The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 06, 1999
Filed:
Oct. 29, 1997
Steven F Chmiel, Cudahy, WI (US);
Rexnord Corporation, Milwaukee, WI (US);
Abstract
A control circuit (10) is provided for an electric motor brake (12) having an electromagnetic brake coil (14) energizable to actuate the brake to a released condition permitting rotation of an electric motor (16), and de-energizable to enable actuation of the brake setting the brake to a braking condition stopping rotation of the motor. The control circuit includes a switch (102) having an on state energizing the brake coil, and an off state de-energizing the brake coil. A discriminating trigger circuit (76 et al) responds to voltage across the motor to trigger the switch between its on and off states, and discriminates between increasing and decreasing motor voltage during energization and de-energization, respectively, of the motor, to trigger the switch to its on state at a first motor voltage, and to trigger the switch to its off state at a second motor voltage higher than the first motor voltage, to compensate for voltage generated by continuing inertia-rotation of the motor following de-energization thereof otherwise delaying actuation of the brake. The triggering of the switch to its off state at the second motor voltage enables faster application of the brake and stopping of the motor. The same switch both energizes and de-energizes the brake coil, without a separate relay for de-energizing the brake coil.