Sometimes You Just Have to Be There

Posted on Tuesday, June 16, 2015 in UEA Blog

A recent visit to a long-time UEA customer reminded us that sometimes you just need to be there.

Over the course of a few years, a UEA customer had noted or reported from end customers of 'water-intrusion' problems with a particular slip ring model. The problem apparently was not reported or recorded with enough frequency to merit a general investigation, but earlier this year an engineer was assigned to research reports of any problems from the end users of their products and UEA was contacted.

'Water intrusion' was the issue reported, but with further discussion it became evident that the slip ring was also not draining adequately or as designed. The same 'splash-guard' style drain , originally designed in conjunction with this same customer 15-20 years ago, has been used successfully in many applications but was apparently prone to being displaced during the installation process of the slip ring. Once displaced the splash shield inside the enclosure could partially or completely block the drain in the bottom of the cover. Moisture could build up within the enclosure rather than draining out per the design. UEA designs slip ring assemblies to always allow drainage because it is almost impossible to keep rain, road spray, condensation, or high pressure cleaning spray out.

Suggestions were given for ways to provide better drainage as well as for better sealing of the slip ring assembly itself. Photos of original assemblies and photos from the field were exchanged, but nothing was readily apparent as to the actual source of the moisture. Wanting to eliminate the drainage and water intrusion problems it was agreed that a visit to the customer's factory would be valuable for all and the arrangements were quickly made.

At the factory, it soon became evident that the customer had eliminated the drainage problem by completely removing the splash-guard drain at installation. Doing this left a large hole in the bottom of the cover, which left the slip ring open to direct spray from the bottom. Suggestions on how to improve the drainage were discussed and agreed upon but it still left us to determine the source(s) of the moisture that was gaining access to the slip ring.

Moisture passing through the opening at the top of the hydraulic swivel where the center or upper harness from the slip ring exits was our first concern. After review of this, seals and potting material, everything was determined to be in order. Our next area of concern was the position of the end of the heat shrink jacket over the center harness when actually installed and connected. Since these slip ring assemblies are used on more than one model of the customer's machine it was agreed that there were probable instances where the end of the jacket might not be facing downward but could be horizontal or even tilted upward which could allow moisture around the individual wires within the harness and thereby direct access to the slip ring. Again, suggestions were made for better sealing to the end of the center harness.

The lower or brush harness did not seem to be as likely a source for the water intrusion until it was pointed out to the customer that their retention arm for the hydraulic swivel/slip ring combination was extending through a slot in the front of the pedestal frame. The slotted opening was, and is subject to, direct spray from rain off the top of the truck cab as the truck is driven down the road providing a possible source of moisture that the customer had not recognized. Since the brush or lower harness was in direct line with this possible source it was decided to improve the sealing on this harness as well, similar to what was being proposed for the center harness.

It was a very valuable and successful on-site experience for both UEA and our customer. It also added credence, through the actual visualization of the complete application, the machine, and the areas noted above, that though technology provides us with many possibilities for information exchange, you 'sometimes you just have to be there'.

Brent Jensen
Engineering Manager