US 12,404,147 B2
System and method of detecting a dragging brake in an elevator application
John A. Backman, Cedarburg, WI (US); Bryan Radke, West Allis, WI (US); and Marcus Adams, Plymouth, WI (US)
Assigned to Magnetek, Inc., Menomonee Falls, WI (US)
Filed by Magnetek, Inc., Menomonee Falls, WI (US)
Filed on May 17, 2021, as Appl. No. 17/321,991.
Prior Publication US 2022/0363512 A1, Nov. 17, 2022
Int. Cl. B66B 5/00 (2006.01)
CPC B66B 5/0025 (2013.01) [B66B 5/0031 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A system for detecting a dragging brake in an elevator drive, the system comprising:
an elevator brake, including:
at least one braking surface configured to engage a rotating member of the elevator drive to prevent rotation of the elevator drive,
a spring configured to apply a force to the at least one braking surface causing the at least one braking surface to engage the rotating member of the elevator drive, and
an actuator selectively activated to apply a counter force to the spring, wherein when the counter force is applied to the spring, the at least one braking surface disengages the rotating member of the elevator drive, allowing rotation of the elevator drive;
a motor operably connected to cause rotation of the elevator drive; and
a motor drive configured to control operation of the motor, wherein the motor drive further comprises:
a memory configured to store instructions, and
a processor configured to execute the instructions stored on the memory to:
determine a first value of torque when the actuator of the elevator brake initially disengages the at least one braking surface from the rotating member of the elevator drive and prior to causing rotation of the elevator drive,
determine a second value of torque when the motor is rotating at a constant speed, and
compare the first value of torque to the second value of torque to detect when the at least one braking surface of the elevator brake does not fully disengage the rotating member of the elevator drive during rotation of the elevator drive.