Type 4294 permits accurate adjustment of measuring
instrumentation at a standard acceleration level of 10 ms–2 (0 –
70 g load). The reference signal may additionally be used for
velocity and displacement calibration, at 10 mms–1 and 10 µm,
respectively.
Type 4294-002 permits accurate adjustment of measuring
instrumentation at a standard acceleration level of 3.16 ms–2 (0 –
200 g load). The reference signal may additionally be used for
velocity and displacement calibration, at 3.16 mms–1 and
3.16 µm, respectively.
The calibrator embodies an electromagnetic exciter driven by a
crystal oscillator at a frequency of 159.15 Hz (1000 rad s–1).
Servo feedback via a small accelerometer on the underside of
the vibration table is used to maintain a constant and accurate
vibration level independent of the mass of the transducer under
test (70 g for Type 4294 and 200 g for Type 4294-002).
To prevent overload, power for the calibrator is automatically
disconnected if a transducer mass above a certain level is mounted
on the table (70 g for Type 4294 and 200 g for Type 4294-002).
Use of the calibrator is very straightforward. The transducer is
conveniently attached to the calibrator table using a 10–32 UNF
Steel Stud (YQ-2962). Alternatively, the 10 g Mounting Disc
(DB-2996) supplied, provides a convenient means of attaching
transducers manufactured with 3 mm threads or those fitted with
Mounting Magnet UA-0642. The mounting disc also permits the
attachment of transducers with either beeswax or cyanoacrylate
adhesive.
The calibrator is actuated by pressing the small button on the
side of its housing. Following system adjustment, the calibrator is
switched off by pressing the button a second time. To prolong the
useful life of its built-in battery, Type 4294 automatically switches
off after approximately 100 seconds.