Medium voltage cast resin and VPI transformer solutions
As one of the largest manufacturers of cast resin transformers in the world, we design, test and build transformers to meet some of the most challenging applications, sizes and configurations in the market today. Our engineers have been leading the industry for over 35 years in technological advancements, quality and customer support.
Over the years, we have evolved to offer a variety of dry-type transformer solutions including our medium voltage cast resin dry type transformers, vacuum pressure impregnated (VPI) transformers and various application specific solutions.
Maintaining reliable power is a necessity for data centers, renewable energy sites, commercial and industrial buildings and utility substations. We can provide a complete solution specified to your needs. Our efficient production and delivery processes mean you’ll get your equipment faster, helping you meet tight deadlines.
2 - 3 Weeks RFQ Lead Times
2 - 4 Weeks Drawing Approval
22 - 24 Weeks Cast Resin Transformers
20 - 22 Weeks VPI Transformers
Cast resin (epoxy) transformers are the highest on the evolutionary scale of transformer design and offer the best combination of electrical and mechanical performance factors. The robust structure achieved by casting the windings in a solid shell of epoxy provides mechanical strength unsurpassed by any other transformer available on the market. Cast resin transformers offer safety, environmental and sustainability goals set forth by many industries.
Voltage | Up to 40.5 kV |
Basic Impulse Level (BIL) | 200 kV (without surge suppression) |
Rated Power | 100 kVA – 45 MVA |
Primary Voltage | 480 V – 40 kV |
Typical Primary Voltages (kV) | 2.3, 4.16, 8.7, 12.47,13.2, 13.8, 25, 34.5 |
Secondary Voltage | 0.208, 0.24, 0.48, 2.4, 4.16, 6.9, 12.47, 13.2, 13.8 |
Environmentally friendly alternative to liquid-filled transformers
Compact design for additional space-savings
Superior dielectric properties
Robust structure protects against damage due to electrical faults and heavy surges
VPI transformers are an excellent alternative in applications which call for an environmentally friendly, economical solution. They reduce flammability concerns, require less maintenance, and are less prone to contaminating the surrounding environment than oil-filled transformers—avoiding the need for oil containment during construction.
Environmentally friendly alternative to liquid-filled transformers
Designed with self-extinguishing properties for enhanced safety
NOMEX insulation promotes uniform cooling—reducing dielectric loss
Voltage | Up to 35 kV |
Basic Impulse Level (BIL) | 110 kV |
Rated Power | 100 kVA – 14.5 MVA |
Primary Voltage | 600 V – 15 kV |
Typical Primary Voltages (kV) | 2.3 kV, 4.16 kV, 8.7 kV, 12.47 kV,13.2 kV, 13.8 kV, 15 kV |
Secondary Voltage | 208V, 240V, 480V, 2400V, 4160V |
Choose from a variety of enclosure options to meet your specific system needs. Our enclosures are designed to meet all CSA and UL 50 requirements.
Type | Description |
NEMA 1 | Designed primarily for indoor use. This general-purpose enclosure is primarily designed to minimize the risk to personnel of contact with live or hazardous parts. The enclosure also protects against falling dust and debris. |
NEMA 12 | Designed primarily for indoor use. This general-purpose enclosure is similar to NEMA 1 but also provides some additional protection against dripping noncorrosive liquids. Meets drip, dust and rust resistance tests. |
NEMA 3R | Designed for indoor and outdoor applications. The enclosure provides protection against falling dirt and windblown dust, weather hazards such as rain, sleet and snow, and is undamaged by the formation of ice. |
NEMA 4/4X | Designed for indoor and outdoor applications. This watertight design meets the NEMA requirements for excluding at least 65 GPM of water from a one-inch nozzle delivered from a distance of not less than 10 feet for five minutes. Used outdoors on ship docks, in dairies, and in wastewater treatment plants and breweries. X (as in 4X) indicates additional corrosion resistance. Note: NEMA 4/4X does not indicate submersible. |
AFWF Marine Rated | Designed for shipboard, platform and marine applications. This Marine Water Cooled/Hydro Cooler design enhances protection for your transformer in the harshest environments. |
JST Power Equipment fully meets ISO9001, ISO14001,and OHSAS18001 certifications and standards. Our products meet GB, IEC, IEEE, NEMA, CSA, JEC and other international and domestic electrical engineering standards including UL, CE, and EU.
Have a question for our team? Get in contact with us today.