Generator Rewinding · Gauteng
Generator Rewinding.
Restored to Factory Specification.
When generator windings fail due to insulation breakdown, overheating, or electrical damage, rewinding restores full output at a fraction of the cost of a replacement alternator. Professional workshop service across Gauteng.
Signs of Winding Failure
When Does a Generator Need Rewinding?
No or low output voltage
Engine runs normally but the alternator produces no voltage or significantly reduced voltage. Stator winding open circuit or partial winding failure.
Insulation resistance failure
Megger testing reveals insulation resistance below acceptable limits — a reliable early indicator of winding degradation before catastrophic failure occurs.
Burning smell or visible damage
Burnt insulation odour, discolouration of windings, or visible scorching inside the alternator housing. Often follows an overload event or sustained overheating.
Reduced power output
Generator output falls short of its rated kVA. Partial winding failure causes the alternator to produce less than its design capacity under full load.
The Service
Professional Alternator Rewinding Across Gauteng
Generator winding failures are caused by thermal stress, moisture ingress, voltage spikes, mechanical vibration, or gradual insulation degradation over years of service. When windings fail, the common assumption is that the entire alternator requires replacement — a significant cost, particularly on larger industrial generator sets. In many cases, professional rewinding restores the alternator to full factory specification at a fraction of that cost.
Generator Repair Services provides alternator rewinding services across Gauteng, covering stator windings, rotor windings, and excitation windings across all major alternator brands — Stamford, Leroy Somer, Mecc Alte, Marathon, and others. Before any rewinding work is undertaken, we assess the unit thoroughly to confirm that rewinding is both viable and cost-effective for your specific alternator. Not every winding failure justifies rewinding, and we provide an honest assessment before any cost is committed.
Our rewinding process follows original manufacturer specifications in every respect — wire gauge, insulation class, winding pattern, and connection configuration. Deviation from specification produces an alternator that either underperforms or runs hot, reducing service life. The core is cleaned and inspected for lamination faults and slot damage before new windings are installed, ensuring the foundation is sound before work begins.
Workshop rewinding — wound to original manufacturer specification
Once wound, every unit is vacuum impregnated with varnish and oven-cured. This process fills all voids in the winding and provides long-term protection against moisture ingress, contamination, and thermal stress — the same causes that led to the original failure. Skipping this step leaves rewound windings vulnerable to the same failure modes within a short period.
Testing after rewinding is comprehensive. Insulation resistance, winding resistance, and high-potential testing are completed before the unit is reassembled. After reassembly, a full load test confirms the alternator meets its original rated output specification. The unit is not returned to service until every test is passed.
The Rewinding Process
Assessment & viability testing
Insulation resistance, winding resistance, and visual inspection determine whether rewinding is viable and cost-effective against the value of a replacement alternator.
Strip & core inspection
Old windings are stripped and the core is cleaned and inspected for physical damage, lamination faults, or slot damage that would affect the rewound unit's performance.
Rewinding to specification
New coils are wound using quality enamelled copper wire to original manufacturer specification — correct gauge, insulation class, winding pattern, and connection configuration.
Vacuum impregnation & curing
Completed windings are vacuum impregnated with varnish and oven-cured, providing long-term protection against moisture, contamination, and thermal stress.
Testing & load verification
Insulation resistance, winding resistance, high-potential testing, and a full load test confirm the rewound unit meets original output specifications before return to service.
Winding failure on your generator?
Call to discuss rewinding options and get an assessment.
060 316 0484
Rewind vs Replace
Rewinding Is Often the More Economical Choice
On larger generator sets, alternator replacement is a major cost. A quality rewind — done correctly to original specification — delivers the same service life as a new unit while costing significantly less. For industrial and commercial generators where downtime has a direct financial impact, rewinding also offers faster turnaround than sourcing and fitting a replacement alternator, particularly for less common makes and frame sizes.
We assess each unit honestly. Where the core is damaged, where the alternator is beyond economic repair, or where a replacement unit represents better value for the customer's situation, we say so. The assessment is provided before any commitment to rewinding costs.
All alternator makes
Stamford, Leroy Somer, Mecc Alte & more
Honest assessment first
Viability confirmed before cost committed
Factory specification
Wire gauge, class & pattern matched
Warranted workmanship
Covered against materials & labour defects
Service coverage: Generator rewinding services are available across all Gauteng areas including Johannesburg, Pretoria, Sandton, Midrand, Centurion, Randburg, Roodepoort, Kempton Park, Boksburg, Benoni, Germiston, Alberton, Fourways, and surrounding regions. View all service areas →
Need Generator Rewinding?
Call to discuss rewinding options for your alternator. We assess viability honestly before any cost is committed — across all of Gauteng.