Power demand would be reduced by 75 percent.

Lyndon B. Johnson Space Center, Houston, Texas

A magnetostrictive brake has been designed as a more energy-efficient alternative to a magnetic fail-safe brake in a robot. (In the specific application, “fail-safe” signifies that the brake is normally engaged; that is, power must be supplied to allow free rotation.) The magnetic fail-safe brake must be supplied with about 8 W of electric power to initiate and maintain disengagement. In contrast, the magnetostrictive brake, which would have about the same dimensions and the same torque rating as those of the magnetic fail-safe brake, would demand only about 2 W of power for disengagement.