When you have a height restriction, a "pancake" ring - also called a "flat" or "platter" ring - could be the best solution. We build custom versions of this type of ring with anywhere from 4 to 50 conductors to include the required center bore size.
Pancake rings can be configured in two ways:
Component Pancake Ring: In this arrangement, the brush holders are mounted separately onto the host machine and positioned correctly above the separate ring platter.
Self-Contained Pancake Ring: As an alternate to the component-style set up, the brush holders and brushes can be pre-mounted onto a brush carriage that is integrated with the platter.