be certain.
m
Series 242 Actuators
Product Information
Model 242.00
Model 242.01
Model 242.02
Model 242.03
011-562-001 J
Copyright information © 1985, 1987, 1989–1991, 1993, 2000, 2008 MTS Systems Corporation. All
rights reserved.
Trademark information MTS is a registered trademark of MTS Systems Corporation within the United
States. This trademark may be protected in other countries.
DTE is a registered trademark of Mobil Corporation.
Tellus is a registered trademark of Shell Oil Corporation.
Molykote is a registered trademark of Dow Chemical Corporation.
Publication information
Manual Part Number Publication Date
115620-00 A
115620-01 A
115620-01 B
115620-01 C
115620-01 D
115620-01 E
115620-01 F
011-562-001 G
011-562-001 H
011-562-001 J
September 1985
May 1987
December 1987
April 1989
April 1990
March 1991
October 1993
April 1999
December 2000
March 2008
2
Manual Template 4.3
Contents
Technical Support 5
How to Get Technical Support 5
Before You Contact MTS 5
If You Contact MTS by Phone 6
Problem Submittal Form in MTS Manuals 7
Preface 9
Before You Begin 9
Conventions 10
Documentation Conventions 10
Introduction 13
Series 242 Actuator Component Identification 15
242 Actuator Functional Description 17
242 Actuator Mounting 17
242 Actuator/Servovalve Interface 17
242 Actuator Operation 17
242 Actuator LVDT Operation 18
242 Actuator Force Specifications 19
242 Actuator Dimensions 19
Safety Information 21
Hazard Placard Placement 21
Installation 25
Load Unit Configuration 25
Installing a Fixture to the Actuator 26
Mounting Swivels 28
Connecting the LVDT Cable 29
Connecting Hydraulics-242 Actuator 30
Series 242 Actuator Product Information
3
Operation 31
242 Actuator Operating Considerations 32
Sideload Calculation Procedure 33
Maintenance 37
242 Actuator Maintenance Schedule 37
4
Series 242 Actuator Product Information
Technical Support
How to Get Technical Support
How to Get Technical Support
Start with your
manuals
Technical support
methods
MTS web site
www.mts.com
E-mail techsupport@mts.com
Telephone MTS Call Center 800-328-2255
Fax 952-937-4515
The manuals supplied by MTS provide most of the information you need to use
and maintain your equipment. If your equipment includes MTS software, look
for online help and README files that contain additional product information.
If you cannot find answers to your technical questions from these sources, you
can use the internet, e-mail, telephone, or fax to contact MTS for assistance.
MTS provides a full range of support services after your system is installed. If
you have any questions about a system or product, contact MTS in one of the
following ways.
The MTS web site gives you access to our technical support staff by means of a
Technical Support link:
www.mts.com > Contact Us > Service & Technical Support
Weekdays 7:00 A.M. to 5:00 P.M., Central Time
Please include “Technical Support” in the subject line.
Before You Contact MTS
MTS can help you more efficiently if you have the following information
available when you contact us for support.
Know your site
number and system
number
Series 242 Actuator Product Information Technical Support
The site number contains your company number and identifies your equipment
type (material testing, simulation, and so forth). The number is usually written on
a label on your MTS equipment before the system leaves MTS. If you do not
have or do not know your MTS site number, contact your MTS sales engineer.
Example site number: 571167
When you have more than one MTS system, the system job number identifies
which system you are calling about. You can find your job number in the papers
sent to you when you ordered your system.
Example system number: US1.42460
5
If You Contact MTS by Phone
Know information from
prior technical
If you have contacted MTS about this problem before, we can recall your file.
You will need to tell us the:
assistance
• MTS notification number
• Name of the person who helped you
Identify the problem Describe the problem you are experiencing and know the answers to the
following questions:
• How long and how often has the problem been occurring?
• Can you reproduce the problem?
• Were any hardware or software changes made to the system before the
problem started?
• What are the model numbers of the suspect equipment?
• What model controller are you using (if applicable)?
• What test configuration are you using?
Know relevant
computer information
If you are experiencing a computer problem, have the following information
available:
• Manufacturer’s name and model number
• Operating software type and service patch information
• Amount of system memory
• Amount of free space on the hard drive in which the application resides
• Current status of hard-drive fragmentation
• Connection status to a corporate network
Know relevant
For software application problems, have the following information available:
software information
• The software application’s name, version number, build number, and if
available, software patch number. This information is displayed briefly
when you launch the application, and can typically be found in the “About”
selection in the “Help” menu.
• It is also helpful if the names of other non-MTS applications that are
running on your computer, such as anti-virus software, screen savers,
keyboard enhancers, print spoolers, and so forth are known and available.
If You Contact MTS by Phone
Your call will be registered by a Call Center agent if you are calling within the
United States or Canada. Before connecting you with a technical support
specialist, the agent will ask you for your site number, name, company, company
address, and the phone number where you can normally be reached.
Technical Support
6
Series 242 Actuator Product Information
Problem Submittal Form in MTS Manuals
If you are calling about an issue that has already been assigned a notification
number, please provide that number. You will be assigned a unique notification
number about any new issue.
Identify system type To assist the Call Center agent with connecting you to the most qualified
technical support specialist available, identify your system as one of the
following types:
• Electromechanical materials test system
• Hydromechanical materials test system
• Vehicle test system
• Vehicle component test system
• Aero test system
Be prepared to
Prepare yourself for troubleshooting while on the phone:
troubleshoot
• Call from a telephone when you are close to the system so that you can try
implementing suggestions made over the phone.
• Have the original operating and application software media available.
• If you are not familiar with all aspects of the equipment operation, have an
experienced user nearby to assist you.
Write down relevant
Prepare yourself in case we need to call you back:
information
• Remember to ask for the notification number.
• Record the name of the person who helped you.
• Write down any specific instructions to be followed, such as data recording
or performance monitoring.
After you call MTS logs and tracks all calls to ensure that you receive assistance and that action
is taken regarding your problem or request. If you have questions about the status
of your problem or have additional information to report, please contact MTS
again and provide your original notification number.
Problem Submittal Form in MTS Manuals
Use the Problem Submittal Form to communicate problems you are experiencing
with your MTS software, hardware, manuals, or service which have not been
resolved to your satisfaction through the technical support process. This form
includes check boxes that allow you to indicate the urgency of your problem and
your expectation of an acceptable response time. We guarantee a timely
response—your feedback is important to us.
The Problem Submittal Form can be accessed:
• In the back of many MTS manuals (postage paid form to be mailed to MTS)
• www.mts.com > Contact Us > Problem Submittal Form (electronic form to
be e-mailed to MTS)
Series 242 Actuator Product Information Technical Support
7
Problem Submittal Form in MTS Manuals
Technical Support
8
Series 242 Actuator Product Information
Before You Begin
Preface
Before You Begin
Safety first! Before you attempt to use your MTS product or system, read and understand the
Safety manual and any other safety information provided with your system.
Improper installation, operation, or maintenance of MTS equipment in your test
facility can result in hazardous conditions that can cause severe personal injury or
death and damage to your equipment and specimen. Again, read and understand
the safety information provided with your system before you continue. It is very
important that you remain aware of hazards that apply to your system.
Other MTS manuals In addition to this manual, you may receive additional MTS manuals in paper or
electronic form.
If you have purchased a test system, it may include an MTS System
Documentation CD. This CD contains an electronic copy of the MTS manuals
that pertain to your test system, including hydraulic and mechanical component
manuals, assembly drawings and parts lists, and operation and preventive
maintenance manuals. Controller and application software manuals are typically
included on the software CD distribution disc(s).
Series 242 Actuator Product Information Preface
9
Conventions
DANGER
WARNING
CAUTION
Conventions
Documentation Conventions
The following paragraphs describe some of the conventions that are used in your
MTS manuals.
Hazard conventions As necessary, hazard notices may be embedded in this manual. These notices
contain safety information that is specific to the task to be performed. Hazard
notices immediately precede the step or procedure that may lead to an associated
hazard. Read all hazard notices carefully and follow the directions that are given.
Three different levels of hazard notices may appear in your manuals. Following
are examples of all three levels.
Note For general safety information, see the safety information provided with
your system.
Danger notices indicate the presence of a hazard with a high level of risk which,
if ignored, will result in death, severe personal injury, or substantial property
damage.
Warning notices indicate the presence of a hazard with a medium level of risk
which, if ignored, can result in death, severe personal injury, or substantial
property damage.
Caution notices indicate the presence of a hazard with a low level of risk which,
if ignored, could cause moderate or minor personal injury, equipment damage, or
endanger test integrity.
Notes Notes provide additional information about operating your system or highlight
easily overlooked items. For example:
Note Resources that are put back on the hardware lists show up at the end of
the list.
Special terms The first occurrence of special terms is shown in italics.
Illustrations Illustrations appear in this manual to clarify text. It is important for you to be
Electronic manual
conventions
Preface
10
aware that these illustrations are examples only and do not necessarily represent
your actual system configuration, test application, or software.
This manual is available as an electronic document in the Portable Document
File (PDF) format. It can be viewed on any computer that has Adobe Acrobat
Reader installed.
Series 242 Actuator Product Information
Documentation Conventions
Hypertext links The electronic document has many hypertext links displayed in a blue font. All
blue words in the body text, along with all contents entries and index page
numbers, are hypertext links. When you click a hypertext link, the application
jumps to the corresponding topic.
Series 242 Actuator Product Information Preface
11
Documentation Conventions
12
Preface
Series 242 Actuator Product Information
Introduction
m
Contents Series 242 Actuator Component Identification 15
The Series 242 Actuator is a linear actuator. A linear actuator is a hydraulically
powered device that provides displacement of (or force into) a specimen or
structure for testing.
242 Actuator Functional Description 17
242 Actuator Mounting 17
242 Actuator/Servovalve Interface 17
242 Actuator Operation 17
242 Actuator LVDT Operation 18
242 Actuator Force Specifications 19
242 Actuator Dimensions 19
Features The Series 242 Actuator is a low force, double-ended, fatigue-rated actuator with
very low friction operation. It has a high sideload tolerance and includes an
integral servovalve mounting manifold. The following are typical applications:
Series 242 Actuator Product Information Introduction
13
• Low force structural fatigue
• High velocity, short stroke component tests
• Low friction, low signal distortion vibration testing
• Structural resonance searching and modal analysis
Actuator ID A plate on the actuator (typically located on the front end cap opposite the drain
line) contains the following information:
• Model number
• Serial number
• Force rating
• Area
• Stroke specifications
This information is required when contacting MTS Systems Corporation
regarding the actuator.
What you need to
know
This manual assumes that you know how to use your system controller. See the
appropriate manual for information about performing any controller-related step
in this manual’s procedures. You are expected to know how to:
• Turn hydraulic pressure on and off.
• Select a control mode.
• Manually adjust the actuator position.
• Install a specimen.
• Defining a simple test.
• Running a test.
14
Introduction
Series 242 Actuator Product Information
Series 242 Actuator Component Identification
Piston Rod End
Pedestal Base
Retraction Port
Extension Port
Piston Rod
Drainback Port
Piston Rod Seal
LVDT Assembly
Piston Rod Seal
Cushion
Cushion
Piston Rod Bearings
LVDT Connector
Viscous Seal
Spacer Tube
Series 242 Actuator Component Identification
Series 242 Linear Actuator
Series 242 Actuator Product Information Introduction
15
Series 242 Actuator Component Identification
Series 242 Actuator Component Descriptions
C
OMPONENT DESCRIPTION
Piston rod
Piston rod seal
Piston rod
bearings
Extension port/
Retraction port
Spacer tube
The actuator is equipped with a double-ended piston rod. The double-ended piston has
equal areas on both sides for balanced performance. It is machined from a single piece
of heat-treated alloy steel, hard-chrome plated, and precision ground to a fine finish for
reliable operation. The piston rod is hollow to allow for installation and accurate
alignment of a displacement transducer.
One low-pressure seal assembly in each end cap contains a seal to guide excess fluid to
the drainback port and a wiper to prevent external contamination from entering the
actuator.
These high-capacity nonmetallic bearings are bonded directly to the end caps. The
nonmetallic bearings are standard due to their high sideload tolerance and resistance to
failure from galling and seizure.
The close tolerance fit between the piston rod and bearing surface creates a low leakage
viscous seal. A small amount of hydraulic fluid is allowed to flow across the bearing for
lubrication, and is then ported back to the system hydraulic reservoir.
Ports allow fluid flow up to 57 L/m (15 gpm) for high-velocity or high-frequency
operation. Internal passages are designed to minimize fluid flow restrictions.
High-pressure hydraulic fluid is ported into the cylinder through the retraction port or
the extension port. The flow is regulated by a servovalve. As hydraulic pressure is
applied to one port, the other port is opened to a return line causing the actuator to
extend or to retract.
Extends the pedestal base to accommodate different actuator displacements.
LVDT connector
Pedestal base
LVDT assembly
Drainback port
Cushions
Viscous piston
seal
Piston rod end
Connects the LVDT to the system controller. The controller provides an excitation
signal and the LVDT returns a feedback signal. The feedback signal indicates the
actuator displacement to the controller.
The pedestal base allows the actuator to be rigidly mounted to a reaction mass, or
permits attachment of a swivel mounting accessory. The base is also used to mount the
LVDT connector receptacle and LVDT coil locking collar.
The internally mounted LVDT indicates the actuator piston rod displacement. The
LVDT consists of a coil, core, and core extension. The core is secured to the piston rod
by a core mount. The core extension is secured to the inside of the hollow piston rod by
a locking setscrew, and can be adjusted to establish a zero reference point for the
actuator.
The drainback port allows fluid that manages to leak past the seals to be routed out of
the actuator. This prevents pressure pockets from interfering with the actuator
performance.
Hydraulic cushions protect the end caps during full-stroke, high-velocity operation.
The close tolerance fit between the piston and cylinder provides an effective viscous
seal. Grooves on the piston ensure lubrication of the piston surface during short-stroke,
sideloaded tests.
The piston rod end has a center position internal thread and a circular pattern of
threaded holes for mounting load cells, swivels, and interface fixtures.
16
Introduction
Series 242 Actuator Product Information
242 Actuator Functional Description
A linear actuator is used to push on a specimen to cause it to crush or compress
(compression testing), or to pull it apart causing it to stretch (tensile testing).
A linear actuator consists of a cylinder that contains a piston and a manifold to
mount a servovalve. An integral part of the actuator is a LVDT (linear variable
differential transformer) which measures the displacement of the actuator
(extension or retraction) and sends the information to the system controller. The
LVDT is mounted inside the actuator. It can be replaced with other specialized
measuring devices.
The double-acting, double-ended actuator operates under precision servovalve
control in MTS closed-loop servohydraulic systems. The actuator is a
hydraulically powered piston that can extend or retract (double-acting). It can
also provide equal power in tension and compression (double-ended). The
actuator includes a closed-housing linear variable differential transformer
(LVDT) which measures the displacement of the actuator.
242 Actuator Mounting
242 Actuator Functional Description
The actuator can be mounted to a wide variety of fixtures and assemblies.
• Component test systems usually have one end of the actuator connected to a
custom test frame base and the other end connected to the test specimen.
Either end of the actuator may use mounting fixtures (such as swivels) to
attach it to the specimen or base.
• Material test systems usually mount the actuator in a load unit assembly.
The actuator can be mounted below the base plate or above the crosshead.
The end of the actuator uses fixtures (such as grips) to attach the test
specimen to it.
242 Actuator/Servovalve Interface
The actuator has a built-in servovalve manifold. The manifold allows a Series
252 Servovalve to be mounted directly to the actuator. It can accept a wide
variety of servovlaves, with flow ratings up to a maximum of 57 L/min (15 gpm).
242 Actuator Operation
Actuator piston rod movement is accomplished by supplying high- pressure
hydraulic fluid to one side of the actuator piston and opening the other side to a
return line. High-pressure hydraulic fluid is ported into the cylinder through the
retraction port or the extension port. The differential pressure across the piston
forces the piston rod to move. The amount of hydraulic fluid and the speed and
direction of piston rod movement is controlled by a servovalve.
If the piston rod contacts some external reaction point, then a force is applied to
that point equal to the effective piston area times the actuating pressure. The
main criteria for selecting an actuator are the force and stroke (displacement)
required for the job.
Series 242 Actuator Product Information Introduction
17
242 Actuator LVDT Operation
Locking
Screw
Retainer
Core
LVDT Core
Extension
Hollow
Piston Rod
LVDT Coil
Locking
Collar
Pedestal
Base
LVDT
Connector
242 Actuator LVDT Operation
The internally mounted LVDT provides an indication of the actuator piston rod
displacement.
The LVDT is an electromechanical device that provides an output voltage which
is proportional to the displacement of a moveable core extension. The core
extension is mounted inside the hollow piston rod and moves as the piston rod
moves. The LVDT coil is secured to the pedestal base by a locking collar. The
core extension is positioned in the LVDT coil to provide a zero reference point,
and is locked in place with a locking setscrew.
As the piston rod moves during operation, the output voltage from the LVDT
indicates how far the piston rod has moved from the zero reference point.
18
Introduction
Series 242 Actuator Product Information
242 Actuator Force Specifications
Actuator Force Specifications
M
ODEL*
ORCE RATING
F
†
242 Actuator Force Specifications
PISTON AREA ROD DIAMETER
K
NKIP
242.00 2.7 0.6 136 0.21 28.6 1.12
242.01 4.5 1.0 271 0.42 28.6 1.12
242.02 10.0 2.2 594 0.92 28.6 1.12
242.03 15.0 3.3 760 1.18 28.6 1.12
* Each model has a standard stroke length of 101.6 and 152.4 mm (4
and 6 in). This value is total stroke minus the total cushion length, 12.7
mm (0.50 in). Optional stroke length in 25.4 and 50.8 mm (1.00 and
2.00 in).
† Nominal force with 17.2 MPa (2500 psi) pressure drop across the
piston. Actual force may be up to 20% higher depending on servovalve
size and test conditions.
242 Actuator Dimensions
D
YNAMIC STROKE
(ALL MODELS)
MM
2
2
IN
MM IN
Actuator Dimensions
IMENSIONS*
D
ABC
MM IN MM IN MM IN MM IN
25.4 1 40.64 1.6 215.9 8.5 322.07 12.68
50.8 2 66.04 1.6 215.9 8.5 347.47 13.68
101.6 4 116.84 4.6 279.4 11.0 461.77 18.18
152.4 6 167.64 6.6 660.2 13.0 563.37 22.18
* The dimensions listed are shown in the following figure.
Series 242 Actuator Product Information Introduction
19
242 Actuator Dimensions
76.2 mm
(3.0 in) sq.
1/2 - 20 UNF-2B x 1.0 in
(25.4 mm)
1/2 - 20 UNF-2B x 3.62 in
(91.95 mm)
6.35 mm
(0.25 in)
19.05 mm
(0.75 in) min.
31.75 mm
(1.25 in)
31.75 mm
(1.25 in)
2.54 mm
(0.10 in)
A
(3.5 in) sq.
46.00 mm
(1.81 in)
88.9 mm
(3.5 in) sq.
B
C
31.75 mm
(1.25 in)
6.35 mm
(0.25 in)
4 holes, 5/16 -18 UNC x 0.5 in
(12.7 mm) deep, equally spaced
on a 2.5 in. (63.5 mm) diameter
deep
Cushion
Dynamic
Stroke
Cushion
minimum
4 holes, 7.11 mm (0.28
in) diameter through
maximum
20
Introduction
Series 242 Actuator Product Information
Safety Information
4
(27.6 MPa).
2
4
Hazard Placard Placement
Hazard placards contain specific safety information and are affixed directly to the
system so they are plainly visible.
Each placard describes a system-related hazard. When possible, international
symbols (icons) are used to graphically indicate the type of hazard and the
placard label indicates its severity. In some instances, the placard may contain
text that describes the hazard, the potential result if the hazard is ignored, and
general instructions about how to avoid the hazard.
The following labels and icons may be found on an actuator.
L
ABEL DESCRIPTION
Hazard Placard Placement
Part #46-140-101
Part #46-140-201
WA RN I NG
Hydraulic pressure above 3000 psi can rupture
components. Can cause severe personal injury
or damage to equipment.
Do not exceed 3000 psi (20.7 MPa).
Read instructions before operating or
servicing.
WA RN I NG
Hydraulic pressure above 4000 psi can rupture
components. Can cause severe personal injury
or damage to equipment.
Do not exceed 4000 psi (27.6 MPa).
Read instructions before operating or
servicing.
Series 242 Actuator Product Information Safety Information
21
Hazard Placard Placement
L
ABEL DESCRIPTION
CAUTION
High drain pressure can cause rod seal damage
and hydraulic oil leakage.
Remove drain line shipping cap and connect
drain hose before operating.
Part # 045-283-501
Attached mass warning.
Do not exceed maximum attached mass.
Part # 057-230-041
Part # 700-004-198
Hydraulic Actuator ID tag lists the following:
• Model number
• Serial number
• Assembly number/Rev
• Force
• Effective Area
• Static Stroke
• Dynamic Stroke
• Hydrostatic/Non-Hydrostatic
• Maximum attached mass
Safety Information
22
Series 242 Actuator Product Information
L
ABEL DESCRIPTION
Hydraulic Actuator ID tag lists the following:
• Model number
• Serial number
• Assembly number/Rev
• Force
• Effective Area
• Static Stroke
Hazard Placard Placement
Part # 037-588-801
Part # 57-237-711
Part # 57-238-5xx
• Dynamic Stroke
• Hydrostatic/Non-Hydrostatic
Pressure icon.
Can be used alone, or in conjunction with
pressure rating label (Part # 057-237-711).
Pressure rating. Actual rating listed on this
label will vary. This label is used in
conjunction with the Pressure icon (Part #
057-238-503). Located directly beneath
pressure icon on actuator.
Series 242 Actuator Product Information Safety Information
23
Hazard Placard Placement
Safety Information
24
Series 242 Actuator Product Information
Installation
Contents Load Unit Configuration 25
Load Unit Configuration
Installing the Series 242 Actuator depends on the testing application.
• For materials or component testing, the actuator is typically installed in a
load frame configuration or test fixture. For more information, see the
following load unit configuration topic.
• For structural or vibration testing, the actuator is typically secured to a
reaction mass using a swivel or pedestal base. This section describes how to
install the actuator for this type of configuration.
Installing a Fixture to the Actuator 26
Mounting Swivels 28
Connecting the LVDT Cable 29
Connecting Hydraulics-242 Actuator 30
Load Unit Configuration
When a Series 242 Actuator is mounted in a load frame configuration, the
actuator is installed on the crosshead of a tabletop load frame at the factory.
Actuator options such as servovalves and manifolds are also installed on the
actuator at the factory. The only installation required is to connect system
hydraulic hoses and system cables.
Series 242 Actuator Product Information Installation
25
Installing a Fixture to the Actuator
1/2-20 UNF-2B x 1.5 in.
(38.1 mm)
4 holes, 5/16-18 UNC x 0.5 in
(12.7mm) deep, equally spaced on a
2.5 in (63.5 mm) diameter
Front
End Cap
See the system assembly drawing, system functional drawing, and console
assembly drawing (typically located in a System Reference manual supplied with
your system documentation) for information about hydraulic and electrical
connections.
Note Actuators mounted in a load unit should not be removed from the load
unit. Alignment should not be performed in the field.
Servovalves A Series 252 Servovalve is typically mounted directly to the actuator. See the
Series 252 Servovalve Product Information manual (MTS part number 011-182-
906) for servovalve installation information.
Installing a Fixture to the Actuator
The actuator is equipped with an upper end cap and a pedestal base which has
from two to eight threaded mounting holes. Fixtures can be mounted to the
actuator piston rod, the upper end cap, or the pedestal base.
Mounting to the piston
rod or end cap
The front end cap of the actuator contains four threaded holes which may be used
for mounting the actuator to a load frame or other fixture. The following figure
shows the mounting hole specifications. Tighten the mounting bolts to 17.6 N·m
(13 lbf·ft).
Piston Rod and Front End Cap Mounting Holes
The piston rod of the actuator also contains a center position threaded hole. This
mounting hole is typically used to attach a swivel mounting accessory or a
specimen supporting fixture (shaker head or vibration table) to the actuator.
26
Mounting to the
pedestal base
Installation
The pedestal base has four unthreaded mounting holes (one in each corner).
These mounting holes may be used to bolt the actuator directly to a reaction mass
or other fixture. Do not tighten the mounting bolts to more than 15 N·m (11
lbf·ft). The pedestal base also contains a center position threaded hole which may
be used to attach a swivel mounting accessory.
Series 242 Actuator Product Information
Installing a Fixture to the Actuator
1/2-20 UNF-2B x 1.0 in
(25.4 mm)
4 holes, 0.28 in (7.11 mm)
Pedestal Base
diameter through
deep
Pedestal Base Mounting Holes
The previous figure shows the thread specifications. To install a swivel mounting
accessory, thread the swivel into the mounting hole and tighten the hex nut to 108
N·m (80 lbf·ft).
Series 242 Actuator Product Information Installation
27
Mounting Swivels
Piston Rod Swivel
Force Transducer
Actuator Assembly
Pedestal Base Swivel
Mounting Swivels
Swivels can be mounted to the piston rod and the pedestal base. A Series 249
Swivel can be used with the Series 242 Actuator. See the Series 249 Swivel
Product Information manual for additional information.
The swivel is mounted with four M10 x 1.50 (3/8-16) socket head bolts. Before
mounting the swivel, apply Molykote G grease, or equivalent, to the threads and
under the head of each mounting bolt. Tighten each bolt until it is firmly seated
against the swivel. Then, using the pattern shown in the figure to the right,
tighten the bolts to one-half of the recommended torque value. Continue using
this pattern to tighten the bolts to 53 N·m (34 lbf·ft)
28
Installation
Series 242 Actuator Product Information
Connecting the LVDT Cable
1
2
3
4
E
B
A
C
D
+EX
-EX
+FB
-FB
Yel lo w
Blue
Black
Red
Exitation
Ground
Output
A
C
D
E
F
B
The following figure shows the electrical connections of the LVDT. See your
controller manual for cable specifications or cable assembly numbers.
Connecting the LVDT Cable
.
LVDT Cable Connection
Series 242 Actuator Product Information Installation
29
Connecting Hydraulics-242 Actuator
Servovalve
Hydraulic
Ports
Servovalve
Mounting Holes
(each corner)
Return Port
Drain Port
Pressure Port
CAUTION
Connecting Hydraulics-242 Actuator
Hydraulic connections to the Series 242 Actuator are made through a manifold
that connects the ports of each end cap. The manifold has hydraulic pressure,
return, and drain ports stamped P, R, and D, respectively. These ports are
connected to matching ports located on a hydraulic service manifold (HSM).
Note When the Series 242 Actuator is installed in a load unit, the hydraulic
connections are made through a manifold.
Do not use inferior quality hydraulic fluids.
Using fluids other than those specified by MTS may cause component or
system failure or both.
Use Mobil DTE 25 or Shell Tellus 46 hydraulic fluid only.
30
Installation
Series 242 Actuator Product Information
Operation
Contents 242 Actuator Operating Considerations 32
This section describes the operation of the Series 242 Actuator and the internally
mounted LVDT.
Sideload Calculation Procedure 33
Series 242 Actuator Product Information Operation
31
242 Actuator Operating Considerations
B
F
P
C
Sideload Forces
242 Actuator Operating Considerations
Piston rod banding Piston rod banding can occur if the actuator is operated for a long period of time
at a moderate to high frequency, with short stroke displacement and loads of 25%
or more of the actuator capacity. Piston rod banding is the aggravated erosion of
the piston rod chrome plating in a band slightly wider than the width of the seal
encircling the circumference of the piston rod.
If the actuator is being used for this type of testing, the starting position of the
actuator piston rod should be changed approximately every one million cycles.
This will extend the life of the piston rod and minimize the possibility of
banding. If the system configuration allows it, the piston rod starting position can
be changed by using the displacement transducer conditioner zero control and
repositioning the load frame crosshead or fixture.
Sideload forces To avoid damaging the actuator bearings and to ensure proper actuator operation,
tests that subject the actuator to nonaxial loads require special consideration.
Nonaxial loading can occur from sideload forces applied directly to the piston
rod (P in the figure) and from moments caused by off-center loads (F in the
figure).
There are four things that must be considered to determine the suitability of an
actuator for nonaxial loaded tests:
• Bearing pressure generated during the test
• Piston rod stress caused by sideload
• Maximum allowable piston rod velocity
32
Operation
Series 242 Actuator Product Information
• Minimum allowable sideload frequency
B
F
P
C
Sideload Forces
Sideload Calculation Procedure
The following procedure provides you with information to determine the
suitability of a particular actuator model for tests requiring nonaxial loading.
Some of the constants used in this procedure are defined in the steps and others
are listed in the following table.
Note The examples included in this procedure assume that the values of F
and P are measured in pounds force and that B, C, and S (stroke) are
measured in inches.
Sideload Calculation Procedure
Sideload Constants
S
TROKE (S) BEARING SPACING (A)
25.4 mm (1 in) 96.8 mm (3.82 in)
50.8 mm (2 in) 96.8 mm (3.82 in)
76.2 mm (3 in) 109.5 mm (4.31 in)
101.6 mm (4 in) 109.5 mm (4.31 in)
1. Determine the magnitude of nonaxial loads F and P and the point of
application of these loads (B and C respectively). These parameters are
dependent on the test setup configuration. If any parameter is variable
during the test, use the maximum values.
2. Calculate the actuator bearing load (L) using the following formula:
Series 242 Actuator Product Information Operation
33
Sideload Calculation Procedure
L
PS A D C+++()FB×()+
SA+()
----------------------------------------------------------------------=
bearing pressure (V)
L
E
----=
Piston Rod Stress
32 PD C+()F B×()+()
π G
3
×
-------------------------------------------------------------=
Maximum Allowable Piston Rod Velocity
5200
V
------------- in/sec=
where:
S = Actuator stroke (see table)
A = Actuator bearing spacing (see table)
D = Bearing length = 35.8 mm (1.41 in)
E = Bearing area = 42.2 mm (1.66 in)
G = Rod diameter = 28.6 mm (1.12 in)
K = Cyclic sideload = 3.6
3. Divide the actuator bearing load (L) by the actuator area constant (E) to
determine the bearing pressure (V).
where: E = Constant based on actuator bearing area
The maximum allowable bearing pressure (V) is 6.55 MPa (950 psi). If the
value produced by this step exceeds 950 psi, then you will have to select an
actuator with a larger piston rod diameter.
4. Calculate the bending stress placed on the actuator piston rod.
where: G = actuator piston rod diameter
The maximum allowable piston rod stress is 275.8 MPa (40,000 psi). If the
value produced by this step exceeds 40,000 psi, then you will have to select
an actuator with a larger piston rod diameter.
5. If the sideload force is applied to the actuator continuously, then determine
the maximum allowable actuator piston rod velocity for the bearing pressure
(V) calculated in Step 3. This is the highest velocity that the actuator can be
allowed to experience when the current sideload is present.
Use the following equation:
Operation
34
6. If the sideload force is applied to the actuator cyclically (sideload varies
equally through zero), then determine the minimum frequency for the
sideload force. If the test parameters require a lower sideload frequency,
then you will have to select an actuator with a larger piston rod diameter.
Series 242 Actuator Product Information
Use the following equation:
Minimum Sideload Frequency K L× 0.01×=
Sideload Calculation Procedure
Series 242 Actuator Product Information Operation
35
Sideload Calculation Procedure
36
Operation
Series 242 Actuator Product Information
Maintenance
The Series 242 Actuator is designed for extended periods of operation without
extensive maintenance requirements.
242 Actuator Maintenance Schedule
The following table lists the recommended interval for each of these procedures.
242 Actuator Maintenance Schedule
Maintenance Intervals
WHAT TO DO WHEN TO DO IT HOW TO DO IT
Make daily inspections
Clean the actuator
Inspect the actuator for
wear
Replace the actuator
seals
* The interval is based on an 8 hour a day, 5 days a week operation schedule. Dusty or dirty environments
require more frequent maintenance.
Before the start of each day’s
testing
Every 40 hours of continuous
operation or weekly
Monthly Inspect the actuator piston rod and seals for
Yearly or sooner if the actuator
inspection show excessive leakage
*
Check for hydraulic fluid leaking from the
actuator.
Clean exposed areas of the actuator piston
rod with a clean, dry, lint free rag.
If the actuator is continually exposed to a
dirty operating environment, clean the
piston rod on a daily basis.
excessive wear and/or leakage.
Small scratches in the axial direction of the
piston rod or polishing of the rod surface is
considered normal operating wear.
Arrange service with MTS Systems
Corporation
Series 242 Actuator Product Information Maintenance
37
242 Actuator Maintenance Schedule
38
Maintenance
Series 242 Actuator Product Information
m
MTS Systems Corporation
14000 Technology Drive
Eden Prairie, Minnesota 55344-2290 USA
Toll Free Phone: 800-328-2255
(within the U.S. or Canada)
Phone: 952-937-4000
(outside the U.S. or Canada)
Fax: 952-937-4515
E-mail: info@mts.com
Internet: www.mts.com
ISO 9001 Certified QMS
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