Rewind or Replace? A Cost Guide for Failed Industrial Electric Motors

When an industrial electric motor fails, the question is rarely “can it be fixed?” — almost any motor can be rewound. The real question is whether rewinding or replacing gives you the lower total cost over the life of the machine. For a busy plant, the answer depends on the motor’s size, how hard it works, its efficiency class and how quickly you need it back. Here’s a practical framework.

Start with total cost of ownership, not the invoice

The purchase price of an industrial motor is a small fraction of what it costs to run. For a motor that runs most of the day, energy typically accounts for well over 95% of its lifetime cost — the electricity it draws dwarfs both the original purchase and any repair. That single fact reframes the decision: a few percentage points of efficiency matter far more than the gap between a rewind quote and a new-motor quote.

So the useful comparison isn’t “rewind price vs new price.” It’s the total cost of ownership of each option — purchase or repair, plus the energy the motor will consume over the years you keep it, plus the cost of downtime while you wait.

Does rewinding hurt efficiency? Not if it’s done properly

There’s a long-standing myth that rewinding always makes a motor less efficient. Independent testing says otherwise. The EASA/AEMT rewind studies — first published in 2003 and reaffirmed in 2019 on premium-efficiency (IE3) motors — found that when good-practice procedures are followed, the average change in efficiency falls within the ±0.2% accuracy of the test method. In several cases efficiency actually improved slightly.

The catch is “good practice.” The biggest risk to efficiency is overheating the stator core during winding removal; done carelessly, that raises core losses for the rest of the motor’s life. Reputable service centres control burn-off temperatures, measure core loss before and after, and follow recognised standards such as ANSI/EASA AR100 and IEC 60034-23. Ask your repairer how they manage core temperature — the answer tells you a lot.

Efficiency classes and where the rules are heading

Motor efficiency is graded on the international IE scale: IE1 (Standard), IE2 (High), IE3 (Premium) and IE4 (Super Premium). Australia has regulated three-phase motor efficiency for years, with minimum standards (MEPS) set at IE2. That bar is rising: in 2026 Australia’s energy ministers approved lifting the minimum to IE3 for medium and large motors and widening the range of sizes covered, with IE4 flagged for some larger motors in future.

Why it matters for a repair decision: if you’re running an older IE1 or IE2 motor that works long hours, replacing it with an IE3 unit may pay for itself in energy savings — while a motor that runs only occasionally rarely justifies the upgrade on energy alone.

Size: the rough rule of thumb

As a general guide:

• Small motors (roughly under 7.5–11 kW): Mass-produced and relatively cheap to buy, so replacement is often the economical choice — particularly if the motor is low-hours or an efficiency upgrade is on the table.
• Medium to large motors: Here rewinding usually wins. A quality rewind costs a fraction of a new unit and returns the motor to full service with no measurable efficiency penalty when done well.
• Large, specialty or hard-to-source motors: Rewinding is almost always the sensible path — a new equivalent can be expensive and slow to obtain.

These are starting points, not rules. A low-hours medium motor facing an efficiency upgrade might still favour replacement; a critical small motor you can’t afford to have offline might favour a fast repair.

Lead time: the factor that’s easy to underestimate

New industrial motors — especially larger frames, specific mounting arrangements or non-standard voltages — can carry lead times of weeks or months. If that motor drives a critical process, every day it’s down has a cost. A rewind can often return your existing motor far sooner, which is why lead time frequently decides the question for critical equipment regardless of the headline price.

A quick decision checklist

• How many hours a year does it run? (More hours → efficiency matters more.)
• What’s its current efficiency class, and would IE3 save enough energy to justify replacing?
• How big is it? (Smaller → lean replace; larger → lean rewind.)
• How fast can you get a new equivalent, and what does downtime cost per day?
• Is it a standard off-the-shelf frame, or specialty and hard to source?

Work through those five and the answer usually becomes clear. When it doesn’t, a workshop that does both — and will give you an honest comparison rather than defaulting to the pricier option — is worth its weight.

Perth Rewind Industries has rewound and repaired electric motors from our Bayswater workshop since 1981, for industrial, commercial and domestic customers across Perth and WA. Learn more about our electric motor repairs and rewinding, browse our electric motor range, or contact us for an assessment.