The Perfect Solution for all your Transformer Needs

Dry - Type Transformers
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Bringing safety, liability, and satisfaction to all segments of the electrical industry. Our innovative approach allows collaboration and growth as we innovate product solutions 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.



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


Secondary unit substation

Primary unit substation


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


Special Options


Up to 36 pulse transformer​

Water cooled reactor

Meet The Expert

Trey S.

Trey S.

Product Line Manager Transformers

“Why JST? Our transformers combine superior quality without compromising on lead time!”


Headquarters –

Lake Mary Office

30 Skyline Drive,

Lake Mary, FL 32746

Contact Us

  • Phone Numbers
  • +1 407-632-4050
  • 844-631-9046 (Toll Free)
  • Fax Number
  • +1 407-982-1153

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