Electrical Engineering Design & Drawing II Prepared By: Sanjeev Kumar Kalra Lect. in Electrical Engg. Guru Gobind Singh Govt. Polytechnic, Cheeka
Contractor Control Circuits (Unit-I) Contractor: It is a switching Device sed to connect & disconnect the circuit from main supply. It consist mainly two basic parts: The Contacts The Coil
Features of Contractor Similar to relay that is used for switching Handle Heavy Loads like Electric Motor, Lighting & Heating Equipment Size of contractor varies acc. to the load handled. Available in Market acc. To current rating ie 6A, 16A, 25A, 32A & so on. Used for switching purpose, they don t interrupt a short circuit current like circuit Breaker
Simple View of Contractor
Push Button Used to switch ON/OFF equipment by pressing it & remains ON/OFF till the pressure is applied on it Types of Push Button: Normally Open Push Button (NO) Normally Closed Push Button (NC)
Normally Open (NO) & Normally Closed (NC) Push Button Normally Open (NO) Push Button: It is normally open & closes the circuit when pressure is applied on it. Circuit remain closed until pressure is applied on it & become open when pressure is released from it. Available in market in GREEN Colour Normally Closed (NC) Push Button: It is normally closed & open the circuit when pressure is applied on it. Circuit remain open until pressure is applied on it & become closed when pressure is released from it. Available in market in RED Colour
Time Delay Relay (TDR) This relay operates with some delay of time. TDR is a type being of relay which takes some time to operate its contacts after it is connected with supply but returns back to the original position quickly when disconnected from main supply. Similar to relay/contractor, it has two contacts: Normally Open (NO) Normally Closed (NC)
DOL Starter (Schematic Diagram)
DOL Starter (Wiring Diagram)
3 Phase Induction Motor getting supply from selected feeder (Schematic Diagram)
3 Phase Induction Motor getting supply from selected feeder (Wiring Diagram)
Forwarding / Reversing of 3 Phase Induction Motor (Schematic Diagram)
Forwarding / Reversing of 3 Phase Induction Motor (Wiring Diagram)
Two Speed Control of 3 Phase Induction Motor (Schematic Diagram)
Two Speed Control of 3 Phase Induction Motor (Wiring Diagram)
Limit Switch Control of 3 Phase Induction Motor (Schematic Diagram)
Limit Switch Control of 3 Phase Induction Motor (Wiring Diagram)
Sequential Operation of Two Motors using TDR (Schematic Diagram)
Sequential Operation of Two Motors using TDR (Wiring Diagram)
Automatic Star Delta Starter for 3 phase Induction Motor(Schematic Diagram)
Automatic Star Delta Starter for 3 phase Induction Motor(Wiring Diagram)
Manual Star Delta Starter for 3 phase Induction Motor
Earthing (Unit-II) Earthing is an electric connection with the general mass of earth in such a manner that immediate discharge of fault current takes place immediately without danger. The basic function is to bring the body of electrical equipments to the zero potential in case of fault
Difference Between Grounding & Earthing Grounding: It means connecting live part of electrical system to earth. Example: Neutral Point of Supply System. Earthing: It means connecting the non current carrying metal parts used in electrical system to general mass of earth. Example: Electrical Motor Body etc.
Purpose of Earthing It provides Safety of Human Body from Electric Shock It prevents risk of Fire due to earth leakage current Protection against static electricity produced due to frictions Keeps system voltage within permissible limits under fault conditions
Quality of Good Earthing System Must be of Good Corrosion resistance Must be able to dissipate high leakage current repeatedly Has adequate current carrying capacity Has long Durability Must be of low resistance so that fault current should be flow through earth wire instead of Human body
What Equipments is to be earth? Neutral Point of star connection of machines Metal body of all machines (generator, motor etc) Earth Terminal of 3-pin socket outlet All tracks used in railway & tower/poles should be earthed after each 1.5 KM All metal body non current carrying part of electrical installation i.e Energy Meter, Main Switch etc
Different Type of Earthing According to Earthing Methods: Neutral Earthing Equipment Earthing According to Types of Electrode Used: Rod Earthing Strip Earthing Plate Earthing Pipe Earthing According to Material Used: Chemical Earthing Ground Compounding Earthing
Plate Earthing
Pipe Earthing
Material Required for Earthing Earth Electrode: Any strip, pipe, plate or rod embeded in the earth for earthing of electrical equipments is known as Earth Electrode. Earthing Chamber Cover: It is generally used to cover & protect the earthing from undesirable accidents. Made of Supreme quality of Raw Materials. Back Fill Compound: Empty space around electrode is filled with compound to maintain moisture & enhance conductivity around the electrode. Salt: Pure & premium quality of salt is used to reduce resistivity of Soil. Charcoal Dust: It is filled in the Earth pit to enhance conductivity of soil
Methods of Reducing earth Resistance By connecting many number of electrode in parallel By increasing the areas of electrode By deeper excavation of Pit By adding more salt & charcoal calcium chloride, copper sulphate around the electrode In dry seasons fresh water is poured in pipe to reduce the earth resistance
Relevant I.S. Specifications of Earth Electrode Governing Specifications: IS: 3043-1987 (Codes of Practice for earthing-first Revision) Indian Electricity Rules (1956-latest Edition) National Electrical Code (1985 of Bureau of Indian Standards)
Key Diagram of 11KV Substation
Key Diagram of 33 KV Substation
Key Diagram of 66 KV Substation
Key Diagram of 132 KV Substation
8051 Microcontroller & Interfacing Presented By: Meenakshi Goyal 1
CONTENTS Introduction. Microcontroller vs Microprocessor. Architecture. Pin diagram. Pin configuration. Memory Organisation. Timers. Interrupts. 2
Serial Communication. Interfacing. a) +5 volt power supply. b) switch interfacing. c) LED interfacing. d) 7-Segment display interfacing. e) LCD interfacing. f) ADC interfacing. g) keypad interfacing. h) relay interfacing. Applications. 3
INTRODUCTION A single chip computer or A CPU with all the peripherals like RAM, ROM, I/O, Timers, ADCs, etc on the same chip. OR A microcontroller is meant to be more self- - contained and independent, and functions as a tiny, dedicated computer. 4
FEATURES OF 8051 useful for small computing tasks. adequate for many control and monitoring application. packaging(ram,rom,timers on-chip). Less power consumption. Easily upgradable. Cost per unit is less. Availability of tools of microcontroller such as proteus(simulator) and keil(compiler). 5
MICROPROCESSOR vs MICROCONTROLLER General purpose device. do not contain on-chip I/O ports, Timers, ADC Memory etc. used as CPU in computer. design is complex and expensive. it has zero status flag. single chip computer. it includes RAM,ROM,Timers, ADC, DAC, interrupts etc. performs control oriented applications. simple and less expensive it has no zero flag. 6
TYPES OF ARCHITECTURES 1) Von-Neumann Architecture only one bus. used for both data transfer and instruction fetches. cannot be performed at same time. 2) Harvard Architecture Separate data and instruction buses. Transfers to be performed simultaneously on both buses. 7
ARCHITECTURE 8
PIN DIAGRAM 9
PIN CONFIGURATION ALE/PROG-: when this pin is high it latches the low byte of the address during accesses to external memory. This pin is low during EPROM programming. PSEN-: Program Store Enable is the read strobe to external program memory. EA/VPP-: This pin is an active low pin connected to ground when microcontroller is accessing the program code stored in the external memory and connected to Vcc when it is accessing the program code in the on chip memory. 10
PIN CONFIGURATION RST -: applying a high pulse to this pin, the microcontroller will reset and terminate all activities. PORT 0 to 3 -: These are 8-bit bidirectional I/O port. Port 0 does not contain any internal pull-ups. Alternate function of port 3are RxD, TxD, INT0, INT1,T0,T1,WR,RD. XTAL1 & XTAL2 -: connected to oscillator amplifier. VCC-: Supply voltage. VSS-: Circuit ground potential. 11
MEMORY ORGANISATION Code Memory. External RAM. On-Chip Memory. Internal RAM. Special Function Register. Machine Cycle. 12
Code Memory holds the actual 8051 program. limited to 64K. may be both internal or external. slow accessing speed. it gains in quantity. limited to 64K. External RAM 13
On-Chip Memory It refers to that memory that physically exists on the microcontroller itself. Two typesa) Internal RAM. b) SFR(Special Function Register.) Total 256 bytes. Equal memory for RAM and SFR i,e 128bytes. 14
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SPECIAL FUNCTION REGISTER Accumulator. B Register. Program Status Word. Stack Pointer. Data Pointer. Ports 0 to 3. Timer Registers. Control Register. 16
+5 VOLT POWER SUPPLY 17
SWITCH INTERFACING 18
LED INTERFACING 19
7 SEGMENT INTERFACING 20
LCD INTERFACING 21
RELAY INTERFACING 22
ADC INTERFACING 23
MATRIX KEYPAD INTERFACING 24
APPLICATION OF 8051 Automobile. Rail Transport. Industrial Processing. Remote sensing. Robotics. Consumer electronics. Security(e-commerce and smart cards). Medical. Defense application. 25
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