A useful first step to remove enclosure moisture is to characterize the enclosure environment using a temperature/humidity data logger. These low-cost, battery-powered devices (~$200) record Electronic Dry Cabinets. They also indicate the dew-point conditions inside the enclosure (Fig. 6). Maintaining enclosure temperatures above dew-point temperatures is a requirement for condensation prevention.
Pursuing this alternative can be accomplished in a number of ways, ranging from desiccant to thermoelectric dehumidifiers-the process would be to select an alternative that is inexpensive to both implement and keep. This type of water-absorption ability of desiccant is influenced by a number of factors (e.g., desiccant type, humidity, temperature). As an example, silica gel can absorb approximately 40% of their weight in water. A 4’ x 6’ x 2’ electrical enclosure in a hot/humid environment would saturate 125 g of desiccant in approximately two air exchanges. Therefore, the resulting frequency of required desiccant change-outs (which affects maintenance costs) is basically driven by how well the enclosures are sealed. Unfortunately, in terms of desiccant regimes, each act of opening an enclosure to examine the desiccant functions as an air exchange.
Dehumidifiers are relatively inexpensive, although finding convenient available power inside an enclosure may be problematic. The positive feature is that dehumidifiers get rid of the manual intervention connected with a desiccant regime. The negative feature of dehumidifiers is that they introduce one more device that can ultimately fail.
Another method is to minimize the chance of condensation through internal heaters (or light bulbs) to keep the interior enclosure temperature well above dew-point temperatures. The downside is the fact that higher temperatures may be detrimental to a few heat-sensitive electronic components, as well as the higher temperature actually allows the air to hold more moisture. Venting and fans can help avoid condensation in some situations-although the Moisture Control Cabinets still exists. One interesting product the makers of GORE-TEX® have produced involves screw-in vents which allow enclosures to breathe, while providing a barrier to moisture and contaminants. The theory behind this sort of venting is it reduces the stress on door seals when you will find pressure differentials involving the enclosure and also the environment. By equalizing pressure, the possibility of moist air at higher pressure defeating your door seals is lessened.
Moisture-hardening of electronics includes a variety of techniques. When it comes to connectors, using waterproof connectors or hardening existing connectors and splices with heat-shrink tubing can come in handy to lower water intrusion and corrosion. Avoiding horizontal orientation of components like printed circuit boards inside the enclosure can minimize surfaces where condensation may collect for prolonged time periods. Conformal coatings for lower-voltage printed circuit boards and using potting (see Fig. 7) of higher-voltage components greatly boost the moisture resistance of components. Potting costs vary according to the scale of order, material selection jmmhra part geometry, but representative costs for tiny orders (lower than 10) typically fall inside the range of $18 to $45 per part. An extra benefit from potting is definitely the added defense against shock and vibration.
Moisture protection of electronics is most beneficial approached by pursuing practices that maximize Desiccant Dry Cabinets during equipment installation, in conjunction with being prepared to mitigate failure through anyone moisture-protection measure during operations. This plan, in addition to tracking equipment-maintenance performance to comprehend how well moisture-protection measures work, can lead to long-term minimization of electronics moisture-induced problems. MT.