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					         A Better Way to Repair
            Electric Motors:


                 Adhere to ANSI/EASA AR100




                                      Thomas H. Bishop, P.E.
September 2011           EEMODS        Electrical Apparatus
                                        Service Association
ANSI/EASA AR100
 Since 1998, the
  American National
  Standard for repair of
  rotating electrical
  apparatus
 Focus here will be on
  aspects of AR100
  related to polyphase
  squirrel cage motors,
  the “workhorses of
  industry”
September 2011     EEMODS
ANSI/EASA AR100
 More than 3 dozen changes in 2010
  edition
     Most notably good practices for
      maintaining motor efficiency
          From EASA/AEMT Rewind Study in early
           2000’s
     AR100 and Rewind Study can be
      downloaded free from
      “Energy/Environment” tab of EASA
      website (www.easa.com)
September 2011          EEMODS
Section 1: General
 Scope includes: Record keeping,
  tests,   analysis,    and     general
  guidelines for repair of electrical
  motors and generators
 Many “standards” or specifications
  focus on topics related to testing
     AR100 provides added value via
      findings and good practice corrective
      actions
September 2011      EEMODS
Section 2: Mechanical Repair
 Includes shaft, bearings, frame,
  bearing housings and laminations
 Text supplemented with 14 tables
  with dimensions and mechanical
  tolerances
     Bearing fit tables are probably most used
 2010 addition: Inspect for stator-
  rotor contact and evidence of post-
  manufacture rotor OD machining
September 2011         EEMODS
Bearings
 AR100-2010     edition    addition:
  Replacement bearings should be
  equivalent   to     the    original
  manufacturer’s specifications
     Incorrect replacement bearings could
      result in:
          Reduced bearing life
          Reduced motor efficiency


September 2011           EEMODS
Section 3: Rewinding
 A primary concern with rewinding is
  possibility of reduction in efficiency
  during repair
 Drawing from Rewind Study, AR100-
  2010 added more specific details about:
     Core testing
       Often cited concern is increased core loss
     Increasing wire area when feasible
       Efficiency gain is incremental
     Use of magnetic wedges
       Reduce no-load (magnetizing) current
       Improve efficiency
September 2011           EEMODS
Rewinding -- specification
 Rewind specification
     Maintain same electrical
      characteristics as original
     2010 addition: Wire area at least
      equal to original
 Review data for accuracy
     Calculate magnetic flux and current
      densities
     Check that resulting values are
      reasonable
September 2011       EEMODS
Rewinding -- stator cores
 Loop or commercial core
  test
     Before & after winding
      removal
     2010 addition: Compare
      results
 Burnout oven
     Temperature control – water
      suppression
     2010 additions:
       Part, not oven, temperature
        sensing
       Part placement in oven to
        avoid distortion
September 2011          EEMODS
Section 4: Testing
 Topics include
   Winding tests
   Bearing insulation test
          First standard to address this topic
     No-load tests




September 2011            EEMODS
Winding tests -- including
 IR and PI
 Winding resistance
 Surge comparison
     AR100 provides test level
 High potential
     Caution about non-
      reconditioned windings
     AC and DC test level tables


September 2011        EEMODS
No-load tests
 Check exact operating rpm
 Compare no load current
  to full load rating
 Check for bearing
  temperature stability
 Vibration tests – resilient
  and rigid mounting
 Verify cooling system
  operation

September 2011      EEMODS
Conclusion
 Repair processes detailed in ANSI/EASA
  AR100 Recommended Practice for the
  Repair of Rotating Electrical Apparatus
  have been described
     Emphasis on: Methods and procedures that can
      affect motor efficiency and reliability
     AR100-2010 incorporated repair good practices
      from Rewind Study of early 2000’s

 Adherence assures that reliable and
  quality repairs will be made in accordance
  with a recognized national standard

September 2011         EEMODS
Questions?



Thank You!


                          www.easa.com
September 2011   EEMODS

				
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