Low Power Requirements No Safety Concerns due to High Current
PROBLEMS WITH HIGH POWERED RING FLUX TEST •
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AVAILABILITY OF POWER RUNNING HIGH CURRENT/HIGH VOLTAGE CABLES AND MECHANICAL STRESSES
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TIME REQUIRED FOR TEST
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MANPOWER REQUIRED FOR TEST
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SAFETY PRECAUTIONS AND PROCEDURES
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NO ACCESS TO STATOR BORE WHILE THIS TEST IN PROGRESS
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COOLING OR HEATING TIME BETWEEN TEST/REPAIR/ TEST ETC.
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POSSIBILITY OF INCREASED DAMAGE DUE TO TESTS - NO COOLING ETC. -
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PHYSICALLY SMALL BUT SERIOUS FAULTS NOT ALWAYS DETECTABLE IF DEEP SEATED OR BENEATH WINDINGS
THE SOLUTION - ELCID INITIALLY DEVISED BY CEGB - LOW EXCITATION POWER REQUIREMENTS
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FAST - EASILY SET UP
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LOW MAN POWER REQUIREMENTS
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NO SAFETY HAZARDS OR COMPLICATIONS
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INSTANT TEST RESULTS
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STATOR CAN BE REPAIRED SIMULTANEOUSLY WITH FURTHER TESTING - NO NEED TO COOL DOWN OR DISMANTLE TEST GEAR •
POWER LEVEL TOO LOW TO CASE FURTHER DAMAGE
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FAULTS NOT OBSCURED BY WINDINGS
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SPEED ALLOWS FAST TESTS TO BE CARRIED OUT BEFORE AND AFTER OTHER MAINTENANCE WORK (E.G. WEDGING) •
AUTOMATIC PERMANENT RECORDS FOR FAULT H ISTORY MONITORING OR QA PROCEDURES •
EQUIPMENT VERY PORTABLE
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Typical Hydrogenerator Excitation System
Typical Turbo generator Excitation System
System Configuration
Positioning the Chattock
Interpretation of Data
Required Excitation Levels
Loop Test
ELCID
100% +
4%
( o f r at e d f l u x d e n s i t y )
System Configuration
Measuring Fault Current with a Chattock Potentiometer
Digital ELCID - Model 601
Method of Scanning
Method of Scanning
Business Justifications
Improved Machine Efficiency
Increased Reliability
Reduced Outages
Reduced Power Consumption during Test
Alternator with Rotating Field
Functional Layout Reference Coil
Chattock Coil
Signal Conditioning
Distance Transducer
Distance Encoder
A/D Converter Digital Processor RS-232 Interface
Portable Computer
D/A Converter
X-Y Chart Recorder
Advantages
Low Excitation Power - 4%
Fast - Easy to Setup
Low Manpower Requirements
Significant Reduction in Safety Hazards
Instant Interpretation of Test Results
Minimal Risk of Further Damage
Ability to Re-Test During Maintenance Cycle Permanent Data Storage
Portability
Suggested Usage Predictive Maintenance:
Global Scan at available planned intervals
Service/Repair:
Beginning of the Maintenance Cycle During Repair Procedures After Completion of Work
Manufacturing/Quality Control:
Throughout Stacking Process QA for Final Acceptance Acceptance Baseline Test for End-User
Excitation & Induced Voltages Across Laminations
Flux produced by Excitation Voltage induced across one pair of laminations Voltage induced across damaged laminations Voltage induced along complete core length
Excitation, Fault Volts and Fault Current
Flux produced by Excitation Voltage induced across damaged laminations Fault Current Phase angle that Fault Current lags Fault Voltage
Excitation, Fault Volts, Fault Current and Quad Fault Current
Flux produced by Excitation Voltage induced across damaged laminations Fault Current Quadrature component of Fault Current Watts dissipated due to fault
Excitation, Fault Volts and Fault Currents 1 & 2
Flux produced by Excitation Voltage induced across damaged laminations Fault Current 1
Phase Angle for If1
Fault Current 2
Phase Angle for If2
Quadrature Fault Current 1 Quadrature Fault Current 2
