessories. With the exceptionof Carrying Handles and Tie-down Bars 0108, all accessories requirethe installation of Bearing Housing Clamps. These clamps are factoryinstalled on the Model 113 Armature if the accessary is ordered withthe Model 113, otherwise, they are included in the box. Refer toSection 4 for instructions of installation of the clamps. These clampsmay remain in place if it is desired to use the shaker without theaccessories. The clamps increase the basic Armature weight to5.5 lb, 2.5 kg. (Refer to Section 5).

Each accessory is packaged in a wooden storage box, complete withall parts and tools required for installation.

AUXILIARY TABLES 0052, 0077, AND 0078

Auxiliary Table Kit 0078 contains all the parts for either the 0052 or0077 configuration. The installation instructions for the 0052 and 0077also apply to the 0078.

The Feet Extension Bars may be installed at this point. With theshaker in a vertical position, remove the rubber feet normally suppliedwith the shaker. Install the bars with screws referenced in theInstallation Drawing for 0052 or 0077.

Prior to installation of the table, select and install the internalsuspension bands in the configuration appropriate for the intendedapplication. Refer to Figure 2-1 for the various possible configurationsand their installation.

The Horizontal Table (P/N 0052) is installed with the shaker in ahorizontal position. To mount the table, proceed as follows:

1. Remove the two top suspension adjustment assemblies and storefor other shaker applications.

2. Place the Table Spacer Bars in position on the Bearing HousingClamps, with through holes aligned directly above the threadedholes in the clamps.

3. Place the table on the spacer bars with mounting screw holesaligned with those in the spacer bars.

4. Install the four Socket Head Cap Screws referenced in theInstallation Drawing.

5. Gradually and progressively tighten the four mounting screws.

2-5


Model 113

NOTES


2-6

The Vertical Table (P/N 0077) is installed with the shaker in the verticalposition. To mount the table, proceed as follows:

1. Locate the vertical table support tubes in position on the BearingHousing Clamps. Install four Socket Head Cap Screws,referenced in the Installation Drawing to the upper BearingHousing Clamps, but do not tighten.

2. Install four Socket Head Cap Screws through the SuspensionSupport Bracket to the lower Bearing Housing Clamps, but do

not tighten.

3. Place the table over attachment points and install the four SocketHead Cap Screws referenced in the Installation Drawing - finger

tight only.

4. Tighten screws installed in Step 1 and Step 2.

5. Tighten screws installed in Step 3.

6. Install suspension bands to the external support pins as requiredto support the table and test article.

7. Adjust the internal suspension bands for mid position of the armature.

* CAUTION *

DO NOT ADJUST THE SUSPENSION BANDS WHILE THESHAKER IS OPERATING. ADJUST SUSPENSION BANDS FORMID POSITION OF ARMATURE BETWEEN STOPS BEFOREOPERATING SHAKER.

CRADLE ASSEMBLY 0072

The following procedure provides instructions for attaching theArmature Cradle to the shaker armature.

1. Arrange the armature suspension bands as indicated inFigure 2-1 for near horizontal operation.

2. Place the shaker in a vertical position.

3. Attach the Cradle to the four Bearing House Clamps with the fourSocket Head Cap Screws referenced in the Installation Drawing.

4. Return the shaker to the horizontal position.

Model 113

NOTES

2-7


5. Adjust the leveling screws, if required, depending on the mountingsurface condition.

6. Clearance holes in the Cradle Base may be used to fasten theCradle Assembly to a horizontal surface.

7. Secure the Armature leads to the test structure to prevent contactwith the shaker body during long stroke operation.

REACTION MASS ASSEMBLY 0112

Replace the knob-type suspension adjustment assemblies with thealternative adjustment assemblies (socket head cap screw type) asfollows:


2. Remove corner covers, bands and knob-type assemblies.

3. Replace with alternative assemblies placing a pair at each endand replace the suspension bands.

4. Replace the corner covers.

The following procedure provides instructions for attaching the FeetExtension Bars and Handles/Mass Support Bars to the shaker body:


2. Remove the four rubber feet supplied with the Model 113 and storefor future use.

3. Attach the Feet Extension Bars and Handles with the eightSocket Head Cap Screws referenced in the Installation Drawing.For vertical operation, place the handles on top. For horizontaloperation, reverse the location for one pair of handle/feet.

Following this procedure for attaching the Reaction Mass Blocks to theArmature:

1. Place the shaker in a horizontal position.

2. Locate a Reaction Mass and Spacer Blocks over the four BearingHousing Clamps and fasten with the four Socket Head CapScrews referenced in the Installation Drawing.

3. Rotate the shaker 180 degrees and attach the second ReactionMass unit. Operation of the shaker with a single Reaction Massunit installed is not recommended.

Model 113

NOTESPlace the shaker in the vertical position and install the externalsuspension bands. Use up to 4 Extra Heavy Bands (P/N 0091-0)and up to 4 Heavy Bands (P/N 0091-1) as required to support theload. Place the bands over the suspension points located on theHandles and Reaction Mass Block Spacers. Fine adjustment forcentering the mass may be done with the internal SuspensionAdjustment Assemblies. When used horizontally, four bands arerecommended. The Feet Extension Bars are faced with a non-skidsurface. If a more rigid support is required, cap screws located inthe feet may be extended. Attach the armature leads to the armatureterminal strip. Provide a loop, approximately 6 inches, 150 mm, indiameter, to allow free motion of the armature and leads. Clamp theleads with the cable clamp and the ground lead attachment screw.

Set the Power Amplifier for operation in the Voltage Mode. Operationin the Current Mode will result in large amplitude near the reactionmass suspension resonance. For operation above 5 Hz, the currentmode may be used. The force level may be monitored by any of thefollowing:

1. Visual measurement of armature displacement and calculationof acceleration and force.

2. Measurement of armature/mass acceleration with anaccelerometer. A 10-32 tapped hole in each reaction massblock is provided on an accelerometer.

* CAUTION *

DO NOT RESHIP THE MODEL 113 SHAKER WITH REACTIONMASS ATTACHED. EXCESSIVE TRANSPORTATION SHOCKLOADS MAY DAMAGE THE SHAKER GUIDANCE BEARINGS.

CARRYING HANDLES & LEVELING FEET 0108

The Carrying Handles & Leveling Feet 0108 are shipped in a separatecontainer and are installed by the user.

The following procedure provides instructions for attaching the FeetExtension Bars and Carrying Handles to the shaker body:


2. Remove the four rubber feet supplied with the Model 113 and store for future use.

3. For vertical orientation of the shaker, attach the Feet ExtensionBars and Carrying Handles with the eight Socket Head CapScrews referenced in the Installation Drawing.


2-8Model 113

NOTES


4. For horizontal orientation of the shaker, attach the Feet Extension Bars and Carrying Handles with the eight Socket Head Cap

Screws referenced in the Installation Drawing.

In operation the shaker may be placed on a flat surface using thenon-skid backing to resist slipping of the shaker body.

Model 113 2-9

NOTES

33333Principles of OperationPrinciples of OperationPrinciples of OperationPrinciples of OperationPrinciples of Operation

3-1

Figure 3-1 Principle of electrodynamicforce generation

NOTES

THEORTHEORTHEORTHEORTHEORY OF OPERAY OF OPERAY OF OPERAY OF OPERAY OF OPERATIONTIONTIONTIONTION

FORCE GENERATION

The Model 113 ELECTRO-SEIS Shaker is fundamentally a forcegenerator. Its basic operating principle is that of force generationin a current carrying conductor, located in a dc magnetic field whichis perpendicular to the direction of the current. See Figure 3-1.

In Figure 3-1, N and S are north and south poles of the magnetcreating flux density, B, in the air gap. Force, F, is generated andacts on the conductor carrying current, I. The magnitude of thegenerated force is directly proportional to the instantaneous valueof current, and the force acts in a direction mutually perpendicularto the directions of current and magnetic field.

Corresponding to the force generated on the current carryingconductor and associated armature structure, there is an equaland oppositely directed reaction force, F, developed on the magneticfield structure or body of the shaker. The Model 113 Shaker is thuscapable of generating any time waveform of force acting between itsarmature and body, in accordance with an identical time waveform ofcurrent supplied to it. The force magnitude is directly adjustable,independent of the frequency or time waveform of operation, and itmay be instantaneously terminated by interrupting the current.

For a given force, the relative motion which results between thearmature and body of the shaker is a function of the mechanicalimpedance of the structures to which the two portions of the shakerare attached. That is, for a given current a resultant force will beproduced whether either or both the armature and body are blockedor free, or loaded to any degree between these extremes.

MAXIMUM FORCE AND CURRENT RATINGS

The continuous duty force rating of the Model 113 is dictated bythe maximum allowable temperature rise of the natural convectioncooled armature coil. This establishes a maximum electrical powerdissipation and corresponding force and nominal current limits of21.2 lb, 94 N rms and 3.54 A rms. Therefore, for continuous sinusoidal

Model 113

NOTES

Section 3: Principles of Operation

3-2

Figure 3-2 Principle of velocity voltagegeneration

operation above 0.1 Hz, the maximum ratings are 30 lb, 133 N peakand 5.0 A peak. For sinusoidal operation between dc and 0.1 Hz,where the period of the current waveform is long compared to thethermal time constant of the armature coil, the maximum ratingsare 21.2 lb, 94 N peak and 3.54 A peak (0.707 times the higherfrequency values). Above 20 Hz, because of an increasing voltagerequirement, force may be limited to less than the maximum ratingdepending on the amplifier capability. Refer to performance envelopesin Figures 3-7 and 3-8. The Model 113-HF has an intermittent forcerating of 42 lb, 186 N with a 50% duty cycle over a 1/2 hour period.

MAXIMUM STROKE

Many structures have resonance frequencies which lie in the1 to 20 Hz frequency region. Their resonance frequencies arelow by virtue of their large dimensions and/or corresponding lowstiffness/mass ratio. While vibrating at resonance, the antinodesor points of maximum deflection on such structures can executedisplacements exceeding an inch, and yet the stresses remainwell below the elastic limit. Since the most efficient drive point ona resonant structure is at or close to the antinode of the mode beingexcited, a seismic frequency range modal shaker should thereforehave sufficient stroke capability to accommodate such loaddisplacements. Furthermore, as discussed below, the stroke rangemust also accommodate significant motion of the shaker body, todevelop force at low frequencies when operating in a free body mode.For these reasons, the Model 113 Shaker has a 6.25-in, 15.9-cmpeak-to-peak relative stroke capability. The Electro-Seis series ofshakers are designed so that linear force is developed at any pointwithin the stroke range.

MOTIONAL IMPEDANCE

When a relative velocity occurs between the shaker body andarmature/test structure, an electromotive force or voltage is generatedalong that portion of the armature coil conductor which lies in themagnetic field. See Figure 3-2. As before, N and S are north andsouth poles of the magnet creating flux density, B, in the air gap.Induced voltage E, is generated along the conductor as a result ofthe relative velocity, v, between the conductor and magnetic field.The arrow, E, indicates the direction of generated voltage rise.The magnitude of the induced voltage is directly proportional tothe instantaneous value of relative velocity; its polarity is such asto oppose the external voltage that was applied to circulate theforce-producing current. For this reason it is sometimes termed“velocity voltage” or “back emf”. Thus through electrodynamic action,the mechanical motion produces an additional electrical voltage drop

Model 113

itlladmin

Highlight

NOTES


3-3

in the armature circuit. This “motional” impedance adds vectorallyto the inherent electrical impedance of the circuit. Therefore, toestablish a given current and corresponding force, the power amplifiermust generally supply more voltage when that force produces a relativevelocity, than would be the case if the armature and body were blockedand remained motionless.

RESONANT LOAD DRIVE REQUIREMENTS

The mechanical input impedance of a drive point on a test structureis defined as the ratio of the applied force to the resulting absolutevelocity at that point. In the vicinity of structural resonances, thisimpedance varies widely in magnitude and associated phase angleas frequency is varied. At resonance, its magnitude is low, and itappears resistive; at frequencies off resonance, its magnitude isrelatively greater, and it appears predominantly reactive (spring-likeor mass-like). When viewed in terms of reflected motional impedancein the armature electrical circuit, the low resistive mechanicalimpedance at resonance reflects as a high electrical resistance;the greater mechanical impedance off resonance reflects a smallerreactive electrical impedance. Thus, for a given force, the shaker’selectrical power requirements are generally greater when driving astructure at resonance than when driving off resonance.

At resonance, a large amount of reactive kinetic and potential energyis contained in a structure, and the driving amplifier and shaker mustaccommodate the resulting velocity and displacement. This reactiveenergy is introduced and stored during the transient build-up of thestructure’s resonant response, and it alternates back and forthbetween kinetic and potential forms twice during each cycle ofvibration. However, to sustain the resonant vibration level after thetransient build-up period, the amplifier and shaker need only supplyto the structure the real mechanical power dissipated by dampingmechanisms within the structure.

MATCHED RESONANT LOAD

If a drive point on a structure in resonance is vibrating with a velocityof 30 in/s, 76.2 cm/s, and a force of 30 lb, 135 N is required to sustainthe vibration level, then the shaker will be delivering approximately50 W to the structure. Since these are the maximum ratings of theModel 113 Shaker, such a load is termed the matched resonant loadfor the shaker. It is resistive, since the load force and velocity are inphase at resonance. From a maximum power transfer standpointtherefore, the shaker should also dissipate approximately 50 W,and the total real power required from the driving amplifier would beapproximately 100 W. The Model 113 Shaker design is optimized inthis manner.

Model 113

NOTES

3-4


MODES OF OPERAMODES OF OPERAMODES OF OPERAMODES OF OPERAMODES OF OPERATIONTIONTIONTIONTION

GENERAL

The Model 113 Shaker is a versatile source of mechanical force forlong stroke, low frequency excitation. With its body mounted on arigid bench or floor, the shaker may be used to support and vibrateloads attached to its armature in a shaker table mode. Auxiliarytables are available for such applications. Refer to the "AccessoryInformation" in Section 1 of this manual. Its primary application,however, is in the excitation of resonant modes of large structures.To accommodate a diversity of resonance or modal test configurations,the shaker has been designed specifically to operate in three primarymodes. These modes are termed: fixed body, free body, and freearmature.

FIXED BODY MODE

In the fixed body mode, the shaker body is fixed and the armature isattached to the test structure. In this mode, force delivered to the teststructure can be measured by inserting a force transducer in the thrustlinkage between the armature and test structure. Alternatively, withthe armature/body suspension bands removed, shaker current canbe used as a direct measure of the generated force. The generatedforce is approximately equal to the force delivered to a resonant teststructure, because the armature mass is typically small comparedto the modal mass of most large test structures. Furthermore, thesmall component of force acting to accelerate the armature is inquadrature with the force delivered to the damping of the resonantstructure.

FREE BODY MODE

The desired force input points on many test structures lie at aconsiderable distance above ground level. For tests on such items,it becomes difficult and expensive to design, build, and use fixedbody mode support structures which remain non-resonant over thefrequency range of interest. For such applications, the free bodymode can be employed to advantage. In this mode the shakerbody is used as the reaction mass by suspending the shaker froman overhead support. Refer to Figure 3-3.

In the free body mode, force delivered to the test structure can bemeasured by inserting a force transducer between the armatureand structure. Also, as before, armature current may be used,but only at frequencies well above the suspension resonancefrequency. It does not provide an accurate measure of the forcedelivered to the armature and load at very low frequencies. However,

Figure 3-3 Model 113 Shakerpendulously suspended by cables

Model 113

NOTES


3-5

NOTES

a very convenient measure of the load force is the axial accelerationof the shaker body. As stated before, the mass of the armature istypically small relative to the modal mass of most large structures,and the force required to accelerate it acts in quadrature with theforce delivered to the structural damping. Neglecting this small forcecomponent, the net force acting on the resonant structure is equalto the net force acting on the shaker body as measured by thebody mass and acceleration, even in the vicinity of and below thebody-armature suspension resonance. This can allow considerablesimplification of the test system instrumentation, in that force canbe measured with an accelerometer system which is essentiallyidentical to that used to measure the structural response.

In the pendulously suspended free body mode, there is no additionalexternal constraint on the body for static weight support. Hence, anaxially oriented accelerometer on the body will produce an accurateforce signal. However, when using the body acceleration method inconjunction with pendulous suspension of the body by means ofvertically oriented support lines, it is necessary that the naturalfrequency of the “pendulum” formed by the support lines and shakerbody be located several octaves below the lowest operating frequency.

Certain test structures that are to be excited by forces acting ina generally horizontal plane, also contain appropriately locatedhorizontal surfaces which can be employed for the “cradle” versionof the free body mode. Examples of these types of surfaces includefloors, roofs, enclosures, tanks, etc. In the cradle mode, force isintroduced to the structure in a direction parallel to the surface onwhich the shaker is mounted.

In most instances the cradle may be simply rested on the mountingsurface, without bolting to it; the peak shaker force is less than itsweight and is transmitted to the structure via the friction between thecradle and mounting surface.

Figure 3-4 shows the Cradle Assembly 0072 accessory unit. Thevertical members pass through openings in the Model 113 coversand attach directly to the armature support points.

FREE ARMATURE MODE

Many large test structures having horizontal surfaces such as floorsrequire vertical force applied to these surfaces to excite resonantmodes of vibration. The Model 113 Shaker may be used in a verticalfree armature mode by resting the rear end frame of the shaker on thehorizontal surface of the test structure. In this mode, the armatureprovides reaction mass and allows the generated force to be appliedthrough the shaker body to the horizontal surface on which the shakeris placed.

Figure 3-4 Armature Cradle Assembly(P/N 0072) with Model 113 Shaker

Model 113

NOTES


3-6

Figure 3-5 Model 113 Shaker equippedwith Reaction Mass Assembly 0112

Figure 3-6 Model 113 Shaker equippedwith Auxiliary Table Assembly 0052

NOTES

With the armature experiencing maximum acceleration, rated force isapplied to test structure through the shaker body. Without additionalmass attached to the armature, the armature stroke limits thegenerated force. Below this frequency, the stroke-limited force isproportional to the square of frequency.

The purpose of the Reaction Mass Assembly 0112 is to lower thestroke-limited crossover frequency. Thereby gaining rated forceoutput to a lower frequency and to lower the armature velocityminimizing the amplifier voltage requirement. Figure 3-5 shows theReaction Mass Assembly 0112, including leveling feet and carryinghandles attached to the Model 113 Shaker.

SHAKER TABLE MODE

Auxiliary table accessory units for both horizontal and vertical useemploy the high load capability of the Model 113 armature guidanceand suspension systems to provide long stroke tables for excitationof test loads. Figure 3-6 shows the Auxiliary Table Assembly 0052attached to the Model 113 Shaker.

Twenty-Five holes with helical inserts in the table provide for fixtureor direct load mounting. In general, it is advisable to employ as manyof the holes as possible when securing a load or fixture to the table,particularly if the load is expected to be resonant in the operatingfrequency range. Also, to equalize the loading on the shaker’sguidance system, it is preferable to locate the center of gravity ofa heavy load directly above the central mounting hole on the table.

The maximum mass load that may be placed on the table is limitedby the allowable forces on the armature guidance bearing systemand bearing shaft deflection. The recommended maximum staticplus peak dynamic vertical load on the table is 50 lbf, 22 kgf.

The mechanical input impedance at the base of a test load that isresonant in the operating frequency range can vary by several ordersof magnitude. At certain frequencies the impedance can be verymuch larger, while at others it can be very much smaller than thenon-resonant values. Thus, the acceleration response of the tableand test item base will exhibit the familiar “peaks” and “notches” asfrequency is varied.

ENVELOPES OF PERFORMANCE

The Model 113 Shaker’s performance is most meaningfully stated interms of the maximum force and velocity that can be obtained whendriving a matched resonant (resistive) load. At very low frequencies,

Model 113

NOTESthe maximum load or structure velocity at the drive point is limitedby the 6.25-in, 158-mm maximum relative stroke between armatureand body. The degree of limitation depends upon whether the shakeris being used in the fixed body mode or in the fixed armature freebody mode. Maximum low frequency force is also limited by strokein the fixed armature and free body mode. Therefore, characteristicperformance is best given in the form of graphs which presentenvelopes of the maximum force and velocity that can be deliveredto a matched resonant structural input impedance as a function offrequency.

Figures 3-7 and 3-8 (See page 3-8) present the typical force andvelocity envelopes for the free body modes, i.e. pendulously suspendedbody, and cradle suspended body. In this mode the shaker body isallowed to move, and this reduces the absolute motion available tothe armature and drive point such that relative motion lies within themaximum relative stroke.


3-7Model 113


Figure 3-7 Force envelope for Model 113 Shaker in the fixed and free body modes

Figure 3-8 Velocity envelope for Model 113 Shaker driving a resonant load in the fixed or free body modes

3-8Model 113

NOTES

44444MaintenanceMaintenanceMaintenanceMaintenanceMaintenance

4-1

REPLACEABLE PARTS

Figure 4-1 is a photograph of a partially disassembled shaker whichillustrates the replaceable parts listed in Section 5. Callout numbersin the figure correspond to item numbers in the list.

The list in Section 5 contains a listing of all replaceable parts andsubassemblies of the Model 113 Shaker. It provides a description ofeach part, its part number, and the total quantity used in the shaker.

ORDERING INFORMATION

All replaceable parts may be obtained from APS Dynamics. Whenordering replacement parts, give the full description and part number,the quantity desired, and the model and serial number of the shaker.

LISTS OF SERVICE TOOLS AND MATERIALS

In order to perform preventative maintenance and part replacementprocedures, the following service tools and materials are recommended:

1. 3/16-inch hex key wrench (for 1/4-inch cap screws)

2. Torque wrench with 3/16 hex bit, long (for critical tightening ofindicated cap screws).

INSPECTION AND PREVENTATIVE MAINTENANCE

The Model 113 Shaker does not require any periodic adjustments;however, certain inspection and preventative maintenance operationswill insure trouble-free performance. Refer to the above paragraph fora list of service tools and materials.

Every 30 days or before any period of extended operation clean thebearing shafts with a lint-free wipe, removing any accumulated debris.Every 90 days or before any period of extended operation, check the

Model 113

NOTES

4-2

Section 4: Maintenance

magnet structure air gap for ferrous particles and clean if required.Follow the procedure for cleaning and parts replacement below.

CLEANING AND PARTS REPLACEMENT PROCEDURES

In order to internally clean the Model 113 Shaker or to replace theArmature, Guidance Bearings or Bearing Shafts, proceed as follows:

DISASSEMBLY

1. Place the unit on a bench with the thrust axis in a verticalorientation with armature load attachment bridge upward.

2. Remove the four corner covers and armature suspension bands,allowing the armature to rest on the rear rubber stops.

3. For cleaning and installation of Bearing Housing Clamps, loosenthe four 3/8-24 x 1-1/2 Cap Screws in the forward end frameabout 1/4 inch, 6 mm. With care to prevent the side coversand slide guides from falling, raise the forward end frame.

4. Lift off the side covers and suspension slide guides. Refer toFigure 4-1.

5. For cleaning and inspection of the armature, no other partsneed be removed. Wipe all aluminum parts with a damp clothto remove dirt. Wipe the bearing shafts with a lint-free wipe.Magnetic particles lodged in the magnet assembly air gap maybe removed with masking tape. Proceed to Step 6 in the"REASSEMBLY" section.

6. To remove the armature, the forward half of the body structurecontaining two magnet assemblies must be removed asfollows.

7. Remove the end frame screws (Step 3 above) and end frame,and the two 1/4-28 x 3/4 Socket Head Cap Screws located inthe pockets of two of the magnet assemblies.

* CAUTION *

DO NOT ATTEMPT TO PLACE THE UNIT IN A HORIZONTALPOSITION FOLLOWING REMOVAL OF THE END FRAME.DAMAGE TO THE ARMATURE COIL MAY RESULT.

Model 113

NOTES


8

19

11

7

9

6

521

1

4

2

13, 14

16 15

10

2012

3

18

17

17

Figure 4-1 View of partially disassembled shaker showing parts listed in Section 5

8. Remove the central 1/4-28 x 2-1/4 Socket Head Cap Screwin the deep counterbore which joins the two forward magnetassemblies.

* CAUTION *

DO NOT REMOVE ANY OF THE OUTER CAP SCREWSLOCATED IN THE MAGNET ASSEMBLIES. DISASSEMBLYOF A MAGNET ASSEMBLY WILL CAUSE LOSS OF FLUXDENSITY AND REQUIRE RE-MAGNETIZATION FOR PROPEROPERATION.

9. Before commencing this step, note that each magnet assemblyweighs 16 lb (7 kg); exercise care in lifting and handling. In turn,remove the two forward magnet assemblies, lifting each sufficientlyto clear the locating pins joining the forward and rear body halves.

10. Lift and remove the armature assembly, including the shafts, fromthe rear pair of magnet assemblies. Do not remove shafts fromthe armature.

4-3

NOTES

Model 113

NOTES


REASSEMBLY

1. Insert the armature containing the bearing shafts into the rear halfof the body structure.

2. Replace each of the two forward magnet assemblies onto therear half of the body, exercising care to align the locating pins

and holes.

3. Replace the two 1/4-28 x 3/4 Cap Screws in the pockets of theupper and lower magnet assemblies and tighten to 175 in-lb,

19 N-m.

4. Replace the 1/4-28 x 2-1/4 Cap Screw in the counterbore andtighten to 175 in-lb, 19 N-m.

5. Replace the forward end frame, engaging the forward magnetassembly shoulders and bearing shafts.

6. Replace the slide guides and side covers. Be certain all piecesare in their proper location before replacing the End Frame Cap

Screws.

7. Install four 1/4-28 x 1-1/4 End Frame Cap Screws and graduallytighten to 130 in-lb, 14 N-m.

8. Replace the suspension slides, suspension bands, and corner covers.

9. Return the shaker to the horizontal position, resting on its feet,and check for free travel of the armature. The unit is now ready

for operation.

ACCESS0RACCESS0RACCESS0RACCESS0RACCESS0RY INF0RMAY INF0RMAY INF0RMAY INF0RMAY INF0RMATI0NTI0NTI0NTI0NTI0N

The following information applies to the Auxiliary Tables, 0052 and0077, Cradle Assembly 0072, and Reaction Mass Assembly 0112.

The Installation Drawings in Section 5, contain lists of all replaceableparts for these accessories.

INSTALLATION OF BEARING HOUSING CLAMPS

If the Shaker was purchased without accessories, it is necessaryto install Bearing Housing Clamps before installing the followingaccessories.

Model 113 4-4

NOTES


To install the four Bearing Housing Clamps (P/N 8238) on the shakerarmature, it is necessary to remove the side covers and corner covers.Proceed as follows:

For Auxiliary Tables 0052, 0077, and 0078:

1. With the shaker axis vertical, complete Steps 1 through 4 for thebasic shaker. Refer to "DISASSEMBLY" on page 4-2 of this

manual.

2. Place a Bearing Housing Clamp (Item 3, Dwg. 0052M) over thetop side of one of the lower (rear) Bearing Housings, open sideoutward, oriented such that the two tapped holes in the side ofthe clamp face downward and in alignment with the holes inthe Bearing Housing Block. Install two 10-24 Torx Button HeadScrews from the underside with the Torx wrench provided.Finger tighten only.

3. Then, with tapped holes facing upward, install a second BearingHousing Clamp against the underside of the upper (forward)Bearing Housing on the same side.

4. Repeat Steps 2 and 3 for the other side of the shaker.

5. Secure the upper end frame without replacing the side coversor corner covers. Seat the four upper End Frame Cap Screws.


7. Place the two Table Spacers, (Item 2), on top of the clamps.Place the Load Mounting Plate (Item 1) in position on thespacers. Insert the four Socket Head Cap Screws (Item 5) downthrough the table and spacers to engage the threads. Do nottighten.

8. Adjust the vertical positions of the four clamps so that there isno rocking of the table plate on the spacer bars, and tighten theeight screws in the clamps.

9. Temporarily remove the table and spacers.

10. Return the shaker to the vertical position and loosen the upper(forward) End Frame Cap Screws and End Frame.

11. Complete Steps 5 through 9 for the basic shaker. Refer to"REASSEMBLY" on page 4-4 of this manual.

4-5Model 113

NOTES


For the Cradle Assembly 0072:

1. With the shaker axis vertical, complete Steps 1 through 4 for thebasic shaker. Refer to "DISASSEMBLY" on page 4-2 of thismanual.

2. Place a Bearing Housing Clamp (Item 3, Dwg. 0072M) over thetop side of one of the lower (rear) Bearing Housings, open sideoutward, oriented such that the two tapped holes in the side ofthe clamp face downward and in alignment with the holes in theBearing Housing Block. Install two 10-24 Torx Button HeadScrews from the underside with the Torx wrench provided.Finger tighten only.





7. Place the Cradle Assembly, (Item 1, Dwg. 0072M), inverted ontop of the clamps. Insert the four Socket Head Cap Screws(Item 2) down through the cradle to engage the threads. Do nottighten.

8. Adjust the vertical positions of the four clamps so that there isno rocking of the Cradle Assembly, and tighten the eight screwsin the clamps.

9. Temporarily remove the Cradle Assembly.



For the Reaction Mass 0112:

1. With the shaker axis vertical, complete Steps 1 through 4 for thebasic shaker. Refer to "DISASSEMBLY" on page 4-2 of thismanual.

4-6Model 113

NOTES2. Place a Bearing Housing Clamp (Item 2, Dwg. 0112M) over thetop side of one of the lower (rear) Bearing Housings, open sideoutward, oriented such that the two tapped holes in the side ofthe clamp face downward and in alignment with the holes in theBearing Housing Block. Install two 10-24 Torx Button HeadScrews from the underside with the Torx wrench provided.Finger tighten only.





7. Place the two Reaction Mass Spacers (Items 4 & 5, right andleft hand) on top of the clamps. Place a Reaction Mass Block(Item 6) in position on the spacers. Insert the four Socket HeadCap Screws (Item 8) down through the block and spacers toengage the threads. Do not tighten.

8. Adjust the vertical positions of the four clamps so that there isno rocking of the Reaction Mass Block on the spacer bars, andtighten the eight screws in the clamps.

9. Temporarily remove the Reaction Mass Block and Spacers.




4-7Model 113

NOTES

Model 113 4-8


REPAIR/REPLACEMENT ACTION

If a problem occurs in the operation of the shaker or partrepair/replacement action becomes necessary, contact:

APS Dynamics, Inc.5731 Palmer Way, Suite ACarlsbad, California 92008

Phone: (760) 438-4848FAX: (760) 438-8845E-mail: [email protected]

Be prepared to give the serial number of the unit, the part numbersinvolved, and a complete description of the nature of the problem.

Refer to SECTION 5, SUPPORT DOCUMENTATION.

NOTESThis section contains the following Support Documentation:

1. Calibration Information

2. Performance Graphs

3. Outline and Installation Drawing C-0113M

4. Model 113/Amplifier Interconnect C-0113S

5. Replaceable Parts List (Model 113 ELECTRO-SEIS SHAKER)

6. Optional Accessories

7. Applicable Modification/Revision Information

55555SupporSupporSupporSupporSupport Documentationt Documentationt Documentationt Documentationt Documentation

5-1Model 113

MODEL 113 SHAKER - ITLL · CHARACTERISTICS AND PERFORMANCE ... MATCHED RESONANT LOAD . . . . . . ....

Documents

Transcript of MODEL 113 SHAKER - ITLL · CHARACTERISTICS AND PERFORMANCE ... MATCHED RESONANT LOAD . . . . . . ....