VFDB brakes are designed to operate in dynamic situations. Existing motor brakes are designed as holding brakes, to be applied when the VFD has brought the motor to zero rpm. Their friction material is specifically formulated to have a high static friction coefficient. Typically, this is accomplished at the sacrifice of the dynamic friction coefficient. At 1500 rpm motor speed, the typical motor brake has about 50% of its static torque.
Therefore, a design engineer is faced with a dilemma, select a brake on static torque for the sake of design cost or significantly upsize the brake to handle the dynamic torque. The VFDB brake eliminates this dilemma. If there is the potential for a critical situation in which the motor brake has to stop a dynamic load to avoid serious consequences, then the VFDB brake is the best choice. To assure performance and validate each VFDB’s dynamic torque, PT Tech tests these brakes under extreme operating conditions on our extensive line of test stands prior to shipping.
VFDB brakes are the only motor mounted brakes to address the issue of low frequency friction-induced vibration during high-speed stops that can damage expensive drive components, including bending motor shafts.