ENDEVCO 2911
INSTRUCTION MANUAL
IM2911
Page 3-1
SECTION 3
OPERATING INSTRUCTIONS
1. UNPACKING AND INSPECTION
Remove the top layer of packing material exposing the shaker. Invert shipping container while supporting the shaker.
Allow the shaker to slide out of the box slowly to avoid damage. Visually inspect the exterior of the shaker for any signs of
mishandling. Dings and dents on the exterior surface may indicate rough handling.
Gently grab the armature between two fingers and attempt to move the armature up and down. The armature may bind
a little, this is normal, but it should move up and down without applying much force. If the armature does not move easily
after applying air to the shaker and the armature still binds, thenshaker should be returned to ENDEVCOas soon as
possible for repair.
2. INSTALLATION
The shaker can be installed on any hard, level, stationary surface. An optional isolator is useful in reducing any effects
vibrations from the mounting surface might cause.
The shaker may also be “hung” from the square spacer plate spacer with appropriate hardware and support.
3. CHECKOUT
After connecting the air, 25-pin cable and the reference transducer the shaker is ready for checkout. If the shaker is
connected to an AACS system, then appropriate changes to the system configuration file, exciter definitions and model
test definitionsare required for the system to recognize the shaker. (Consult IM68357 for specific instructions.)Then
selecting and starting a sweep that specifies the 2911 shaker to be used will activate the shaker. After the audible “click” of
the air solenoid, push down on the armature slightly. If it moves freely this means that the system applied the air and the
system configuration and the connections are correct. If not, read the IM68357 sections about “System Configuration
Editor”, “Exciter Definitions” and “Model Test Definitions”.
The UUT goes to the PE/IEPE input on the front of the “Calibration Input Panel”. Upon actual starting of the test, a
sinusoid wave should appear in REF window, if not check to see if the reference input specified in the “System
Configuration Editor’ and where the reference transducer are connected to, see if they are in agreement.
Without an AACS, check out is as simple as applying air, connecting to a power amp through the 25-pin connector and
applying a small amplitude signal at first to establish the fact that the shaker responds to an input. Excessive signal input
will drive the shaker to the stops, indicated by an audible thumping. If this should occur, reduce the signal immediately.
4. OPERATION
Operation is accomplished by monitoring the reference accelerometer while applying a sine wave to the shaker. This is
done automatically by the AACS system. The reference accelerometer determines the acceleration that the Unit Under
Test (UUT) is subjected too. Comparing the reference accelerometer response to the UUT response determines the
characteristics of the UUT.
The reference accelerometer is operated with a constant current source of usually 4mA. The actual signal output is
compliance voltage changing to maintain the 4mA current. All of this is transparent to the AACS user.
