Humidity and Condensation: Qualify the Enclosure Around an LRS-75-48
A request for a humid environment power supply is incomplete until “humid” describes a location and an exposure condition. Warm surrounding air, a cooler cabinet surface and visible moisture on an electrical assembly are different observations. For an LRS-75-48 integration, qualify the enclosure around the supply rather than treating its silver case as a weatherproof barrier.
This guide proposes an exposure-event record for protected equipment compartments. It does not declare the supply suitable for condensation, assign an operating humidity limit, or authorize drying and restarting equipment. The illustrations show dry, unconnected assemblies, not moisture tests or successful customer installations.
Identify what is actually inside the compartment
The photographed specimen is LRS-75-48. Its label shows 48V DC 1.6A output and 100–240VAC/1.52A, 50/60Hz input. Five covered terminal positions read L, N, protective earth, −V and +V. The current complete drawing gives a 99mm front-to-rear depth, 97mm width and 30mm height, with underside and side threaded mounting locations. It is a chassis-mounted supply, not a DIN-rail unit.
ที่ WEHO LRS-75 product table agrees with the 48V column and 99 × 97 × 30mm case. Its generic feature bullet gives a different length; do not use that bullet to change this specimen or invent a revision explanation. The photographed input label and broader family input ranges also remain separate fields.
None of these identity details proves an IP grade, conformal coating, corrosion resistance or a condensing-environment rating. In particular, a humidity value attached to an isolation-resistance test condition is not an operating humidity permission. Obtain environmental coverage for the exact ordered revision and the complete equipment assembly.
Separate humid air from a condensation event
Vaisala’s dew-point explanation distinguishes temperature-dependent relative humidity from the condition at which cooling can lead to condensation. A sufficiently cool surface can collect water even when a nearby air reading appears acceptable. That is a reason to record where and when a measurement was taken, not a reason to invent a safe percentage for the supply.
An air measurement outside the cabinet does not describe every internal surface. A reading taken after the door has been open may not describe the earlier closed-compartment condition. If a surface temperature, dew point or local humidity was not measured, mark it as unmeasured. Do not reconstruct a numerical result from a photograph of dry metal or from an operator’s description of “damp weather.”
Build one event record, not a collection of unrelated readings
Give a suspected exposure a single identifier that links observations, equipment state and subsequent decisions. Preserve the sequence instead of mixing a morning air reading with a later photograph and presenting them as simultaneous evidence.
| Record field | Keep in the event entry | Leave unresolved when missing |
|---|---|---|
| Location and identity | Enclosure, compartment, supply full model and source revision | Coverage for substituted parts or another cabinet |
| Time and equipment state | Timestamp, door state and documented shutdown or cooling transition | Unobserved earlier conditions |
| Measurement context | Air or surface location, method, instrument identity and recorded conditions | Unmeasured dew point or hidden-surface temperature |
| Observed exposure | Component or surface affected, moisture location and original photographs | A cause inferred only from appearance |
| Disposition | Responsible owner, authorized isolation status and documented assessment | Permission to restart or a passed electrical safety check |
Keep “observed,” “reported” and “proposed to check” as distinct statuses. For example, “door opened after shutdown” may be a documented state change; “moist air reached the supply and condensed” is a separate causal claim requiring evidence. A closed door is not itself proof that the compartment remained dry.
Assess interfaces around the supply
The record should locate the supply relative to door openings, cable entries, adjacent process zones and cooler enclosure surfaces. These are interfaces for the equipment designer to assess, not a list of protective features already supplied by the LRS-75-48. A vented roof is not a water seal, and the chassis is not a substitute for the host enclosure.
Maintain the real mounting relationship in layout documentation. The unit’s bottom threaded locations attach it to a supported chassis floor; do not add rail clips or unsupported feet to make an illustration fit. Keep ventilation and accessibility requirements subject to the applicable assembly documentation. This article supplies neither an invented clearance nor a heater, drain or sealing design.
Where moisture is suspected on electrical parts, route the condition to the responsible qualified personnel under the site’s authorized isolation and assessment procedures. An apparently dry exterior is not evidence that inaccessible parts are dry or that insulation remains acceptable. Do not use a nominal output label, an earlier normal reading or this illustration as restart authorization.
Close the environmental question with explicit coverage
Ask WEHO and the equipment owner to identify the exact revision’s environmental limits and the enclosure conditions covered by the assembly assessment. Attach the exposure-event record and list missing measurements separately. If coverage remains unclear, keep the integration question open instead of relabelling a dry product photograph as evidence for a condensing environment.
