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NORA Oilheat Technicians Manual

Chapter 8 Basic Electricity Figure 8-1: Water analogy 8-4 Basic Electricity voltage pushes the electricity through the wires, it keeps it under pressure. Once the electricity has finished doing its work (turning a motor, making a spark), it returns to where it came from under no pressure. The voltage is all “used up”. Therefore, voltage supplied to the circuit is voltage used by the circuit. Amps = water flow Amperes, or amps for short, are a way of expressing the amount of electricity flowing through the wire, the rate of flow (current). They are like the gallons per hour flow of water through a pipe. Figure 8-1. The voltage is like the force of the water in the pipe and the amps are like the amount of water flowing out of the faucet. Ohms = resistance to flow As water flows through a pipe, it encounters resistance to the flow depending upon the physical characteristics of the pipe. How much water flows through the pipe, at any given amount of water pressure, is affected by the size of the pipe and even the smoothness of the inner walls. Amps also meet resistance from insulation, motors, circuits or anything that restricts the free flow of electricity. This resistance to the flow of Amps is called Ohms. Resistance to flow makes friction and friction makes heat Resistance to flow, whether it is water or electricity, creates friction, and friction converts energy to heat. Electricity faces much resistance trying to fight its way through wiring, and it creates a lot of heat doing it. The greater the resistance to flow in the wire, the more heat is produced. This isn’t all bad. The heat can be used to make Oilheat is to power our motors that pump oil and water, make the spark needed for ignition; and automatically control the entire heating process. Electrical current flows through wires, switches, and transformers to our heating appliances. The force that pushes the current through the wire is called Voltage, which is measured in Volts. The amount of current flowing through the wire is called Amperage or Current, which is measured in Amps. The Resistance to this flow is measured in Ohms. The power used to run our motors and create spark is measured in Watts. To better understand these important words, it might be helpful to compare electricity to the flow of water in a pipe. Volts Voltage is like water pressure (pounds per square inch), and like water pressure, does not need an actual flow. Regardless of the faucet being open or closed, there is still water pressure in the pipe. Likewise, there are volts at an electrical outlet even though nothing is plugged into that outlet and there is no flow. Of course, the potential for flow is there and that is why volts are referred to as electric potential; it could flow if the conditions were right even though it is not flowing now. Voltage is the force created by the power source (the battery, transformer, or generator). This is called the electromotive force (EMF). When water comes out of a faucet, it flows under pressure. But when that water drains out of the sink, it has no pressure except gravity. Voltage is the same. As


NORA Oilheat Technicians Manual
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