After having success with Isomag magnetic bearing isolators in top drive applications, NOV decided to use the Isomag MP-V3 to replace the industry standard labyrinths on winch gearboxes. The upgrade proved worthwhile when leaks and offshore environment contamination no longer occurred. While effectively protecting the bearings these older style Isomag magnetic seals were found to run at relatively high face temperatures, concerning the end users. Nonetheless the V3 was still the best option when compared with competitive technology and over100 units were purchased in 2011-2012. In 2013 the Isomag MP-V6s XL was released and the Isomag magnetic seals operating temperature dropped below the host equipment bearing temperatures. NOV started purchasing these in 2013 and since then have bought nearly 400 units, none of which have had a single reported leak or contamination issue.
Figure 1: Isomag MP-V3 (Left), Isomag MP-V6S (right)
Statement from the OEM:
"I’m very impressed with the longevity of the Isomag magnetic seal technology, even at high speeds in a salty and humid environment."
Winch/Gearbox: NOV Power: 1,500 - 6,000 HP
Shaft Diameter: 4.250 inch Shaft rotation: Bi-directional
Speed: Variable, 2800 RPM typ. Lubrication: Bath/flooded