Electricity

2023-11-112023-11-10

A pigeon. Photo: Viktor Forgacs, 2017-12-12

This post was originally called Digital Power Transmission. It began with content about the use of artificial intelligence (AI) to find faults in electrical power assets in Kansas and Missouri. That introduction became ancient history on 2023-10-26, when I read an article about pigeons using the same approach as AI to problem solving. I wondered if pigeons would make AI more understandable.

So, now this post begins with a scientific study of pigeons!

Pigeons

Columba livia domestica, has been found in records that are 5 000 years old. Its domestication is far older, possibly stretching back 10 000 years. Among pigeons that are bred specifically for particular attributes, homing pigeons are bred for navigation and speed.

Pigeons are able to acquire orthographic processing skills = the use of visually represented words/ symbols, and basic numerical skills equivalent to those shown in primates.

In Project Sea Hunt, a US coast guard search and rescue project in the 1970s/1980s, pigeons were shown to be more effective than humans in spotting shipwreck victims at sea.

A study was undertaken at the University of Iowa, by Brandon Turner, lead author, a professor of psychology, and Edward Wasserman, co-author and a professor of experimental psychology. 24 pigeons were given a variety of visual tasks, some of which they learned to categorize in a matter of days, and others in a matter of weeks. The researchers found evidence that the mechanism pigeons use to make correct choices is similar to that AI models use to make predictions. Using AI-speak, nature has created an algorithm that is highly effective in learning very challenging tasks, not necessarily fast, but with consistency.

On a screen, pigeons were shown different stimuli, like lines of different width, placement and orientation, as well as sectioned and concentric rings. Each bird had to peck a button on the right or left to decide which category they belonged to. If they got it correct, they got a food pellet; if they got it wrong, they got nothing.

Pigeons learn through trial and error. With simple tasks, pigeons improved their ability to make right choices from 55% to 95% of the time. With more complex challenges, accuracy increased from 55% to 68%.

In an AI model, the main goal is to recognize patterns and make decisions. Pigeons do the same. Learning from the consequences of being given a food pellet (or not), they show a remarkable ability to correct their errors. Similarity function is also at play for pigeons, by using their ability to find resemblance between two objects.

Those two mechanisms alone, can be used to define a neural network = an AI-machine that solves categorization problems.

The area served by Evergy, a Topeka, Kansas based electric utility company.

Back to the original content, Digital Power Transmission

Now, this post will examine the use of AI, and other digital technologies, in electrical energy transmission. Sometimes one has to venture outside of one’s backyard, to gain new insights. Today, the focus is on the Kansas and Missouri. More than four percent of this blog’s readers have roots in Kansas, in Leavenworth and Riley counties, making it one of the “big six” American states. The others being (in alphabetical order) Arizona, California, Michigan, New Hampshire and Washington. Yes, this weblog does have American content, because – sometimes – Americans are at the forefront.

Much of the initial work into the use of AI in grid management was done by Argonne National Laboratory, of Lemont, Illinois. After conducting AI grid studies, they stated that: “In a region with 1 000 electric power assets, such as generators and transformers, an outage of just three assets can produce nearly a billion scenarios of potential failure.” The calculation actually being: 1 000 x 999 x 998 = 997 002 000, which is close enough to a billion, for most people.

The Norwegian company, eSmart Systems, with its headquarters in Halden, bordering Sweden, in south-eastern Norway, provides AI based solutions for the inspection and maintenance of critical infrastructure related to electrical power generation and distribution.

Note: the term, asset, as used here, generally refers to a large structure, such as a electrical power generating station, or a substation, that transforms voltages (and amperages). For me, an asset will always be an accounting term, associated with the credit (left) side of a balance sheet, in contrast to a liability on the debit (right) side. My preferred terminology would be structure, works or plant.

eSmart

In this project eSmart will act as project management lead alongside engineering consultants EDM International, Inc. of Fort Collins, Colorado and GeoDigital, of Sandy Springs – near Atlanta – Georgia. Together, these will provide large-scale data acquisition and high-resolution image processing.

eSmart Systems is working with Evergy, a Topeka, Kansas based electric utility company that serves more than 1.6 million customers in Kansas and Missouri, to digitize Evergy’s power transmission system. It is also working with Xcel Energy, based in Minneapolis, Minnesota, and an unnamed “major public utility in the Southeast” of the United States.

Grid Vision tracks the performance of ongoing inspection work, provides instant insight of the location and severity of verified high-priority defects, and provides utility managers and analysts a deep and flexible framework for further asset intelligence.

The three-and-a-half-year-long Evergy project will improve reliability and resiliency of over 14 000 km of Evergy’s power transmission system by using Grid Vision to create a digital inventory of its assets, accelerating image analysis capabilities, and improving inspection accuracy by using AI combined with virtual inspections. The expected result is a significant cost reduction for inspections, maintenance and repairs.

There is a need for a dynamic energy infrastructure to ensure efficient, safe and reliable operations. AI, and especially machine learning, are increasingly used as tools to improve the reliability of high-voltage transmission lines. In particular, they can allow a grid to transition away from fossil and nuclear sources to more variable sources, such as solar and wind. This will become increasingly more important for several reasons. Extreme weather will offer increasingly more challenging operations, and the grid will have to support an increasing number of electric vehicles.

The vast number of choices means that random choices cannot be relied upon to provide results when facing multiple failures. Some form of intelligence is needed, human or machine, real or artificial, if problems are to be resolved quickly.

Wind and solar generation

Kansas state senator Mike Thompson (R-Shawnee), is a former meteorologist, who is currently chair of the Kansas Senate Utilities Committee. He has introduced bill SB 279, “Establishing the wind generation permit and property protection act and imposing certain requirements on the siting of wind turbines.” This bill would require wind and solar farms to be built on land zoned for industrial use. The problem with this proposal is that half of Kansas’ 105 counties are unzoned. These counties that want wind or solar energy would have to be zoned as industrial.

The Annual Economic Impacts of Kansas Wind Energy Report 2020, reports that wind energy is the least expensive energy source, providing 22 000 jobs (directly and indirectly). After Iowa, Kansas ranks second in the US for wind power, contributing 44% of Kansas’s electricity net generation.

Typically, there are two reasons for objections to wind and solar power. First, some people have an economic connection with fossil fuels. Second, and especially for wind, they don’t like their visual and aural impact on the environment.

Another source of conflict is aboriginal rights. This topic will be covered in an upcoming but unscheduled post, Environmental Racism.

2021-07-172021-07-16

Off the Grid

The Briceburg energy system provided by BoxPower. Photo: BoxPower

On 2019-10-07, Briceburg in Mariposa County, near Yosemite National Park, in California, lost the only power line connecting it to the electrical grid in a wildfire that devoured over 20 square kilometers. The system, owned by Pacific Gas & Electric (PG&E), but installed and developed by BoxPower, provides Briceburg with a self-reliant, stand-alone power system made of solar panels in an array, batteries and a backup generator. It began operating 2021-06-01.

The solar array consisting of 36.5 kW of photovoltaic solar panels, a 69.12 kWh lithium ferro phosphate battery bank. This can provide 27.2 kW of continuous power output with a surge capacity of up to 48 kW. The system has two integrated 35 kVA propane prime power generators and a fire suppression system to protect the hardware. PG&E and BoxPower will be able to monitor/ control the system via satellite.

While wildfires in 2019, forced PG&E to file for bankruptcy in 2019, the main reason for using this technology is to improve energy resilience in California as extreme heat, drought and wildfires devastate the American west. Human-based climate change is causing blackouts and disrupting power supply. Wind-storms led utilities to deliberately shut off power to large areas of California to keep high-voltage transmission lines from starting fires. Then 2020-08-14 & 15, an oppressive heat wave forced the California Independent System Operator, which manages the state power grid, to declare a stage 3 emergency Friday night, which set off rolling power outages for the first time since 2001. More than 800,000 homes and businesses lost power.

Meanwhile, back at the Blue Lake Rancheria (BLR), members of the Wiyot, Yurok, and Hupa tribal nations, living northwest of the city of Blue Lake, Humboldt County, California on 0.31 km² of property, keep electricity flowing using two microgrids that can disconnect from the larger electrical grid, and switch to using solar energy generated and stored in battery banks near its hotel-casino. This is not strictly off the grid, but a supplement to the grid.

After the 2011-03-11 Tōhoku earthquake and tsunami caused local panic but little damage, the tribal nation complex decided to install a microgrid. Humbolt University’s Schatz Energy Research Center was the prime contractor and lead technology integrator for the project. A final report for the project was published in 2019.

Other participants included: The California Energy Commission (major funder), the BLR (site host and major funder), Pacific Gas & Electric (local utility), Siemens (MicroGrid Management System = MGMS), Tesla (battery energy storage system), Idaho National Laboratory (testing and simulation), Robert Colburn Electric (electrical contractor), REC Solar (turnkey PV system), McKeever Energy & Electric (PV installation), GHD, inc. (electrical engineering), and Kernen Construction (civil construction for the project).

It consisted of a 430-kW solar photovoltaic array with a 500 kW/ 950 kW/h Tesla battery storage system and two legacy diesel generators with a combined capacity of 1.8 MW. These are designed to retain electricity after storms/ wildfires/ earthquakes and to supply the grid with power, during peak demand. Construction started in 2015 and was completed in 2017. During the microgrid’s first year of operation it was able to reduce the tribe’s greenhouse gas (GHG) emissions by about 175 tons and lower its energy costs by about $195 000.

The microgrid investment made sense to ensure service and business continuation during nuisance outages that were typical in the region, lasting for an hour or two. The tribe also recognized how climate change was amplifying local impacts including wildfires and volatile weather. This led them to develop a comprehensive lifeline strategy for energy, water, food, transportation and communications/IT. They started with energy, because it supports all the other lifelines.

When the microgrid was constructed, they were not thinking of extended power outages to prevent the grid from causing or contributing to wildfires. Today public-safety power shutoffs happen regularly and they are projected to occur more frequently with a duration of two to five days or even longer. This situation may be the norm for the next decade.

The MGMS automates large portions of microgrid functions. This eliminates the need for 24/7 monitoring, and allows the microgrid to buy and sell power to the larger grid.

As most of sat in the dark during a planned shutoff in October 2019-10-08 to 10, the Blue Lake Rancheria became a lifeline for thousands of rural Humboldt County residents: The gas station and convenience store provided fuel and supplies, the hotel housed patients who needed a place to plug in medical devices, saving at least four lives, the local newspaper used the conference room to put out the next day’s edition, and a hatchery continued pumping water to keep its fish alive.

Islanding: The electrical service to BLR was reconfigured to create one point of common coupling (PCC) between the microgrid and the main utility grid. This PCC includes the powerline protections and control functionality required for the microgrid to automatically disconnect from the main grid during an outage, and then reconnect when grid power has been restored. Operators at BLR can also manually island the microgrid for energy management, maintenance, or security reasons. Seamless transitions between connected and islanded states are unnoticeable to building occupants, and have been approved by PG&E.

Optimal battery dispatch: Under normal conditions, the microgrid uses an energy load forecast, the solar availability forecast, and the current electricity rate schedule to determine when to store energy in the battery and when to dispatch it to the main grid.

Resiliency: If the main grid loses power, the microgrid automatically disconnects and begins operating in island mode. When islanded, the microgrid management system (MGMS) prioritizes clean generation — but if needed, the MGMS can also seamlessly bring a 1 MW isochronous backup generator online to support the PV and battery.

Conceptual Microgrid, as provided by Schatz Energy Research Center

2021-02-062022-06-24

Heat

The U.S. consumes about 100 EJ = 100 Exajoules = 100 x 10¹⁸ Joules of energy, annually. Americans, being Americans don’t often express energy in Joules. Rather, they prefer to use British Thermal Units (BTUs), where 1 BTU = 1055 J. Another way of expressing this is to say that Americans use about 100 quads of energy, where 1 quad = 10¹⁵ BTUs. If one is willing to accept a 5.5% error, one can say that 1 EJ is about equal to 1 quad.

Only about one third of energy consumed is used for productive work. The above Sankey diagram shows energy inputs and outputs, productive work is clumped together as energy services, in a dark gray box. The other 2/3 is wasted as heat, which in the above diagram is referred to as rejected energy, which is clumped together in a light gray box.

Renewable energy comes from solar (1.04 quads), hydro (2.5 quads), winds (2.75 quads) and geothermal (0.21 quads) sources, for a total of 6.5 quads. Thermal energy systems burn fuel or split atoms, and accounted for about 93.5% of American energy inputs in 2019. Most of this fuel come from fossil sources, that is responsible for most of the carbon emissions associated with climate change. Wasted/ rejected energy is a proxy/ surrogate/ substitute for the damage being done to the planet. The exception is the energy provided by nuclear power, although it also has issues of its own. In contrast, renewable energy (wind, solar, hydro, geothermal) capture energy, without creating heat. While there are some transmission loses, most of that energy provides energy services.

A modern electric vehicle (EV) with regenerative braking is about 95% energy effective. Even the most efficient internal combustion engine (ICE) vehicles, can only achieve about 30% energy efficiency. This means that an EV only needs about 1/3 of the energy inputs that an ICE vehicle needs.

The United States transportation sector uses 28% of the total energy. Of this, cars, light trucks, and motorcycles use about 58%, while 23% is used in heavy duty trucks, 8% is for aircraft, 4% is for boats and ships, 3% is for trains and buses, while the last 4% is for pipelines (according to 2013 figures). This means that road transportation accounts for over 80% of the total. From the Sankey diagram, one can see that the transportation sector has 28.2 quads of input of (mostly) fossil-fuel energy, which means that 22.5 quads are road related. This results in 5.93 quads of transportation services, of which 4.75 quads are road related. These figures show about a 21% efficiency, because transportation related engines are considerably less efficient than other engines, including those used for electrical power generation.

If one uses renewable energy for road transportation, 4.75 quads of transportation services could be produced from about 5.0 quads of renewable (wind/ solar/ hydro/ geothermal) energy. At the same time, 22.5 quads of oil production would be eliminated, without any negative energy-related consequences. In fact, there would be benefits in terms of improved health, and less pressure on the environment.

A shift to renewable sources in other sectors would also have benefits. Natural gas and coal currently make a large contribution to inputs for electricity generation used elsewhere, 11.7 and 10.2 quads each, respectively, for a total of 21.9 quads. However, using the 1/3 service, 2/3 rejected formula, this means that these fossil-fuel inputs only produce 7.3 quads of electrical services. This contribution could be replaced by 7.5 quads of renewable energy.

Gasoline has an energy density of about 45 MJ/kg, which can provide about 15 MJ/kg of energy services, and 30 MJ/kg of rejected energy, as discussed above. A litre of gasoline has a mass of 0.76 kg and produces 2.356 kg of CO₂ and 11.4 MJ of energy.

For American readers: The United States Energy Information Administration (EIA) estimates that “About 19.64 pounds of carbon dioxide (CO₂) are produced from burning a gallon of gasoline that does not contain ethanol. About 22.38 pounds of CO₂ are produced by burning a gallon of diesel fuel. U.S. gasoline and diesel fuel consumption for transportation in 2013 resulted in the emission of about 1 095 and 427 million metric tons of CO₂ respectively, for a total of 1 522 million metric tons of CO₂. This total was equivalent to 83% of total CO₂ emissions by the U.S. transportation sector and 28% of total U.S. energy-related CO₂ emissions.Under international agreement, CO₂ from the combustion of biomass or biofuels are not included in national greenhouse gas emissions inventories.”

Since 1 MJ = 0.2778 Kilowatt hours (kWh), 11.4 MJ is the equivalent of 3.17 kWh. According to Electric Choice, the average price a residential customer in the United States pays for electricity is 13.31 cents per kWh in December 2020. This means that gasoline would have to sell for 42.19 cents per litre to be cost effective. Since there are 3.785 litres per American gallon, a gallon would have to sell for about $1.60 to provide an equivalent price. According to Global Petrol Prices, the average price of mid-grade/ 95-octane gasoline was $2.752 per gallon, the equivalent of $0.727 per litre, as of 2021-02-01.

In Norway, the price is about NOK 1 per kWh for electricity, but with wide variations. The price of 95-octane gasoline is about NOK 16.33 per litre, once again according to Global Petrol Prices. This helps explain why EVs are so popular. To be price equivalent, gasoline would have to sell for about NOK 3.17 per litre. Currently, Stortinget, the Norwegian parliament, is debating increasing the CO₂ tax by NOK 5 per litre, which would bring the price to over NOK 21 per litre. Not all political parties are in agreement, with this proposal.

There is a great deal of discussion about consumption figures for electric vehicles in Norway. In part, this is because the terrain varies greatly. Some people drive in urban landscapes, others out in the country. Some people are flatlanders, while others have more mountainous environments. However many consumers have experienced real-world energy consumption levels of about 15 kWh/100 km for vehicles such as a Hyundai Kona, Kia Soul and Tesla Model 3. This gives a fuel cost of about NOK 15/ 100 km. In American terms, this would be about 24 kWh/ 100 miles, or $3.20/ 100 miles, with the electrical costs noted above.

Update: 2021-06-12 at 15:00.

The amount of energy used to refine gasoline (and diesel) is more than the electricity required to drive the same number of miles/ kilometers, using equivalent battery electric vehicles. Fossil fuel vehicles make absolutely no sense. When a country substitutes EVs for ICE vehicles, electrical consumption actually declines.

2018-01-252021-12-21

Electric Power

In a quest to find inventor heros, Nicola Tesla (1856 – 1943) is frequently attributed as the inventor of alternating current (AC). Unfortunately, the world is a messy place, and a long list of contributors to the development of AC needs to be acknowledged. In 1831, Michael Faraday (1791 – 1867) devised a machine that generated electricity from rotary motion. This was made into a machine by Hippolyte Pixii (1808 – 1835) in 1832. Independently of this, Joseph Henry (1797 – 1878) devised the same thing in the United States.

Wechselstromerzeuger — Pixii’s AC generator (Illustration: F. Niethammer 1906 Ein- und Mehrphasen-Wechselstrom-Erzeuger)

ZBD from the names of Károly Zipernowsky (1854 – 1942), Ottó Bláthy (1860 – 1939) and Miksa Déri (1854 – 1938) invented a highly efficient transformer in 1885. Transformers are important because they allow different voltages to co-exist on a network. High-voltages reduce transmission losses when transferring energy over long distances. Low-voltages offer safer environments in domestic, commercial and industrial settings.

Tesla did play a role in AC development, but is usually remembered for the invention of an AC motor, rather than anything to do with transformers or generators. The challenge at the end of the 19th century and the beginning of the 20th, was to develop a safe, convenient electrical system that could be commoditized.

Perhaps one should go further back in time, with William Gilbert’s (1544 – 1603) experiments on the relationship between static electricity and magnetism, recorded in De Magnete (1600). Benjamin Franklin (1706 – 1790), is famous for his kite in lightning experiment of 1752. Alessandro Volta (1745 – 1827) is credited as the inventor of the first electrical battery, the Voltaic pile in 1799. Even if one regards Faraday’s thought experiment as the starting point, it took almost 50 years for the technology to reach a commercially viable stage. In 1878 the time was ripe. Joseph Swan (1828 – 1914), Thomas Edison (1847 – 1931) and perhaps as many as fourteen others developed domestic light bulbs. which led to the first commercial power plant in 1881.

As AC systems rapidly expanded in the United States, at the expense of DC systems, a media war of the currents emerged in the late 1880s and early 1890s. Many see it as a propaganda campaign by the (DC oriented) Edison Electric Light Company to stifle commercial competition by raising electrical safety issues that put its rival, (AC oriented) Westinghouse Electric Company, in a bad light.

Unfortunately, one of the main challenges with DC, is its inability to transform to lower or (especially) higher voltages, which was needed for the economic transmission of power over long distances. DC power conversion is not a hurdle today, and HVDC (high-voltage, direct current) systems always includes at least one rectifier (converting AC to DC) and one inverter (converting DC to AC). HVDC systems can be less expensive to construct, and offer lower electrical losses compared to equivalent AC systems. HVDC is especially allows transmission between unsynchronized AC transmission systems. ABB entered into a contract in China in 2016 to construct an ultra-high-voltage direct-current (UHVDC) line featuring 1.1 MV voltage, 3,000 km transmission length and 12 GW of power, which, when completed, would set world records for highest voltage, longest distance and largest transmission capacity.

There is a lot of uncertainty about reason having any role in the selection of an AC frequency. Since the main purpose of electricity was to provide lighting, the only consideration was to prevent flicker. Thus, a multitude of frequencies emerged, in the period 1880 through 1900. Single-phase AC was common and typical generators were 8-pole machines operating at 2000 RPM, a common frequency was 133 Hz.

At the other extreme 16.7 Hz is used in AC railway electrification system in Germany, Austria, Switzerland, Sweden and Norway. The low frequency was chosen to reduce energy losses from early 20th century traction motors. The high voltage (15 kV) enables high power transmission. The preferred standard frequency for new railway electrifications is 50 Hz with an evening higher voltage (25 kV). Yet, extensions to existing networks, often use 15 kV, 16.7 Hz electrification. High conversion costs mean that older systems keep their voltage and frequency, despite potential on-board step-down transformer weight reductions to one third that used on the older system.

Preferred Numbers

In 1877, Charles Renard (1847 – 1905) proposed a set of preferred numbers, later adopted as international standard ISO 3 in 1952. This system divides the interval from 1 to 10 into 5, 10, 20, or 40 steps, leading to the R5, R10, R20 and R40 scales, respectively. For some, the R5 series provides a too fine graduation. Often a 1, 2, 5 series is used, a R3 series rounded to one significant digit, a pseudo preferred number.

Myth has it, that when AEG built their European generating facility, its engineers decided to fix the frequency at 50 Hz, because the number 60 wasn’t a “R3” preferred number. This standard spread to the rest of the continent, including Britain after World War II.

Lower frequencies have a number of negative characteristics. Not only is 50 Hz 20% less effective in generation, it is 10-15% less efficient in transmission, and requires up to 30% larger windings and magnetic core materials in transformer construction. Electric motors are much less efficient at the lower frequency, and must also be made more robust to handle the electrical losses and the extra heat generated. But there are advantages too, such as lower impedance losses.

Yet, there are enlightened countries with the insight to follow Tesla’s advice and use the 60 Hz frequency together with a voltage of 220-240 V: Antigua, Guyana, the Leeward Islands, Peru, the Philippines and South Korea.

Originally Europe was 110 V too, just like Japan and North America today. Voltages increased to get more power with less voltage drop (power loss) from the same copper wire diameter. At the time the US also wanted to change but because of the cost involved to replace all electric appliances, they decided not to. At the time (50s-60s) the average US household already had a fridge, a washing-machine, etc., but this was not the situation in Europe.

The end result is that now, the US seems static. It appears to be the same now as it was in the 1950s and 1960s. It still has to cope with transformer related problems, such as light bulbs that burn out rather quickly when they are close to the transformer (too high a voltage), or too far away, with insufficient voltage at the end of the line (105 to 127 volt spread !).

Most new North American buildings provides a 240 volt residential service in the form of two 120 volt conductors and a neutral conductor. When a load is applied from either 120 volt conductor to the neutral it uses 120 volts. When a load is applied from one 120 volt conductor to the other, without using the neutral, 240 volts is used, which is useful for air conditioners, clothes dryers, electric furnaces, stoves, water heaters and others high power appliances.

There is some confusion about North American voltages. It is 120 V, not 110 V. This was increased starting in the 1950s. The historic reason for 110 V was due to Thomas Edison’s DC power systems, which probably used 110 V because that was the optimal voltage for his light bulbs. These systems converted to AC, but the voltage wasn’t changed so existing lighting didn’t need to be replaced.

North Americans could get a better system than Europeans, with no infrastructure changes, except inside buildings. Since houses get 240 V delivered, wall outlets could be supplied this too, offering the lower current and higher power advantage of the European system.

In terms of safety, current (amperes) kills, not electrical potential (volts). Even so, 240 V is regarded as more dangerous than a 120 V system. To compensate Europeans use high quality insulation and wiring methods, that include Ground Fault Current Interruptor (GFCI) or Residual Current Device (RCD) in the breaker box to cut the supply instantaneously if any significant difference is detected between the currents flowing in the live (hot) and neutral wires. This saves lives.

This weblog post was updated 2021/12/21. to eliminate Seeds from the title. This post formed part of a Needs, Seeds and Weeds website that belonged to my daughter, Shelagh. In addition, other things are also out of date, or my opinions have changed. Apart from the title, updating the text to a block format and other minor formatting changes, the text above this paragraph remains as it was before. Birth and death dates have been added to many of the people named in the text. Any significant content changes are found below this paragraph.

2017-11-252019-08-05

Ethan & Ethel 03: Electrical Power

Some things in life are just so important that they just have to be learned. Memorization can be the right approach for some. For others, it might mean keeping a piece of paper handy, with formulas written out. Regardless, Ohm’s law and related formulas have to be learned.

Fortunately, a cool soldering iron will help explain Ohm’s law, and the related formulas. The soldering iron is a Miniware TS100.

Ethan has saved up his money to buy a TS 100 soldering iron. Unfortunately, he didn’t have enough money to buy a new power supply, so he wants to know if he can use this one, which he has lying around:

12V2A — A power supply with 12 V and 2 A output values. Is it good enough to power a TS 100 soldering iron?

This gives him an opportunity to learn about electricity and how it works. A plumbing analogy is often used to explain electric power. Think of voltage, the pressure driving electricity through a wire, as water pressure forcing water through a pipe. The cross-section area of a pipe is like current, or amperage. The bigger the pipe, the more water that can be pressed through. The diameter of the electrical wires determines how much current is allowed through the system. If more current is pressed through than the wires are designed for, a device could fry.

The problem.

The TS 100 instruction sheet says that a maximum of 65 W can be obtained with a 24 V power supply. It also says that the minimum requirement is 17 W with a 12 V power supply. The power supply itself confirms that it provides 12 V output. But it doesn’t mention amperage, only wattage. The easiest way to find out if a correct amperage is being supplied is to use a power triangle. This is what it looks like, in three almost identical versions:

vip — The power triangle allows Ethan to find an unknown value, when two values are known. In this thought experiment we know the power (P=17 W) and the voltage (V=12 V) but not the amperage (I). (illustration: http://www.electronics-tutorials.ws)

Ethan uses the middle power triangle, because he knows the power (17 watts) and the voltage (12 volts) but is missing the current or amperage, abbreviated as I. So he takes out his cell phone, uses the calculator app and inputs the necessary numbers, as shown here: I = 17 / 12 = 1.41 A. Since 1.41 A is less than 2 A, Ethan can use the power supply he already has.

A soldering iron works by using a resistor to heat up a metal tip. The relationship between the Voltage, Current and Resistance forms the basis of Ohm’s Law, which can be shown as another triangle, the Ohm’s Law triangle, also in three version, below:

vir — The Ohm’s triangle shows relationships between I = current, measured in A = amperes or amps, V previously E = voltage, measured in volts. R = resistance, measured in Ω (ohms).

Using the third triangle, the resistance is found using the following formula: R = V /A = 12 / 1.41 = 8.5 Ω.

Starting off only knowing two values, Ethan ends up knowing four. These relationships are summarized in the Ohm’s law pie chart:

The Ohm’s law pie shows all of the twelve calculations that can be made. If you know two values, then you will only need to use two formulas to calculate the missing two values. The secret is knowing which two.

These relationships are explained even better in an Ohm’s law matrix. If any two values are know, the relevant row can be found by looking at the leftmost column. That row will show the two formulas that are needed to calculate the missing values.

ohm matrix

Electricity comes into houses in the form of alternating current (AC). This is because AC can be easily transformed into lower or higher voltages as required. Most workshop equipment uses standard household voltage. In North America, this is 120 V. In Europe, it is 220 (or 230 or 240) V. The other big difference is that North America supplies electricity at 60 Hz, while in Europe it is 50 Hz.

These differences used to create lots of problems, but if you look at the power supply shown above, you will see that it can use any input from 100 V to 240 V. There is also no problem using 50 Hz or 60 Hz. This means that the same power supply can be used anywhere in the world. The only thing needed is a plug adapter.

adapter US to EU — An adapter is useful when travelling from one part of the world to another. This adapter allows North American devices, for example a power supply, to be plugged into European wall sockets.

Not everything works this well. Clocks are notoriously bad, because many tell time based on the frequency of the network. A European clock brought to North America, may show 28.8 hours in the course of a day. A North American clock brought to Europe, may show only 20 hours in the course of the same day.

The biggest difference between North America and Europe is in the wiring that is required to run equipment. That is because current or amperage (and not power or wattage) determines the thickness of wires used. A 2 000 W mitre saw on a 120 V system needs a 20 A circuit breaker and #10 wire which is 5.26 mm² (in Europe, it has just exceeded the 16 A wiring limit, 2.5 mm²). On a 240 V system this same mitre saw only needs a 10 A circuit breaker and #14 wire which is 2.08 mm² ( In Europe, one could actually get away with 1.5 mm²).

Workshops need a lot of electrical power because they use machines that are transforming material into useful products. The work being done requires energy. That is not the only use of energy. Heating and dust extraction are also major energy consumers.

The Cost of Heating

Ethel and Ethan have a problem. They find the work space soooo cold that they have installed a 1500 W heater. The twins turn on the heat one hour before they begin working, and turn it off half an hour before they plan to stop. So far this month, they have had the heater on 46 hours.

A workshop needs energy to do work or create heat. Work is officially measured in joules ( J ). One joule is the same as one watt-second. If one knows how many watts one is using, and how many seconds it is being used, it is easy to calculate the number of joules.

Work = 1500 W · 46 hours · 60 min/hour · 60 sec/min = 248 400 000 J or 248.4 MJ (mega-joules). When calculating joules, it can be useful to know that there are 3 600 seconds in one hour, and 86 400 seconds in one day (24 hours).

When it comes to buying electricity, the kilowatt-hour is the standard units of energy recorded by the electricity meter. This can be a lot easier to calculate: 1 500 W, is the same as 1.5 kW; 46 hours is the same as, well, 46 hours. The heater’s electrical consumption is 1.5 kW · 46 h = 69 kWh. The price of 1 kWh varies, but in some places is about 15 cents. So the cost of heating the work space for a month is 69 kWh · $0.15 = $10.35.

Bonus Questions. Since the twins live in Canada, they have 120 V electrical power in their workshop. Calculate: What is the Amperage required for a 1500 W heater? What is the resistance inside the heater? (answers: 12.5 A; 9.6 Ω)

Power Requirements

Here are the wattages I use in the Unit One workshop. If all of the machines and other equipment were all turned on, they would use over 19 kW. Fortunately, that has never happened.

Use	Wattage
Workshop
Lighting	100 W
Computing	100 W
Compressor	750 W
Workshop air cleaner	200 W
Dust extractor	1 100 W
Heating	2 000 W
Stationary machines
Jointer	1 250 W
Planer	1 500 W
Compound mitre saw	2 000 W
Table saw	1 400 W
Band saw	750 W
Drill press	500 W
Sander	500 W
Bench grinder	400 W
Portable tools
HVLP spray gun	600 W
Jig saw	800 W
Bayonet saw	1 000 W
Plunge (Track) saw	1 400 W
Router	1 400 W
Power drill	500 W
Angle grinder	800 W

Load

Because only one (perhaps two) power tools are being used at any one time, the workshop’s maximum load is 6 250 W. The worst tool to use is the compound mitre saw (2 000 W). In addition, there is a need for lighting (100 W), computing (100 W), workshop air cleaner (200 W), dust extractor (1 100 W). At times a compressor is in use (750 W), and in winter, a heater may be turned on (2 000 W).

Three-phase power is supplied to the workshop at 230 V and 16 A with three load lines (L1, L2 and L3) coming in. These load lines are paired up to make 3 single-phase circuits. The total power coming into the workshop is 6370 Watts.

Several illustrations for this blog post have been borrowed from: http://www.electronics-tutorials.ws, which is the place to go for electronics tutorials.

2017-10-122018-06-27

Electrical Installation: A prerequisite to Technical Innovation?

Norway has become a consumer society. In the first few decades after the second world war, house purchasers were encouraged to put physical labour into house construction. This reduced the total price of a house. Today, this is not happening. People are simply consumers of houses, and have little understanding of how they are actually made.

In this post, I want to look at the consequences of this consumerism, but focus on just one area, electrical installation.

Everywhere electrical material is sold in Norway, one is met with the following or similar warning, in Norwegian:

“Although installation materials, such as heating cables, can be purchased by anyone, only registered companies can install the equipment. Stores are required to inform the buyer about this before the purchase is made. It is also not possible to install the equipment yourself, then ask an authorized installer to connect it to the facility in the house. That is a breach of regulations. In addition, there are no serious companies that will take responsibility for a work they do not control.” (from Jula.no)

For many people from other parts of the world, this warning is an affront. Where are the electrical inspectors? Registered electricians are given carte blanche to install electrical materials, but their work remains unsupervised by public officials representing other stakeholders, including house owners. Some electrical inspectors do exist, but they are not public employees. Frequently, they are employees of a major producer of electricity, and they only visit a house every twenty years or so, to ensure that it is in conformity with regulations. When they do come, they have a vested interest in finding mistakes, because they can require a house owner to hire a registered electrician to make changes.

Contrast this with the situation in Canada. Here is a typical sign at a store:

bty — Sign at Home Hardware, Essex, Ontario (photo: Brock McLellan)

There is no discussion as to who is will do the work. In essence, anyone can do it. The requirement is that all work done, has to be inspected. This treats professional electricians and talented amateurs as equals, which in many cases they are. Without inspections, electricians can be tempted to take shortcuts or do shoddy work.

Inside the Home Hardware store, in Essex, Ontario, there is a display that shows precisely how to wire specific items in a house, including the breaker box:

bty — Electrical wiring display, Home Hardware, Essex, Ontario (photo: Brock McLellan)

Amateurs in Canada are able to take night school courses in electricity. Here is a description of a night school course, open to anyone, at Saint Clair College, in Windsor, Ontario:

“Electricity 200 is for non-electrical tradespersons and related. Emphasis is placed on safety practices. Electrical protection of motors. Basic test equipment, purpose and testing of fuses, overloads and circuit breakers. Basic relationship of voltage, current and resistance. Basic relays and A.C. 3 phase motor control, interpreting basic motor nameplate information. Introductory residential wiring. Introductory diodes and rectifiers.”

The course lasts 12 weeks, one night a week, for three hours, from 19.00 to 22.00.

One of the resources used by many Canadian home owners is: Ray Mullin, Tony Branch, Sandy Gerolimon, Craig Trineer, Bill Todd and Phil Simmons 2015 Electrical Wiring Residential, 7th Canadian edition.

Electrical Wiring Residential E7 Can

Despite having an electrical code that requires the use of professional electricians, Norway has a much higher rate of house fires caused by a failure in the electrical system, than many other countries, including Canada. This is to be expected. Without training and experience, a house owner is unable to understand where electrical problems can arise. Because of the high cost of using professionals, potential problems may be ignored, which puts lives in danger.

As a former teacher of Entrepreneurship, there is one other reason to encourage people to do their own home wiring. Consumers are not good at understanding how products work. With a society of consumers, there will be nobody working in basements and garages to develop new products. Garage culture made America great. Amazon, Apple, Disney, Google, Harley Davidson, Hewlett-Packard, Lotus Cars, Maglite, Mattel and even Microsoft all started in garages. http://www.businesspundit.com/11-famous-garage-startups-that-rule-the-world/

Disney-Garage — Walt Disney was living at 4651 Kingswell Ave. in Los Angeles, California, when he started his company in a garage owned by his uncle, Robert Disney.

There is a trend in government to encourage coding, but most of the developments in the “Internet of Things” or robotics involve physical computing, a combination of electrical circuits, mechanical components including sensors and actuators as well as code.

It is possible for people to innovate without insight into residential wiring, but being able to wire will provide insights that will help a person to be more innovative.