The TE 81 Single Station Fuel Lubricity Test Rig is a simplified version of the TE 90 Multi-Station Reciprocating Tribometer. It incorporates a test station with heater pad. Load is applied manually by dead weight.
Machine controls are limited to speed control of the drive motor to give the required frequency, temperature control of the specimen bath and test duration. Test data is limited to post-test wear scar measurement only, however, analogue outputs are provided for data logging, including instantaneous and r.m.s. friction, contact potential and friction noise.
The moving specimen is mounted in a carrier. A number of different geometries can be accommodated by using a range of simple clamping fixtures.
6 mm ball carrier in standard sleeve 10 mm ball carrier 6 mm diameter line contact tooling
The moving specimen is oscillated mechanically against the fixed lower specimen. The mechanical drive comprises a motor driven cam and scotch yoke assembly, providing pure sinusoidal motion. The drive mechanism runs inside an oil bath.
The stroke length is altered manually by changing the cams. Five cams are provided as standard allowing strokes to be set from 1 to 5 mm in 1 mm increments.
The moving specimen is loaded against the fixed specimen through a dead weight loading yoke, which transmits a normal force directly onto the moving specimen, through a needle roller cam follower on the moving specimen carrier.
The fixed specimen is located in a stainless steel reservoir. The reservoir is clamped to a block that is heated by two electrical resistance elements and the temperature is monitored by a thermocouple located in the centre of the reservoir 2 mm below the surface.
The heater block is mounted on flexures, which are stiff in the vertical (loading) direction, but offer limited resistance to horizontal forces. Movement in the horizontal direction is resisted by a piezo-electric force transducer, which measures the friction forces in the contact.
A piezo electric transducer is used to measure the friction force. The signal is passed through a true r.m.s./d.c. converter amplifier and the final output is the true mean friction force. The r.m.s. and instantaneous friction signals are available for data logging using a suitable data acquisition interface.
Electrical Contact Resistance Measurement
The moving specimen carrier is electrically isolated from the fixed specimen assembly. This allows a millivolt potential to be applied across the contact using a Lunn-Furey Electrical Contact Resistance Circuit. The voltage signal is taken to a true r.m.s./d.c. converter amplifier to generate a time-smoothed average of the contact potential. The time-smoothed and instantaneous values of contact potential are available for data logging using a suitable data acquisition interface.
By rectifying the instantaneous friction force signal and subtracting the r.m.s. average, a resulting signal corresponding to the perturbations (friction noise) can be produced. If this signal is subsequently passed through a second true r.m.s. to d.c. converter, an r.m.s. signal of friction noise can be generated. This can be used as an analogue measure of the orderliness or otherwise of the friction signal. The friction noise signal is available for data logging.
Contact Geometry: Ball on Plate (Point Contact) Cylinder on Plate (Line Contact) Ball Specimen: 6 mm diameter 10mm diameter Cylinder Specimen: 6mm diameter x 10mm Load: 2 N to 20N Stroke: 1 mm to 5 mm Frequency: 5 Hz to 50 Hz Maximum Stroke @ 50 Hz Frequency: 1 mm Maximum Frequency @ 5 mm Stroke: 20 Hz Temperature: ambient to 100°C Controlled Parameters Frequency Temperature Test Duration Load Analog Outputs Friction Force RMS Friction Friction Noise Contact Potential Services Electricity: 220/240V, single phase, 50/60 Hz, 2 kW
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