THE CHALLENGE: Measure speed for ocean-going vessels |
The Electrodyne Company created the magnetic tape for IMS, combining a magnetic sheet containing high-energy magnetic fields or stripes with an adhesive backing. The stripes have alternating north and south poles, so a magnetic sensor can register the poles as they pass. The shorter the time between poles passing, the faster the propeller is spinning; the longer the interval between poles, the slower the shaft and propeller are moving. The magnetic stripes are skewed, which allows the sensors to detect the direction of rotation and indicate whether the vessel is moving forward or in reverse.
While using magnets to determine shaft speed isn't new, using the tape offers a significant benefit—the tape imparts no stress to the propeller shaft, in contrast to using welded targets or bolted collars to interact with the sensor. It also requires no routine maintenance.
Contact Ken Koch, The Electrodyne Co., Batavia, OH; 513-732-2822, [email protected].