1. Developing repair scope for rotating machinery
NC-AWWA Spring Symposium
2018
Asheville, NC
Developing repair scope for rotating machinery
Tim Hebert A&W Electric, Inc. (704)

2. Benefits of having a firm repair scope
Create a level playing field for all involved
Eliminate the “Worst Case Scenario” approach
Effectively manage contractors and service centers
Insure you are getting the proper level of work done.
Create an economic plan for decision making
Once you determine scope, you can determine which equipment you will not repair
Tim Hebert A&W Electric, Inc. (704)

3. Considerations in developing a repair scope
Cost and scope (Can we have too much scope?)
Equipment Efficiency
Lead time (both repair and replacement)
Age of Asset vs. Expected Life
Planned upcoming system replacement
Availability of parts/obsolescence
Footprint/Piping pattern of replacement unit
Local repair capabilities
Tim Hebert A&W Electric, Inc. (704)

4. Repair scope – Electric Motors
Cost of Repair vs. new – The 60% rule
What is a standard recondition
Wash and Bake windings
Test Windings
Micrometer check all machine fits – Housings AND journals
Rewind
Class H Insulation Materials
Inverter Rated Magnet Wire
Correct number of leads
Are the leads lugged
Tim Hebert A&W Electric, Inc. (704)

5. Repair scope – Electric Motors - Continued
Testing
Core Loss tests before and after wind
Rotor Bar test
Test Run
Load Test
Additional Repair
Dynamic Balancing
Removal/Installation
Alignment … Laser?
Tim Hebert A&W Electric, Inc. (704)

6. Repair scope – Electric Motors - Continued
Process
Motor burnout temp
Materials stored in climate control
Winding in clean room
Document machine fits
Provide test results
Root Cause failure analysis
Tim Hebert A&W Electric, Inc. (704)

7. Repair scope - Mechanical
Will you repair or replace shafts
Shaft stubs acceptable or no?
Method of repair
Knurl
Sleeve
Weld up and Turn
Metallize
Done in house or contracted out?
Tim Hebert A&W Electric, Inc. (704)

8. Other rotating equipment – Pumps, Gearboxes, Blowers
Parts - OEM or Aftermarket (Aftermarket may be the same
Balancing of rotating assemblies
Recording of tolerances
Wear ring and efficiency ring
Gear Lash in gearboxes
Blower wheels and housing in Regenerative Blowers
Stator/Rotor clearance in lobe style blowers/prog cavity pumps
Post repair seal testing
Ship dry or with oil
Pickup and Delivery incouded
Tim Hebert A&W Electric, Inc. (704)

9. Summary - Questions Level Playing Field
Helps you make repair/replace decision
Manage and evaluate providers
Make sure you are getting exactly what you want.
Questions?
Tim Hebert A&W Electric, Inc. (704)