High-tension (HT) motors are the workhorses of cement, power and chemical plants — driving mills, fans, compressors and crushers. When one fails unexpectedly, the whole line can stop. That is why HT motor overhauling is one of the most important, and most specialised, jobs in industrial electrical maintenance.
This article explains what a proper HT motor overhaul actually involves and how to choose a competent overhauling company in Rajasthan.
What a proper HT motor overhaul includes
A real overhaul is far more than "clean and refit". It should cover:
- Incoming inspection and testing — insulation resistance (IR), polarization index (PI), winding resistance and, where needed, surge comparison tests to find weak insulation before it fails.
- Dismantling and cleaning — careful removal, cleaning of windings, and inspection of the stator, rotor, bearings and cooling paths.
- Rewinding (when required) — replacing degraded windings with correctly specified insulation class conductors, proper coil forming and re-varnishing.
- Bearing replacement and alignment — new bearings, checked clearances and precise alignment on refit.
- Testing before return to service — no-load run, vibration check and final electrical tests to confirm the motor is fit for heavy plant duty.
A contractor who skips the testing stages is gambling with your production.
Warning signs of a poor overhaul
- No before-and-after test records handed over
- Windings re-used when readings clearly show degradation
- No vibration or no-load run before dispatch
- Vague answers about insulation class and varnish process
Insist on a documented test report at handover. It is your proof the motor will last, and your evidence if it does not.
Why local, experienced contractors matter
HT motor work often happens under shutdown pressure. A contractor who has overhauled motors at operating cement plants — for example, multiple HT motor overhauls alongside ESP, transformer and HT panel wiring modification at a Rajasthan cement works — understands how to work within a tight window and still deliver on quality.
At Shree Kalyan Projects & Solutions, HT motor overhauling is a core service, backed by 16 years of plant experience and a "B" Class electrical licence (No. 14090). Overhauls are carried out with full test records, task-specific safety certification, and proper tooling.
The safety dimension
HT motor overhauling is high-voltage, high-risk work. A serious company will:
- Certify technicians specifically for HT and high-voltage tasks
- Run a documented risk assessment before starting
- Equip every worker with correct PPE
- Follow IEC / OSHA-aligned safety practices
Questions to ask an overhauling company
- Will you provide IR, PI and winding-resistance readings before and after?
- What insulation class and varnish process do you use for rewinds?
- Do you carry out a no-load run and vibration check before return?
- Can you work within our shutdown window?
- What is your experience with motors of our rating and application?
The bottom line
A good HT motor overhaul buys you years of reliable service and protects plant efficiency; a bad one is a failure waiting to happen. Choose a company that tests rigorously, documents everything, and treats safety as non-negotiable.
Planning a shutdown or facing a motor issue? Request a quote and we will scope the overhaul with you.
Shree Kalyan Projects & Solutions is a ‘B’ Class licensed electrical contractor (Licence No. 14090) with 16 years serving cement, power, chemical & solar plants across Rajasthan.
