Tuning fork calibration device KGU-3M

(non-standard equipment for special purposes)

KGU-3M is used for dynamic calibration of strain gages of all types, which are used for testing parts of gas turbines and turbojet engines directly on a full-scale object. It can be used for calibration of strain gages for all types of bench tests (static, dynamic). Another possible application is determining the conversion factors for electrical signals from strain gages (connected in half-bridge or full-bridge circuits) in mechanical quantities arising in test objects.

KGU-01 is produced in rectangular metal housing in a compact form-factor.
Measurement of tuning fork stem oscillation amplitude is carried out visually using external optical ocular with a linear limb.
Tuning fork is mounted unambiguously, which eliminates necessity of manual adjustment of the ocular focus.
Inner side of the KGU-01front panel has a 12-channel flat-spring connector for strain gages connection. There is also a special pocket for placement of lead wires coils to avoid their unwinding during operation and creation of interferences. Outer part of the front panel features connector for testing equipment, fixed amplitude switch and power supply switch. Power cord and ground terminal are located on the rear panel.
Delivery set includes 1 or more (depending on the order) tuning forks, made of AISI 4340 class steel, fastened with three M8 screws. Each tuning fork is supplied with graduation certificate. Oscillating frequency identity is reached by thickness selection and precise polishing of the tuning fork halves during manufacturing process.


Tuning fork properties:
—        Tension at the tuning fork base 0.5 – 10 kg/mm2
—        Measured deformation accuracy ±10 ppm relative strain


TypeTabletop equipment
Operating temperature18 to 35°C, RH 98% max, atmospheric pressure: 960 mbar min
Strain gage resistance rangeUnlimited
Subject for periodic metrology controlOnly optical ocular
Number of connected strain gagesDetermined by tuning fork design and strain gage connection scheme.
Strain gage base0.5-20mm
Supply voltage220 V
Protection against electric shockClass 1
Consumed power40 W max
Overall dimensions300x150x150
Weight6 kg
LifetimeNot less than 10 years

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