Download to read offline
More Related Content
Similar to basic of control component description.pdf
More from IbrahimAbdelhalim1
basic of control component description.pdf
- 1. Basics of Control Basicsof Control Components Components INC 100 INC 100 Electrotechnology Electrotechnology Assist. Prof. Pakorn Assist. Prof. Pakorn Kaewtrakulpong Kaewtrakulpong, Ph.D. , Ph.D. INC, KMUTT INC, KMUTT
- 2. Objectives Objectives „ „ State thepurpose and general State the purpose and general principles principles of of control control components components and and circuits circuits „ „ Identify various Identify various symbols symbols which represent control which represent control components components „ „ Read a basic Read a basic line diagram line diagram „ „ Describe the construction and operating principles of Describe the construction and operating principles of magnetic contactors magnetic contactors and and control relays control relays
- 3. Control Loads and ControlLoads and Control Devices Control Devices „ „ The The control load control load is an electrical device that uses is an electrical device that uses electrical power. E.g. electrical power. E.g. „ „ Pilot lights, Pilot lights, „ „ relays, and relays, and „ „ Contactors. Contactors. „ „ Control devices Control devices are used to activate the control load. are used to activate the control load. E.g. E.g. „ „ Pushbuttons and Pushbuttons and „ „ switches. switches.
- 4. Electrical Symbols Electrical Symbols „ „Contact Contact „ „ Switch Switch „ „ Pushbutton Pushbutton „ „ Coil Coil „ „ Overload Relay Overload Relay „ „ Pilot Light Pilot Light „ „ etc etc
- 5. Contact Contact „ „ used toindicate an used to indicate an open or closed path of open or closed path of current flow current flow. . „ „ require an action to change their require an action to change their state state. . „ „ can be can be „ „ Normally Open ( Normally Open (NO NO) or ) or „ „ Normally Closed ( Normally Closed (NC NC). ).
- 6. Switch Switch „ „ also usedto indicate an also used to indicate an open or closed path of open or closed path of current flow current flow. . „ „ require another device or action to change their require another device or action to change their state state. . „ „ can be can be „ „ Normally Open ( Normally Open (NO NO) or ) or „ „ Normally Closed ( Normally Closed (NC NC). ).
- 7. Selector Switch Selector Switch „ „Two Two- -position position „ „ Three Three- -position position „ „ Etc. Etc.
- 8. Switch (cont.) Switch (cont.) „ „Variations of this symbol are used to represent Variations of this symbol are used to represent „ „ limit limit switches, switches, „ „ foot foot switches, switches, „ „ pressure pressure switches, switches, „ „ level level switches, switches, „ „ temperature temperature- -actuated actuated switches, switches, „ „ flow flow switches, and switches, and „ „ selector selector switches. switches.
- 9.
- 10. Pushbutton (cont.) Pushbutton (cont.) „ „2 basic types of pushbuttons: 2 basic types of pushbuttons: „ „ momentary momentary „ „ maintained maintained (latches in place when the button is (latches in place when the button is pressed.) pressed.) „ „ can be can be „ „ Normally Open ( Normally Open (NO NO) or ) or „ „ Normally Closed ( Normally Closed (NC NC). ).
- 11.
- 12. Pilot Light Pilot Light „ „a small electric light used to indicate a specific a small electric light used to indicate a specific condition of a circuit. condition of a circuit. „ „ E.g., a red light might be used to indicate a motor is E.g., a red light might be used to indicate a motor is running. running. „ „ The The letter letter in the center of the pilot light symbol in the center of the pilot light symbol indicates the indicates the color color of the light. of the light.
- 13.
- 14. Control Relays (cont.) ControlRelays (cont.) „ „ Relays are widely used in Relays are widely used in control circuits control circuits. . „ „ They are used They are used „ „ for switching multiple control circuits and for switching multiple control circuits and „ „ for for controlling light loads controlling light loads e.g. starting coils, pilot e.g. starting coils, pilot lights, and audible alarms. lights, and audible alarms.
- 15.
- 16. Coil Coil „ „ used in usedin electromagnetic starters electromagnetic starters, , contactors contactors, and , and relays relays. . „ „ The purpose of The purpose of contactors contactors and and relays relays is to open is to open and close and close associated contacts associated contacts. . „ „ A letter is used to designate the A letter is used to designate the coil coil; the ; the associated associated contacts contacts have the have the same identifying same identifying letter letter. .
- 17. Coil (cont.) Coil (cont.) „ „Associated contacts Associated contacts can be can be „ „ Normally Open ( Normally Open (NO NO) or ) or „ „ Normally Closed ( Normally Closed (NC NC). ).
- 18.
- 19.
- 20. Basic Contactor Operation BasicContactor Operation
- 21. Magnetic Contactors: Interior MagneticContactors: Interior
- 22.
- 23.
- 24. On On- -Delay, Time Closed Delay,Time Closed
- 25. Off Off- -Delay, Timed Open Delay,Timed Open
- 26. Line Diagrams Line Diagrams „ „also referred to as a also referred to as a ladder diagrams ladder diagrams. . „ „ show the show the functional functional relationship of relationship of components and devices in an electrical circuit, components and devices in an electrical circuit, not not the the physical physical relationship. relationship. „ „ made up of 2 circuits, made up of 2 circuits, „ „ the the control control circuit and circuit and „ „ the the power power circuit. circuit.
- 27. Line Diagrams (cont.) LineDiagrams (cont.) „ „ Electrical wires in a line diagram are represented by Electrical wires in a line diagram are represented by lines. lines. „ „ Control Control- -circuit circuit wiring is represented by a wiring is represented by a lighter lighter- -weight weight line and line and power power- -circuit circuit wiring is represented by a wiring is represented by a heavier heavier- - weight weight line. line. „ „ A small A small dot dot or node at the intersection of 2 or more or node at the intersection of 2 or more wires indicates an wires indicates an electrical connection electrical connection. . „ „ Line diagrams are read from Line diagrams are read from left to right left to right. .
- 28. Example: Power Circuitand Control Example: Power Circuit and Control Circuit Circuit
- 29. Connecting Loads and ConnectingLoads and Control Devices Control Devices „ „ Control circuits are made up of control loads Control circuits are made up of control loads and control devices. and control devices.
- 30.
- 31. Two Two- -Wire Control Wire Control „ „A two A two- -wire control circuit provides wire control circuit provides low low- -voltage voltage release release but but not not low low- -voltage protection voltage protection. . „ „ low low- -voltage release voltage release „ „ In the event of a power loss the contactor will In the event of a power loss the contactor will deenergize deenergize, stopping the motor. , stopping the motor. „ „ However, when power is restored, the motor will However, when power is restored, the motor will restart without warning if the control device is still restart without warning if the control device is still closed. closed.
- 32. Two Two- -Wire Control (cont.) WireControl (cont.) „ „ This type of control scheme is used for This type of control scheme is used for remote remote or or inaccessible inaccessible installations such as water installations such as water- - treatment plants or pumping stations. In these treatment plants or pumping stations. In these applications it is desirable to have an immediate applications it is desirable to have an immediate return to service when power is restored. return to service when power is restored.
- 33. Two Two- -Wire Control (cont.) WireControl (cont.)
- 34. Holding Circuit Holding Circuit Three Three- -WireControl Wire Control „ „ low low- -voltage protection voltage protection. . „ „ If an overload causes the If an overload causes the “ “OL OL” ” contacts in the control contacts in the control circuit to open, circuit to open, „ „ the the “ “M M” ” coil is coil is deenergized deenergized and and „ „ the motor shut down. the motor shut down. „ „ When the overload is cleared, When the overload is cleared, „ „ the motor will not suddenly restart on its own. the motor will not suddenly restart on its own. „ „ An operator must depress the An operator must depress the “ “Start Start” ” button to restart the button to restart the motor. motor.
- 35. Holding Circuit Holding Circuit Three Three- -WireControl (cont Wire Control (cont.) .)
- 36. Interposing a Relay Interposinga Relay „ „ A 24 VAC coil may A 24 VAC coil may not not be be strong enough strong enough to to operate a operate a large starter large starter. E.g. . E.g. „ „ the electromagnetic coil of the the electromagnetic coil of the “ “M M” ” contactor contactor selected is rated for selected is rated for 460 VAC 460 VAC. . „ „ The electromagnetic coil of the The electromagnetic coil of the control relay control relay (CR) (CR) selected is selected is 24 VAC 24 VAC. .
- 37. Interposing a Relay(cont.) Interposing a Relay (cont.)
- 38.
- 39.
- 40. Some Simple MotorControl Some Simple Motor Control Applications Applications „ „ Forward Forward- -Reverse Motor Control Reverse Motor Control „ „ Star Star- -Delta Motor Delta Motor- -Starting Control Starting Control
- 41. Forward Forward- -Reverse Motor Control ReverseMotor Control e.g. e.g. „ „ Jogging circuits Jogging circuits „ „ Reversing Reversing- -after after- -stop stop circuits circuits
- 42. Jogging Circuits Jogging Circuits usingselector switch without short- circuit protection with short- circuit protection
- 43. Reversing Reversing- -After After- -Stop Circuits Stop Circuits withoutshort- circuit protection with short- circuit protection
- 44. Star Star- -Delta Motor Delta Motor- -StartingControl Starting Control