Evidence shall show that knowledge has been acquired of safe working practices and developing and connecting control circuits. All knowledge and skills detailed in this unit should be contextualised to current industry practices and technologies. KS01-EG109A Electrical control devices and circuits Evidence shall show an understanding of electrical control devices and circuits to an extent indicated by the following aspects: T1 Basic relay circuits encompassing: Identification of given circuit diagrams (schematic) symbols and explain the operation of the components represented labelling wires and terminal (numbering systems) control relay - operating principles, basic contact configurations and identification and common applications push button - switching configurations and common applications selecting pushbuttons/pilot lamps from manufacturer’s catalogues for specific applications development of simple stop-start relay circuit that incorporates pilot lights and latching circuit. connection and testing of control circuits T2 Relay circuits and drawing conventions encompassing: circuit diagram drawing conventions selecting relays from manufacturers’ catalogue for specified applications circuit development of electrical control circuit in accordance with a written description (specification) and list the sequence of operation of the circuit connecting simple electrical control circuit from circuit diagrams applying safe working practices when testing an electrical control circuit T3 Remote STOP-START control and electrical interlocking encompassing: operation of local and remote start-stop control of relays operation of an electrically interlocked relay circuit development of a relay circuit incorporating local and remote start and stop buttons and electrical interlocking. connecting electrical circuits with local and remote start-stop control and with electrical interlocking. applying circuit checking and testing techniques to an electrical control circuit. T4 Time delay relays encompassing: timers - operating principles, basic contact configurations and identification and common applications selecting timers for specified functions from manufactures’ catalogues development of timer controlled circuits from a written description and list the sequence of circuit operation connecting a timer controlled circuit using a circuit diagram as a guide. timer circuit checking and testing procedures. T5 Circuits using contactors encompassing: contactors - operating principles, basic contact configurations and identification and common applications thermal overloads - operating principles, basic contact configurations and identification and common applications circuit diagram symbols circuit development using a contactor using contactors for motor control. compliance requirements for devices for isolating circuits. T6 Jogging and interlocking encompassing: purpose and application of jogging control of motors operation of motor control using start, stop and jog buttons purpose and application of electrical/mechanical interlocking developing a multiple motor starting circuit from a description of the circuit operation including jog and interlock functions. selecting circuit components using manufacturers’ catalogues for appropriate duty ratings connecting and testing a multiple motor starting circuit which incorporates start, stop and jog control. T7 Control devices encompassing: common control devices used in automatic control circuits: limit switches, proximity switches, photoelectric cells, pressure switches, float switches, light sensors and temperature sensors basic operating principles of common control devices advantages and disadvantages of common control devices applications for common control devices selecting control devices using manufacturers’ catalogues for specified applications connection of control devices into control circuits T8 Programmable relays encompassing: programmable relays - advantages over electromagnetic relay circuit control. typical applications of programmable relays. block diagram representation and basic operating principles input and output parameters, listing, connections and output types. connecting input and output devices to a programmable relay using a diagram basic programming of ladder circuits consisting of inputs, outputs i.e. stop-start circuit using the monitoring facility of the programmable relay to verify each ladder circuit operation. programming timers and using the monitoring facility of the programmable relay to check the values of the timer external devices implications of programming normally closed field devices conversion of control circuits installation of programmable control relays common faults and their symptoms T9 Three-phase induction motor starters encompassing: reasons for limiting the starting current of large motors. requirements of the wiring rules (AS/NZS 3000) and the local supply authority service rules, with regard to starting and control of induction motors. DOL starter operating principles, applications and circuits electronic (soft) starter operating principles, applications and circuits connecting a DOL motor starter and testing the operation of the power and control circuits installation of DOL and soft starters T10 Three-phase induction motor starters- reduced voltage encompassing: star-delta starter operating principles and circuits primary resistance starter operating principles and circuits auto-transformer starter operating principles and circuits secondary resistance starter operating principles and circuits common applications for each starter type comparison of motor starters basic characteristics selecting the most suitable motor starter for a given situation connecting motor starter power and control circuits for correct operation measuring starting current and torque of selected motor starters installation of reduced voltage starters T11 Three-phase induction motor reversal and braking encompassing: reversing operating principles and control circuits plug braking operating principles and circuits dynamic braking operating principles and circuits regenerative braking operating principles and circuits eddy current brakes operating principles and circuits mechanical brakes operating principles and circuits comparison of the difference braking methods used. typical applications for each braking method. connecting a circuit with a braking feature to operate a three-phase motor. installation of motor braking control circuits T12 Three-phase induction motor speed control encompassing: pole changing operating principles and circuits variable frequency drives operating principles and circuits slip-ring motors operating principles and circuits installation of motor speed controllers. |