Machine manufacturers
select drive components such as gears, couplings, motors and
converters so as to ensure that the machines have the necessary
torque available to them at the required operating speed.
For cost reasons, increasingly lighter and smaller gears and
couplings must transmit ever more power. This can lead to
sudden, dangerous torsional vibration and even fatigue fractures.
Drive specialists know that after the second shaft fracture
on identical machines – at the latest – it is
time for torque measurements with strain gauges. The only
way to measure static and dynamic loads over several weeks
is by mechanical torque measurement at high frequency. Critical
natural vibrations are also looked for at this time.
Fig. 1 shows the arrangement of measurement equipment used
for simultaneous torque measurement on the upper and lower
spindles of a rolling mill drive. Strain gauges (Fig. 2),
connected as a Wheatstone bridge and protected against humidity
and contamination, are applied to the twisting shaft. The
telemetry components that must additionally be installed are
shown in the illustration on the front page. The sensor signal
amplifier and the antenna rotate with the shaft. The strain
gauge bridge feed and the modulated torque signals are transmitted
via the stationary pickup antenna and the evaluation unit.
The measurement results can be continuously recorded with
VIBNODE,
VIBROWEB
XP or VIBRONET
Signalmaster monitoring systems. |
