Also eliminated are the problems associated with trying to send a 1-millivolt signal across a mechanical interface that becomes noisy from dirt and wear. Factors such as torque, strain, temperature, and pressure can be relayed from sensors on the machinery. Commercially available strain gauges are simple to install and mount instantly with adhesive. In most applications, only a single stamp gauge is required, and alignment is accomplished visually. The strain gauges in the steel mill revealed that two sets of rollers were operating much more slowly than the first set, impeding steel throughput.
Misaligned rotors reduce turbine output and increase the risk of breakdown.
The turbine is rotated slowly for two revolutions, and signals from the strain gauges are sent to a data logger. If realignment is needed, maintenance personnel use the SSA to check the rotor alignment before and after adjusting it to ensure improvement. Other methods of alignment checks traditionally involve measuring the angular deviation of the rotor-shaft couplings. Maintenance crews must take several days to dismantle the shaft couplings and insert measurement fittings, then reassemble the couplings. Plant management was able to save a minimum of five 12-hour shifts during full shaft outage, according to John Cizek, senior staff engineer at Gerald Gentleman.