Solar Inverter Enclosures

Stockwell Elastomerics has a well-established expertise manufacturing gaskets for all kinds of electrical enclosures, sometimes referred to as NEMA enclosures or UL 50 enclosures. These enclosures house sensitive electronics that need protection from a variety of environmental conditions. These can range from indoors to the desert, heat, rain, dust, freezing, wash-down – all real environment conditions that challenge the enclosure and its sealing.

Utilizing this experience and proficiency, Stockwell Elastomerics is now a leading manufacturer of enclosure gaskets for solar inverters, also called photovoltaic inverters.

Solar Inverter Applications

Solar inverters or photovoltaic (PV) inverters are used in a range of applications, from small residential to utility size solar fields. It is not uncommon for inverters and related electrical enclosures to be mounted on roof tops or reside in the desert. Inverter electronics need to be protected from environmental conditions that can include wind driven rain, formation of ice, and accumulation of dust, dirt and sand. Most reputable inverter manufacturers have their inverter enclosure tested to either NEMA, UL 50 and IEC 60529 (IP54, IP64, IP65) standards. These tests are performed by a 3rd party to ensure an electrical enclosure meets the prescribed environmental sealing requirements.

Solar Inverter Types

Types of inverter gaskets from Stockwell Elastomerics include:

• Micro Inverter Gaskets – Given the size of micro inverters, Stockwell Elastomerics can efficiently die cut gaskets from various materials. The smaller size of micro inverters allows them to be mounted strategically to help protect them from environmental conditions. This in turn allows for more gasket material options.
• String Inverter Gaskets – String inverter enclosures can vary in size but are usually mid-size. Depending on volumes, dispensed gaskets may be an option or Stockwell Elastomerics offers dovetail gasket kits, bonded gaskets and gasket tape made from UL 50 gasket materials and UL 94 flame rated gasket materials.  Stockwell Elastomerics’ Applications Engineers are available to help select the best material and manufacturing process for your project.
• Central Inverter Gaskets – Central inverters are generally large units so cutting a single piece gasket for outdoor central inverters would not be efficient.  In cases of large NEMA enclosures, Stockwell Elastomerics offers gasket tape or cut to length gasket sets. If a single piece gasket is needed, Stockwell Elastomerics offers UV bonding of gasket legs to make large, adhesive backed gaskets ready to be peeled and stuck in place. Sealing requirements, enclosure design, and enclosure protection levels generally dictate what materials are required. Indoor central inverters may only require gasketing for dust and light spray (IP52 or IP53) but may need a better flame rating such as UL 94V-0.

Solar Inverter Gasket Materials

Silicone gasket materials are a top choice for solar inverter gaskets because of their wide temperature range, long performance life and range of firmness. Given the variety of inverter enclosures, Stockwell Elastomerics can offer the right product to seal most inverter enclosures, large and small.

Examples of Inverter Gasket Materials

• Soft closed silicone sponge for low closure force
• Closed cell silicone foam for UL 94 flame rated inverter gaskets
• Low durometer (soft) solid silicone for IP67 for submerged (tidal surge)
• Silicone gasket tape for large central inverters

Temperature Cycling in Solar Inverter Enclosure Gaskets

Solar inverter enclosure gaskets need to be stable under temperature cycling. While inverter enclosures dont get extraordinarily hot, the temperatures are high enough to accelerate compression set and stress relaxation in certain gasket materials. This combined with rapid temperature cycling, such as cooling from rain, can create a vacuum that can suck moisture into the enclosure. To ensure proper sealing, inverter manufacturers certify to NEMA 3R, NEMA 4X, UL 50 Type 4X, IP64 or IP65.

Related Inverter Products

Inverter thermal pads – Since inverters are heat sensitive, managing internal temperatures are important to protect electronics. When inverters reach critical temperature, they go into derating. Derating effectively cycles the inverter down to reduce the heat it generates. This heat, combined with ambient heat, directly affects PV output. Stockwell Elastomerics offers thermal gap filler pads that eliminate air between heat sinks and heat sources; this in turn increases the efficiency of the heat sink. Many inverters rely on convective cooling so efficiently sinking to the enclosure is critical.

Inverter EMI gasket – Stockwell Elastomerics has been protecting electronics from water ingress for decades, but as more and more electronics are introduced to the world, the more electronic noise is generated. Solar inverters can have power spikes and fast switching that can generate interference. As PV systems continue to grow, EMC regulations for inverters will require EMI management. Stockwell Elastomerics offers cost effective EMI shielding gasketsfor commercial applications. Stockwell Elastomerics offers EMI strip gaskets, die cut EMI gaskets and molded EMI gaskets.

Controller display gasket – LCD display gaskets and touch screen gaskets are manufactured by Stockwell Elastomerics for many industries. Touch screen gaskets are manufactured to integration guides or customer specifications. Often LCD gaskets are very thin and require soft material as to not interfere with the display. Touch screen gaskets need to reside outside of the active area as to not generate false touches. Stockwell Elastomerics can cut low volume display gaskets without tooling, die cut LCD display gaskets for higher volume requirements or even mold specialty display gaskets from soft solid silicone materials for IP67 or EMI display gaskets.

Card cage gaskets – Larger central inverters incorporate electronic card cages that house complex electronics. Card cages usually require EMI management and dust sealing. Very often Stockwell Elastomerics offers foam dust gaskets that can be custom cut to size. Some applications warrant a conductive fabric wrap to manage EMI.

Wind power converter gasket – From a gasket and sealing standpoint, wind power converter enclosures have the same NEMA, UL 50 or IP requirements for protection against dust and water ingress.

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