AC Motor Repair

HECO provides expert AC motor and AC generator repair services, restoring industrial units of all sizes. Our team specializes in rewinding, bearing replacements, shaft repairs, and electrical diagnostics, ensuring long-lasting performance for your AC motors and AC generators. With decades of experience and advanced testing capabilities, we deliver precision repairs that minimize downtime and extend motor life.

General Capabilities

Electric motor and generator repair and rewinding
AC motor testing capabilities of up to 13.8kV, 4000kVA
Lathe machining capabilities up to 96-inch swing
10-foot diameter Vacuum Pressure Impregnation (VPI) system
Clean winding rooms, the largest with 50-ton lifting capacity
Von Roll Mica MAX Insulation system for up to 15kv+ VPI motors
AC HiPot (High Potential Testing) up to 50 KV, 3.5 Amps
Rotor Repair, including new bars and end rings or windings for Wound Rotor and Synchronous Motors
Dynamometer testing up to (1,200HP) 4,400 foot-pounds
EASA-accredited for electric motor and generator repairs
Stator/Rotor design and manufacturing

AC Synchronous Motors/Generators

Dimensional analysis and bracing assessment
Coil insulation evaluation
IEEE-standard electrical testing
Temperature-controlled stripping of old windings
Winding data analysis and potential design improvements
Precision stator and rotor rewinding with integrity testing
Evaluation of the existing insulation system
Application of improved insulation for heat transfer and dielectric integrity
Vacuum Pressure Impregnation (VPI) with solventless epoxy resin
Rotor balancing and alignment correction
Vibration spectrum analysis (FFT)
Dynamic rotor balancing to correct imbalance
Shaft alignment adjustments to prevent excess wear
Root cause analysis for motor failures
Identification of structural issues, misalignment, or imbalance
Diagnosis of bearing defects, broken welds, loose fasteners, and rotor/stator faults
Resonance condition analysis to prevent operational failures
Design improvements for increased motor reliability
Thermal management solutions to enhance longevity
Application of best practices for energy-efficient operation
Slip Ring Repair and replacement

AC Slip Ring Motor/Wound Rotor Motor Repair

Dimensional analysis and bracing assessment
Coil insulation evaluation
IEEE-standard electrical testing
Temperature-controlled stripping of old windings
Winding data analysis and potential design improvements
Precision stator and rotor rewinding with integrity testing
Evaluation of existing insulation system
Application of improved insulation for heat transfer and dielectric integrity
Vacuum Pressure Impregnation (VPI) with solventless epoxy resin
Rotor balancing and alignment correction
Vibration spectrum analysis (FFT)
Dynamic rotor balancing to correct imbalance
Shaft alignment adjustments to prevent excess wear
Root cause analysis for motor failures
Identification of structural issues, misalignment, or imbalance
Diagnosis of bearing defects, broken welds, loose fasteners, and rotor/stator faults
Resonance condition analysis to prevent operational failures
Design improvements for increased motor reliability
Thermal management solutions to enhance longevity
Application of best practices for energy-efficient operation
Slip Ring Repair and replacement

How a HECO Repair is Different

The way we think is what makes us and our repairs different. You’ll experience it with the first job when we ask you a variety of questions, such as:

Why are you removing the unit? Did it fail?
What is the application for your unit?
How long has the unit been in service?
What type of starting is used?
Are there any special instructions?

Using these questions as a means to uncover the “why” of any issue you are having, HECO then focuses on potential issues to make the right repair on the first service and prevent the need for recurring repairs.

Learn more about how a HECO Repair is different.

Take A Virtual Tour

Want to see what kind of shop your motors will be going to? Check out a virtual tour of our Kalamazoo location.

Industries Served

The way HECO approaches electric motors, generators, pumps, gearboxes, and complete performance systems is tailored to your industry’s specific needs and characteristics. By asking “why” and incorporating the answers into specialized solutions, we are better equipped to find the right solution that will work for your industry.

See Industries We Serve

800HP Coal Crusher Electric Motor Repair Case Study

After years of repetitive failures, a Midwest-based coal-fired power generation plant turned to HECO for help in 2006. Recurring issues with an 800HP, 900RPM, 4000V coal crusher motor’s rotor needed our attention and unique approach to repair.

After diagnosing an issue with circulating currents from a variable frequency drive and electrical discharge damage, we implemented a custom grounding solution to eliminate the harmful currents.

By addressing the root cause, HECO significantly extended the motor’s lifespan and improved system reliability. As a result, the customer reduced unplanned downtime and maintenance costs, ensuring smoother operations.

This case study was originally presented at the Reliability, Process, and Maintenance (RPM) Symposium in September 2016.

9000HP Boiler Feed Pump Motor Rotor Case Study

After bringing a coal-fired power generation plant’s 9000HP Siemens Allis Boiler Feed Pump Motor in for vibration analysis and noise concerns, HECO’s motor repair team uncovered severe contamination and structural damage.

The motor’s windings were packed with debris, its bearings showed signs of rust, and the shaft journals suffered oxidation-related damage. Additionally, clogged air filters prevented proper ventilation.

A deeper inspection revealed multiple hairline cracks in the rotor assembly’s bar-to-shorting ring joints, making repairs impossible. As a result, a full rotor cage replacement was proposed, reusing only the shaft spider assembly.

Read the full blog series dedicated to this case study, including: