Medium Voltage Dry-Type Transformers

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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Medium voltage dry type transformer
CapabilitiesTech SpecsGET STARTED

To see our full inventory of low voltage products visit our webstore and filter by sku, voltage, or transformer type. If the unit you are looking for is not available on our webstore, or you need additional assistance please fill out the form at the bottom of this page.

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Capabilities

Transformer coils

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 corrosion 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.

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 switchgear

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.

I have purchased many pieces of equipment from Maddox ranging from 1000 kVA transformers to 10,000 kVA transformers as well as fused and nonfused load interrupter switches. I am happy with the cost and the lead time which has been perfect for the fast paced schedules with tight budgets we have been facing. Maddox has helped me meet budget and schedule. The equipment meets our rigid specifications. The customer service has been on the spot when questions arise. Maddox has been competitively bid with other gear manufacturers and even when cost is similar their lead time has been the deciding factor for my purchase orders.

Corey Zachel

Worked hard to meet my deadline. very helpful & knowledgeable.

Joshua Hargate

Worked excellent, tech support was incredible with helping me figure out what I needed as well

Heath Plemons

We've bought numerous transformers from Maddox. Excellent service both before and after the sale. The rebuilt units are coming out looking like brand-new transformers. No surprise up-charges, no problems in shipping. Highly recommend!

Scott Hotsinpiller

We ordered a unit from Maddox that had a very small leak on a weld on the top of cabinet. These things are going to happen I understand that. The unit was time sensitive to one of our customers. The Maddox Team went above and beyond to make sure they fixed the problem, got it delivered back in time! Now key factors in this was communication and they were honest and upfront keeping their word. That goes a long way in this industry. Thanks again for great customer service !!

John Wixson

Very responsive to inquiry, prompt shipping, protective packaging, on time delivery. Will be back!

Ralph Bloom

Wonderful service. Very responsive, offered all the guidance, and really stayed on top of it (I mean, really did so - send at least 10 emails on confirmation, status of the order, invoice, delivery, instructions on how to receive etc). Shipping was lightning fast (to Dallas, Texas) and without a single issue (this is not the first time I ordered commercial equipment, and every time it's a hassle). I couldn't find the unit for the same price anywhere. Overall, fantastic. I wish all companies cared as much about the product they sell

Alex Ivanov

Website was easy to navigate where I could order my own transformer with little assistance.

Christopher Bizauskas

We had a customer who lost their primary transformer in the middle of the night. Maddox was able to get a temporary transformer on site in hours. They also rebuilt the damaged transformer in record time while no sacrificing any quality. We were able to install and power up the transformer with no issues. The transformer was phased properly and the rotation matched the previous transformer. I would recommend Maddox to anyone for transformer needs.

Nicholas Wagner

We worked with Maddox most recently to repair a transformer at our site. Cameron and the repair team were very communicative, professional, and understanding of our needs to get back online as quick as possible. We are very impressed with the level of service we received and look forward to working together in the future.

Kate Bennett

Very prompt delivery and service

Paul mulcahey

We have used you recently a few times, and will continue to do so as needed, however I have had to go elsewhere many times due to cost of shipping from Maddox puts us over the top for quote, but other than shipping issue, you guys have been great, especially Gabe, very fast and knowledgeable . thank you for everything so far. Tony.

Tony Favia

We are a solar installation company based in MA. We've used many suppliers and distribution partners, and none have been as good as the kind folks at Maddox. They deliver high quality products on budget, and more importantly, on time. We've had many growing pains, and Maddox have helped us along the way with more than flexible payment plans as well as delivery timelines that matched up perfectly for our projects. They've won our business for life and we'll continue to order from them for our commercial and utility scope projects.

Tom Wu

Was in a rush need for s transformer and called these guys...best thing i ever did! they were super helpful and actually had a transformer i wanted but didn't think i could afford. had it within 3 days!!! transformer works great and the folks were very nice and knowledgeable about what i needed. didn't try and upsell me or anything like that. THANKS!!!!

Riley Wicker

Very professional and available people. I'll definitely do business with them

Andre Tapxure

Very Pleased with the product and pricing I received. Will use them again in the future.

Jordan Young

Very pleased with delivery and the transformer works great so far. Thanks!

Brandon Frazier

very knowledgeable and qualified with assisting us to purchase the correct transformer

Will's way

Very good company.

Alixon Machado

Transformer that I ordered showed up when expected

Todd Horning

Transformer was ordered mid-day and arrived the next morning. Excellent service!

Paul Novotny

Transformer came in very quick got installed the next day worked great will use Maddox again

Jason L Canton

This was an easy company to deal with. They were very helpful in the sizing of the transformers that I needed. From the time I order them, it was delivered to the jobsite in 3 days. Impressive.

Patrick Callan

This is our first purchase with Maddox. They were very easy to talk to. The representatives were knowledgeable and the shipment came sooner than expected for the shipment.

JOAQUIN GALLEGOS

They made a recommendation to suit my needs at a good price.

LeRoy Finnigan

This is my first time ordering from Maddox & you guys have been great! Stephen & Laura have been a joy to work with & made this the easiest purchase I've made in a while. It's good to find companies that make the buying process easy. I don't know if we'll need many transformers in the future, but I'll definitely be recommending you to our electricians.

Jesse Whittington

This is a great company to work with! The customer service people are friendly and helpful and keep you updated; Especially Josh! He has just been great! :) The items ship so fast and are packaged very well. Fair prices as well. Will be happy to order from them again. Thanks

David Major

They respond fast and fast shipping.

TT Nguyen

They have stock when others don't and are quick to ship and fill their orders. VERY THANKFUL we found them

Mike Adams

These guys are on their game! I have placed several orders this year and they deliver as promised.

William Perry

The transformer I ordered was delivered onsite at our project in two business days. Great service!

Jerome Trammer

The best place to buy used, now refurbished transformers

Faith Trent

The transformer looked and worked great. Very fast shipping. Will use these guys again.

Advanced Performance

Thanks for quick answer , quick action, and best part and fast shipping.

Turhan OZTURK

Super fast shipping, as promised.

CAHAS CLOSETS

Shipped promptly, no fuss. Had a minor issue that the rectified same day. Absolutely recommend using maddox for all of your transformer needs. Shipped halfway across the country in 3 days or less, we are very satisfied.

Frank M

Super efficient and lightning fast shipping!!! Shipping cost was great and our 15kva 208to480 transformer is great!!

Rob Frankel

Service cant be beat. Chris helped me out with all the questions I had. When I needed to change the delivery to a lift gate, they did it without giving me any hassle. Also didn't even cause a delay in the shipping. Top notch professionals.

Josh Wei

Received what we ordered, and fast.. Good Service.

John Belotti

Received the correct Transformer in just a couple days. Excellent packaging.

Jim Mangarella

Quick order fulfillment and knowledgeable customer service personnel. Will use again in the future.

Cogsdill Tools

Real knowledgeable chat representative. Fast delivery. Product is exactly what I needed. Looks like really quality transformer and price was good value.thank you.

Ron Slinger

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

Austin Spiegel

Quick, communicative, and accurate transaction. Would buy through Maddox again!

John Parke III

Quick shipping and good protection

jay graybill

Quick service and great transformer. I could not be happier with both! Thank you

Samuel Ramsey

Quick Dellivery and very reponsive to questions/concerns. We had a good experience dealing with Maddox

Fred Nugent

Quick delivery and hassle free service!

Shain Hammons

Prompt Shipping and delivery, Ordering to delivery very smooth process

CADNASTY850

Quick delivery and great products

don rob

Quick delivery and great pricing!

Branden Schell

Quick and dependable service. We will use again in the future.

Liquid Metal Concepts

Quick , reliable and very professional company!!

Oleg Burshtyko

Purchased a step-up transformer from Maddox knowing nothing about them...These guys went above and beyond on top of excellent pricing. I honestly could fill this up with nothing but good things to say about my experience with Maddox. If I could give them 10 out of 5 stars I would.

Michael Leslie

Prompt service, Make ordering and verifying your needs so you get the correct part easy and friendly

Patrick Weeks

Prompt and friendly service! Will use these guys again for next project!

Todd Boos

Prompt and courteous service!

Todd P

Price was good. It was delivered fast. I am happy with the purchase.

Jared Loberg

Placed two orders, fast deliveries, great communication! Looking forward to do more business with Maddox !

Thomas Danet

Our salesperson helped us to find a transformer that fit within our budget and met design requirement. Excellent service, clear communication, and quality product.

Casey Place

Ordering was easy and when I had a question the knowledgeable staff answered promptly and courteously.

Kenny C

Ordering through Maddox was painless and they shipped a 200lb+ Transformer to our door in 3 days when we needed it urgently. Thanks again!

Tony Jr Masone

Ordering was easy and item arrived quickly. I want to say thank you to the Maddox team.

Roy Pennington

Ordered transformers to use on 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

Ordered online, shipped very quickly. Great communication. Would recommend.

Leo Dunlavy

nice and easy transaction with good price and good delivery time

fred j. vacanti jr.

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

Maddox Transformer offered a great buying experience. They had the transformer I needed at a great price and shipped it promptly! I received it the next day and am happy with the purchase!

Mitchell Lance

Made an Online order. Maddox was extremely helpful and was emailing me with updates on my order. They even called to make sure that I would be available to receive the transformer or if they had to delay the shipment, as I ordered closer to the end of the year I really appreciate the dedication they showed to making sure I got the product I ordered. The unit arrived and works great.

Calvin Kitchen

Maddox, your company is awesome !! very knowledgeable, great service and turn around time. thank you

james christopher

Maddox website was easy to navigate, and showed what transformers were in stock. Luckily the step up transformer I needed was in stock, shipped within 24 hours, and was on my dock in 4 days. If you know exactly what you need, I would highly recommend Maddox based on my experience!

Andy Gredell

Maddox Transformers is a great company to work with... Circuit Breaker Sales in Florida has had great experiences with Maddox recently. Prompt responses to our requests and excellent work on reconditioning transformers. Very Pleased with Maddox and will continue to utilize them in the future.

Paige Hahn

Maddox Transformer is a reliable product and a highly professional company. Mac Spiller was very responsive and helpful with all my questions and concerns. His attention to detail and curtesy made my experience with Maddox over the top!

Richard Butera

Maddox - Great company and great products, little slow on the customer service side in the beginning but increase 10 fold after Jassen started helping us get back on track and get us our 2- 2500KVA transformers. Will definitely order from them again, Thanks Jassen!

JaY Chapman

Maddox id a great company to work with for buying any transformer that you need. Super Fast Shipping and great communcation. Plus a great price!!!

stephen theriault

Looked around hands down the best bang for the buck saved me over 1200 bucks from my supply house beers on me lol

Jason Ambrogi

Mac and his crew did an absolute fantastic job installing my transformer. I had a transformer fail due to the heat and age, but Mac quickly had a replacement for me at a great price. His team did a bang up job getting it on my site, so we could get it installed. HIs team saved me a week of downtime and lost product. We will be using them again in the future! Thanks from the team at Great Western Malting at the Port of Vancouver. -GWM Maintenance Manager

Irl Kellum

Great to work with!! Very knowledgable and fast service!! thanks!!

Randy Deweese

Its been a pleasure working with the Maddox Team. Equipment pricing is competitive and staff expertise is strong. Our initial purchase of 4 large Transformers has gone seamlessly. Considering we are engaged in a multi-year purchase of transformer replacements across our communities we remain confident that this project will continue to be successful due to our work with Maddox.

Roy Manno

It was nice and easy ordering the transformer delivered in time I recommend Maddox strongly don’t look any ware else

abdelkader chaabane

It was easy to find what I needed and order through the website. After my order arrived, I had a technical question, and the support staff was knowledgeable and helpful. Overall, it was a great experience.

J.T. Johnston

I wasn't sure what size step up transformer I needed. Called the tech support line and these people are great. Very hepful and friendly. Unit shipped following day after the order and arrived soon after. Great product and company. I highly recommend and will use them for future purchases. Thanks Maddox!!

Dan Selph

In a post Covid world where nothing is available in the construction market, Maddox Industrial Transformer had what I needed. Reasonable price and fast shipping. Pretty shocked and pleasantly surprised to find a company that still values service and support. Thank you for your help.

scott bancroft

I’m thoroughly impressed. The transformer arrived 3 or 4 days after ordering online. It was well packaged, and well constructed. I’ll definitely use Maddox the next time I need a transformer.

Nathan Willi

I'm a trucking company owner that delivered here. Nice new facility. Friendly, helpful staff. Easy to get to and didn't take long to unload. Hopefully I have the pleasure of ending up here again!

Justyn Anderson

I would like to tell everyone what a great experience I had dealing with Maddox transformers. Every one that I had any contact with form sellin buying and warehouse was great.

Clemme Queen

I work in the Data Center space. We have well over 100 Maddox Transformers. They have preformed exremely well over the past two years. Customers service is always top notch. Highly recommend this company.

Matrim Tuon

I will have to say that I was very impressed with the way you processed our order. We were provided updates through the entire process, from quoting to the delivery. I absolutely would recommend you to anybody looking to purchase or repair transformers.

Ben Liddic

I was very pleased with the quick response and shipping I received on a short timeline I had for the project I was doing.

Greg Andrie

I was very happy with the product, service, and delivery on time. Especially Josh long was helping me out deciding which transformer to use. I purchased a transformer 30KVA step down from 240V to 208V 3 phase. The transformer has 7 tap inside which you can choose or adjust exactly output Voltage. Our voltage input 252V, 3 phase with high leg 208V phase B. But our new machine need to run at 200-208 Volts. Thank you so much! super highly recommended.

Bao Nguyen

I spoke with Josh Long and he was the most knowledgeable sales rep on transformers I had the pleasure of speaking with during my 2 month long ordeal to find a very specific transformer for my machine from overseas. I really appreciate his expertise on the matter and I look forward to working Josh again.

Hien Tran

I ordered two transformers from Maddox within a week, both were for a trade show and both were urgent. The first was delivered to us in a 2 day timeline which was awesome, the second one we had our courier pick up from their warehouse and we had it next day. Transformers ran perfectly, excellent service from this company.

Cullen Ellis

I ordered a transformer to go from my 3 phase RPC from 240 delta to 480v Y. There team really helped me with different options to suit my needs now and the future instead of just selling me what "they had laying around." As my needs grow, I will be a returning customer.

John Allen

I love this company. I'm an electrical contractor and I use them for all my transformer needs and recommend them wherever I can. Josh Long and Chris Stouffer always return my calls and answer my emails. They provide a great, personalized service. It's nice to go straight to the source to buy rather than going through an electrical supply house or another middle man.

Naomi Doire

I called Maddox to order a transformer, I found them to be very helpful and they had the transformer in stock! It was shipped the next day. I'm very happy with their service!

Steve Farrell

I called for info on an item these guys don't even sell and Nick went above and beyond in helping me out. If that's how he's like with someone who's not even a customer of his then you can be pretty sure that if you did buy from these guys that you'd get superior customer service.

F S

I am looking to purchase a step up transformer and started to read the reviews. Hats off to you Maddox for your efforts and responses to all the reviews. I look forward to working with you!

dennis mitchell

Had an issue with shipping scheduling. Shipping manager called me directly apologized and is compensating for the miscommunication. Said this is not how we normally do things . Super happy to see a company taking accountability and respecting truck drivers time

laxislove laxislife

Have purchased two transformers from this company over the past year and they have exceeded expectations every time. Super fast delivery, easy to order and very helpful. would recommend!

Todd Robertson

great service, quick delivery

Daniel Hatfield

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Medium voltage dry type transformer on a forklift