Medium Voltage Dry-Type

Unit substation dry-type transformers are designed for medium voltage power distribution where liquid-cooling is not an option, such as indoor power distribution line-ups, or outdoor areas with environmental concerns.

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Capabilities Tech Specs Get Started

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Capabilities

Maddox medium voltage dry-types are designed, built, and tested in accordance with the highest industry standards including NEMA, ANSI C.57, DOE, and IEEE as applicable. They can be configured for general purpose and unit substation applications and are customizable to give you greater control over your unit’s function and safety.

Product Scope

300 kVA - 5,000 kVA
Up to 35,000v

Technical Specs

Standard specs

Self-cooled (AA)
Aluminum windings
Voltage adjustment taps
Impedance 5.75% (±7.5%)
NEMA 1 indoor enclosure
High-grade silicon-steel core
Ground pads/lugs
150 degree C rise
VPI windings
Stub-up/down bus
Stainless steel hardware

Optional upgrades

Forced air cooling system (AA/FA)
Copper windings
NEMA 3R outdoor enclosure
Lightning arresters
80C or 115C degree rise
Solar step-up design
Electrostatic shielding
K-rated design
Cast-coil windings
Bus to ends
Transition section/terminal chambers
Temperature monitoring system
Primary load-interrupter switch
Double-thick varnish for corruption protection

Get Started

We make it easy to get a quote and order a transformer. Follow the steps below to get started.

01

Request a Quote

Call or fill out the form below to get a quote. Most quotes are turned around the same or next-day.

02

Place your order

Send us a purchase order, or give us a credit card number, and your dedicated customer service rep will send you an order confirmation and answer any questions you may have.

03

Receive your transformer

We’ll handle all transportation and logistics. Maddox has the shortest lead times in the industry so you can get the power on when you need it.

"Over the last couple weeks Maddox responded quickly to our customers needs. They provided two transformers on a short time table allowing us to get our customer re-energized. One transformer was in stock, and shipped immediately. The second had to be reconditioned and they turned it around and shipped in just a few business days. Great service with good communication along the way."

Brian Rodgers, NETA level III tech

"My company ordered a new transformer from Maddox. Kurt was an AMAZING sales rep that listened to all my concerns and met them all with solutions that fit our timeline. Dale pulled off a miracle in getting our shipment on the road and delivered not only at the exact time I requested, but 2 hours early. I cannot express how happy I am with this company. They made me look like a hero! Which is exactly what THEY were to me."

Jen Glab, microgrid sales

"We ordered transformers to use for our industrial equipment applications due to market shortages for our standard stepdown transformers. Delivery was incredibly quick and products look and operate without issue. Priced very well in comparison to other outlets - very happy to utilize Maddox in the future for our continued needs."

Todd Griffieth, ops manager

"I have purchased dozens of Maddox transformers, both low voltage dry-types and large reconditioned medium voltage units. Always great service and quality builds, with faster than industry standard lead-times."

Eric Raybould, distributor

"Quick delivery with helpful friendly staff. Great service and highly recommended. A great company to work with on all your transformer needs."

Austin Spiegel, project manager

"Over the last couple weeks Maddox responded quickly to our customers needs. They provided two transformers on a short time table allowing us to get our customer re-energized. One transformer was in stock, and shipped immediately. The second had to be reconditioned and they turned it around and shipped in just a few business days. Great service with good communication along the way."

Brian Rodgers, NETA level III tech

"My company ordered a new transformer from Maddox. Kurt was an AMAZING sales rep that listened to all my concerns and met them all with solutions that fit our timeline. Dale pulled off a miracle in getting our shipment on the road and delivered not only at the exact time I requested, but 2 hours early. I cannot express how happy I am with this company. They made me look like a hero! Which is exactly what THEY were to me."

Jen Glab, microgrid sales

"Over the last couple weeks Maddox responded quickly to our customers needs. They provided two transformers on a short time table allowing us to get our customer re-energized. One transformer was in stock, and shipped immediately. The second had to be reconditioned and they turned it around and shipped in just a few business days. Great service with good communication along the way."

Brian Rodgers, NETA level III tech

"My company ordered a new transformer from Maddox. Kurt was an AMAZING sales rep that listened to all my concerns and met them all with solutions that fit our timeline. Dale pulled off a miracle in getting our shipment on the road and delivered not only at the exact time I requested, but 2 hours early. I cannot express how happy I am with this company. They made me look like a hero! Which is exactly what THEY were to me."

Jen Glab, microgrid sales

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