8) This describes the required skills and knowledge and their level, required for this unit. Evidence shall show that knowledge has been acquired of safe working practices and solve problems in polyphase electronic power control circuits. All knowledge and skills detailed in this unit should be contextualised to current industry practices and technologies. KS01-EI149A Polyphase electronic power control circuit Evidence shall show an understanding of polyphase electronic power control circuit to an extent indicated by the following aspects: T1 Three Phase Rectifier Circuits encompassing: Three-Phase Circuit Configurations Resistive/Inductive Loads Output Voltages/Waveforms Ripple Voltage/Frequency Peak Reverse Voltages Free Wheeling Diodes Measurement of rectifier output parameters. T2 Three-Phase Half Wave Controlled Rectifiers encompassing: Phase control Purpose/operation of half controlled rectifiers Circuit configuration Rectifier performance and operation - resistive loads Output voltage – resistive load Rectifier performance and operation - inductive loads Rectifier output waveforms Applications and limitations Advantages and disadvantages three-phase controlled rectifiers. T3. Three-Phase Half Controlled Bridge Rectifier encompassing: Purpose/operation of a half controlled bridge rectifiers Circuit configuration and connections Rectifier output - resistive loads Output voltage – resistive loads Rectifier output - inductive loads Output voltage - inductive loads Flywheel diode Output voltage calculations Applications and limitations Advantages and disadvantages three-phase half controlled bridge rectifiers. T4. Three-Phase Fully Controlled Bridge Rectifier encompassing: Purpose/operation of a fully controlled bridge rectifiers Circuit configuration and connections Rectifier output - resistive loads Output voltage – resistive loads Rectifier output - inductive loads Output voltage - inductive loads Flywheel diode Output voltage calculations Applications and limitations Advantages and disadvantages three-phase fully controlled bridge rectifiers. T5. Three-Phase a.c. Controllers encompassing: Circuit configurations Circuit operation Triacs and SCRs circuits Triggering requirements Output voltage and waveforms Determination of output voltage Applications Advantages and disadvantages T6. DC Converters encompassing: Purpose and operation of d.c. converters Circuit configurations Voltage control methods Forced commutation methods Calculation of load voltage Output voltage/waveforms Applications Advantages and disadvantages T7. Cycloconverters encompassing: Purpose/operation of a cycloconverter Basic circuit configurations Measurement of output voltage Calculation of load voltage Output voltage/waveforms Applications and limitations Advantages and disadvantages T8. Invertors encompassing: Purpose/operation of a inverter Basic circuit configurations Measurement of inverter outputs Output voltage Applications and limitations Advantages and disadvantages T9. Thyristor Protection encompassing: Power Control Devices Failure Protection Techniques Snubber Networks Series Inductors Amp Trap (HRC) fuses Gate Pulse Suppression 10. Installation of Thyristor Devices and Circuits encompassing: Need for heat sinking of power thyristor devices Heat sink features and types Installation methods for all types of thyristor packages Basic thermal model, only to demonstrate the effect of different heat sink Types and profiles and installation methods on thyristor junction temperature. T11. Series and Parallel Thyristor Connections encompassing: Purpose of Series/Parallel Connection Series Connections Reasons Operational Problems Parallel Connections Reasons Operational Problems T12. Fault Finding Three Phase Thyristor Circuits encompassing: Fault finding procedures Typical faults – power and trigger circuits Characteristics displayed by common faults Comparison of test data with expected data (voltage/current waveforms) Location and replacement of faulty components |