Workshop 48–72 hrs standard

Dynamic Balancing & Rotor Machining

ISO-Grade Balancing: Because Rotor Forces Grow With the Square of Speed

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50–2000kg

Rotor Capacity

G1.0

Balance Grade Achievable

0.001mm

Dial Gauge Resolution

ISO/API

Certified Standards

Why Our Engineers

A rotor at 3,000 RPM generates 100× more imbalance force than at 300 RPM. The same residual imbalance that is invisible at slow speed will destroy a bearing at full speed. We balance to ISO 1940 Grade G1.0 where required, not just 'good enough'.

Overview

Rotor imbalance is one of the most common and most preventable causes of turbine bearing failure, seal damage, and shortened rotor life. Keshav Enterprises performs precision journal machining and ISO 1940 / API 670 dynamic balancing for rotors from 50 kg to 2,000 kg at our dedicated workshop facility. The rotor is first machined to restore geometric integrity (round journals, concentric labyrinth lands, correct surface finish) before balancing. This sequence matters: balancing a geometrically distorted rotor merely masks the problem. Our balancing reports document initial unbalance, correction planes, mass corrections, residual unbalance, and the ISO balance grade achieved, providing full traceability for your maintenance records.

Our Process

Rotor Receipt & Initial Measurement

Rotor received and cleaned. Initial mechanical runout measured using precision dial gauges at all journals, coupling fits, and labyrinth lands on a precision static stand. Electrical runout checked. All diameters measured and recorded versus OEM specification: out-of-round, taper, and journal undersizing documented.

Journal Condition Assessment

Surface finish measured using profilometer at 3 positions around each journal circumference. Visual inspection for scoring, Babbitt transfer, corrosion pitting, and wear patterns. Hardness checked. Minimum material removal calculated to restore geometry and finish within OEM limits.

Journal Grinding & Polishing

Precision cylindrical grinding of journals on CNC grinding machine: roundness restored to 0.005 mm max, taper to 0.005 mm per 100 mm max. Ground surface polished to Ra 0.4 μm (OEM bearing surface specification) using precision polishing lathe. Absolute minimum material removed to preserve shaft life.

Labyrinth & Gland Portion Machining

Re-machining of labyrinth seal lands, gland areas, balance disc faces, and coupling fits on precision CNC lathes. All surfaces set concentric to journal datum before machining using a 4-jaw chuck and dial gauge zeroing, essential to maintain rotor geometric integrity and avoid introducing new runout.

Dynamic Balancing: Two-Plane Correction

Rotor mounted in hard-bearing dynamic balancing machine. Initial unbalance measured simultaneously in two correction planes (coupling end and governor/impeller end). Trial masses applied and removed. Balancing iterations repeated until residual unbalance in each plane meets ISO 1940 / API 670 grade specified for this rotor service.

Post-Balance Runout Check

Mechanical and electrical runout re-measured post-balancing at all journal positions. Comparison against pre-balance baseline confirms improvement from machining and balancing. Any residual runout exceeding OEM limits is investigated: if caused by bent shaft, straightening or replacement is recommended.

Documentation & Dispatch

Complete balancing report issued: initial unbalance (g·mm), correction plane locations, correction masses applied, final residual unbalance in each plane, balance grade achieved (G1.0, G2.5, G6.3), and all runout measurements. PMI certificate and hardness test results attached. Rotor packed and dispatched with documentation.