Electromagnetic brake vs lock
The EM brakes are normally designed for spring-set, EM-release operation. With that design, the brake does not release if power is lost or the driver circuit fails. For most applications, that is the "safe" mod of operation. To convert such a brake to EM-set, spring-release operation, it would need to be mechanically altered so that the direction of the spring force and EM force would be interchanged with each other. That is not likely to be practicable.

Since EM-set brakes are rarely used, you may not be able to find one that is suitable. You might find an EM operated clutch that is suitable for installation as a brake.