Generator Rewinding · Gauteng
Generator Rewinding.
Restored to Factory Specification.
We rewind generator alternators across Gauteng when our tests show the stator or rotor windings have failed. If your set runs with no output, low voltage or a burning smell, we test the alternator, AVR and excitation first, so you pay for a rewind only when a rewind is the repair. Alternator rewinding typically costs R6,000 to R18,000+, depending on the alternator.
Callout fee waived when you accept our written quote. 1-year workmanship guarantee. See prices
- Windings tested before any rewind
- AVR and excitation checked first
- Stator and rotor rewinds
- Written quote before work
The Service
What generator alternator rewinding involves
Generator rewinding replaces the failed copper windings in your alternator, usually the stator and, when the tests call for it, the rotor or the exciter winding. We recommend it once generator fault finding has ruled out the breaker, the AVR and the excitation circuit. The wider electrical diagnosis that comes first is our generator alternator repairs service.
A generator that runs with no electricity, or with low or unstable voltage, often needs a simpler repair than a rewind. Burnt insulation, an earth fault or a short between turns can cause it, and so can a failed regulator. Read more about a generator not producing power, low voltage and unstable voltage.
When a rewind is the repair, we strip the old winding and inspect the core for damaged laminations and slots. The new coils follow the wire gauge, insulation class, winding pattern and connections of your alternator. We then varnish-treat the finished winding to seal out the moisture and heat that often caused the first failure.
Winding faults sit where electrical and mechanical engineering meet. Our lead technician, Charlie, holds a Degree in Electrical Engineering and a Degree in Mechanical Engineering and is a Diesel Plant Fitter, so we look at the cooling, bearings and load that damaged the winding as well as the copper itself.
We assess alternators across Gauteng, including Johannesburg, Pretoria, Centurion, Sandton and Midrand. To book, call 082 057 4605 or send us the details. We test any alternator make on the unit, and you approve the rewind only once you have the test results and the written quote.
Winding failure on your generator?
Call or WhatsApp 082 057 4605 to book an alternator test. If a winding failure has left you without power, we arrive within 1 hour, 24/7.
Signs of Winding Failure
When does a generator need rewinding?
Each of these is a reason to test your alternator. Our tests then show whether the windings need rewinding or a simpler repair will do.
01
Burnt alternator windings
A burning smell, darkened varnish or scorched copper often follows overload or long overheating. It tells us where to look, and our insulation and resistance tests show whether the winding has failed.
02
No electricity while the engine runs
A healthy engine with no usable voltage can mean a tripped breaker, a failed AVR, lost excitation or a winding fault. We separate those four before we condemn the stator or rotor.
03
Low or unstable voltage
A low but steady reading and a reading that moves are different faults. Either can come from engine speed, the load, the regulator or the windings, and our meter readings show which.
04
Insulation deterioration
Moisture, age and heat break down the insulation between turns and to earth. An insulation-resistance test measures it. If the reading is low, we dry the winding and retest before we recommend a rewind.
05
Overheating
A hot alternator can mean blocked cooling air, overload or failing insulation. We find out which, because only failing insulation calls for new copper.
06
Short circuits and earth faults
A short between turns, or a winding down to earth, trips the set as soon as it takes load. We confirm stator and rotor faults with resistance and insulation tests.
Diagnosis
How a winding fault is confirmed
We test the alternator before we recommend a rewind, and on the same visit we rule out the faults that look identical from the building.
Visual inspection
We open the alternator end with the set isolated and look for burnt varnish, loose connections and mechanical damage before anything is stripped.
Winding resistance
We measure resistance between phases, and on the rotor where we can reach it, to find open circuits and shorted sections. We compare the readings with the figures for your alternator.
Insulation resistance
We measure insulation from the windings to earth. A weak result can mean moisture or failed insulation, so we dry the winding and retest before we recommend a rewind.
Voltage regulation and excitation
We check the AVR and the excitation circuit with the engine running at a steady speed, because a regulator fault produces the same no-power complaint as a dead winding.
Alternator assembly
When noise or heat points to the alternator, we inspect the bearings, the fan and the mounting, and we quote any mechanical repair separately from winding work.
Repair or replacement
We weigh the core condition, the frame size and the price of a replacement alternator against a rewind, and give you our recommendation in writing before you approve any work.
The Rewinding Process
How a rewind is carried out
- 01
Assessment & viability testing
Insulation resistance, winding resistance and a visual inspection show whether a rewind is viable and worth it against the price of a replacement alternator.
- 02
Strip & core inspection
We strip the old windings, then clean and inspect the core for lamination faults and slot damage that would weaken the rewound unit.
- 03
Rewinding to specification
We wind new coils in quality enamelled copper to the original specification: the correct gauge, insulation class, winding pattern and connections.
- 04
Vacuum impregnation & curing
We vacuum-impregnate the finished windings with varnish and oven-cure them to protect against moisture, dirt and heat.
- 05
Testing & load verification
Insulation resistance, winding resistance, a high-potential test and a full load test confirm the rewound alternator meets its original output before it goes back into service.
Rewind vs Replace
When rewinding is viable, and when replacement is better
Rewinding makes sense when the core is sound and only the winding has failed, especially on a larger alternator or a frame that is slow to replace. Replacement makes more sense when the core is damaged, the alternator has a history of earth faults, or a small replacement unit is easy to get.
You get our assessment and a written quote before you commit to any rewind cost, and we tell you plainly when a replacement alternator is the better buy. Our cost guide puts alternator rewinding at R6,000 to R18,000+, depending on the size of the alternator.
Core inspected first
A damaged core can rule a rewind out
Quote before work
You approve the cost in writing first
Matched to your alternator
Gauge, class and pattern follow the unit
Replacement still an option
We say so when it is the better buy
Common Questions
Generator rewinding — questions
Can a generator alternator be rewound?
Yes, when the winding has failed and the core is sound. A small alternator, or one with a damaged core, is often better replaced, and we tell you which after testing.
What causes generator windings to burn?
Overload, poor cooling, moisture in the insulation, voltage spikes and age. If you notice a burning smell after any of these, switch the set off and book a test before you run it again.
When does a generator need rewinding?
A generator needs rewinding when tests show a winding or insulation fault. We check the AVR, breaker and excitation first, because many no-power faults turn out to be one of those and never need a rewind.
Can a generator produce low voltage because of damaged windings?
Yes. Engine speed, the load and the AVR can cause low voltage too, so we measure all of them before we name the windings.
Is generator rewinding better than replacement?
Rewinding is the better choice when the core is sound and the alternator is large or hard to replace. Replacement is better when the core is damaged or a small alternator is easy to source. We price both so you can compare.
How much does generator rewinding cost in Gauteng?
Our cost guide puts alternator rewinding at R6,000 to R18,000+, depending on the size and type of alternator. You get a written quote after testing, before any work starts.
Can an alternator produce no power while the engine runs?
Yes. That pattern is electrical and comes from the AVR, the breaker, the excitation or the windings. A healthy engine tells you nothing about the alternator, so we test it.
Do you rewind Leroy-Somer alternators?
Yes. We test Leroy-Somer alternators the same way as any other make and recommend a rewind only when the results support it.
What are signs of an alternator winding fault?
No output, very low output, or a set that trips the moment it takes load can all point to the windings once the AVR is ruled out. A burning smell or visible damage adds to the evidence, and our tests confirm it.
Can bearings be part of an alternator visit?
Yes. If there is noise or play at the alternator end, we check the bearings and quote that work separately from any winding repair.
Is rewinding done at my premises?
Yes. All our repairs, alternator work included, are carried out at your premises. We test the windings first and explain whether a rewind or a replacement alternator makes more sense before any work starts.
Still unsure what the fault is? Call or WhatsApp 082 057 4605 for onsite diagnosis.
Related Services
Other generator services
- Alternator Repairs Diagnosis before a rewind is chosen
- Not Producing Power Engine runs, no usable electricity
- Low Voltage Voltage is present but low
- Unstable Voltage Voltage moves or flickers
- Fault Finding The visit before a part is named
- AVR Repairs The regulator, not the windings
- Contact Book a winding assessment
Service Areas
Generator rewinding across Gauteng
We assess alternators for rewinding across Gauteng, including Johannesburg, Pretoria, Centurion, Sandton, Midrand and the surrounding suburbs.
Free written quote
Need Generator Rewinding?
Tell us whether the engine runs, and whether the voltage is missing, low or unstable. We test the alternator and give you a written quote before you commit to any rewind cost.
- Call
- 082 057 4605
- Message us on WhatsApp
What happens next
- We reply with questions about the generator, or to book a visit.
- A technician comes to you. For a breakdown we arrive within 1 hour.
- The fault is diagnosed on site and you get a written quote. No work starts until you accept it.
Charlie, lead technician: Degree in Mechanical Engineering, Degree in Electrical Engineering, Diesel Plant Fitter. Generator specialists since 2000.