Shaw Makaremi, PhD, PESr. Electrical EngineerClipper Windpower, Inc.

Clipper’s Design Approach to Improving Reliability and Integrated Conditioned Based Monitoring

2Clipper Windpower, Inc.

The Clipper approach to enhance reliability is comprised of three main activities:

• Predictive Maintenance

• Scheduled Maintenance

• Integration of the two

3Clipper Windpower, Inc.

Predictive Maintenance:

• Continuous remote monitoring enables predictive maintenance.

• Predictive maintenance minimizes downtime especially during optimal wind conditions.

• On the Liberty Turbine continuous monitoring is used on the

• Gearbox• Generators• Blades

4Clipper Windpower, Inc.

Predictive Maintenance

• The monitoring measures and tracks in temperature, vibration, the number of particles in the gearbox lubricant and blade loads.

• Monitoring the trends will provide an indication of reduced efficiency or warning of future failure of components.

• The challenging task is to create a reliable algorithm for merging disparate information to accurately identify the condition of the turbine.

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Predictive Maintenance: Measurements

The monitoring states are:• Temperature of

• Gearbox oil• Gearbox high speed bearings• Generator windings

• Vibration of • Main shaft and bearings• Intermediate pinion and bearings• Gear mesh frequencies• High speed pinion and bearing• Generators

• Cooling Fans• Bearings

6Clipper Windpower, Inc.

Predictive Maintenance: Measurements

• Oil particle counter• Counting ferrite and non-ferrite particles in the gearbox lubricant

• Blade loads • Using a Fiber Bragg Grating system incorporating optical sensors

on the blades to measure micro- strain .• The strain measurements are both flap wise and edge wise.

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Scheduled Maintenance

• Is performed regularly and is a complimentary practice to the predictive maintenance.

• Scheduled maintenance consists of many well defined and organized tasks with detailed procedures.

• Scheduled maintenance is performed on parts where the malfunction or replacement of component will not result to extensive cost and down time of the turbine.

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Scheduled Maintenance: Tasks and Documentation

In general these tasks include:• Taking an oil sample of the gearbox in compliance with ISO-4406

referenced to the oil cleanliness 16/14/11 with 100ppm moisture content.

• Visual inspection of listed components • Hydraulic oil leakage, cables, connectors general cleanliness.

• Part replacement suggested by manufacturer with reference to MTBF of components.

• Pumps, motors, bushings etc• Greasing and lubricating bearings

• It is planned to use Infrared Thermography to detect mechanical and electrical hot spots on parts such as bearings, contactors, circuit breakers, fuses and brushes.

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Infrared Thermography showing hot spot on the fuses

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Infrared Thermogrphy indicating hot spots on the contactor

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Hot spot on the fuse holder

Maintenance & Repair

Should be Simple & Safe

The Liberty machine incorporates a number of features to enable this

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Ease of Assembly, Maintenance and service

• Hub accessed through nacelle ports• Full head-room and walk-around• 2 ton jib crane services

• Brakes• Generators• Pinion cartridges• Yaw motors• Hydraulics and cooling

systems

All this should result in enhanced turbine availability and easy maintenance

Ease of Assembly, Maintenance and service

• Hub accessed through nacelle ports• Full head-room and walk-around• 2 ton jib crane services

• Brakes• Generators• Pinion cartridges• Yaw motors• Hydraulics and cooling

systems

All this should result in enhanced turbine availability and easy maintenance

Maintenance & Repair should be done with ease

14Clipper Windpower, Inc.

Maintenance & Repair Should be done with easeLiberty: Designed for enhanced availability and easy maintenence

15Clipper Windpower, Inc.

16Clipper Windpower, Inc.

Enhanced Reliability & Serviceability

• Rugged design• Fewer parts and higher reliability• One up-tower-serviceable bearing per

generator• Replaceable with on-board crane• Turbine can continue to operate with 2 or

3 generators• Generators completely isolated from

grid, which allows for easier voltage ride-through capability and complete isolation from grid disturbance

• Low weight < 4000 Lbs. per generator

Maintenance & Repair should be done with easeGenerator

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The Quantum DriveTM distributed powertrain3 Patents Issued

• Four high-speed output shafts• Lighter and more efficient than other

commercial GBs• Split load by a factor of 16, 400% more

than the commercially available GBs• Two stages, versus the three used in

commercially available gearboxes• Increased efficiency• Ability to replace all high-speed stage

components using on-board gantry crane (in less than four hours by two people)

The Quantum DriveTM distributed powertrain3 Patents Issued

• Four high-speed output shafts• Lighter and more efficient than other

commercial GBs• Split load by a factor of 16, 400% more

than the commercially available GBs• Two stages, versus the three used in

commercially available gearboxes• Increased efficiency• Ability to replace all high-speed stage

components using on-board gantry crane (in less than four hours by two people)

Maintenance & Repair should be done with easeGearbox

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Remote and quick access to the behavior & operation of turbine enhances reliability

• Arial view of the site• Traffic light representation of the

condition of turbine• Easy and remote access to more details

• On the gearbox• On the generators

• Vibration• Temperature• Oil particles

19Clipper Windpower, Inc.

Liberty Turbine – Breakthrough TechnologyIntegrated main shaft

Clipper 2.5 MW

Conventional 2.5 MW

Twin parking brakes

4 permanent magnet generators (higher availability)

D-Gen gearbox• Splits loads 4X greater than

conventional gearbox• 40% lighter• 30-year design life• Install with same crane as

conventional 1.5 MW turbines

Same scale

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Integration of Predictive and Scheduled Maintenance

• This integration will give us a comprehensive understanding of the behavior of the turbine.

• Feedback to engineering and manufacturing for modification and product improvement.

• Timely information to O&M people for scheduled maintenance such as • Preparation of parts and tools for repair.• Collection of knowledge and documentation.• Special equipments and crane.• Safety consideration.

• In general this integration enhances and prolongs the productive life of the turbine.

• The integration is done at the Remote Monitoring & Diagnostic Center

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Tools of predictive maintenance are also used for quality control and to reduce infant mortality rate

• Quality Control• Mechanical assembly of gearbox and generator involve bearings

(rolling elements) and gears. • Improper assembly of these elements introduce:

• Misalignment• Resonance• Imbalance• Gear-tooth wear• Looseness

They all can be detected using accelerometers and vibration measurements.

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• Infant mortality reduced by design and QC – reduced in prototype• Late stage fatigue failure reduced by CBM – allows replacement prior

to failure extending the component and machine life.

Condition Based Monitoring (CBM)

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Infant Mortality Rate

• Transportation and installation of heavy equipments such as gearboxes, generators and blades are difficult and damage to these parts should be avoided.

• As part of commissioning, vibration measurements and comparison with some known baseline will clearly verify the proper installation of the equipment.

• Continuous measurements and monitoring of the gearbox and the generators during the first 1000 hours of operation will drastically reduce the infant mortality rate of the turbine.

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Following are some scattered spectrums and plots depicting the operating condition of the turbine

Generators - Gen-2 - Vertical [Tach] - Acc Freq 2000 Hz [Tach]1/26/2007 3:39:48 PM

Hz0 200 400 600 800 1,000 1,200 1,400 1,600 1,800 2,000

g rm

s

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07O/All 0.114 g rms

1/26/2007 3:39:48 PM O/All 0.114 g rms 804.829 RPM

Pow

er (g

rms)

0.3

00.3

00.3

0

Gearbox - Intermediate UL - Vertical [Tach] - Acc Freq 1000 Hz [Tach]2/5/2007 4:27:18 PM

Hz0 100 200 300 400 500 600 700 800 900 1,000

g rm

s

0

0.002

0.004

0.006

0.008

0.01

0.012

0.014

0.014 g237.418 orders376.25 HzCursor A:O/All 0.031 g rms

2/5/2007 4:27:18 PM O/All 0.031 g rms 95.085 RPM

Pow

er (g

rms)

0.3

0

Gearbox - Bull Gear - Vertical [Tach] - Vel Freq 100 Hz [Tach]2/1/2007 7:58:49 AM

Hz0 10 20 30 40 50 60 70 80 90 100

g rm

s

0

0.0002

0.0004

0.0006

0.0008

0.001

0.0012

0.0014

O/All 0.001 g rms

2/1/2007 7:58:49 AM O/All 0.001 g rms 15.466 RPM

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Shaw Makaremi, PhD, PESr. Electrical EngineerClipper Windpower, Inc.

Thank You