Jefferson Products
The trusted authority in dry-type transformers
Not every connection is visible. But all of them matter.
Jefferson has been engineering transformer and reactor solutions since 1915 — and in that time, we’ve learned that great products start with great relationships.
Every unit we build is backed by over a century of expertise and an ISO-based quality system that ensures it performs exactly as promised. From design to delivery, we work closely with you to get the details right — because when the job is critical, precision isn’t optional.
Industries Served
Renewable Energy
Data Center
Commercial & Industrial
Utilities
EV
Product
General Purpose: 15 – 1,650 kVA
Application
For all general loads, indoors or out, including lighting, industrial and commercial
Specifications
– Meets DOE-2016 and NRCan-2019 standards for energy efficiency
– Cores of high quality electrical steel
– NEMA 3R rated enclosures standard – Heat-cured ASA-61gray powder coat finish
– 60 Hz operation
– Aluminum windings
– Primary taps on most units
– 150°C temperature rise
– 220°C insulation class standard
Features, Functions, Benefits
– Large connection compartment for ease of wiring and installation
– Quiet operation for installation flexibility
– Seismic certification for all units through 333 kVA
Standards
Built in accordance with NEMA, ANSI, UL and CSA standards
Options and Accessories
– Other sizes, voltages and temperature rises available
– CE Marked units available as custom
– Wall brackets available for units up to 75 kVA
– NEMA 3R-rated enclosure with weathershields
Ventilated Transformers
Our ventilated transformers are built for reliable, day-in, day-out performance. Designed for a wide range of commercial and industrial applications, they deliver efficient, consistent power—quietly and dependably. Backed by decades of engineering expertise and responsive service, these units are a proven solution when performance can’t be compromised.
Single-Phase Ventilated Transformers
Products
- General Purpose: 15 – 1,650 kVA
Applications
- For all general loads, indoors or out
- Including lighting, industrial and commercial applications
Specifications
- Meets DOE-2016 and NRCan-2019 standards for energy efficiency
- Cores of high quality electrical steel
- NEMA 3R rated enclosures standard
- Heat-cured ASA-61 gray powder coat finish
- 60 Hz operation
- Aluminum windings
- Primary taps on most units
- 150°C temperature rise
- 220°C insulation class standard
Features, Functions, Benefits
- Large connection compartment for ease of wiring and installation
- Quiet operation for installation flexibility
- Seismic certification for all units through 333 kVA
Standards
- Built in accordance with NEMA, ANSI, UL and CSA standards
Options and Accessories
- Other sizes, voltages and temperature rises available
- CE Marked units available as custom
- Wall brackets available for units up to 75 kVA
- NEMA 3R-rated enclosure with weathershields
Three-Phase Ventilated Transformers
Products
- General Purpose: 15 – 1,650 kVA
Applications
- Products
- General Purpose: 15 – 1,650 kVA
Applications
- For all general loads, indoors or out, including lighting, industrial and commercial applications
Specifications
- Cores of high quality electrical steel
- Meets DOE-2016 and NRCan-2019 standards for energy efficiency
- NEMA 3R-rated enclosures standard
- Heat-cured ASA-61 gray powder coat finish
- 60 Hz operation
- Aluminum windings
- Primary taps on most units
- 150°C temperature rise
- 220°C insulation class
Features, Functions, Benefits
- Compact design for easier handling and installation
- Large connection compartment for ease of wiring and installation
- Quiet operation for installation flexibility
- Hassle-free front cover installation
- Taps provided on primary to compensate for voltage variations
- Seismic certification for all units through 1,000 kVA
Standards
- Meets NRCan C802 2019 requirements for energy efficiency
- January 1, 2018 Ontario requirements
- Canada-wide May 1, 2019 requirements
- Built in accordance with NEMA, ANSI, UL and CSA standards
Options and Accessories
- Other sizes and voltages available as custom
- CE Marked units available as custom
- Wall mount brackets available for units up to 75 kVA
- For all general loads, indoors or out
- Including lighting, industrial and commercial applications
Specifications
- Meets DOE-2016 and NRCan-2019 standards for energy efficiency
- Cores of high quality electrical steel
- NEMA 3R rated enclosures standard
- Heat-cured ASA-61 gray powder coat finish
- 60 Hz operation
- Aluminum windings
- Primary taps on most units
- 150°C temperature rise
- 220°C insulation class standard
Features, Functions, Benefits
- Large connection compartment for ease of wiring and installation
- Quiet operation for installation flexibility
- Seismic certification for all units through 333 kVA
Standards
- Built in accordance with NEMA, ANSI, UL and CSA standards
Options and Accessories
- Other sizes, voltages and temperature rises available
- CE Marked units available as custom
- Wall brackets available for units up to 75 kVA
- NEMA 3R-rated enclosure with weathershields
Non-Linear Transformers
Products
K-factor rated transformers are designed to meet the non-linear load demands caused by computers and other modern electronic equipment. These types of loads can cause severe overheating in distribution transformers designed to meet the needs of a pre-electronic era. The Jefferson line of non-linear transformers provides safe and efficient operation in non-linear load environments.
- 15 – 750 kVA (some restrictions on larger kVA units)
Applications
- For electronic load demands caused by modern office equipment
- For indoor/outdoor applications
Specifications
- K-4, K-13, K-20 units standard
- Meets DOE-2016 standard for energy efficiency
- Cores of high quality, low loss, electrical steel
- Aluminum windings
- Cores designed for reduced flux densities to compensate for harmonic voltage distortion
- NEMA 3R-rated enclosures standard
- Heat-cured ASA-61 gray powder coat finish
- Electrostatically shielded
- 150°C temperature rise
- 220°C insulation class standard
Features, Functions, Benefits
- Designed with lower weight and smaller size for easier handling and installation
- Large connection compartment for ease of wiring and installation
- Quiet operation for installation flexibility
- Hassle-free front cover installation
- Primary taps provided to compensate for voltage variations
- Seismic certifications for all units
Standards
- Built in accordance with NEMA, ANSI, UL and CSA standards
Options and Accessories
- CE Marked units available
- Other sizes, voltages, and connections available as custom
- Other K-factor rated units available as custom
- Wall mount brackets available through 75 kVA
Harmonic Mitigating/Zig-Zag Transformers
Products
The HMT (Harmonic Mitigating Transformer) is a three phase transformer with 0° or -30° displacement between the primary and the secondary. The HMT is used to reduce current harmonics on the primary side of a transformer and voltage distortion on the load. A single HMT reduces the flow of triplen harmonics—3rd, 9th, 15th, 21st, etc.—into the transformer primary. Used together on the same power line, a 0° and -30° HMT will also reduce the 5th and 7th harmonics. These transformers are designed to reduce voltage distortion when powering non-linear loads.
Applications
- For use in environments with non-linear loads such as computers and variable speed drives
- Where there is high computer, printer and communication equipment usage, and stable operation is necessary
- Medical facilities including hospitals
- Data centers
- Office buildings
- Schools
Specifications
- DOE-2016 efficiency
- 3 phase, 60 Hz
- 480V primary
- Zig-Zag secondary design voltage 208Y/120V
- 0º and -30º phase shifts
- 15 – 1,500 kVA range
- Aluminum windings
- K-13 standard
- 150°C temperature rise
- 220°C insulation class
- NEMA 3R enclosure
- Heat-cured ASA-61 gray powder coating finish
- Electrostatic shield
- Cores of high quality electrical steel
- UL / cUL Rated
Features, Functions, Benefits
- Space saving design for easy handling and installation
- Termination lugs provided for ease of installation through 75 kVA
- Vibration isolation pads provide quiet operation
Standards
- Meets DOE-2016 standard for energy efficiency
- Built in accordance with NEMA, ANSI, UL and CSA standards
- UL and CSA Listed
- 50 Hz compatible
- Other voltages available
- Copper windings
- K-4 and K-20 options
- Dual electrostatic shield
- 115°C, 80°C temperature rise options
Single-Phase Ventilated Transformers
Products
- General Purpose: 15 – 1,650 kVA
Applications
- For all general loads, indoors or out
- Including lighting, industrial and commercial applications
Specifications
- Meets DOE-2016 and NRCan-2019 standards for energy efficiency
- Cores of high quality electrical steel
- NEMA 3R rated enclosures standard
- Heat-cured ASA-61 gray powder coat finish
- 60 Hz operation
- Aluminum windings
- Primary taps on most units
- 150°C temperature rise
- 220°C insulation class standard
Features, Functions, Benefits
- Large connection compartment for ease of wiring and installation
- Quiet operation for installation flexibility
- Seismic certification for all units through 333 kVA
Standards
- Built in accordance with NEMA, ANSI, UL and CSA standards
Options and Accessories
- Other sizes, voltages and temperature rises available
- CE Marked units available as custom
- Wall brackets available for units up to 75 kVA
- NEMA 3R-rated enclosure with weathershields
Three-Phase Ventilated Transformers
Products
- General Purpose: 15 – 1,650 kVA
Applications
- Products
- General Purpose: 15 – 1,650 kVA
Applications
- For all general loads, indoors or out, including lighting, industrial and commercial applications
Specifications
- Cores of high quality electrical steel
- Meets DOE-2016 and NRCan-2019 standards for energy efficiency
- NEMA 3R-rated enclosures standard
- Heat-cured ASA-61 gray powder coat finish
- 60 Hz operation
- Aluminum windings
- Primary taps on most units
- 150°C temperature rise
- 220°C insulation class
Features, Functions, Benefits
- Compact design for easier handling and installation
- Large connection compartment for ease of wiring and installation
- Quiet operation for installation flexibility
- Hassle-free front cover installation
- Taps provided on primary to compensate for voltage variations
- Seismic certification for all units through 1,000 kVA
Standards
- Meets NRCan C802 2019 requirements for energy efficiency
- January 1, 2018 Ontario requirements
- Canada-wide May 1, 2019 requirements
- Built in accordance with NEMA, ANSI, UL and CSA standards
Options and Accessories
- Other sizes and voltages available as custom
- CE Marked units available as custom
- Wall mount brackets available for units up to 75 kVA
- For all general loads, indoors or out
- Including lighting, industrial and commercial applications
Specifications
- Meets DOE-2016 and NRCan-2019 standards for energy efficiency
- Cores of high quality electrical steel
- NEMA 3R rated enclosures standard
- Heat-cured ASA-61 gray powder coat finish
- 60 Hz operation
- Aluminum windings
- Primary taps on most units
- 150°C temperature rise
- 220°C insulation class standard
Features, Functions, Benefits
- Large connection compartment for ease of wiring and installation
- Quiet operation for installation flexibility
- Seismic certification for all units through 333 kVA
Standards
- Built in accordance with NEMA, ANSI, UL and CSA standards
Options and Accessories
- Other sizes, voltages and temperature rises available
- CE Marked units available as custom
- Wall brackets available for units up to 75 kVA
- NEMA 3R-rated enclosure with weathershields
Drive Isolated Transformers
Products
- Three-Phase Encapsulated: 3 – 11 kVA
- Three-Phase Ventilated: 14 – 990 kVA
Applications
- For industrial and commercial applications with SCR-controlled adjustable speed motor drives
- AC adjustable frequency or DC drives
Specifications
- Sized to match standard drive loads
- Cores of high quality electrical steel
- NEMA 3R-rated enclosures standard on 3 – 11 kVA units
- NEMA 1-rated enclosures standard on 14 – 990 kVA units, convertible to 3R with optional weather shield kit
- Heat-cured ASA-61 gray powder coat finish
- Electrostatically shielded
- 150°C temperature rise standard
- 220°C insulation class units
Features, Functions, Benefits
- Large connection compartment for ease of wiring and installation
- Internally braced for short circuit stress protection
- Low impedance for better voltage regulation
- Low flux density to minimize core saturation
- Primary tap arrangements provided to compensate for input voltage variation
- Quiet operation for installation flexibility
- Seismic certification for all units
Standards
- Built in accordance with NEMA, ANSI, UL and CSA standards
- Meets NRCan-2019 standards for Canada
Options and Accessories
- CE Marked units available as custom
- Wall mount brackets available for units up to 75 kVA
- Weathershields available on units 14 kVA and larger
Non-Linear Transformers
Products
K-factor rated transformers are designed to meet the non-linear load demands caused by computers and other modern electronic equipment. These types of loads can cause severe overheating in distribution transformers designed to meet the needs of a pre-electronic era. The Jefferson line of non-linear transformers provides safe and efficient operation in non-linear load environments.
- 15 – 750 kVA (some restrictions on larger kVA units)
Applications
- For electronic load demands caused by modern office equipment
- For indoor/outdoor applications
Specifications
- K-4, K-13, K-20 units standard
- Meets DOE-2016 standard for energy efficiency
- Cores of high quality, low loss, electrical steel
- Aluminum windings
- Cores designed for reduced flux densities to compensate for harmonic voltage distortion
- NEMA 3R-rated enclosures standard
- Heat-cured ASA-61 gray powder coat finish
- Electrostatically shielded
- 150°C temperature rise
- 220°C insulation class standard
Features, Functions, Benefits
- Designed with lower weight and smaller size for easier handling and installation
- Large connection compartment for ease of wiring and installation
- Quiet operation for installation flexibility
- Hassle-free front cover installation
- Primary taps provided to compensate for voltage variations
- Seismic certifications for all units
Standards
- Built in accordance with NEMA, ANSI, UL and CSA standards
Options and Accessories
- CE Marked units available
- Other sizes, voltages, and connections available as custom
- Other K-factor rated units available as custom
- Wall mount brackets available through 75 kVA
Harmonic Mitigating/Zig-Zag Transformers
Products
The HMT (Harmonic Mitigating Transformer) is a three phase transformer with 0° or -30° displacement between the primary and the secondary. The HMT is used to reduce current harmonics on the primary side of a transformer and voltage distortion on the load. A single HMT reduces the flow of triplen harmonics—3rd, 9th, 15th, 21st, etc.—into the transformer primary. Used together on the same power line, a 0° and -30° HMT will also reduce the 5th and 7th harmonics. These transformers are designed to reduce voltage distortion when powering non-linear loads.
Applications
- For use in environments with non-linear loads such as computers and variable speed drives
- Where there is high computer, printer and communication equipment usage, and stable operation is necessary
- Medical facilities including hospitals
- Data centers
- Office buildings
- Schools
Specifications
- DOE-2016 efficiency
- 3 phase, 60 Hz
- 480V primary
- Zig-Zag secondary design voltage 208Y/120V
- 0º and -30º phase shifts
- 15 – 1,500 kVA range
- Aluminum windings
- K-13 standard
- 150°C temperature rise
- 220°C insulation class
- NEMA 3R enclosure
- Heat-cured ASA-61 gray powder coating finish
- Electrostatic shield
- Cores of high quality electrical steel
- UL / cUL Rated
Features, Functions, Benefits
- Space saving design for easy handling and installation
- Termination lugs provided for ease of installation through 75 kVA
- Vibration isolation pads provide quiet operation
Standards
- Meets DOE-2016 standard for energy efficiency
- Built in accordance with NEMA, ANSI, UL and CSA standards
- UL and CSA Listed
- 50 Hz compatible
- Other voltages available
- Copper windings
- K-4 and K-20 options
- Dual electrostatic shield
- 115°C, 80°C temperature rise options
Harmonic Suppression System (HSS™)
Harmonics Limited*
The Phenomenon of Odd Harmonics
Electronic equipment today is powered by SMSPs (switch mode power supplies) that convert AC current to DC current. SMSPs use rectifiers and capacitors drawing current in sharp bursts which distorts the sinusoidal waveform. It is now non-linear.
Non-linear loads are rich in odd harmonics (3, 5, 7, etc.), which are multiples of the fundamental 60 Hertz frequency. The major components of harmonic currents in switched mode power supplies are the third and fifth harmonics.
The 3rd harmonic current (180Hz), due to the design of the 3-phase system, is additive in the neutral and can result in a neutral current twice the phase current, even in a balanced system.
*Harmonics Limited is now a part of Jefferson Electric
How Harmonics Affect Transformers
When odd-harmonic currents are present, winding losses increase. The I2R (conductor) losses are higher because harmonics increase the current. Stray losses in windings also increase due to additional eddy currents circulating within the conductors.
This combination of losses generates excess heat in the transformer coils. Transformer insulation systems are designed to accommodate temperature increases due to normal stray losses. However, with non-linear loads, this excess heat may exceed the design rating—reducing transformer life and risking premature failure.
Read this article for additional information.
De-rating is Not the Answer
De-rating a traditional linear transformer to compensate for heat build-up increases installation costs and reduces energy efficiency due to increased core losses.
Solutions for Harmonics in the Power System
The Harmonic Suppression System (HSS™) eliminates the harmful 3rd harmonic current generated by electronic power supplies. It removes this current from the distribution system entirely.
Patented HSS technology allows transformers to be sized to the load—no need to de-rate or oversize panels. This reduces installation costs and energy consumption while increasing equipment life. ROI can be less than 24 months.
For additional information, see these articles:
Three Options
SysteMax™
SysteMax is a standalone 3rd harmonic suppression filter connected to the neutral of an existing distribution transformer. It is sized to the transformer (15 kVA to 1,000 kVA).
TransMax™
TransMax is a SysteMax filter incorporated in an enclosure with a high-efficiency transformer. The basic transformer is 480V primary, 208Y/120V secondary, with either copper or aluminum windings, 115°C rise, and electrostatic shielding.
Options include 80°C rise, low noise (-3dB), and 208V primary. Enclosure type is UL/NEMA Type 1, ANSI–61 gray paint. Standard sizes range from 30 kVA to 500 kVA.
GenMax™
GenMax is a passive, tuned harmonic suppression system for generators. This technology allows generators with different winding pitches to operate at full capacity by reducing circulating 3rd harmonic ground currents.
For additional information, please see these articles: EGSA Paper, Magee Case Study, and Zook Case Study.
Please contact us for more information on this product line.
18 Pulse Transformers
Products
- 18-Pulse: 15 HP through 500 HP
Applications
- Special purpose multi-pulse magnetics can be manufactured to meet specific requirements of your application
- Each autotransformer reduces the harmonic current at the input of the transformer as well as harmonic voltage distortion from non-linear loads applied to the outputs
- Water and wastewater treatment facilities
- HVAC installations
- Pump lift stations
Specifications
- 15 to 500 HP
- Core and Coil
- 60 Hz operation
- Three phase: 15 — 500 kVA
- Aluminum windings
- 150°C temperature rise with 40°C ambient (customer supplied forced air cooling)
- 220°C insulation class
- Cores of high quality electrical steel
Features, Functions, Benefits
- Reduces the neutral current and harmonic distortion generated by triplen harmonics
Standards
- Built in accordance with NEMA, ANSI, UL and CSA standards
- UL and cUL Listed
- Models with CE Marking are available
Options and Accessories
- 50 Hz
- Copper windings
- Other sizes and temperature rises available
- NEMA 1 enclosures
Seismic Qualified Transformers
Products
- Jefferson Electric offers many transformers that have been tested and certified to meet the standards required for safety during seismic activity
Applications
- Healthcare facilities
- Emergency response locations (fire stations, police stations)
- Other critical government facilities may be required to be seismic qualified
Specifications
Single & Three-Phase Encapsulated
- Wall mount: 1 – 25 kVA
- Floor mount: 3 – 75 kVA
- NEMA 3R enclosures
- SDS = 2.00g ; z/h = 1.00 ; Ip = 1.5
Single-Phase Ventilated
- Floor mount: 1 – 167 kVA
- NEMA 1 or 3R enclosures
- SDS = 2.0g ; z/h = 1.00 ; Ip = 1.5
Three-Phase Ventilated
- Floor mount: 1 – 1,000 kVA
- NEMA 1 or 3R enclosures
- SDS = 2.00g ; z/h = 1.00 ; Ip = 1.5
Features, Functions, Benefits
- Many construction projects and their components are now required to be seismic qualified.
Standards
- Meets the International Building Code (2015 IBC)
- Meets California Building Code (2016 CBC) requirements
- Met in accordance with ICC-ES AC156 seismic qualifications
Additional Literature
- Jefferson Seismic White Paper
- Seismic Unit Installation Sheet
- See our YouTube video of the test in progress
Encapsulated Transformers
When the environment is tough, our encapsulated transformers are tougher. Sealed against dust, moisture, and corrosion, they’re built to perform in demanding conditions without missing a beat. From remote job sites to indoor washdown areas, these transformers provide dependable power and long-term durability.
Three-Phase Encapsulated Transformers
Products
- General Purpose: 3 – 75 kVA
Applications
- For all general loads, indoors or out
- Including lighting, industrial and commercial applications
Specifications
- Encapsulated with electrical grade resin
- Cores of high quality electrical steel
- NEMA 3R-rated enclosures
- Heat-cured ASA-61 gray powder coat finish
- 135°C temperature rise
- 180°C insulation class
Features, Functions, Benefits
- Large connection compartment with knockouts for ease of wiring and installation
- Quiet operation for installation flexibility
- Slotted mounting holes for quick and easy mounting
- Convenient wall mount design with lifting hooks up to 15 kVA
- Floor mounted 30 kVA and larger
- Seismic qualification certification for all units
Standards
- Built in accordance with NEMA, ANSI, and UL standards
Options and Accessories
- CE Marked units available as a custom product
- Other sizes and voltages available as a custom product
- Class I Div 2 units available
Single-Phase Encapsulated Transformers
Products
- General Purpose: 50 VA through 25 kVA
- International: 1 – 25 kVA
Applications
- For all general loads, indoors or out
- Including lighting, industrial and commercial applications
- Units may be banked for 3-Phase operations
Specifications
- Encapsulated with electrical grade resin
- Cores of high quality electrical steel
- NEMA 3R-rated enclosures
- Heat-cured ASA-61 gray powder coat finish
- 60 Hz operation standard, 50/60 Hz optional
Features, Functions, Benefits
- Large connection compartment with knockouts for ease of wiring and installation
- Quiet operation for installation flexibility
- Slotted mounting holes for quick and easy mounting
- Lifting hooks above 5 kVA
- Wall mount design through 25 kVA
- Seismic qualification certification for all units
Standards
- Built in accordance with NEMA, ANSI, UL and CSA standards
- International units are CE Marked
Options and Accessories
- CE Marked units available as a custom product
- Other sizes and voltages available as a custom product
- Class I Div 2 units available
Pool & Spa Lighting Transformers
Products
- Lamp Watts: 100 through 1,000
Applications
- For use with submersible fixtures including swimming pools, water fountains, low voltage circuits near water or other shock hazards
- Note: transformers themselves are not submersible
Specifications
- Single-Phase encapsulated
- Encapsulated with electrical grade resin
- Cores of high quality electrical steel
- NEMA 3R-rated enclosures
- Heat-cured ASA-61 gray powder coat finish
- 60 Hz operation
- Electrostatically shielded
- 12, 13, 14 volt taps to compensate for voltage drop on long electrical runs
Features, Functions, Benefits
- Resettable power circuit breakers to interrupt current if a short or over-voltage occurs
- Quiet operation for installation flexibility
- Convenient wall mount design with slotted mounting holes
Standards
- Built in accordance with NEMA, ANSI, UL, and CSA standards
Options and Accessories
- Other sizes and voltages available as custom
Class 1 Division 2 Transformers
Products
- Single Phase: 1 kVA through 25 kVA*
- Three Phase: 3 kVA through 75 kVA*
Applications
Class I Division 2 units are key in hazardous locations in maintaining a safe environment, such as:
- Petroleum and gas refineries, storage and dispensing areas
- Chemical factories
- Spray finishing areas
- Aircraft hangars
Specifications
- Class I Division 2
- Groups A, B, C & D
- T3C – Temp Classification
- Aluminum Windings
- Indoor and Outdoor use
- Encapsulated with electrical grade resin
- Cores of high quality electrical steel
- NEMA 3R-rated enclosures
- Temperature Rise – 115°C at 40°C ambient standard
- Heat-cured ASA-61 gray powder coat finish
- Wall-mount up to 25 kVA standard
- Electrostatically shields optional
- 60 Hz Standard, 50 Hz optional
Features, Functions, Benefits
- Large connection compartment with knockouts for ease of wiring and installation
- Quiet operation for installation flexibility
- Slotted mounting holes for quick and easy mounting
- Convenient wall mount design with lifting hooks up to 15 kVA
- Permanently affixed wiring diagram
- Seismic certification for all units
Standards
- Built in accordance with NEMA, ANSI, UL, and CSA standards
Options and Accessories
- CE Marked units available as a custom product
- Other sizes and voltages available as a custom product
Buck Boost Transformers
Products
- 50 VA – 10 kVA
Applications
- For correcting voltage drop, landscape lighting, low voltage lighting, international voltage adaptation and motor applications
- Note: Buck-boost transformers do not compensate for fluctuating line voltages
Specifications
- Encapsulated with electrical grade resin
- Cores of high quality electrical steel
- NEMA 3R-rated enclosures
- Heat-cured ASA-61 gray powder coat finish
- 95°C temperature rise for 0.5 to 1 kVA
- 135°C temperature rise for 1.5 to 10 kVA
- 180°C insulation class
Features, Functions, Benefits
- Slotted mounting holes for quick and easy mounting
- Convenient wall mount design with lifting hooks above 5 kVA
- Permanently affixed wiring diagram
Standards
- Built in accordance with NEMA, ANSI, UL and CSA standards
Additional Literature
Industrial Control Transformers
Precision starts with a stable power source. Our industrial control transformers are designed to support control panels, relays, and automation systems with consistent, clean power. Built for reliability in the field, they help keep your systems running exactly as they should—day after day.
Industrial control transformers
Products
- 50 through 5,000 VA
Applications
- For control panels and machine tool equipment
Specifications
- Cores of high grade silicon steel
- Machine wound copper coils
- 50/60 Hz operation
- Phil-Slot-Hex terminal screws
- 55°C temperature rise for 50 – 100 VA
- 80°C temperature rise for 150 – 750 VA
- 115°C temperature rise for 1,000 – 5,000 VA
Features, Functions, Benefits
- Finger safe terminals on units 350 VA and above
- Parallel connections on units with dual windings
- Secondary fuse clips standard on units with single secondary voltage (300 units)
- Units 2,000 VA and less are UPS shippable
Standards
- Built in accordance with NEMA, ANSI, and UL standards
- UL and cUL Listed
- Models with CE Marking are available as special order
Options and Accessories
- Optional primary fuse clips available
- Finger-safe terminal covers available
- Finger-safe fuse covers available
Medium Voltage Transformers
Our medium voltage transformers are trusted across critical infrastructure and utility applications for one reason: they perform. Built to handle higher voltages with the same care and attention we bring to every product, these units deliver power you can count on—supported by a team that knows what it takes to get it right.
Medium Voltage Transformers
Products
- 5 kV Class: 150 kVA to 10 mVA
- 15 kV Class: 300 kVA to 10 mVA
- 25 kV Class: 300 kVA to 10 mVA
- 35 kV Class: 500 kVA to 10 mVA
Applications
- Commercial buildings
- High rise buildings
- Industrial facilities
- Manufacturing process lines
Specifications
- NEMA 1
- Mitered core design of high quality electrical steel
- Single and Three-Phase, 60 Hz
- 150°C temperature rise
- 220°C insulation class
- Aluminum windings
- Energy efficient to DOE-2016 standards
- Meets NRCan SOR/2018-201 standard for energy efficiency
Standards
- Built in accordance with NEMA, ANSI, UL, and CSA standards
Optional Features
- Copper windings
- 50 Hz
- Electrostatic shielding
- 80°C and 115°C temperature rise
- Terminals with flexible connectors
- Lightning arrestors
- Grounding resistor
- Digital thermometer and monitor
- NEMA 3R enclosure
- Forced air cooling
- Multiple secondaries
- Rectifier, traction, mining duty
Medium Voltage Industrial Control Transformers
Products
- 0.5 kVA through 5 kVA
- To step down 4,160V or 2,400V primaries
Applications
- For stepping down medium voltage power (4,160V or 2,400V primary) to a lower voltage for commercial, institutional or industrial applications
- Where large load diversity is necessary in an industrial application
- Connection to a primary distribution circuit
Specifications
- Single Phase
- 0.5 kVA through 5 kVA
- Copper windings
- 115°C temperature rise at 40°C ambient
- 180°C insulation class
- Standard 48 inch leads on primary, terminal block connections on secondary
Features, Functions, Benefits
- Specifically designed to address the demands of industrial control applications
- Tough and reliable
- Six voltage combinations offered as standard for quick delivery
Standards
- Built to UL insulation system standards
- Built in accordance with NEMA and ANSI standards
Optional Features
- Consult factory for more information
- 50 and 60 Hz designs available
- Other sizes and voltages available as custom
Fusible Switch Assembly
Fully Integrated Medium Voltage Enclosed Assembly
You can now order a fusible switch that is fully integrated with our medium voltage transformers. These systems provide dependable, secure, cost-effective switching and fault protection.
The switch and transformer assembly are used as the primary main switches of unit substations, acting as a primary load break switch while also providing circuit protection (fused models).
Coordinated System
By ordering the switch and the transformer at the same time from the same manufacturer, you are assured of system coordination and a smooth set up. We wire and test the system at our factory before shipment. Upon arrival, you’ll find conveniently labeled cables ready to be properly connected from the transformer to the switch.
Specifications & Features
- 5 & 15 kV Class
- 600A & 1200A Continuous & Load-Interrupting Rating
- Selection from Industry Leading Manufacturers
- Fused or non-fused models
- Compact Design
- Left Side or Right Side Orientation
- Close coupling cable connections to transformer primary
- Easy assembly with all cabling housed and installed on transformer
- NEMA 1 Enclosures
- ANSI 61 Grey Powder Coat Paint
Standards
- NEMA 1 & 3R ratings
- ANSI 61 Grey Powder Coat Paint
- Built in accordance with IEEE, ANSI, UL, and cUL standards
Options & Accessories
- NEMA 3R Enclosure
- Kirk Key Interlocks
- 4” Infra-Red Window
- Current Limiting Fusing
- Blown Fuse Indicator
- Fuse Clips
- Spare Fuse Pocket
- Surge Arrestors
- Thermostat
- Strip Heater
- Insulated Bus
- Ground Ball Stud w/Cover
- Indicator Lights
- Auxiliary Switch
- Voltmeter
- Ammeter
- Current Transformer
- Potential Transformer
- Control Transformer
Accessories
Our full range of cataloged accessories makes it easy to find exactly what meets your project needs.
All Accessories
Accessory Parts by Catalog Number
This list of the accessories for our transformers is organized by unit type. Find the catalog number of the item that fits your specifications in the charts below.
*Note: All kVAs are listed for reference only. These are based on standard, 150°C temperature rise, K-1 units. Measure your unit for exact specifications.
Quote Tool Users: Most of these part numbers are available in the pricing feature. Use the catalog numbers you find here.
Custom Solutions
No two projects are exactly alike—and that’s where we come in. Our custom solutions are built to meet your exact specifications, whether you’re facing space constraints, unique voltage requirements, or application-specific challenges. With decades of engineering expertise and a hands-on, responsive approach, we work closely with you to deliver the right solution—on time and built to last.
Custom Power Magnetic Solutions
The Transformer Authority
Jefferson Electric has provided innovative transformer and reactor products since 1915. We enjoy a rich tradition of meeting the highest industry standards for quality, durability, and reliability for the commercial, industrial, and OEM markets. Pioneer’s Dry Type Transformer Division continues the tradition today, providing new magnetic products for a wide variety of applications and industries.
For More Information About Custom Transformers
- Find a representative for assistance
- Call our technical services department at 800.892.3755 or 414.209.1620
- Fill out our contact form
Industries We Serve
- Oil and gas
- Transit
- Elevator
- Commercial construction
- Industrial manufacturing
- Medical
- Alternative energy
- Battery charging
- Switchgear
- Power quality
- Plant automation
- Drive manufacturing
- Data center
- HVAC
