Some original equipment alternators made in recent years feature a “floating stator” that is more sensitive to proper handling than previous designs.

“The stator, or set of windings that surround the rotor, is press fitted or in a very tight tolerance situation in most alternator designs,” said Fred Padgett, group product manager for starters and alternators for Bosch.

“In recent years, however, some manufacturers have chosen to center the stator in the alternator housing and simply clamp it in place, resulting in what is known as a ‘floating stator,’” Padgett said.

“The design works great, but it’s more sensitive to proper handling than previous designs with press fitted stators,” Padgett continued. “If an alternator with a floating stator is subjected to undue shock during the shipping or installation process, the stator actually can ‘float’ out of concentricity.

“This floating stator can result in a noisy alternator, an alternator that rubs internally, or even one that is locked up or won’t turn at all,” Padgett explained.  

How do your know? Look for a warning label on the alternator, alerting you to handle alternator with care. “Each Bosch remanufactured alternator, for instance, that features a floating stator comes with a quite obvious warning label.”

“As the warning label states, ‘Prying on the external housing for alignment or tensioning of drive belt and/or rough handling of the part will result in internal damage,’” Padgett noted. “Keep your customers happy and avoid comebacks by using care to handle alternators with floating stators.”

Source: Robert Bosch LLC