Nova Eclipse TG930 - Users Manual
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7.3 Material Misidentification . . . . . . . . . . . . . . . . . . . . . . . . . . .
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7.4 Worn or Malfunctioning Probes . . . . . . . . . . . . . . . . . . . . .
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7.5 Material Stacks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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7.6 Plated or Painted Materials . . . . . . . . . . . . . . . . . . . . . . . . .
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7.7 Abnormal or Unusual Thickness Readings . . . . . . . . . . . .
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8. ACCESSORIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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8.1 Standard Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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8.2 Optional Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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9. PROBES AVAILABLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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10. MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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WARRANTY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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PRELIMINARY Rev 1.1
Nova Eclipse TG930 - Users Manual
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1.0. INTRODUCTION
NDT Systems thanks you for your purchase of the
NOVA
TG930
handheld
Ultrasonic Thickness Gage, a precision instrument that provides exceptional
value and unmatched features. The TG930 provides ultra-high resolution
(0.0001 inch/0.001 mm) in a light-weight, handheld thickness gage found
only in larger, bulkier portables and bench-tops. The many additional
features contribute to the exceptional ease of operation and flexibility in
applications. The TG930’s rugged design assures dependable performance
for a wide variety of field and lab inspection requirements.
1.1 Principle of Operation
The NOVA TG930 enables measurement, display, evaluation, and recording
of corrosion and other conditions that can impair the safety and function of
countless structures, systems, and materials. Measurements are made with
access to only one accessible surface of the test object. A large selection of
high frequency single-element contact, delay-line, and bubbler-type
transducers can be used interchangeably to satisfy a multitude of
applications.
1.1.1 Basics of Ultrasonic Thickness Gaging
The NOVA operates on a principle similar to Sonar, but at much higher
frequencies (Megahertz range) and electronic speeds. An ultrasonic
frequency sound-beam is generated which emanates from the transducer
and is coupled into the test object.
High-frequency ultrasonic waves travel through monolithic materials at
essentially constant velocities, depending upon the type of material
supporting the ultrasonic wave. This fact provides the basis for accurately
measuring the thickness of metals and some non-metals, with access to only
one side of the test object.
The NOVA accurately senses the time interval between the initiation of a
short pulse of ultrasonic energy into the test object and the time taken to
travel through it. This time interval is short; for example, the velocity of
ultrasound in steel is approximately one-quarter inch (6.3 mm) in one
millionth of a second (one microsecond). Thus, in order for the NOVA to
accurately measure steel thicknesses from as small as 0.0050 inch to 20.00
inches (0.25 to 25 cm), it must have highly stable and accurate timing
circuitry. Think of it as a highly sophisticated, super-accurate stop-watch.
Attached to the NOVA is a cable connected to an ultrasonic transducer, or
