EMAIL TIPS A Learning Publication from Full Spectrum Diagnostics Vol. 90 March 2013

90

Understanding the Planetary Gearbox

New TWF Wall Chart

EMAIL TIPS Volume 90 March 2013 Perspectives

Recent trends in Vibration Analysis training indicate that students are favoring shorter sessions that focus in specific aspects of analysis. Formal 3-4 day seminars tend to pack a lot of information into short blocks that might not be adequately absorbed by the student. The solution might not be to repeat the course, or just proceed to the next level. Rather, many students benefit from “concentrated” courses on specific concepts that are eluding them.

Full Spectrum Diagnostics fills this gap with short (2-day) seminars on Spectrum Analysis, Time Waveform Analysis, Phase Analysis and hardware specific Rolling Element Bearing & Gear Analysis.

These courses also benefit the student by contributing formal classroom hours required by ASNT and ISO for certification at VA-III (Cat IV) levels. See the training schedules included in this publication.

This Month’s Features:

Planetary Gearbox Tips

Real Data: Compressor Pulsations

Real Measurements: Natural Frequency Mass Modification

2013 Training Schedules

New Time Waveform Wall Chart

4

2013 Training Schedules CORE TRAINING SERIES: ASNT: Intro (IVA) – VAI – VAII – VAIII ISO: Intro (Cat I) – Cat II – Cat III – Cat IV CONCENTRATED TRAINING TRACK:

• Concentrated Time Waveform • Concentrated Spectrum Analysis • Concentrated Phase Analysis • Concentrated Rolling Element Bearings

& Gear Analysis

Concentrated Courses Earn ASNT VAIII & ISO Cat IV Hours

SPECIALTY & ADVANCED TRAINING • ODS/Modal • Precision Balancing • On-site Mentoring

Another Look at the Cover:

The cover image shows a 1.6 MW Wind Turbine that was experiencing bearing problems within the planetary gearbox. The gearbox included four rotating shafts supported by nine rolling element bearings and three sets of meshing gears (including a planetary set). To define and understand the bearing signatures required an understanding of the entire gearbox.

The [95:1] gear ratio required both high and low speed vibration analysis techniques, Time Waveform analysis, and ultrasonic analysis. Adding in the planetary system and things get real interesting. More analysis details inside.

GEARBOX TIP

The analysis of “Planetary” or “Epicyclic” Gearboxes are not the most “straight forward” of tasks. Just following the step-by-step directions can be challenging. After analysis the hard way, a simplified table was discovered online that makes analysis much easier. The table outlines the seven (7) dominant configurations of these gearbox systems. Plugging tooth counts in the formulas allows the user to calculate the relative speed of the gears with respect to the reference (known) driving member speed.

Step 1: Choose planetary configuration.

Review of the gear system should indicate a stationary Gear, a Driving Member, and a Driven Member.

In this case, the Driving Member is the Turbine Input. The Ring Gear is Fixed in the gearbox housing. The Sun Gear is the Driven Gear. The system corresponds to Table Configuration #3.

Step 2: Input the Gear Tooth counts.

The tooth counts (not the Gear Ratios) are important for this analysis. If a drawing cannot be found that discloses the tooth counts, the analyst must gain access to the gearbox and manually count the teeth on each Sun, Planet, and Ring gear.

TRING = 75 TPLANET = 28 TSUN = 18

SRATIO = [(R+S)/S] = [(75+18)/18] = 5.167 PRATIO = [(R/P)] = [(75/28)] = 2.678 Step 3: Scale to Driving Member Speed. The table results are presented as a ratio of the driving member rotational speed.

For an Input Speed of 19 RPM (Planet Carrier) the Output (Sun Gear) speed is 5.167 x 19 RPM or 98.2 RPM. The Planet Gear rotating speed is 2.678 x 19 RPM or 50.9 RPM.

There is only ONE Gear Meshing Frequency generated in this system:

GMF = 19 x 75T = 1425 CPM GMF = 50.9 x 28T = 1425 CPM GMF = (98.2 – 19) x 18T = 1425 CPM

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2013 CORE VIBRATION TRAINING SCHEDULE Implementing A Successful PdM Program (1) AUG 27-28 St. Paul, MN 2013-PdM-01 Tuition: $ 975.00 / 2-day Format Proficiency Test: Included Introduction to Vibration Analysis (CAT I)(1) In-Plant by Request Tuition: $ 975.00 / 2-day Format Proficiency Test: Included

Vibration Analysis (VAI/CAT II)(1) APR 02-05 St. Paul, MN 2013-VA1-03 MAY 14-17 Cedar Rapids, IA 2013-VA1-04 JUL 09-12 Quakertown, PA 2013-VA1-05 DEC 10-13 Charlotte, NC 2013-VA1-06 Tuition: $ 1,350.0 / 3-day Format Certification Exam: $ 200.00

Vibration Analysis (VAII/CAT III)(1) MAY 07-10 Wheeling, WV 2013-VA2-02 MAY 21-24 Chicago, IL 2013-VA2-03 JUN 04-07 Eugene, OR 2013-VA2-04 JUN 11-14 Cedar Rapids, IA 2013-VA2-05 OCT 01-04 St. Paul, MN 2013-VA2-06 Tuition: $ 1,450.00 / 3-day Format Certification Exam: $ 200.00

Vibration Analysis (VAIIIa/CAT IVa) (1) NEW! OCT21-25 St. Paul, MN 2013-TVA-01

Tuition: $ 1,650.00 / 4 1/2-day Format Certification Exam: $ 200.00

Vibration Analysis (VAIIIb/CAT IVb) (1) NEW! NOV 04-08 St. Paul, MN 2013-PVA-01 Tuition: $ 1,650.00 / 4 1/2-day Format Certification Exam: $ 200.00

2013 SPECIALTY VIBRATION TRAINING SCHEDULE Modal & ODS Analysis (2) NOV 19-21 Cedar Rapids, IA 2013-ODS-02 Call for In-Plant Training Course! 763-577-9959 Tuition: $ 1,695.00 / 3-day Format One Month ME’scope Software Included Concentrated Time Waveform Analysis(1) APR 16-17 Wheeling, WV 2013-TWF-01 JUN 25-26 St. Paul, MN 2013-TWF-02 SEP10-11 Cedar Rapids, IA 2013-TWF-03 Tuition: $ 975.00 / 2-day Format Proficiency Test: Included Concentrated Spectrum Analysis(1) JUL 30-31 Vancouver, WA 2013-CSA-02 AUG 13-14 St. Paul, MN 2013-CSA-03 SEP 24-25 Cedar Rapids, IA 2013-CSA-04 Tuition: $ 975.00 / 2-day Format Proficiency Test: Included Concentrated Phase Analysis JUL 16-17 Youngstown, OH 2013-CPA-01 OCT 08-09 Cedar Rapids, IA 2013-CPA-02 Tuition: $ $ 975.00 / 2-day Format Hands-on Exercises: Included Concentrated REB & Gear Fault Analysis(1) APR 23-24 Cedar Rapids, IA 2013-BGA-02 JUN 18-19 Rock Island, IL 2013-BGA-03 Tuition: $ 975.00 / 2-day Format Proficiency Test: Included Vibration Analysis For Motor Repair Shops(1) OCT 15-17 Columbia, SC 2013-VAM-01 DEC 03-05 New Orleans, LA 2013-VAM-02 Tuition: $ 1,295.00 / 3-day Format Hands-on Exercises: Included Precision Balancing(1) APR 09-11 Cedar Rapids, IA 2013-BAL-02 MAY 28-30 Milwaukee, WI 2013-BAL-03 SEP 17-19 Thornton, IL 2013-BAL-04 NOV 12-14 Chillicothe, OH 2013-BAL-05 Tuition: $ 1,295.00 / 3-day Format Hands-on Exercises: Included

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INSTRUCTORS:

Full Spectrum Diagnostics’ Lead Instructor & Seminar Author is Dan Ambre. Dan is a graduate of The University of Iowa with a Bachelor’s degree in Mechanical Engineering, and has completed additional graduate level course work in Engineering Dynamics from The University of Illinois at Chicago, and Florida Atlantic University. Dan is a Certified Vibration Analysis Level III Instructor (Category IV) with over 16 years of Vibration Training and Certification Experience.

Dan’s 25+ years of vibration experience in the Aviation & Aerospace Industries comes from positions at Sundstrand Aviation Corporation and Pratt & Whitney (United Technologies Corporation). This fieldwork includes Vibration & Acoustic testing, Rotor Dynamics analysis of high speed Rotor Systems, Experimental Modal, and Finite Element Analysis.

His consulting experience base comes from positions at Technical Associates and Full Spectrum Diagnostics, which he founded in June of 2000. He is a Registered Professional Engineer in the States of North Carolina and Minnesota.

Dan can be contacted by phone at (612) 875-9959, or via Email at ModalGuy@aol.com

ModalGuy@aol.com

In 2004, after years of close association, Louis G. Pagliaro joined Full Spectrum Diagnostics. Lou fulfills multiple roles as our Seminar Sales Coordinator, Senior Instructor and course content co-author. Lou is a certified Level III Vibration Analyst (since 1996) and was recently re-certified by American Society of Nondestructive Testing as an ASNT PdM Level III in Vibration Analysis (Category IV). He has over 30 years of varied industrial experience, including Maintenance Management, Vibration Analysis, Vibration Training, Certification, and course development in areas of Noise Control, Precision Maintenance, Precision Alignment, Preventive Maintenance, and Maintenance Skills Enhancement. His worldwide teaching credentials include instruction of TAC, Update International, CSI, Entek and SKF customers in eight countries. Louis is a graduate of Niagara College in Welland, Canada. Lou can be contacted by phone at (704) 620-1028, or via Email at Lpagl@aol.com.

LpagL@aol.com

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