R1 Wurks V21 Motors to Remain on ROAR Approved List
July 9, 2019
ROAR has extensively evaluated samples of the R1 Wurks V21 motor series taken from events, purchased from retail sources and submitted as part of our approval process for conformance with ROAR rules. Our evaluation focused on areas which would affect performance including wire diameter, stator length and the practice of chamfering the wire webs or legs of the stator. Our investigation confirms that the motors we have inspected meet ROAR requirements for wire diameter and stator length. Ground chamfers present on the stator webs of the motors which were inspected were consistent with the configuration on the samples previously submitted to ROAR for inspection and approved by vote of the Executive Committee. As a result, the R1 Wurks V21 series of motors will remain on the ROAR approved list.
We are aware that BRCA / EFRA has taken action to remove these motors from their approved list; primarily due to finding stators which did not meet the minimum length requirement. ROAR did not find short stators in our inspection of field motors. There are important differences in the rules issued by ROAR and those of BRCA / EFRA. One such difference is that ROAR has instituted a specific minimum resistance for each approved motor. This minimum resistance serves as an overall check on motor configuration issues which affect wire length such as stator length and chamfering so long as the wire diameter is consistent with the rules. Significant changes from the approved configurations will result in measurable differences in resistance and motors with more aggressive chamfering or short stators will fail for low resisitance. This is one reason conformance to the wire diameter requirements is critical.
There are also often differences in the products submitted and approved by BRCA / EFRA compared to those submitted to ROAR. This is reflected in different part numbers for the R1 V21 motors on the ROAR approved list compared to those on the BRCA / EFRA list.
These differences in rules and product and the results of our field inspections have resulted in ROAR reaching a different decision that BRCA / EFRA regarding continuing approval of the R1 V21 series of motors.
Our investigation also determined that beginning no later than 2016, ROAR has approved several motor families from multiple motor manufacturers where a ground chamfer was present on the edges of the stator wire legs or webs of the top and bottom lamination in the stator stack. In addition, our investigation revealed varying degrees of deburring or chamfering of these edges in multiple brands of motors from the field. Because of confusion in the interpretation of the rule requiring that all stator laminations in the stack have the "same overall shape" as it relates to edge treatments on the end laminations, ROAR will be updating our rules to clarify what is and isn't acceptable.
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