A solid riser commutator is one in which the riser, into which the coils are inserted, is made of the same piece of copper as the rest of the bar. In a solid riser v-ring commutator, a rectangular shaped bar of copper has the three sections machined away - at each end for the dovetail,
and along the brush track, leaving the riser.
If a riser is very long, a tremendous amount of copper would be wasted to leave the riser. Instead, an inserted riser design was developed.
Winders, however, often prefer to work with solid riser designs, so how can you tell if your commutator is a candidate for conversion?
Alloy 116 (silver bearing commutator copper) is typically readily available in sizes up to 4, or even 5, inches in width. If your commutator from the inside diameter of the copper to the outside diameter of the risers fits within this, conversion may be a viable option.
What if the bar needs to be wider than available copper sizes?
An alternative to a solid riser is a lap joint design. A separate riser is brazed to the copper bar, but shaped to match the trapezoid of the bar itself. Though typically more expensive than an inserted riser unit, a lap joint riser will provide all the benefits of a solid riser commutator, i.e. carbon contamination prevention behind the risers.
What should you consider in a conversion?
If the risers in question are quite long, you will be adding weight to the unit, potentially
affecting performance. In addition, if cooling and airflow are considerations for your
application, note that the solid risers or lap joint will cut off this air flow versus the inserted riser design.
Call your ICC sales representative to discuss the possibility of conversion of any
commutator you have in house.