What is Transformer Rewinding: Process and Benefits

Transformer downtime is expensive. So is buying a brand-new transformer. And on top of that, it may take weeks or months to arrive. Even when it does arrive, it likely won’t have the same dimensions as the previous unit. 

If your transformer only has damaged windings, there may be a better option. Transformer rewinding.

In this article, we’ll look at transformer rewinding: how it works, why it’s worth considering, and how Maddox does it. 

What are transformer windings?

Transformer windings are the metal coils of copper or aluminum wrapped around a transformer’s core. They are responsible for stepping the voltage up or down. Without them, the voltage conversion process couldn’t happen. 

A number of things can damage transformer windings. Excessive loading, system faults, and even general wear-and-tear can cause the insulating paper to break down over time.

When the windings fail, the transformer has to be repaired or replaced. That’s where rewinding comes in. 

What is rewinding?

Transformer rewinding is the process of removing damaged coils, reverse-engineering them, and building or “winding” a brand-new set of coils. Engineers redesign and build brand-new coils using all-new wire, insulating paper, and foil sheets. These new coils are then re-installed around the existing steel core and placed back into the original tank. Your transformer is now basically a brand-new unit that’s ready for service.

Why should you consider rewinding your transformer? 

Transformer rewinding provides three main benefits: space, speed, and savings.

Keep the Same Footprint

One of the biggest headaches of replacing a transformer is dealing with retrofit issues. Newer transformers might not match your old dimensions. That means a replacement unit may not physically fit in your current space–especially if it’s close-coupled to other electrical devices. 

You might also have to pour an entirely new concrete pad. And, if the new dimensions are different, the original cables might not reach the new bushings. Then you have to completely remake those connections.

Rewinding reuses your original tank. No pouring new pads, and no remaking connections. You get to keep the exact dimensions of your old transformer, ensuring it fits perfectly into your space with the exact same connections.

Get Your Unit Twice as Fast

Depending on market conditions, industry lead times for a brand-new transformer can stretch anywhere from 35 to 80 weeks. But with rewinding, you’re not waiting on a full factory build. We’re only waiting on materials and labor for the new coil. Maddox can rewind your old transformer in half the time it takes to build a new one. 

Need something even faster? If you don't need an exact match, Maddox keeps thousands of new and remanufactured transformers in stock. While industry lead times for new units stretch into the months or years, our ready-to-ship new or remanufactured transformers can often be delivered in days or weeks for emergencies.

Save on Costs

Buying a brand-new transformer comes with a premium price tag. Especially if it has to match your current space and layout exactly. When you buy new, you’ll pay for a new tank, a new core, and all the other components, plus the time and expertise to design everything from scratch. 

Rewinding bypasses those expenses. Since you’re keeping everything else in the original transformer, you’re only paying for the materials and labor to build the new windings, and only pay for the necessary component upgrades. 

Why rewind with Maddox?

So rewinding is worth considering. But why do it with us? 

We’ve invested heavily in the training, machinery, and people needed to rewind transformers. Rewinding transformers can’t be taught from a textbook. It’s first-hand knowledge that has to be  passed down from one person to another. 

Additionally, our rewound transformers go through a thorough battery of tests including Transformer Turns Ratio, Winding Resistance, Megger, and more. Maddox tests every rewound transformer to make sure it runs like new. 

Plus, if you need something temporary while your unit’s in the shop…we’ve got you covered. We have thousands of rental transformers across the country ready to ship to you. 

Conclusion

Damaged transformer windings don’t have to destroy your budget. Or your project schedule. Transformer rewinding means you keep your footprint, save money, and get your transformer back a whole lot faster. 

If you need a transformer rewind, fill out the form below. 

We’re here to get your project online and on time.