A useful initial step to eliminate enclosure moisture is to define the enclosure environment using a temperature/humidity data logger. These economical, battery-powered devices (~$200) record Dry Storage Cabinets. Additionally they indicate the dew-point conditions inside the enclosure (Fig. 6). Maintaining enclosure temperatures above dew-point temperatures is a necessity for condensation prevention.
Pursuing this alternative can be accomplished in a quantity of ways, ranging from desiccant to thermoelectric dehumidifiers-the task would be to select a choice that is certainly inexpensive to both implement and maintain. This type of water-absorption ability of desiccant is influenced by a number of factors (e.g., desiccant type, humidity, temperature). For instance, silica gel can absorb approximately 40% of its 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 serves as an air exchange.
Dehumidifiers are comparatively cheap, although finding convenient available power inside an enclosure may be problematic. The positive feature is the fact dehumidifiers eliminate the manual intervention associated with a desiccant regime. The negative feature of dehumidifiers is they introduce yet another piece of equipment that can ultimately fail.
Another technique is to minimize the opportunity of condensation through internal heaters (or light bulbs) to keep the internal 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 certain situations-even though Dry Cabinets For PCB Storage still exists. One interesting product the designers of GORE-TEX® have produced involves screw-in vents that enable enclosures to breathe, while providing a barrier to moisture and contaminants. The thought behind this type of venting is it decreases the stress on door seals when you will find pressure differentials between the enclosure as well as the environment. By equalizing pressure, the potential of moist air at higher pressure defeating your home seals is lessened.
Moisture-hardening of electronics includes a number of techniques. With regards to connectors, using waterproof connectors or hardening existing connectors and splices with heat-shrink tubing can come in handy to reduce water intrusion and corrosion. Avoiding horizontal orientation of components like printed circuit boards inside the enclosure can minimize surfaces where condensation may collect for extended periods of time. Conformal coatings for lower-voltage printed circuit boards and the use of 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 (less than 10) typically fall inside the range of $18 to $45 per part. An additional advantage of potting is definitely the added protection from shock and vibration.
Moisture protection of electronics is better approached by pursuing practices that maximize Moisture Control Cabinets during equipment installation, coupled with being ready to mitigate failure through anyone moisture-protection measure during operations. This tactic, together with tracking equipment-maintenance performance to know how well moisture-protection measures work, can lead to long-term minimization of electronics moisture-induced problems. MT.