Page 22 - 2019 How-to-Specify E-Book
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 TE Connectivity’s new MULTIGIG RT 3 connector has a four-point, quad-redundant contact design ideal for use in high-vibration applications.
Today, many manufacturers offer beam designs with four points of contact. In addition to mitigating the impact of fretting corrosion, they also significantly reduce the risk of accidental disengagement. For example, if the probability of contact disengagement for a given contact is 0.01, the probability that all four points of a four-point contact could be simultaneously affected is (0.01)4 or 10-8. This risk reduction illustrates the power of redundancy.
The shape of the beam also effects wear levels, because an optimum beam radius helps balance the load and surface pressures within the contact system. In a four-point contact design, contact beam length and areas are not symmetrical to one another. Different lengths give each beam a unique frequency mode in response to vibration, which helps eliminate the possibility of both beams simultaneously achieving resonance. In addition, even with increased contact points, these enhanced contact systems do not increase mating forces.
The wafers in the mating half of these designs can also be slightly modified to take full advantage of the four- beam structure. By making two of the four contact points on the split beams deeper, the signal pads on the wafer can be extended by 1.2mm to maintain at least 2mm of contact wipe during mating. This feature helps maintain quad redundancy throughout the entire mating range of the original design.
Guide posts can also be manufactured into the module to increase stability. The tolerances between mating guide posts and receptacles are more generous than for mating contacts. Even so, mated guides help restrict motion, as well as provide a keying function during mating. In addition, recent technological advances have tightened tolerances. Highly machined posts are now available to provide a precision fit that increases stability under extreme vibration to reduce fretting motion.
A precision-fit guide pin and ruggedized multipoint contact.

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