High Voltage in AC

Your air conditioner (and whole HVAC system) are a strange mix of parts. On the one side, we have low voltage, DC electronics that couldn’t tickle a fly. On the other, we have high voltage, AC equipment that could turn an ill-prepared reptile or rodent into a charred chunk of bones. How exactly do we mate these two, different systems together safely?   The Safety Issue In all electronics, we strive to separate high voltage and low voltage. We don’t want them to touch each other. In some systems, you have no choice but to put high and low voltage equipment on the same board, in other cases you try to keep them on separate boards altogether. If there’s any sort of electrical short between high voltage and low voltage, the low side is going to get destroyed. That’s your best case scenario. 240 volts or 440 volts blasting into some tiny microprocessors and capacitors, which then explode in a terrifying, but mostly harmless show of pyrotechnics. If the board is really well built, a diode will take the brunt of the failure before anything scary does. Sometimes though, these shorts don’t go like that. Some older equipment or equipment which never passed any reviews like Underwriters’ Laboratories can send high voltage straight to frame components, a button, or other areas where a user could come in contact with it. 220 Volts is not a pleasant experience, let me tell […]

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How to Tame Your Cooling Costs

Air conditioning is expensive, but essential for most of the world except perhaps the arctic circle. It improves employee productivity and attracts customers on the hottest of days. Unfortunately,  it also makes an electric meter look more like a helicopter, buzzing along as we suck down ever more watts in search of comfort.   The Little Things Use light-colored windows blinds and curtains. Every place that light gets into your building is some place it’s going to raise the temperature. Light ultimately creates heat, the sun is giant, nuclear, laser ball. If we can make sure its light falls on reflective things, like lighter colors, curtains and blinds, we can reduce the amount of heat generated inside the room. It would be impractical to close off grand entry ways with curtains, but everywhere else is probably fair game. Even some window blinds in the office can reduce the heat coming in by half, while still keeping the room fairly bright for your staff. Dial back the temperature The greater the temperature difference, the harder the air conditioner has to work to maintain that difference. Remember that you need to only create apparent comfort. If it’s 100 degrees out, your employees and customers will probably be grateful for anything less than 85 degrees. You don’t need to make the office 60 degrees. Close the doors Ensure you’re not venting cool air wastefully. Keep the doors closed or install a closing mechanism […]

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We still use Ice in AC TODAY!?

In the early days, perhaps up to the 1950s or so, Ice was your standard cooling solution. If you didn’t have a refrigerator, you had an ice box. This solution wasn’t as on-demand as modern AC, but it had a nice benefit: no high electricity bills. Every summer as we turn to AC to avoid sweating to death, we’re faced with our soaring cooling bills. With this in mind, some manufacturers actually still use ice in HVAC systems today.   Why ICE? Prior to the invention of air conditioning, ice was pretty much the only cooling thing available. Today, we have a million and one ways to cool things, but they don’t entirely hold up to ice. Water by itself is amazing at storing and conducting energy. Just think of the last major snow storm and how long it took for that to melt off afterwards. North of Philly here, our last major storm dropped eight inches or so that actually stuck to the ground and it took days of 50+ degree weather for it to melt. This makes Ice an excellent way to store “coolness”. On top of that, water is non-toxic, abundant, easy to store, and easy to cool. The other famous alternative might be liquid helium or liquid nitrogen, both of which are used in industrial cooling applications such as MRI machines and particle accelerators. The problem is that they’re not easy to cool, can involve vast […]

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Electrical Fire Safety

There are a ton of safety devices that are preventing you from being shocked, from starting fires, and from destroying expensive equipment. The problem is, no matter how many safety devices we put in the building, something is always going to go wrong. When things go wrong, it’s essential to be prepared for the absolute worst.   Causes of Electrical Fires The absolute root cause of electrical fires always comes down to energy. The copper wiring carries electricity, electricity is energy. The movement of electricity always creates heat. More electricity means more heat. When things go wrong, there’s too much electricity or not enough insulation to contain the electricity, or some other fault that allows heat to build up or electrical arcs to occur and start a fire. This can happen any number of ways. There can be an electrical short, perhaps water getting into a non-GFCI bathroom or kitchen outlet. There could be something shoved into a socket that really doesn’t belong there, thanks to an overly curious toddler. There can be corrosion, causing an electrical short. It could even be down to a cheaply made product skipping out on essential internal safeties (this happens more often than most people realize). In all of these cases, there’s going to be a battle on two fronts.   Stopping the Power and the Fire If you’re not quite thinking straight, you might try to extinguish an electrical fire with water. The […]

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Electrical Measurements Explained

What does 24 Volts, @ 15 amps mean? What is a watt? What’s a watt-hour? What about an amp-hour? These are all crucial ways of measuring how much electricity is present, at what rates, and just how much that electricity wants to move. We are going to be greatly simplifying these concepts, so as always, consult an electrician before working on or making any electrically involved decisions. Volts and Amps We’re going to start with the basics: What’s in the wire. The wires around you contain electrons. The movement of these electrons is electricity. When there is electricity, such as a light switch being turned on, electrons are moving through  the wire, creating magnetic fields and heat, among other things. Volts are the amount of force pushing those electrons. A low voltage source such as a double A battery has just enough force inside it to make electrons move through a wire. It doesn’t quite have enough force to shoot electrons into the air and make lightning like an industrial transformer could. The flow of these electrons is called Current, which we measure in Amps (amperes). It’s easiest to picture the current as a flow-rate, “one gallon per hour.” We can measure the total amount of amps with an Amp-Hour. For example, if we have a pump that needs 10 Amps to run, and it runs for One Hour, that it runs at 10 Amp-Hours. In 24 hours, it will […]

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What Causes Electrical Arcing?

Most everyone in the world has seen an electrical arc. Lightning, certain short circuits, and other times when there is literally electricity moving through the air are all Arc Flashes. We’re going to look into the fundamental causes of electrical arcing.   Moving Power Electricity is essentially a charge being conducted through a wire. All electrical charges want to disperse as quickly as possible. They’re like water behind a dam: it always wants to get out. In the case of electricity, the charge wants to disperse, positive to negative. It always wants to get to ground. The problem with this is that we want to actually use the electrical charge, so it can’t go straight to ground. We use insulators to keep the electricity essentially safely inside the wire. Without the insulator, the charge would get out and work it’s way to ground like water out of a burst pipe following gravity. Insulators can be a wide range of things. The rubber casing around wire is it’s insulator. The gigantic, ceramic cones on utility poles are insulators that prevent the charge from trying to discharge into the wooden pole. The air itself is also an insulator. Electricity generally does not want to move through the air. This is why we can have electrical sockets exposed to the open air, but not to water. The air won’t easily conduct an electrical charge but the water will. Water isn’t a great conductor, […]

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Common Electrical Safety Devices

How do we stay safe with electrical failures? We’ve covered a bit about how grounding is essential. When there is an excess of electrical power, send it to ground. This is not the end of the problem. If there is a physical fault or a problem with the incoming power supply, we need to cut off power altogether. Surge Protectors These are in many ways, the first line of defense. Surge protectors work mainly to protect equipment. In the event of electrical shorts, they may not protect you. There are numerous protection mechanisms inside. Some surge protectors use resistors, some have gas discharge tubes, others use special diode systems, dump the charge to ground, and more. The important thing to always keep in mind with surge protectors is that many surge protectors are power strips, but not all power strips have surge protection built in. In fact, surge protection exists as a whole corner of the industry all its own. There are large-scale surge protectors that can be built directly into buildings. These devices arrest and mitigate surges before they can cause damage and before a breaker or other safety device would have time to react. Ground Fault Circuit Interrupters There should be as much current, as many amps coming back into an AC Outlet, as leave it. If the current coming back into an outlet is significantly less than the outbound current, that energy must have gone somewhere. Running […]

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Why is my Building Grounded to the Water?

In the US, we commonly have three prongs for our electrical devices. Two of these deliver the AC Current, being both positive and negative over time and a third which goes to Ground. This is a safety thing. Whenever there is an electrical short, a static build up,  or even a lightning strike, we want to divert that somewhere safe. The safest place for these excess charges is straight to the Earth, the ground below us. As big as the Earth is, it basically has an absurdly powerful negative charge. You can disperse power into the ground and it’ll dissipate safely. Getting to Ground It is essential for every electrical and metal component of a building to be grounded. This can be a real nightmare to actually implement. You need something that is going everywhere in the building. On the one hand, you could run additional conductors, miles and miles of additional conductors, or you use the one conductor that’s already there: the water pipes. That’s right, older buildings ran their electrical grounds straight to the plumbing. On the one hand, this does kind of work. The copper pipes in most buildings are excellent conductors. These pipes are going to make contact with the ground at some point. If there’s a well, the pipes are going deep underground. If there’s municpal water, they’re still going to be several feet below the surface before long. For the early days of electrified […]

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Why Do Transformers Hum?

We recently talked about transformers. Not the robots, but the electrical ones. In a follow up to that, we’re going to look at why transformers are noisy. We’re pretty sure everyone has experienced this noise at some point or other. You’ll find yourself next to an electrical room and hear a loud humming or whining sound. It’s not like the sound of a motor exactly. It’s just this constant, low sound. For those unfamiliar, we found a good recording on Soundcloud below:   What Am I Hearing? Let’s establish what actually makes the sound. Electricity itself doesn’t exactly make noise afterall, it’s just the conduction of energy through metal. Sure, lightning makes a good boom, but that’s totally different. When we talked about transformers, we mentioned that they’re pretty much solid parts, nothing inside moves. There’s no axles, hinges, shafts, or anything noisy. What part of that transformer are you hearing? It turns out, the coils move. In most cases, the coils are too small to make a notable sound or the current going through them isn’t enough to make a loud noise. The transformers powering your HVAC equipment or converting high voltage AC current to your building’s 110 VAC however, are more than sufficient to make lots of sounds. It comes down to just how much material there is and how much energy is making it move. As an aside.. If you put enough power into a transformer, it […]

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