What is a Multispindle Head

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Section View of Multispindle Head Gearbox
What is a Multispindle Head?
Gearbox (13 shafts, 26 bearings)
Spindle-Drive Motor (1795 RPM)
Precision Spindle Cartridges (5 spindles, 5921
RPM)
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FEEDBACK Report
Block Machiningop 130-05LMultispindle Head

Z03 position 3 Bearing was Spalled
(2) Bearings Identified with Vibration Analysis
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FEEDBACK Report
Block Machiningop 130-05LMultispindle Head

Z03 position 3 Bearing was Spalled
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GM Spring Hill Manufacturing
Ecotec Predictive Technologies Group
Andy Calcagno - Tom Holloway - Brad Noel - Rick
Ratz
Vibration Analysis Integrated with...
Bearing Analysis
Formula to Calculate Outer Race Bearing Defect
Frequency

• Nb Number of Balls
• Bd Ball Diameter
• Pd Bearing Pitch Diameter
• Theta Brg Contact Angle

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For additional information regarding the
integration of Vibration Analysis and Bearing
Analysis...
published August 2006
available FREE on-line _at_ www.uptimemagazine.com/su
bscribe.htm
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GM Spring Hill Manufacturing
Ecotec Predictive Technologies Group
Andy Calcagno - Tom Holloway - Brad Noel - Rick
Ratz
Motor Circuit Analysis
Today's Presenter
Rick Ratz
Motor Circuit Analyst
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Motor Test Equipment

• Presently used in P/T ECOtec Engine PdMA-MCEMAX,
  ALLTEST PRO-MD
• Both test units have static and dynamic
  capability
• Both have route collection capabilities
• Both have ability to identify fault zone failure
  modes

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Static Motor Testing

• Ensure motor circuit and power circuit health
• Trend motor condition over time
• Maintain integrity of motor inventory
• Track history of motors and repairs
• Troubleshoot failed motors for proper repair and
  reduce overall costs

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The Polyphase Induction Motor
Rotor
Stator Windings
Stator Laminations
Bearing
Fan
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Static Testing Strategy

• Test all motors in and out of the plant for
  repair
• Develop routes for critical motors in the plant
• Troubleshoot motors vs. Driven equipment
• Baseline new motors for future trending and
  integrity during installation

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Fault Detection

• Turn Faults
• Coil Faults
• Phase Faults
• Ground Faults
• Cable Faults
• Rotor Eccentricity
• Broken Rotor Bars
• Casting Voids

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Case Study Root Cause
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PI Test
Grounded by Grease
Grease Removed
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Resistive Imbalance 4.39
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Uses for Dynamic Testing

• Power quality
• Identify motor defects and failure modes
• Troubleshoot or identify machine and process
  problems
• Fine tune machine function
• Correlate findings with other technologies

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What is a Motor System?
The Electric Motor System
Three-Phase Input Power
Process Mechanical and Electrical Feedback
Motor/Drive Subsystem
Mechanical Subsystem