Stator rewinding

A burnt winding is repairable. Stators stripped, rewound to the original specification and tested under load.

When to have it looked at

  • An insulation reading that stays low after the stator has been dried.
  • A burnt smell, or visible discolouration on the windings.
  • A phase-to-phase resistance that does not match the other two.

Why it fails

Winding insulation fails from heat, from coolant contamination, or from a short that took one phase with it. A stator that has been soaked can often be dried and saved; one that has been cooked cannot. The measurement after drying is what decides between a clean-up and a rewind, and it is worth waiting for.

How we work

  1. We record the condition in writing before anything is opened, and you get a copy.
  2. The unit is stripped and inspected. It is the only way to know the real state of it.
  3. Everything that matters is measured, not estimated.
  4. You get a written quote before any repair starts. Nothing proceeds without your agreement.
  5. We replace what has actually failed and what will fail next, not the whole assembly.
  6. It is tested under load and returned to you with the findings written up.

What decides the price

What moves the price is the platform, what we find once it is open — which nobody can know beforehand — and whether the original parts can be reused. That is why the quote comes after the inspection and not before it.

Turnaround, warranty and whether a teardown is chargeable are set by this workshop. Ask us before you commit.

When coolant has reached the winding

A motor that has run with coolant inside it is not automatically scrap, and it is not automatically salvageable either. The reading after drying is what decides, and waiting for it is worth doing.

A large drive unit opened at the mating face, gear train and main bearing exposed

How the coolant gets in

Almost always past a worn shaft seal. The seal runs against the rotor shaft, scores it, and stops sealing; coolant then has a path into the motor housing, where it sits in the winding. An insulation fault is the first thing the car notices, and by then the water has usually been there a while.

Dried, or rewound

A soaked stator can often be dried and saved. A cooked one cannot. The insulation measurement taken after drying separates the two, and it is the only thing that does: a stator that looks clean can read low, and one that looks alarming can come back. Where the winding has gone, it is stripped and rewound to the original specification with industrial insulation materials, then tested under load.

What is checked at the same time

  • The shaft seal and the shaft surface it runs on — otherwise the next coolant leak is already scheduled.
  • Bearings, which rarely survive running wet.
  • Phase resistance across all three phases, compared against each other.

Related parts and services in the shop

Book Stator rewinding, or ask us about it first.

Book a repair +385916004222