* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Electricity 15
Survey
Document related concepts
Switched-mode power supply wikipedia , lookup
Electrical engineering wikipedia , lookup
Power engineering wikipedia , lookup
Portable appliance testing wikipedia , lookup
Electrician wikipedia , lookup
Opto-isolator wikipedia , lookup
Voltage optimisation wikipedia , lookup
Electricity market wikipedia , lookup
Ground (electricity) wikipedia , lookup
Three-phase electric power wikipedia , lookup
History of electric power transmission wikipedia , lookup
Electrification wikipedia , lookup
History of electromagnetic theory wikipedia , lookup
Alternating current wikipedia , lookup
Stray voltage wikipedia , lookup
Mains electricity wikipedia , lookup
Transcript
Electricity 15-16 3. Electricity 3.1 Module OSH10030 Published by Articulate® Storyline www.articulate.com 1. Electricity - Part 1 1.1 Module OSH10030 1.2 Learning Outcomes Published by Articulate® Storyline www.articulate.com 1.3 Electricity 1.4 Part 1 Published by Articulate® Storyline www.articulate.com 1.5 What is Electricity? 1.6 Electron / Electricity Flow Published by Articulate® Storyline www.articulate.com 1.7 Electron / Electricity Flow 1.8 Voltage Published by Articulate® Storyline www.articulate.com 1.9 Current 1.10 Resistance Published by Articulate® Storyline www.articulate.com 1.11 Ohm's Law 1.12 Electrical Circuit Published by Articulate® Storyline www.articulate.com 1.13 Direct Current (DC) 1.14 Alternating Current (AC) Published by Articulate® Storyline www.articulate.com 1.15 Alternating Current (AC) 1.16 Three Phase Alternating Current Published by Articulate® Storyline www.articulate.com 1.17 Static Electricity 1.18 Electrical Arcing Published by Articulate® Storyline www.articulate.com 1.19 Summary 1.20 Electricity Published by Articulate® Storyline www.articulate.com 2. Electricity - Part 2 2.1 Module OSH10030 2.2 Electricity Published by Articulate® Storyline www.articulate.com 2.3 Part 2 2.4 Electrical Hazards Published by Articulate® Storyline www.articulate.com 2.5 Electrical Shock 2.6 Alternating Current (AC) Published by Articulate® Storyline www.articulate.com 2.7 Physiological Effects of Electric Shock 2.8 Electrical Supply Published by Articulate® Storyline www.articulate.com 2.9 Electricity Supply 2.10 Live Contact Published by Articulate® Storyline www.articulate.com 2.11 Live Contact 2.12 Live Contact Published by Articulate® Storyline www.articulate.com 2.13 Live Contact 2.14 Switch Published by Articulate® Storyline www.articulate.com 2.15 Switch 2.16 Switch Published by Articulate® Storyline www.articulate.com 2.17 Bird on the Wire 2.18 Don't Try this at Home! Published by Articulate® Storyline www.articulate.com 2.19 Earthing / Bonding 2.20 Fuses Published by Articulate® Storyline www.articulate.com 2.21 Miniature Circuit Breakers 2.22 Fuse Published by Articulate® Storyline www.articulate.com 2.23 Fuse 2.24 Residual Circuit Device (RCD) Published by Articulate® Storyline www.articulate.com 2.25 Residual Circuit Device (RCD) 2.26 Residual Circuit Device Published by Articulate® Storyline www.articulate.com 2.27 Live / Neutral 2.28 Live / Neutral Published by Articulate® Storyline www.articulate.com 2.29 Electrical Distribution Board 2.30 Step Down Transformer Published by Articulate® Storyline www.articulate.com 2.31 Basic Electrical Safety 2.32 Basic Electrical Safety Published by Articulate® Storyline www.articulate.com 2.33 Basic Electrical Safety 2.34 Basic Electrical Safety Published by Articulate® Storyline www.articulate.com 2.35 Basic Electrical Safety 2.36 Basic Electrical Safety Published by Articulate® Storyline www.articulate.com 2.37 Lecture Summary 4. Introduction Video 4.1 Introduction Video Published by Articulate® Storyline www.articulate.com 5. Contact information 5.1 Contact information 6. Concluding Video 6.1 Concluding Video Published by Articulate® Storyline www.articulate.com 7. Self Assessment Questions - Part 2 7.1 SAQ 2.1 (Multiple Choice, 10 points, unlimited attempts permitted) Correct Choice Always X Sometimes Never Feedback when correct: Whilst an RCD will significantly reduce the risk of electric shock there are scenarios in which an RCD will not protect against electric shock. If a person comes into contact with both the live and neutral phases at the same time whilst they are insulated from earth electric current will flow from the live phase through that person's body and back through the neutral phase, however, no electricity will be lost to earth. Therefore Published by Articulate® Storyline www.articulate.com there will be no imbalance between the live and neutral phases of the supply and the fault will not be detected by the RCD. This could lead to a significant shock being received. Feedback when incorrect: Actually it’s 'sometimes', go back and see why. 7.2 SAQ 2.2 (Fill-in-the-Blank, 10 points, 1 attempt permitted) Choice With currents over 30 mA there is the possibility of cardiac arrest. 30 Thirty Feedback when correct: That's right! Well done. Published by Articulate® Storyline www.articulate.com 30 mA is correct Feedback when incorrect: No, that's not right; was it a guess? Have a look at the notes or back through the lecture for the correct response 7.3 SAQ 2.3 (Multiple Choice, 10 points, unlimited attempts permitted) Correct Choice X The equipment Personnel who may come in contact with the equipment Both Neither Feedback when correct: Published by Articulate® Storyline www.articulate.com Well done, that’s right. Feedback when incorrect: No, try again! 7.4 SAQ 2.4 (Multiple Choice, 10 points, 1 attempt permitted) Correct Choice When an electrical cable hangs down between two poles in the shape of an arc A phase in the electrical cycle A serious long term effect when acids are liberated in the blood after electric shock X When electricity jumps across an empty space Feedback when correct: Published by Articulate® Storyline www.articulate.com Well done, that’s right. Feedback when incorrect: No, that’s not correct; have a look at the notes or the relevant slide in Part 1 of the lecture for the right answer. 7.5 SAQ 2.5 (Multiple Choice, 10 points, unlimited attempts permitted) Correct Choice Feedback Under normal circumstances electrical No. Current will only flow through the current will flow in the live, neutral and earth wire if there has been a short earth wires of standard domestic circuit. Try again. wiring. You can only get an electric shock if you No. You CAN get an electric shock from touch the live wire in an electrical touching the neutral wire. Try again. circuit and not when you touch the neutral wire Published by Articulate® Storyline www.articulate.com X Under normal circumstances electrical That's right. Under normal current will flow only in the live and circumstances electrical current will neutral wires of a domestic plug. only flow in the live cable / phase and the neutral cable / phase of an electrical circuit. The amount of electricity flowing in each phase is always the same, hence it is possible to receive a shock from either wire / phase. Current will only flow in the earth wire if there has been a short circuit and electricity has been lost from the intended pathway, flowing to earth down the earth wire. 8. Self-Assessment Questions - Part 1 8.1 SAQ 1.1 (Multiple Choice, 10 points, unlimited attempts permitted) Published by Articulate® Storyline www.articulate.com Correct Choice X AC DC Feedback when correct: Yes, well done! The constantly changing nature of an AC supply can lead to the disruption of heart rhythms if an AC supply passes across the chest area. It can also give rise to an inability to let go of the source of shock in persons who are in direct contact with an AC supply. These are not associated with DC shocks and explain why an AC supply at a given voltage is more dangerous than a DC supply of the same voltage. At a given voltage, say 100v, the DC supply is a constant 100v, whereas the AC supply actually peaks at much higher (approx. 140v) as when we are talking about AC voltages we are referring to average / root mean square voltages. Published by Articulate® Storyline www.articulate.com In addition, when three Phase AC supply is used, three pulses or phases of AC are supplied at the same time, resulting in a much greater voltage and consequently a much greater risk to safety. Feedback when incorrect: I’m afraid not. Go back and click on A) to see the correct answer 8.2 SAQ 1.2 (Multiple Choice, 10 points, unlimited attempts permitted) Correct Choice Feedback X When electricity meets resistance in a That's right, well done. When circuit this generates energy in the form electricity tries to flow through a of heat, thus giving rise to burns along material with high resistance energy in the path that the electricity takes the form of heat is created. This is through the body. because as the electrons try to move through the material they are constantly colliding with the material's atoms, generating energy. It is this Published by Articulate® Storyline www.articulate.com energy that causes a light bulb to light, a kettle element to heat water and for your body to burn when receiving an electric shock. The resistance to flow encountered in Afraid not, try again the body will cause the Residual Current Device to trip due to Ohms Law. The higher the body's resistance to Afraid not, try again electricity the less risk of a shock being experienced. 8.3 SAQ 1.3 (Multiple Choice, 10 points, unlimited attempts permitted) Published by Articulate® Storyline www.articulate.com Correct Choice Feedback X Electricity will only flow between two That's right. Ohms law states that in an points when there is a voltage electrical circuit the voltage always difference between those two points. equals the current multiplied by the resistance - V = C*R. Voltage is a measure of the force which motivates electricity to flow from an area where there are a higher amount of electrons to an area where there are fewer (the earth). If the voltage is zero, then electricity will not flow At any given voltage DC is more That's not right, try again hazardous than AC Electrons are used up when electricity That's not right, try again is used to power equipment Published by Articulate® Storyline www.articulate.com