Dry-Type Transformers
THE BEST COMBINATION OF ELECTRICAL & MECHANICAL PERFORMANCE
Premier Customer Service
Detailed Engineering & Technical Support
Industry Leading Lead Times

Fast Response

Flexible Solutions
Dedicated Project Managers
Premier Customer Service
Whether it is for an initial request, products in manufacturing or after sales service. We are here for you. Our experts are available both on- and offline, quick and thorough to respond and ready to answer any question you have
Short Lead Times / Industry Leading Lead Times
Time is almost always of the essence. Our streamlined production and strategically planned supply chain ensures that you get your gear on time, de-risking your project and giving you certainty in execution.
Fast Response
In line with our customer service speed and efficiency are issues important to us. Our fast response time extends to questions, clarifications to any project and service related issue. Unsure which expert is the right one to contact? Not to worry, we will be happy to connect you.
Flexible Solutions
We meet industry standards but are not constrained by standard solutions. If you have specific requests or more uncommon designs we are flexible in accomodating them. Not sure if it will work? Feel free to ask us anything.
Dedicated Project Managers
Ownership and accountability are words we take seriously – and they are reflected in our project management approach: hands on and professional. All our project managers are engineers and many are certified project management professionals. Whether it is the project plan, shopfloor or site, our project managers ensure that everything is in order and on time.
Detailed Engineering & Technical Support
Our gear is designed and built by experts for experts. Our engineering and R&D teams ensure the highest level of support, to meet your specifications and requirements. Value engineering is as important to us as it is to you – we will frequently suggest improvements, when and where they can be made.

Bringing Safety, Liability, & Satisfaction To All Segments Of The Electrical Industry.
Our approach is based on collaboration and empowered by innovation – with our customers, together!

Cast Resin Transformers
Cast epoxy resin transformers are 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.
Benefits
- Environmentally friendly
- Superior dielectric properties
- Robust structure allows protection against damage due to electrical faults and heavy electrical surges
- Compact design
- Low or no maintenance, which usually consists of wiping off accumulated dirt and dust
- Self-extinguishing insulation system
- Can be used anywhere in all different types of environments
- Can be used up to voltage levels in the 35kV class, basic impulse levels (BIL) to 200kV and partial discharge levels to 10 pico-coulombs and below.
- Overload capable and fans offered for extra cooling
- Lower installation costs
Standard Features
- Voltage: Up to 40.5KV
- BIL: Up to 200kV
- Ratings: Up to 45 MVA
- Fan cooling available
- Enclosure NEMA 1, 12, 3R, 4 & 4X
- Rated power: 100kVA – 45MVA
- High Voltage: 600V – 40kV
- Typical High Voltages (kV): 2.3, 4.16, 8.7, 12.47,13.2, 13.8, 25, 34.5
- Low Voltage: 0.208, 0.24, 0.48, 2.4, 4.16, 6.9, 12.47, 13.2, 13.8
Special Options
- Phase shifting version
- Water cooled options
- Rectifier/Traction version
- Marine
- Secondary unit substation
- Primary unit substation
- Submersible Transformer
- Close Coupled Designs
- RC Snubbers Available
- Triplex Designs available
Forced Air Rating
- 133% increase using fans, maintaining the same temperature rise
- 150% increase using fans, but increasing the temperature rise for the FA (fan) rating
- For example: 3000kVA (AA @ 80C temp rise) / 4500kVA (FA @ 115C temp rise)
- Conductor material: aluminum (standard) or copper (optional)
- Insulation Class: Class H (180C)
- Primary taps: typically, 2 above and 2 below rated voltage, at 2.5% steps
- 95%, 97.5%, 100%, 102.5%, 105%
- Custom designs available also, for example up to 10 taps, or 1.25% steps


VPI Transformers
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 liquid filled transformers avoiding the need for catch basins during construction.
Standard Features
- Voltage: Up to 15 kV
- BIL: Up to 110kV
- Ratings: Up to 14.5 MVA
- Enclosure NEMA 1, 12, 3R, 4 & 4X
- Rated power: 100kVA – 14.5 MVA
- High Voltage: 600V – 15kV
- Typical High Voltages (kV): 2.3, 4.16, 8.7, 12.47,13.2, 13.8,15
- Low Voltage: 0.208, 0.24, 0.48, 2.4, 4.16
- High quality Class R (220C) impregnation varnish certified by UL
Special Options
- Reactor
- Up to 54 pulse transformer
- Water cooled reactor
LV VPI Product Features
- Capacity Range ≤1000kVA
- Rated Voltage Range 3.3kV
- Frequency 50Hz/60Hz
- Structure VPI Dry type
- Standards GB, IEC, ANSI/IEEE, UL etc.
Reactor Features
- Capacity Range ≤10mH
- Rated Voltage Range ≤ 3.3kV
- Frequency 50Hz/60Hz
- Structure VPI Dry type
- Standards GB, IEC, ANSI/IEEE, UL etc.
- Applications; Cranes, drives, propulsion etc.
Enclosure Options
Designed to meet all requirements of CSA and UL 50, we offer a wide array of options when it comes to enclosures to meet your system needs.
NEMA 1
Primarily for indoor use. This general-purpose enclosure protects against falling dust and debris and offers a degree of protection from equipment contact. Its primary purpose is to minimize the risk to personnel of contact with live or hazardous parts.
NEMA 12
Primarily for indoor use. This general-purpose enclosure is similar to NEMA 1 but also provides some protection against dust, falling dirt, and dripping noncorrosive liquids. Meets drip, dust, and rust resistance tests.
NEMA 3R
Designed for both indoor and outdoor applications, the 3R enclosure provides protection against falling dirt and windblown dust, and 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 mean submersible.
NEMA 2
NEMA 2 enclosures are rated for indoor use and protects against accidental contact with device components, against ingress from solid objects and falling dirt and offer protection against light splashing and dripping water. NEMA 2 enclosures a great choice for indoor applications that require more protection than NEMA 1 at an affordable price.
Marine Enclosure
Designed for shipboard, platform and marine applications, the JST Marine Enclosure design enhances protection for your transformer in the most severe applications. This Marine Water Cooled/Hydro Cooler design is the perfect solution for your harshest application needs.

DEDICATED TEAM
Meet The Experts
“Why JST? Our transformers combine superior quality without compromising on lead time.”
“Our quality is your peace of mind. This promise extends from the initial delivery to when our products are in service. Feel free to send us any after sales service request you may have. We are here to help.”
“Engineered to value – this is reflected in the concise level of detail of our proposals and in the quality of our finished product.”
“We offer expert and end-to-end-support from the moment we receive your request until your switchgear is delivered.”
“Our switchgear is designed and tested according to industry standards, while reflecting best practices and learnings we have gathered as a manufacturer.”
“Are you looking for a quality response on your transformer and switchgear needs? JST is here for you: with our team of experts, proven track record and industry insight.”
Office Headquarters
30 Skyline Drive
Lake Mary, FL 32746
Sales@jstpower.com
Contact Us
+1 407-632-4050
844-631-9046 (Toll Free)